Saturday, December 21, 2013

Southeast Ridge Retreating???

I've been studying those 500 millibar maps. They're not that hard to understand if you know what you're looking for.

Areas of red concentric circles indicates ridging, or areas of high pressure, and blue indicates troughing, or areas of low pressure.

Three outstanding features appear on the current 500 millibar map:

West coast ridging
SE ridge
Icelandic Low

The forecast maps show the SE ridge losing its influence on the U.S. over the next several days.

Colder air should have easier access to the region over the next several days.

Precipitation chances are harder to forecast, though. If we're going to get any exciting winter weather, we'll have to either hope for a robust clipper or a Southwest cutoff low ejecting out toward the Plains or southern U.S.

MS


Thursday, December 19, 2013

Year-End Weather Outlook for Kentucky

First, our upcoming weather system looks wet and windy. This morning, I noticed the WPC has shifted an axis of heavy rain east that now encompasses areas along the Ohio River which could produce 3-day totals in excess of 4".

Long term outlook shows a persistent ridge off of the west coast of the U.S., which will keep them unusually dry for this time of the year. That could lead to some low snowpack and drought issues later on next year for many along the coast.

Another persistent feature includes a strengthening trough east of Iceland.

Our weather will include a variety of conditions. West-Southwest flow will be offset by periods of Northwest flow. I don't really see any significant winter storm affecting the region through the rest of the year.

Temperatures will be cold to mild, somewhat below normal to slightly above normal, but no Arctic outbreaks expected. Then again, no record breaking warmth expected after this weekend's storm event.

More on the possibility of flooding for parts of the region later....

MS

Monday, December 16, 2013

Models of a Snowstorm

Perhaps some of you more savvy worshipers of weather models have seen this before.

Since it has to do with our region and was a joint research project conducted by the NWS Louisville and Saint Louis University, I thought it would be a good read.

Unfortunately, the information is very technical. However, maps are provided as well; therefore, any of us non-technical people can download the current maps (for surface, 850mb temperatures, 300mb winds, and so forth) and compare them to the 'modeled' maps to see if we fall or will fall into one of the several types of models favoring a snowstorm.

And by the way, their estimation of a snowstorm counts as anything >=2", which may disappoint some of you. But, there was a map comparison of the January 1994 record snow and cold.

So, enjoy...

http://www.crh.noaa.gov/images/lmk/ResearchPapers/SnowComposites_OhioValley.pdf


Friday, December 13, 2013

How Does This Winter Stack Up Against Last Winter and Past Winters?

It's almost the middle of December. So far, Louisville Int'l has recorded 4 days with high temperatures of <=32 degrees this young winter season (November included). It appears the cold trend will continue, especially for the latter part of the month.

Last year, Louisville Int'l recorded only 6 days for the entire winter season with high temperatures <=32 degrees.

Although the recent cold spell has been relatively brutal, December's average temperature is nowhere near the top ten coldest December's on record for Louisville...yet. We are expecting a blast of winter cold for the period around Christmas, though. If the major block in Alaska continues, then storm systems will have to veer around that block by way of the Siberian and Arctic regions and spill chunks of that cold air into the Plains and Midwest. Therefore, you haven't felt winter's brutality yet.

Do you remember when...?





The year 2000 was the coldest December on record for Louisville and 2nd coldest for Lexington.

You want to see something eerie??? Check out this 500mb forecast for later this month...


Compare this map with the image just above this one. I see quite a few similarities of the winter 2000 brutal cold and the impending cold for later this month.

Snowfall has been variable for parts of the state. Louisville Int'l has received 5.8" as of this date. Lexington has received 2.0".

Last year, both sites had recorded only a trace of snow up to this date.

The winter season is still young but is already ripening as we head into the coldest part of the year in January.

MS

Thursday, December 12, 2013

My Weather Today

Low temperature of 10 degrees at my house in Valley Station this morning.
According to NWS here in Louisville, snowfall could become a minor issue for Friday night-Saturday morning with up to an inch possible.
As of 4:00pm, snow depth here was 1".

MS

Tuesday, December 10, 2013

Overachiever?

At my location in Valley Station, only 0.6" accumulated here. However, timing could not have been worse. This was a low-end storm but high-impact event.

Yesterday, the NAM model reestablished itself after a mini-'vacation' during the last storm. It showed a stripe of heavier snow across southern IN possible.

Reports of 2-3" across southern IN and northern KY did exceed forecast totals. Also, the forecast based on this for Louisville was to be in the range of 0.2 - 0.8". Not too bad in terms of amounts.

As far as eastern and southeastern KY, amounts have verified for many. Latest reports I have seen so far is 1.5" in Pikeville and Prestonsburg as expected. However, within the last hour, a Winter Storm Warning was posted for Pikeville with accumulations forecast in a 3-5" range. Short-range models did show that Pikeville and Prestonsburg would be the 'winners' of this snow event.

To make a long story short, now, I would consider this storm to be a minor overachiever.

By the way, my snow depth is now at 3". I'll be updating my seasonal snow/sleet totals later. But, my total stands at 3.8" as of 8:30am.

MS


Monday, December 9, 2013

Stripe of Snow Possible UPDATED

5:15pm Update
I reviewed the RAP model and am satisfied by the results.
Looks like a weakening band of snow will approach the Ohio River after 4am
0.5 - 1.0" looks like a safe guess for southern IN
Louisville looks to get in on only a dusting to a 0.1" according to the latest run

SE Kentucky looks to get a little bit more snow than the rest of us. Basically from London to Pikeville, 1-3" will be possible, more closer to 1-2". However, cannot rule out upsloping; therefore, some amounts may exceed 2", especially near Pikeville.

---------------------------------------------

NAM model shows light snow entering southern IN and north central KY by 4-8 am time frame.
Amounts are forecast to be light but has been showing signs of increased lift which could produce a burst of moderate to heavy snow for areas especially in southern IN, with perhaps a quick inch or so.

Louisville area may only see anywhere between 0.2 - 0.8".

Nevertheless, needs to be monitored. I'll be looking at the RAP model later today. It only goes out to the 11pm hour as of this post, but it does show a stripe of snow developing to our west out across MO and IL streaking northeast toward IN.

MS

Friday, December 6, 2013

NOWCAST and RAP Model

At 4:05pm
Temp: 27 degrees
Wx: Lt to Mod Snow
Location: Home
Snow-covered roads here in the 'burbs
Accumulation has exceeded an inch; 1.3" of sleet and snow in Valley Station
This is on top of nearly 0.25" ice.
Getting reports of 3-7" across SW and southern Indiana

--------------------------------------

At 3:15pm
Temp: 28 degrees
Wx: Lt to Mod Snow
Location: Home (see below)
Pavement sleet/snow covered; have not checked main roads; traffic cams downtown showing snow-covered to slushy roads.

Snow is now becoming the dominant precipitation in Louisville. Actually, downtown experienced changeover about an hour ago. I just saw my changeover within the past several minutes and now is snowing moderately.
Forecast is still for 2-4"; however, with earlier changeover, I wouldn't be surprised to see some higher totals.

-----------------------------------

At 2:00pm
Temp: 29 degrees
Wx: Moderate sleet
Location: Home (see below)
Pavement slick; minor sleet accumulation
Total Ice Accumulation 0.25" or less

During the last hour, more sleet began mixing with rain; as of this writing, primary precipitation is sleet.
Pavement is becoming slick due to sleet accumulation; secondary roads becoming slick; treated roadways wet, except where sleet is falling more heavily.
Bloomington IN 7.5"
Bedford IN 5.0"
Princeton IN 7.0" (north of Evansville)
Mt Carmel IL 12.0"

Corydon IN experiencing changeover to sleet and snow during last hour.

----------------------------------------
At  12:15pm
Temp: 30 degrees
Wx: Lt rain w/sleet
Location: Home (see below)
Wet pavement, additional icing since last report
Total Ice accumulation - 0.2"

During the last hour, sleet began mixing in with the rain in Valley Station; PRP mostly rain with some sleet trying to mix in.
6" snow near Bloomington IN
In Cadiz, near Hopkinsville I-24 reporting accidents due to icing

--------------------------

At 9:45am:
Temp: 29 degrees
Wx: Very light rain
Location: Valley Station 1 mile north of Gene Snyder Freeway
Wet pavement, thin coating of ice on tree limbs (c. 0.1"), ice on windshields.

15z RAP (Rapid-Refresh Model):
For Louisville, changeover to snow by 3pm
Accumulations vary across county from 2.3" in south part of county to near 4" in northern part by 10pm.
Sleet may begin to become predominant precip between noon and 1:00pm

Snowing now in Covington, Bloomington.
Freezing rain in Evansville.
Moderate sleet in Tell City

Next update in an hour.

MS


Thursday, December 5, 2013

NEW Call for Snowfall

Complicated weather for the next few days.
1st event:
Looking at data yesterday, I felt that more mixing of precipitation types would occur.

That may still be possible as NAM has been having issues deciphering between what falls in the air versus what actually could fall at the surface.

I've repeatedly noticed extraordinary amounts of snow for the region. However, when sleet is forecast, snow accumulations are still occurring, according to the latest runs.

Therefore, that 8-10" snow for Louisville could occur IF it was all snow. However, data suggests that a mix of rain, sleet, and snow will occur for a while before complete changeover here in Louisville.

Some icing may occur here in Louisville. Western KY looks to get significant amounts of ice.

You will notice that I have upped my snow amounts across the board as less amounts of mixing should happen.

Louisville  2-3" (perhaps some 4" amounts)
Lexington 1-2"
London  less than 0.5"
Jackson  less than 0.5"
Cincinnati  3-4"
Bloomington 4-5"
Salem 2-4"

If more mixing occurs, then snowfall amounts will be impacted, perhaps even back toward my original levels from the First Call.

MS

Wednesday, December 4, 2013

First Call for Snowfall

UPDATE 2:45pm EST
NWS conference call ended about 30 minutes ago.
Sounds like a snow maker to me for the first event here while a hydrologic issue just south.
I saw a recent NAM snowfall projection for Louisville 8-12"!
I say give it a few more runs and check back tomorrow.
-----------------------------------

First, let's make one thing clear...this is for entertainment value only. And believe me, there's gonna be plenty of laughs going around as weather forecasters try and tackle the timing and precipitation types for the next 36-60 hours. Expect a lot of changes to the forecast.

I do think we may have a slightly better handle on precip types and possible accumulations within 24 hours of expected changeover to frozen precip.

While this forecast only projects snowfall amounts, don't be fooled by the totals. Wet surfaces, sleet accumulations, mix of p-types will affect these totals.

As far as ice potential with THIS system, I'm not as concerned about it here in Louisville and Lexington. Could be some nuisance icing on mailboxes and cars while a coating of ice could accumulate on tree limbs. Roadways will be warmer than other surfaces for a while. However, after dark, your typical bridges and overpasses will begin to freeze over. It will be difficult to treat wet roadways as rain will wash most of it away. But, I'm hoping that the heaviest rain will be exiting our region by the time temperatures go below freezing. Still, watch out for a brief period of heavy snow during the evening hours Friday.

Louisville  0.5 - 1.0" (some higher amounts possible)
Lexington  0.5 - 1.3" (some higher amounts possible)
Covington 1-3"
Bloomington 2-4"
Salem 1-3"
Jackson KY dusting to 0.5"
London KY dusting to 0.5"

I stress that some amounts may be higher if less sleet and rain mix in with the snow.
Ice accumulations for Louisville and Lexington should be on the order of 0.2" or less.
Again, all of this is subject to change.
As I finish writing this post, Winter Storm Watches are being posted for our region.
I will have an adjusted Call sometime tomorrow.

Otherwise, in conclusion, I'm more concerned about the possible icing that will affect parts of our region later this weekend. If temperatures are cold enough at and just above the surface, prolonged icing may occur as the cold, dense air could have a hard time getting scoured out. Right now, I'm planning for the worst case scenario.

MS

Monday, December 2, 2013

Analog For This Week

Looking at a GFS analog for later this week showed the number one date of the fifteen different analogs. It was December 15-16, 2008.

Conditions in Louisville were wet and mild initially. After frontal passage, temperatures tanked from a high near 60 to 24 degrees. The following day, temperatures struggled to reach the 32 degree mark. Snow showers accumulated across the region.

Louisville recorded 1.1"; Lexington reported 2.5".

This is just one analog, and it's the GFS, and it's a few days out. Take it for what it's worth.

Let's just say this system will need to be watched as we get closer to the event. Lots of rain is forecast on the front end while wintry precipitation is expected to make a quick appearance after frontal passage.

This reminds me of numerous past weather systems that are slow moving and have large temperature gradients over a small distance. With that said, I recall instances when heavy snow had set up a hundred miles or so north of the boundary.

We'll just have to wait for further refinements to the forecast to determine whether this will be a progressive or stationary event. Progressive means less snow and overall precip; stationary means more snow in the colder air and more overall precip for the rest of us near the boundary.

--------------------------

UPDATE 12/02/2013
183800

I just viewed another analog worthy of mention...
The snow/ice storm of January 8-9 1999
Snowfall amounts of 4" in northern KY and southern IN; up to 8" in some areas
Freezing rain occurred over a large area of Kentucky.

Here is a weather map of that storm system
http://www.raymondcmartinjr.com/weather/1999/08-Jan-99-SurfaceMaps.html

Thanks for the map...
MS

Monday, November 25, 2013

Try This - mPING

The National Weather Service is calling for a mixed bag of precipitation for our region. Doesn't that always seem to be the case for our region?

Anyway, one of the forecasters made a reference to a site that some of you may be interested in checking out. The name of it is called mPING, or Meteorological Phenomena Identification Near the Ground.

It is a project specifically designed for identification of precipitation types and involves your input. I have not used it yet but will be checking into it more today.

I've been reading the Frequently Asked Questions section and the different types of precipitation to be reported along with a brief description of each one.

It's been designed for mobile applications and is downloadable at the App Store and Google Play.

http://www.nssl.noaa.gov/projects/ping/

MS

Thursday, November 21, 2013

What Causes Beautiful Sunsets and Sunrises???



I'm sure that I am not the only one who has noticed a barrage of beautiful sunsets lately. My local news station often shares pictures from its viewers. Recently, some of the most numerous photos have been of sunsets and sunrises, and indeed, they have been truly beautiful.

There's just something about a splendid sunset (or sunrise). The arrangement of colors, the position of clouds reflecting those colors, yes, the sheer awe of its lustrous beauty, is better than whatever history's best painters could ever create. The effect, mood, euphoria, whatever you want to call it, is at the very least, therapeutic. It's often been said that being stranded in rush hour traffic is very frustrating. However, a beautiful sunset makes that frustration melt away. In fact, it's the best show rush hour traffic could ever offer, leaving its gawkers wanting just a few minutes longer, please.

My father-in-law and his wife along with a group of their friends traveled by motorcycle from the central part of Florida to the southern tip in Key West to watch a sunset that would not happen until the next evening.

What makes these sunsets so mesmerizing? Where are the best places to view sunsets? What role does air pollution have on sunsets?

Here are a couple of good reads I invite you to peruse....



Tuesday, November 19, 2013

Alaska's Cold Building Up

Zone Forecast: Yukon Flats and Surrounding Uplands Mobile Weather Information
Last Update: 330 PM AKST SUN NOV 17 2013

Detailed text forecast
Tonight: Increasing clouds. Isolated snow showers. . Lows 12 to 22 below. Southwest winds 5 to 15 mph.

Monday: Cloudy with scattered snow showers. Highs 1 to 10 below. Southwest winds 5 to 15 mph.

Monday Night: Cloudy with a chance of snow. Lows 22 to 28 below. Northeast winds to 10 mph.

Tuesday: Cloudy with a isolated snow showers. Highs 9 to 17 below. North winds to 10 mph.

Tuesday Night: Mostly cloudy with a chance of snow. Lows around 25 below. Southwest winds 10 to 20 mph.

Wednesday: Mostly cloudy. Highs around 20 below.

Wednesday Night: Mostly cloudy. Lows around 30 below.

Thursday Through Friday: Partly cloudy. Highs around 15 below. Lows 25 to 30 below.

Friday Night: Partly cloudy. Lows around 20 below.

Saturday Through Sunday: Mostly cloudy. Highs around 10 below. Lows 15 to 20 below.
---------------------------------

Chunks of cold air just waiting to drop south. So far, the Aleutian Low has been manifesting itself nicely. Now, it's just up to those steering winds in our part of the world to determine if we see any of that cold stuff later. Along with progressive weather systems, you never know, we may be up for an early significant snowfall of greater than 3 or 4" within the next few weeks.

MS




Sunday, November 17, 2013

Tornado Watch for Louisville 11/17/13 w/Updates

It took a while, but Norman OK Storm Prediction Center has issued a Tornado Watch for central KY, including Louisville, Bowling Green, and Frankfort until 10pm EST.

Probabilities include a 40 percent chance of 2 or more tornadoes within the Watch area, some possibly strong.

This is not a PDS Watch. However, the threat for isolated tornadoes does exist for the area.

The primary action continues to unfold to our northwest and will eventually affect a chunk of central and northern Indiana.

Major damage east of Peoria IL, resembling EF-3 to EF-4 damage. Unbelievable.

More updates later...

MS
-------------------------
UPDATE 3:15PM EST
Wind damage in Ballard County KY - Barn destroyed; sightings of funnel clouds as well.

Mt Carmel IL - tornado damage

Vincennes IN under tornado warning at this time...tornado on the ground!

--------------------------

UPDATE 3:30PM EST
Tornado on ground in Paducah
More damage reports coming in from Illinois
Line is racing quickly to the east.
--------------------------

UPDATE 6:00PM EST
No severe weather here in Valley Station
Ominous clouds and surface winds running contrary to winds just above the ground.
Eerie scene...no rotation...25-30 mph winds and very little rain (0.03" with this line but 2.36" for the day).
Lots of storm reports coming in from Indy NWS office and Paducah's NWS office
I'll post some of these in a bit.
-----------------------


Tornado Outbreak Likely Today (11/17/13)

SPC issues a HIGH RISK for severe weather for much of Indiana.

Perhaps this could be the most prolific November tornado outbreak since 2005 for our region.

It's difficult to compare weather systems, but this storm system appears to have the potential to exceed the 2005 outbreak (at least 40 confirmed tornadoes).

If the ingredients remain in place, tornadoes will be likely especially across Indiana.

In my opinion, here is a breakdown of cities and nearby locations with the highest chances for tornadoes...

Indianapolis >50%
Lafayette >50%
Kokomo >50%
Terre Haute >50%
Bloomington >40%
Seymour 20-30%
Vincennes 20-30%
Austin 10-20%
Evansville 10-20%
Charlestown near 10%
Madison near 10%
Carrollton KY near 10%
Louisville KY near 10%
Owensboro KY near 10%

The most likely scenario for strong long-track tornadoes exist in an area roughly from south to north, Bloomington to Lafayette and locations within that parameter, including Indianapolis.

Look for activity to break out across NE Arkansas, Missouri, and Illinois by early afternoon.

MS

Saturday, November 16, 2013

Severe Potential November 17

Still awaiting updated run of Top 15 analog guidance.

Latest Analog shows isolated areas north of the Ohio River that could merit 'Moderate Risk' status. That means high winds and isolated tornadoes are possible.

If I could draw a bullseye for the region based on this data (from NAM), Madison IN and Carrollton KY would be it. Areas surrounding that would include Austin IN, LaGrange KY, Sparta KY.

NAM simulated radar shows low-topped storms plowing through the region late in the afternoon on Sunday.

Gusty winds should accompany this line, perhaps widespread 40-50 mph winds. At this time, I see only sporadic reports of severe wind gusts greater than 58 mph. Nevertheless, tree damage and power outages should be expected anywhere along the line.
\
Greatest risk appears north of Louisville.

Expect data to change as this is just a preliminary outlook. Too many variables again have to come together for a widespread event. However, this system appears just as potent as the recent Halloween system.

MS


Monday, November 11, 2013

Snow in Hawaii?

When the winter season begins taking its toll, our minds generally drift to where the climate is less harsh. The first thing that comes to my mind is a nice tropical setting like Hawaii.

Ahh. The beautiful sandy beaches and fresh ocean breezes are indeed a nice change of pace. However, in winter (Northern Hemisphere), the rainy season is well underway in Hawaii and affects several locations.

And yes, during these months of the rainy season, at the highest elevations, snow falls on the summit of Mauna Kea. Interestingly, its name means 'White Mountain' in Hawaiian.


A light dusting of snow atop Mauna Kea
 (Photo courtesy of Andrew Cooper)












MS

Sunday, November 10, 2013

Prologue to Winter Weather Forecast 2013/2014 REVISED

The last two winter seasons have been less than satisfactory for snow lovers here in Louisville and most of central Kentucky. Downright abysmal actually. However, change could be coming for the upcoming winter.

Persistent atmospheric patterns kept moisture to a minimum for the area during the 2012/2013 winter. Prior to last year, persistent atmospheric patterns kept temperatures warmer than average during that winter.

Will this winter be dominated by persistent atmospheric patterns? Most likely not. Let me explain.

I believe drought played a major role in the nation's weather patterns during the past two winters. Some areas of the country received substantial snow totals while others received little accumulations.

Severe droughts are a result of climatic patterns that often can influence or dictate weather patterns. They create subtle boundaries that may affect upper level winds. For example, storm systems driven by the upper level winds either go around these semi-permanent anticyclonic features that are a result of drought or its associated moisture may be sapped by the surrounding relatively drier air.

This year's drought situation has improved significantly over the South and Midwest sections of the U.S., an area where our weather systems tend to develop and attract our attention. Perhaps, this is an indication that the climate pattern has begun a transformation. That should increase variability in weather patterns across the country, especially for our region. Does that mean we here in Louisville will get more snow?

Increased variability will lead to weather systems behaving more normally this winter. In other words, expect a nice blend of cold spells and periodic warm events that could spawn severe weather. Look for a few systems to come out of the Rockies and find their way into the Ohio Valley.

As is usually the case in these parts, a battle ground for precipitation type will affect who gets what and how much. I believe it will be a more exciting winter than the previous ones. That's all I can really say about that.

MS


Sunday, October 6, 2013

Bracing for More Water Issues

Over 5.50" has fallen at my house since 11:00am yesterday. A large shield of moderate to occasionally heavy rain is moving in from the west, promising to dump another 1-2" before tapering later today.

The ground near my house has handled the water mightily, relatively speaking. News reports coming in from the Metro area are impressive, if not scary. Lots of water rescues.

I'm expecting to battle water issues in my basement for the rest of the day....

MS

Saturday, October 5, 2013

Stormy Night

As of 10:00pm, I've recorded 3.75" at my house here in Valley Station (southwest of KSDF). Looking at Radar returns, it looks like this is just the beginning of multiple episodes of heavy rainfall lined up for tonight.

Flash flood warning has just been posted for the Louisville area.

Water is starting to seep into my basement. Once I get 4", water generally tries to get in (I'm going to have to get that fixed)

I wish the atmosphere would hurry up and get overworked so rainfall will diminish. But, it looks like rotating storms out west of Louisville may move in by midnight. If anything, looks like more heavy rain on the order of 1-2 additional inches overnight.

And they're still calling for rain tomorrow???

MS

Thursday, September 12, 2013

Rain Not Looking Impressive Today for Louisville

A welcome cold front (actually 2 fronts) resides in central and northern Indiana. Along the first front, a broad band of weakening showers is sagging south while main energy shunts east.

Infrared satellite showed warming cloud tops as the line approaches our area. Convective temperatures are near 85-86 degrees (and that may be conservative). Yet, our temperatures may struggle to reach that. Therefore, I don't see any thunderstorms for the area with this initial band of weakening showers.

Thunderstorm chances with this initial band look better south of Louisville and to the east where main energy and better instability reside.

However, am noticing colder cloud tops trying to form south of Chicago who has cleared out nicely. Their dewpoints are running in the upper 50's as of this writing. There is a chance we could see a thin line of showers and thunderstorms later this afternoon as this secondary front surges southward.

Precip amounts for Louisville should be in a range of 0.1 to 0.4 inches today. Some areas near our area could get between 0.5 to 0.75" but should be confined again to our south and east where convection is highest.

Nevertheless, looking forward to those cooler temperatures!

MS

Thursday, August 8, 2013

What Are Louisville's Rain Chances?

So far, it's been a guessing game as to when Louisville will see measurable rain. Today, I'm seeing that window shrink. Radar looks like a ring of water around Louisville.

Infrared satellite has been showing warming clouds west of the area and a gradual weakening of its associated complex. However, am starting to see additional convection firing out toward Paducah. These are beginning to form an outflow line of storms that should take over the rest of the afternoon as it moves east.

The bulk of the storms may stay just south of Louisville. But, our chances of getting wet are increasing. One of the short-term models is showing precipitation breaking out near our area after midnight.

Rain may be heavy as evidenced by parts of the Bluegrass region who got swamped last evening.

MS

Monday, August 5, 2013

Wet Week Ahead? (Aug 5-12)

A change in the weather pattern is in store for the region this week. A persistent northwest flow has dominated most of our summer, but the atmospheric pattern will change to a more zonal flow (w to e) this week.

A large fetch of moisture is forecast to impact the region by the middle of the week. Depending on the front's position, periods of heavy rain could set up for some. Widespread 2-3" amounts are expected this week.

A caveat is in the front's position. While the WPC paints widespread amounts, it must be understood that the potential exists for these amounts if any disturbances interact with the slow-moving or stalled front and its favored location.

Heaviest rains at this time appear to reside south of the Louisville area. However, until a better understanding about where the front will be located the next few days, it's more of a guess than a forecast.

If heavy rains do materialize, some areas in our region will have to worry about flooding concerns.

MS

MikeS 66 Index JULY 2013

The official statistics are not out yet for the month of July. However, my index of 66 random locations comprising the various climate regions of the contiguous United States revealed some interesting data.

It was a month dominated by persistent weather patterns. A large ridge in the west. A cutoff low in the Gulf of Mexico. A large upper level low spinning across the Hudson Bay. A bulging southeast ridge. Sometimes, it was a matter of the have's and have not's, especially when it came to precipitation.

Overall, the temperatures averaged out right at normal. However, the overall precipitation came in well above normal. Four of the six climate regions produced above normal readings with the southeastern U.S. coming in with some of the wettest July's in years. This was due to a persistent onshore flow of moisture resulting from a stationary non-tropical low spinning just south of the Florida panhandle.

Now for the numbers...

High Plains 73.4 average of high and low
                                    0.4 Below Normal (temps)
                                    14% Below Normal Precipitation

Midwest  72.3
                              0.3 Below Normal
                              25.8% Above Normal Precipitation

Northeast  75.8
                                 2.2 Above Normal
                                 25.8% Above Normal Precipitation

Southeast  80.0
                      1.2 Below Normal
                                 64.3% Above Normal Precipitation

Southern   80.9
                      1.2 Below Normal
                                 3% Above Normal Precipitation

West         77.1
                     1.7 Above Normal
                               13.7% Below Normal Precipitation

You can tell how the western ridge affected temperatures and precipitation there. Extreme heat prevailed over much of the desert areas. Also, the persistent upper low in the Gulf produced enormous amounts of rain. What I found staggering about those numbers was that normal rainfall amounts start ramping up during tropical weather season. In fact, places like Tampa FL and Wilmington NC generally see at least 7" on average for the month of July. Although Tampa exceeded their average, Wilmington's 5.64" for the month was a stunning 1.84" below normal! There were no tropical systems in July that directly affected the U.S. but many locations added to their June totals making inroads on one of the wettest summers on record.

As for the Northeast, I was there when temperatures soared well into the 90's and touched 100 in a few areas. The dew point was high adding to the discomfort. Power outages occurred. Children often flocked to fire hydrants to keep cool. Some of the places I visited were running on generators just to cut down on the high energy demands.

Here's the final tally for the United States as a whole:

United States (48 contiguous) 76.6
                                  0.0 Average
                                        14.2% Above Average Precipitation

MS

Thursday, June 27, 2013

2013 vs 2012 - 90 Degree Days

It appears we won't reach 90 degrees for the rest of this month. Let's compare this year's number of 90 degree days to last year's up to this point.

2012 (thru Jun 30) - 17 days
2013 - 5 days

Not only is 2013's days in the 90's much lower than last year's, we are  below normal compared to the 30-year average of 7.6 days.

However do not forget about the impressive heat ridge out west. It may not affect us right away, but I expect by the middle of next month, summer will be in full swing.

MS

Rainfall Amounts For Louisville And Surrounding Areas

From midnight on June 26 to 10:00am today, here are a few rainfall totals across Louisville and parts of the state.

St Matthews - 4.21"
Beargrass Creek Pumping Station - 3.66"
J'town - 3.23"
Floyds Fork WQTC - 2.76"
Morris Forman - 2.35"
Jefferson Mall - 2.32"

Since Monday June 24 ending 11:59:59 June 26:

Shepherdsville - 2.98"
Madisonville (Hopkins County) - 6.07"
Shelbyville 3.47"
Lexington 2.45"
Frankfort 2.99"
Louisville (official) 2.71"

MS

Wednesday, June 26, 2013

Rating Severe Chances for Today

So far this year, at least here in Louisville, severe weather has been kept at a minimum. The potential for severe weather was always there but subtle oddities like leftover convective debris inhibiting future initiation during the heating of the day or just the time of the day when strong/severe storms approach the area and weaken as loss of sunlight meant loss of instability or unusually strong cap inhibits storm development.

Here we go again. Severe weather chances are in the forecast. The potential is there. Now, what are the odds?

One cluster of storms pushed through the region early this morning. I'm following two other clusters to the northwest. These storms are leaving a trail of convective debris that might have an effect on our severe storm chances for today.

However, the language from the NWS here in Louisville indicates a good possibility of severe storms for the region, primarily damaging winds.

The analogs I follow are suggesting at least a 40 percent chance for severe storms today/this evening.

The SPC has put the region in a high-end slight risk category for damaging winds.

We've been in this position before. As in those cases, severe weather faded as they approached the area for the most part. No widespread severe weather at least.

What do I expect?

Dew point readings are high. MCV's have been consistently developing to the northwest. They like to travel along high dew point areas. Even if we don't get the MCV's, a front will be in the area. Heavy rains will become a problem. I think that we stand a good chance for widespread damaging winds near Louisville. Other areas include southern Indiana and western KY and southwest IN. Could be an active day.

Expect watches later this afternoon for a large chunk of real estate.

MS


Friday, May 31, 2013

Severe Weather Chances for the Region

Analogs are very consistent in support of severe weather with the approaching storm system this weekend. Let me preface the rest of this post that the potential is there for severe weather across the region, but that means certain parameters do have to be in place for the severe events to happen.

Instability, time of event, wind shear, moisture advection, just to name a few must all work together for the probabilities for severe weather to occur.

According to the latest data that I considered, central and southern parts of Indiana have the best chance for tornadic storm cells, greater than 10 percent. This would be a 'few tornadoes possible' definition for the 10 percent criteria, in my opinion. Louisville is in the 5 percent shading, indicative of 'isolated tornadoes possible'.

Based on the chance for severe weather, the analogs I considered today still show a moderate risk from Salem IN to Muncie IN. Based on how the SPC looks at the data, if they believe enough instability will be present, I would expect a Moderate Risk to go out for these areas for Saturday.

Louisville would be in the high-end slight risk category, again for isolated tornadoes and damaging winds/large hail. Of course, most if not all of the parameters do have to be met for this scenario to unfold. So far, it's not as likely as the analogs are suggesting. Still, we must monitor upcoming forecasts for Saturday, especially.

More later.

MS

Thursday, May 30, 2013

Tornado Chances Increasing for Indiana Fri/Sat

I've been impressed with the analogs the past few days. They've helped predict these tornadoes out west. The same analogs are depicting higher tornado chances for parts of central and southern Indiana during the next 24 to 60 hours.

Although Louisville is not in the main zone, remember, this is not a forecast exactly where tornadoes will occur, but the general region in and around the suggested locations. Therefore, Louisville should be on guard.

A damaging wind threat appears to be the main solution, mostly over Indiana.

I would think moderate risks for severe weather will go up from the SPC for Fri/Sat time frame. This would include Indiana, Illinois, and maybe extreme northern KY.

Stay tuned.

MS

Tuesday, May 28, 2013

Valley Station KY Has Been Dry Lately

During the past two weeks since May 13, Louisville Int'l has recorded 0.77" rainfall. I live about 15 minutes southwest of the airport and have recorded about the same amount (0.76").

I planted my vegetable garden a bit late, on May 13 actually. The frost chances scared me off for a while. Also, I collected nearly 6 gallons of rain water this month. I'm down to 3 gallons or about 25 percent of my 12-gallon capacity.

Since my garden is bigger this year, I need more rain water during the dryer periods. Looks like our best chances will be this weekend. Hopefully, we can get a good soaking.

MS

Additional Tornadoes For This Week?

I decided to play with some of the analogs again. This time of year, predicting where tornadoes will occur based on the analogs can be frustrating.

Although not an actual forecast, based on how similar weather systems have performed in the past helps determine the chances of something like them occurring again.

Let's see, today is May 28. Really, starting late today into tomorrow, isolated tornadoes are forecast across parts of Kansas and Oklahoma. According to the analogs, the event tonight and tomorrow will not be as big of a deal as the chances will be for Thursday.

By then, main action shifts into Kansas, Nebraska, and Iowa. The GFS analogs are showing an enhanced risk for tornadoes for May 30 or Thursday. Could be a late night (Wednesday) or early morning (Thursday) event. That would be bad news since it is much harder to see tornadoes in the dark.

Currently, Wichita KS is only forecasting isolated tornadoes for today and a large hail/damaging wind event for Wed/Thr time frame.

Des Moines IA is forecasting a better chance for severe weather late Wed/early Thursday time frame, not really elaborating too much about that. Obviously, their main concern at the moment is the expectation for more heavy rain in the waterlogged areas.

MS

Tuesday, May 21, 2013

Tornado Deaths Since 2011

Moore OK tornado has now claimed in excess of two dozen individuals (actually revised downward as of late morning) including many young people as of this report. This has been the deadliest tornado day since May 22, 2011. Upwards of 158 people lost their lives near Joplin MO alone.

According to the SPC's Annual Killer Tornado Statistics page, since that day through May 15 2013, the number of people killed by tornadoes had been 107.

Since May 15, the number of tornado deaths has been at least 30. And the threat of tornadoes is not over yet. More tornadic storms are forecast for parts of Texas into Arkansas.

Source:
http://www.spc.noaa.gov/climo/torn/fatalmap.php?yr=2013

MS

Monday, May 20, 2013

Global Hazards Report No Longer Available from National Climatic Data Center

One of the most useful components from the NCDC is now no longer available. The Global Hazards monthly page provided a nice synopsis of extreme weather happening across the globe. Drought, fires, floods, hurricanes, cold, heat, sea ice extent, etc... have all been reported on this page throughout the years. I've used the information not less than a few times on my blog.

The NCDC says it will reevaluate its decision by September. The contribution and impact of the Global Hazards page has been quite useful to me as I'm sure is the case with other weather watchers. It expands my horizons allowing us to look at things outside of the {U.S.} box. I gain a better understanding of how global weather patterns have affected other countries besides our own. How have other countries dealt with natural disasters and what effect do these events have on my pocketbook when I go to the supermarket? For those interested in global warming, these reports help us to understand better how extreme weather could be here to stay. Possibly, it may move us to keep considering how best to do our part in not contributing any extra to the overall warming of the planet.

Hopefully, this is not about money too. So many programs have to be budgeted. It's a shame to eliminate the good programs. In September, I along with others look forward to seeing the Global Hazards page reinstated.

MS

Will We Hit 90???

After a month off, I feel pretty refreshed. Well, perhaps not yesterday or today do I feel refreshed. Humidity levels have been elevated lately making it a bit more uncomfortable outside. Definitely not refreshing.

Forecast highs are aiming for 90 degrees here in Louisville. Would like to see it happen.

However, satellite imagery is showing cloud debris, perhaps from storm blow-off out west. Nevertheless, these clouds have been increasing over the past hour or so.

Radar not showing anything. But the stubborn clouds may keep temperatures down just a bit, if they don't hurry up and scour out of here.

I'm knocking temps down a couple of degrees for today at 88.

MS

Thursday, April 18, 2013

Widespread Damage Expected With Squall Line

Severe Weather Update from SPC:
5:00pm edt - Moderate risk dropped; high-end slight risk for much of the region.
Looking at dewpoints and satellite imagery, instability is strong, but not as strong as expected. Therefore, still looking at wind damage along the line, but perhaps not as widespread as anticipated. Let's hope that trend continues.
---------------------------------

Quick Update from SPC:
12:35pm edt - No graphical changes made. Updated discussion includes support for strong tornadoes across far west KY. Next update by around 4pm or so.
----------------------------------

One of my favorite harbingers of storms is the warm, humid air combined with the presence of cumulus clouds in the morning hours. Typically, those cumulus clouds become favored suspects for thunderstorm development during the afternoon.

Technically, though, a decent cap should keep the precipitation chances down during the daylight hours. Nevertheless, a cold front will approach the region later this afternoon and evening accompanied by a damaging squall line.

Obviously, the cap will not hold. The loss of instability will be gradual during the nighttime hours, especially between 8pm and midnight. Expect widespread damaging winds along that line for anyone impacted before midnight. By 1:00-2:00am, scattered reports of damage can still be expected. This may include areas just east, such as Shelbyville and Frankfort.

The SPC still has Louisville on the edge of a moderate risk for severe weather. Depending on the speed of the entire squall line, Louisville may be upgraded to a moderate risk, as we will be in that 'before midnight' sector. The farther west one goes, the higher the risk for not just damaging straight-line winds but possible tornadoes.

This squall line has the potential for causing extensive damage along it. Power outages, downed trees and lines, and possible roof damage can be expected (as winds may gust to hurricane force in places).

I will update the SPC outlook within the hour. Another one should come out later this afternoon.

MS

Wednesday, April 17, 2013

Moderate Risk for Severe Thunderstorms Thursday/Friday

First, a Severe Thunderstorm Watch is now in effect for a portion of the CWA under Louisville NWS's responsibility till 10pm edt. Counties included are Meade, Breckinridge, and Hardin.

Now, turning attention to the main event, a squall line with possible tornadoes is forecast to impact parts of the region late Thursday/early Friday.

At the moment, far west Kentucky and far west Indiana are in the moderate shading. An upper-end slight risk shading exists for those areas along and just west of I-65.

Current thinking is that robust instability will work with the strong wind fields in place and produce a damaging squall line as it races eastward. However, as the nighttime hours progress, instability is expected to wane.

While that may happen, I do expect an eastward shift of the upper-end slight risk category to include areas along and west of I-75. Damaging winds are looking quite likely for many.

Power outages and downed lines and trees could make a mess of things as preparations for Thunder Over Louisville continue. Right now, we'll just have to wait for future developments as to the timing and strength of the storms that will affect the region.

MS

Severe Wx Looking More Likely Late Thursday/Friday

SPC is closely monitoring a significant severe weather outbreak that should climax during the late Thursday/early Friday time period. Locations to the west of I-65 stand the best shot at seeing damage.

In fact, an upgrade to moderate risk status seems plausible in light of the strong wind fields associated with the front.

A NAM analog did not seem as robust to support severe weather for our region. However, I must be quick to point out that the GFS analogs did a better job on the last storm system in predicting overall severe weather than the NAM.

Regardless, now is the time to start looking at model trends as the timing, wind fields, instability, cap strength, and so forth start becoming clearer. That's what I'll be looking at today.

I'm still quite bullish on the prospects for severe weather here in Kentucky. I'm not going to rule anyone out in this one. But, odds favor the western part of the state that would be exposed to the greatest instability.

More later.
MS

Monday, April 15, 2013

Severe Wx Potential This Week ***0415-0419***

Last week, severe weather affected parts of the state, primarily east of I-65. At least 12 storm reports were received, mainly for damaging winds.

One of those places in Kentucky affected by the high winds was in Montgomery County near Camargo. Quite a bit of damage associated with that wind event, peak gusts were estimated at between 85 and 95 mph. Though there were no findings of tornado damage, the high winds produced damage comparable to an EF-1 tornado.

This week, I look for a more active period of severe weather compared to last week. Already, I'm looking at analogs suggesting a much broader area that will be impacted by severe weather.

As far as Kentucky is concerned, most of our action should occur later this week as a potent cold front enters the region. The top 15 GFS analogs show this strong storm system producing severe weather across much of the south by then.

At just under 5 days out, I'm already looking at a 40% chance for severe weather somewhere in Kentucky. Last week, it was a 30 percent chance about 4 days out. So, the odds are definitely showing a higher likelihood for severe weather.

Just like last week, it's all about timing. Right now, it is difficult to pinpoint who has the best chance at seeing storms. I will defer to Tuesday's look at analogs and a closer look at model consensus by Wed/Thur.

All I can say right now is 'heads up' for later this week.

MS

Tuesday, April 9, 2013

Severe Wx Potential

This is for the April 10-11 time frame. This will be my final look at analogs for this upcoming system.

Severe weather potential starting to come into focus a little bit better. Again, though, remember models are still offering conflicting solutions about the frontal passage in our area.

Nevertheless, a recent NAM analog shows potential for severe weather across southern KY into central TN and northern AL. Greatest threat according to top analogs suggests the areas between Nashville TN and Huntsville AL.

The greatest threat appears to be damaging wind. However, there is a threat for tornadoes, especially across TN and AL. Scattered severe hail reports could occur anywhere along the front.

So, there is a slight chance for damaging wind here in Louisville. But, it looks like the bulk of any severe weather should be limited to the south. Yesterday, though, a GFS analog showed severe weather potential farther south than today's run of the NAM.

Again, this could be related to timing issues amongst the models.

Therefore, we'll have to fine-tune this thing still yet. So, keep up with the latest updates.

MS

Monday, April 8, 2013

Your Weather This Week (Apr 8-12)

Just what we needed. A nice, mild weekend. Ahhh.

Prior to this, we experienced below normal temperatures for 19 days out of 20. Now, we're on a 2-day winning streak with above normal readings that should continue a few more days.

Something else I noticed over the last 15 days, we've received only 0.08" precipitation. Being cut off from the Gulf of Mexico can make that happen sometimes. Now, though, we are in the good graces of that rich moisture source.

Nevertheless, the WPC (formerly known as HPC) is showing about 0.75 - 1.00" for the upcoming week

Another item that may concern some of us is the threat for severe weather during the Wed/Thr time frame. The SPC's Day 3 Outlook has Kentucky divided in half for the slight risk of severe weather, generally along and west of I-65. I'm sure the maps will change because it sounds like the GFS and Euro models aren't in agreement about timing again.

I've been looking at analog data again. At 48-72 hours out, looks like any severe weather would be located primarily south of the region such as in parts of central or western TN. So far, this does not look like a widespread severe weather outbreak...according to the top 15 analogs.

However, the NWS Louisville continues to express concern about the possibility of severe weather this week. The frontal passage's timing should prove crucial as to who stands the best chance at seeing severe weather.

As usual, we'll stay tuned.

MS

Tuesday, April 2, 2013

Teleconnectors 'Telling' Spring Finally

The famous teleconnectors, an alphabet soup of weather and atmospheric patterns, are showing positive signs for spring around this part of the world, finally.

Looking at the AO (Arctic Oscillation), the trend is toward positive, which means warmer conditions for us.

Similarly, the NAO (North Atlantic Oscillation) is showing a positive trend over the next 2 weeks.

Another one that I look at is the PNA (Pacific North American). It is forecast to be near neutral to negative. That generally bodes well for us here. A negative PNA leads to troughiness in the west, which produces cooler, sometimes wetter conditions. On the flip side, that troughiness can lead to a ridge over the Plains states that translates into warmer conditions here. Of course, moisture can be tapped from the Gulf with this scenario as well. Therefore, expect greater rain chances with the inflow of warmer readings.

Bring on the April showers. I just want the warmer air.

MS

Monday, April 1, 2013

MikeS 66 Index - March 2013

My MikeS 66 Index reveals a rather cool and dry March for the country (excluding AK and HI). Thanks to persistent troughing along the east coast, weather east of the Rockies was cooler than normal. However, the west enjoyed warmer than average temperatures.

Although the official numbers from the National Climatic Data Center will be out later this week or the first part of next week, I provide a rough estimate of how temperatures and precipitation totals varied across the country.

Breaking them down into 6 regions, here are the numbers....

High Plains    33.0 (temperature average)
                     (4.3) BELOW AVERAGE
                     73.2% (of average precipitation)

Midwest        31.2
                     (5.2) BELOW AVERAGE
                     92.8%

Northeast      37.3
                     (1.7) BELOW AVERAGE
                     66.9%

Southeast      52.7
                    (5.3) BELOW AVERAGE
                    79.2%

Southern       52.7
                    (2.5) BELOW AVERAGE
                    58.8%

West            50.6
                     1.6.ABOVE AVERAGE
                    42.6%
----------------------------------------------------
United States 43.0
                     (2.9) BELOW AVERAGE
                     69.0%

Temperatures were much cooler than the 30-yr normal. However, precipitation will be among the driest March(es) on record.

Remember March 2012? Yes, it was the warmest March on record. Look at the map below. When the official data comes out later, we can compare the map below to the one from this year...

















MS

Monday, March 25, 2013

Weather Summary Today 03/25/2013

Well, temps have stayed above freezing for the most part in Louisville. Accumulations were a little lighter than I expected here. Still, these off and on snow showers could put down some quick accumulations. However, temperatures will remain above freezing coupled with daylight hours inhibiting any roadway issues.

There were some hefty accumulations north of Louisville. Some totals include 10.5" in Muncie IN and 8.4" in Castleton in Marion county.

As of today, 48.7% of U.S. has snow cover. Remember last year about this time? The warmest March on record? Only 7.7% of U.S. was covered on this date.

Baton Rouge LA could be experiencing freezing temperatures the next couple of mornings, coming close to record lows.

Quite a bit of wind damage in Florida. Winds gusted to 86 mph in Orange county, not far from Orlando.

Here in Kentucky, Wayne county near Monticello reported roofs blown off storage building while concreted post was yanked out of the ground. Also, in Pulaski county, a large metal building was leveled. In Corbin, a roof was torn from a trailer and several trees down.

Mt Washington NH, home of the world's worst weather, has recorded about 280" snow since September. Their 109 mph wind gust yesterday was not the highest gust of the 2013 year. A 129 mph gust occurred last month. At one time, Mt Washington held the world's highest wind gust at 231 mph.

It's going to be close. Louisville still looks to break into the top ten coldest March months ever. Right now, the average is 40.4 degrees. The tenth place average is 40.0. Average temperatures in the 30's will be offset by warmer readings later this week.

Earlier this month, the Hydrometeorological Prediction Center (HPC) has been renamed the Weather Prediction Center (WPC).

Also, the Storm Prediction Center is updating its web page, starting March 28.

The Climate Prediction Center has a nice new tool, complementing its 8-14 day outlook. Check it out here. For Louisville, during the April 1-7 time frame, it shows a 46% chance for below normal temperatures, 21% chance for above normal temperatures, and a 33% chance for near normal temperatures. Pretty cool.

MS

Sunday, March 24, 2013

Complicated Forecast

So much for attempting a forecast yesterday. There was and still is too much uncertainty with this storm system.

A slight southward shift has occurred with the models albeit not enough to bring the heaviest snow into our area. However, the Louisville NWS and local television mets will probably be yanking a few hairs from their scalp before this one is over.

The track of the low is still the most important part to watch. Yet, other significant variables are vying for closer inspection.

Surface-based instability - a fetch of -2 to -4 readings keep showing up in the forecast just south and southeast of Louisville. That could be a fair indication of convection that leads to thunderstorm activity.

CAPE Values - this is also an indication of convective activity that may flare up today in those same areas south of Louisville; values around 250, not bad for no atmospheric heating.

The above factors do not appear to have much influence on the snow that will be falling well north. Many areas today in the Louisville CWA will be seeing rain or a mix of rain/sleet/snow the farther north one goes.

However, as sunset approaches, temperatures in the upper levels will begin transitioning any liquid precipitation to frozen precipitation.

Right now, it looks like the transition to all snow in Louisville will not be till after 8pm tonight. HRRR models are indicating possible snow accumulations as close as the northern part of Louisville CWA by 5pm.

Core of cold air with low pressure - ahead of the low, warmer air will be in place. As the low moves overhead and just east, colder air will quickly change from rain to a mix to all snow though temperatures will be well above freezing. If the snowfall rates are heavy enough, accumulations will occur especially on grassy surfaces.

Just north of Louisville, surface temperatures will be cooling rapidly. Accumulations will be affecting travel before midnight.

I still think a slug of heavy wet snow will affect the Louisville area sometime between 11pm and 4am. Although roadways should generally stay wet, as we continue to cool and the snowfall rates are heavy enough, we could start to see slushy roadways just before morning rush.

This is nowcast mode. My current thinking is that Louisville could get 0.7 to 1.5 inches of wet snow by rush hour tomorrow. After that, convective snow showers could put down another inch in places during the daylight and evening hours. But roadways should be in better shape after rush hour and during the daylight hours.

MS

Friday, March 22, 2013

Winter Storm Advisories/Watches

Update: 2:28pm edt
Just in...I didn't see that, just moments ago while I was writing my thoughts below, Indianapolis NWS has issued a Winter Storm Watch for much of their CWA, including Seymour, Bloomington, and Indianapolis. Accumulations of 5-9" expected along and north of Bloomington and 3-6" south of that line.
-----------------------------------

Winter Storm Watches and Advisories looking more likely for Indianapolis, Seymour, and Dayton. Cincinnati could still get in on some accumulation.

NAM puts deformation band in Indiana. Could be a southward retraction in the NAM's runs. My forecast comes out late tonight/tomorrow morning.

MS

Analog Time: Accumulating Snow for Some

An early February-type system will be approaching our region later this weekend and promises to bring snow to parts of the region.

I've had some success looking at analogs for possible storm scenarios. One that caught my attention this time is from February 6, 2010.

I like the moisture placement for the most part. Granted, these analogs do not mean the exact weather that happened then will happen again in these places.

However, it does show the storm's potential and most likely locations to be impacted.

Remember, this is not a forecast. This is just a look back in time at a weather system that has similar features to the one that will be impacting the region later this weekend.

The February 6, 2010 event put down less than 1" here in Louisville. However, just to the north at Indy and Cincinnati, they had amounts around 6". There were some isolated heavier amounts exceeding 8" around the Cincinnati area.

I'll be looking at the NAM as my trusted source within 36 hours of the main event. Meanwhile, I thought I'd share that little bit of snow history with you looking at analogs.

Some places primarily north of Louisville could be looking at the potential for 4-8". Not bad at all by mid-January standards if you ask me. And this is March???

MS


Tuesday, March 19, 2013

Top Ten Coldest March???

What a difference a year makes. Last year, Louisville recorded its warmest March ever at an average of 59.6 degrees (70.5 / 48.6).

This year, as of the 18th, the average temperature has been 41.2 degrees (49.5 / 33.0). At this time, we still do not qualify for top ten status for coldest March ever. The tenth place average is 40.0 degrees.

However, looking at medium-range forecasts, there is a likely chance we will continue to see below-average temperatures for the rest of the month.

In fact, based on those forecasts, I'm already projecting a finish in the bottom half of the top ten list. For that to happen, our average temperature would have to be in a range of 39.0 and 40.0 degrees, or 6th through 10th place.

I think this is a conservative projection. In other words, we could be looking at a colder scenario, which could vault us as high as 3rd place (38.5 degree average).

For the record, pun intended, the first and second coldest March ever were 1960's 32.5 average and 1947's 37.1 average.

MS

Monday, March 18, 2013

Weather for Second Half of March

Talk about March Madness and I don't mean basketball.

I woke up to my windows vibrating and my dog's paws skittering across the hardwood floors attempting to hide from the sound of thunder this morning. That didn't work. A few more tremendous rumbles found him in his hiding place as well.

On Saturday we exceeded 70 degrees in Louisville. On Sunday, a short trip outside of the city's limits, 3 inches of snow accumulated for a time. This morning, it was 37 at my house with thunder, wind, and heavy rain.

What a way to begin the second half of March.

The weather professionals are promising temperatures well into the 50's today. That's actually down from the lower 60's. Looking at recent observations, though, just before the 10:00am time frame, I'm seeing the warmer air getting pinched off, sliding eastward across the southern and southeastern parts of our viewing area. I would be surprised if we see over 50 degrees today here in Louisville.

Speaking of 50 degrees, I looked at a recent chart of high temperatures here. Here's what I found....

Temps >= 50 degrees (number of days during the month)

January - 10
February - 12
March - 7 (through the 17th)

Technically, we're over half way through the month. If we don't reach 50 today, don't look for it again for the rest of the week. Can you imagine March being cooler than February (which was below normal cool as well)?

I hate to bring up the past. But did you know that at this time last year, we reached 82 degrees? That would begin a 5-day stretch of temperatures in the 80's! And this was after we had already recorded 80 degrees or better for a couple of days earlier in the month.

Looking ahead, here's what the CPC is saying for the rest of the month....

>70 percent chance that temps will be below normal for the March 23-27 time frame.
>50 percent chance that temps will be below normal for the March 25-31 time frame.

Most locations will have equal chances for slightly above or slightly below normal precipitation.

Later.
MS

Tuesday, March 5, 2013

Snow Accumulations Likely Tonight Mar 5-6 2013

Update: 4:40pm
Temperature down to 37. That's a 3 degree drop in 15 minutes. Large flakes have begun falling here in Valley Station.
-------------------------------------------

Update: 4:25pm
Front has pushed through Valley Station during the last few minutes. Gusty winds will increase along with a heavier rain band. Temps have dropped 6 degrees in the last hour from 46 to 40 here in Valley Station sw of Louisville. Snow is getting closer.
------------------------

Update: 2:55pm
Forgot to update the front. Temps are crashing out west, low to mid 30's. Winds are gusting 30-35 mph as close as Breckinridge and Grayson counties.
-----------------------------------

In Nowcast mode, we can still access short-term models such as the HRRR or High Resolution Rapid Refresh for a look at possible accumulations. I'll be posting updates as to whether this storm may overachieve or fizzle out for the region.

Temperatures will be key. As long as surface temperatures are close to the freezing mark, main roads should be slushy to wet. However, I've seen main roads that I travel become snow covered quickly.

Banding of snow will be another key. Where heavier and persistent bands set up, expect robust accumulations.

In general, 2-4" is forecast for the region from Louisville to Lexington. I like that forecast. Some 5-6" amounts are possible in these areas.

The 1400z run of the HRRR at 15 hours out or midnight tonight has Louisville to Cincinnati in a 1-2" range by then. The snow is expected to continue at least till daybreak.

The 1600z run at 15 hours out or about 2:00am still has Louisville closer to 1" while 1-3" surrounds Louisville by then.

Updates later...

MS

Sunday, February 24, 2013

Ready For Spring? Not Yet...

The Climate Prediction Center has published its medium range and long range temperature and precipitation  products for March. If you're hoping for spring-like conditions, well, the first part of the month is not looking too good.

The CPC updates its medium range outlooks often. So check the links below.

For the period covering March 1-9, below normal temperatures can be expected. In fact, probabilities within a range of 50-70% are highlighted. That's an unusually high confidence range.

Precipitation for the same period is expected to come in at below normal. Sounds right to me.

We look to be in a persistent northwest flow pattern which tends to keep the moisture and warmer air from reaching us via the Gulf of Mexico.

However, do not despair. The CPC provided its monthly outlook for March this past Thursday, the 21st.
Once this persistent cold pattern breaks down, the warmer air out west will overtake us. In fact, a persistent warm pattern looks to set in. But, along with the warmer temperatures will bring a better chance for more precipitation.

CPC's 6-10 Day Temperature Outlook

CPC's 8-14 Day Temperature Outlook

CPC's 6-10 Day Precipitation Outlook

CPC's 8-14 Day Precipitation Outlook

March 's 30-Day Temperature Outlook

March's 30-Day Precipitation Outlook

MS

Tuesday, February 19, 2013

Yep, Another One of Those

Ohio Valley winter is dynamic, though at times it may seem static for most (aka no big snow).

Another storm system is ready to confound the weather pros again. However, the final outcome will result in rain.

Initial precipitation is going to be the tricky part. Apparently rain should be the dominant type; however, surface temperatures may be a problem for some.

A recent GFS analog and a NAM forecast support best chance for ice from Louisville to Cincinnati. I would place the best chance from Carrollton to Cincinnati. At least 0.1" ice accumulation is possible before surface temperatures warm above freezing.

Expect changes to the forecast as storm track data becomes more readily available.

MS

Wednesday, January 30, 2013

Cold Front on the Move 01/30/13

A cold front has pushed through. However, temperatures are still in the 50's statewide. A large shield of rain and wind continues advancing eastward across eastern KY.

Now, as I look at the most recent hourly observations and radar data, the main cold air is still positioned just to our west in east central Illinois, just passing Mt Vernon. A thin line of moderately heavy showers are accompanying the front.

I wouldn't be surprised to see this line advance into the region with another round of precipitation. Regardless, the colder air is going to arrive, with or without the showers.

Summary of severe storm event. A rotating storm cell affecting Grayson County (Leitchfield) moved quickly northeast into Breckinridge, Meade, and Jefferson counties. A Tornado Warning was promptly issued for the possibility of a rain-wrapped tornado.

As far as I know, at least from my vantage point in Valley Station (near Prairie Village for you familiar with the area), I could not determine any rotation in the clouds. However, due to the 'swirly' nature of the winds, it was possible something could have been aloft. But, the rain was affecting any visibilities that seemed favorable for a nighttime viewing.

The main line of strongest gusts (45-50 mph) were what I call straight-line winds from the west and south. A few instances of winds coming from the north and west could have been related to the cold front pushing in at the same time thus producing the possible 'swirly' nature of the winds.

Damage to dead-wood limbs occurred at my residence. However, no impressive tree damage, at least in my neighborhood, and no power outages.

South of my location, about 4 or 5 miles, Auburndale trailer park' s residents lost power, possible due to trees blocking the roadway and affecting power lines along Pendleton road. I have also heard of tree damage in PRP, which I will look at in just a little bit. That's only a few miles away from my location.

MS




Tornado Warning for Louisville

I live in Valley Station near Prairie Village. Winds were strong, but below severe limits (45-50mph). No power outages here and this is usually an outage prone area. Pressure dropped from 29.39" to 29.34" as storm cell approached, about a 10 minute span. After strongest winds passed, 10 minutes later, pressure rose to 29.46". I've never seen my barometer act so erratically. I think something was up there. Thankfully, it didn't make it down here.

MS

Tuesday, January 29, 2013

HRRR Model Potential Wind Gust

With severe weather approaching the region well into the late night hours, I saw a  recent run of the HRRR model, a high resolution rapid refresh model, showing the 10m wind gusts (about 30 feet AGL). By 3am, the line of storms should be approaching the I-65 corridor with a line of 46-77mph winds.

I would hate to have widespread power outages since it appears colder air will be rushing in behind the front.

Don't forget the use the tool 'Mesonet Front Tracker on the side of my blog to keep up with the temps, precip, and wind gusts.

MS

Severe Wx Looking More Likely for Kentucky

















1:00pm Update
MODERATE RISK for severe weather for western KY (latest Day 1 Outlook @12:30pm)
Tornadoes are becoming more likely down that way. Could there be a rare 'HIGH RISK' later for some of those areas near Little Rock and Memphis?
------------------------------------------------------
Previous discussion:
It appears things are coming together for a significant severe weather outbreak across much of the midsouth and lower Ohio Valley regions. What I find most disturbing is the consistency of these analogs I've been following for the past couple of days now.

Analogs are somewhat different than models. By definition, an analog is "a historical instance of a given meteorological scenario or feature that is used for comparison with another scenario or feature."

I've been looking at the top 15 analogs that best represent this storm system. A combined mean or average of them yields a forthcoming, impressive outbreak of severe weather with damaging winds and tornadoes.

One of the analogs hits home for many of us here in western and north-central Kentucky. The number 2 analog of Feb 5-6, 2008 shows up consistently.

I've mentioned this in a previous post. There were 131 tornado reports for that storm system across much of Arkansas, western and central Tennessee, and Kentucky, 84 were confirmed. Also, there were 267 wind damage reports.

This storm system may be rightly compared to that one in Feb 2008. SPC has been on board, upgrading parts of the midsouth to a MODERATE risk for severe weather. It will be worth keeping an eye on the next assessment from the SPC's Day 1 Outlook. Parts of western KY may go into the MODERATE risk later.

Updates later.

MS






Monday, January 28, 2013

Moderate Risk for Severe Weather Tue/Wed 01/29 and 01/30

I've been talking about the analogs and how they have been suggesting a potentially widespread severe weather outbreak. I thought maybe a moderate risk for severe weather would go up soon for Arkansas, west Tennessee, and west KY.

Now, based on what the SPC is showing, its updated outlook has put most of Arkansas, extreme southwest Tennessee, parts of Louisiana and Mississippi within the moderate shading.

For everybody else in Kentucky, a high-end slight risk for far west KY while areas along and west of I-65 are in a slight risk shading.

Outside of thunderstorms, very windy conditions should prevail. I look for Wind Advisories to go into effect for most of our region for Tuesday and Wednesday.

More later.

MS

Ominous Analog Shows Up

While researching data from the top 15 analogs, one that shows up brings back memories for me. My little girl had just been born a few days earlier. However, on February 5, 2008, a super tornado outbreak occurred that affected several areas of Kentucky and even Indiana.


















This is just one of the 15 analogs that has showed up for this storm system. It does not mean things will be exactly as it happened in 2008. In fact, last I heard was this would be a squall-line event with some embedded tornadoes possible.

More updates later...

MS

Analogs Depicting Severe Weather Chances 01/28/13

At times, especially during the spring, analogs have proven to be useful indicators of what types of severe weather can be expected. In fact, I followed some analogs last year that predicted the violent weather that eventually played out across southern IN and parts of eastern KY.

I'll be updating with additional posts concerning these analogs as we get closer to a possible severe weather outbreak.

Today, I'm looking at a 48-hour NAM based on the top 15 analogs' input made at 7pm last evening. So far, just looking at this run, an impressive outbreak of severe weather for this time of the year could occur. According to the latest run, wind damage appears to be the primary threat. However, tornadoes also look likely in some areas.

Breaking it down, the most likely areas to see severe weather will be central and northern Arkansas, much of  western Tennessee, and western Kentucky. Based on percentages I'm looking at this morning, the top 15 analogs are suggesting a 20-30 percent chance for damaging wind across these areas. Also, an impressive 5-10 percent chance for tornadoes looks greatest across eastern and northern Arkansas along with southwestern Tennessee. An area of southern Missouri south of I-44 may be impacted as well.

However, across our region here in Kentucky, tornado chances do exist (2-5 percent). The  most likely scenario will be the threat for wind damage.

Currently, the SPC has issued its Day 2 Probabilistic Outlook and has much of Arkansas in a high-end slight risk category. I may be going out on a limb here, but I do expect some areas to be upgraded to a moderate risk for severe weather. I would include Arkansas, western Tennessee, and maybe western Kentucky.

Updates will be coming this afternoon.

MS

Saturday, January 26, 2013

Ice and De-ice













Good morning, Somerset KY. A little souvenir left over from yesterday's overachieving ice event. You received 0.2 - 0.25" ice accumulations, a common amount for several areas of south-central KY. Things look to improve dramatically today. Still, beware of leftover moisture on the ground that is likely frozen this morning.

Even here in Louisville, black ice looks to be an issue on some untreated subdivision roads, like my street.  Thanks to barely any snowfall, temperatures should rebound above the freezing mark for many locations across Kentucky, except the usual cold spots of far northern Kentucky and elevated parts of eastern Kentucky.

A nice warmup is in store starting tomorrow and should last into parts of Wednesday before we get slapped with another backhand of Ole Man Winter's dry, cracked, and calloused knuckles.

Here's your next teaser. From the CPC, an updated page from yesterday shows the 6-14 day outlook that features below normal temperatures for all of Kentucky and above normal precipitation for parts of the state, roughly from I-71 and I-75 corridor east including all of eastern KY. Well, you figure it out. Probably means nothing, though.

MS

Thursday, January 24, 2013

First Call for Snowfall 01/24/13

Well, I've had a chance to examine the recent runs of the NAM and do lean heavily toward this model as I forecast these amounts. I will throw in what my MrHP forecast will be along with my personal expectations.

First, let me say there will be quite a bit more of mixed precipitation than snow for this event. To summarize, I expect all snow from Carrollton northeast to Cincinnati and east to Ashland. Louisville should expect a mix of snow and sleet. Lexington also a mix of snow and sleet, although more snow than Louisville. Bowling Green could see freezing rain and sleet throughout the event while Somerset could see freezing rain and sleet before changing to all snow later in the event. Again, a very complex setup.

MrHP says...
Cincinnati 1-2"
Louisville <1" + sleet
Lexington 1" + sleet
Ashland  1-3"
Somerset  0.1 - 0.2" ice, <1" snow + sleet
Bowling Green 0.1 - 0.2" ice + sleet

MikeS says...
Cincinnati  1-2"
Louisville <1" + sleet
Lexington  1-2" + sleet
Ashland  2-3"
Somerset  1" + sleet, 0.1 - 0.2" ice
Bowling Green 0.1 - 0.2" ice + sleet

NWS says (as of 12:30pm est)
Cincinnati  1-3"
Louisville 1" + sleet
Lexington 2"
Ashland  1-3"
Somerset  <1"
Bowling Green 0.2" ice

Very subtle differences in the forecasts above. I will say that the NWS has the best track record . However, I'm beating my MrHP forecast model for the season. The most obvious differences are that Lexington is expecting no sleet and Somerset no ice according to NWS offices.

MS

Wednesday, January 23, 2013

Forecasting Snow For the Region - Try This One

Sure, we can look at the forecast models, you know, GFS, NAM, Euro, GEM. Often, we leave it to the pros to interpret what those models will spit out in terms of precipitation for the area. And yes, all eyes are glued to the same models again as they fluctuate in their various runs for the next upcoming system.

Folks, this is basketball country around here. We live and breathe this stuff, the tickling of the nylon, the diaper dandies, and the thunderous throwdowns. The atmosphere around here gets so heated, I think we can alter the weather at times. You know, it could be true.

Looking at our most recent heaviest snowfall in January, it was January 20, 2011 that Louisville recorded 3.6" and Lexington 3.3". I can't remember how the meteorological computer models fared with their forecasts but I found an interesting correlation that may prove useful for our next storm system in a couple of days.

Introducing the NCAA model.

Something else noteworthy occurred in January 2011. The University of Louisville and Kentucky Men's NCAA basketball teams suffered a loss in the same week.

In fact, UL lost to Villanova 88-74 at Villanova on 1/12. UK fared no better at Tuscaloosa on 1/18 when Alabama beat the Cats 68-66.

Two days later, on January 20, 2011, Louisville and Lexington recorded their respective snowfall amounts previously mentioned.

Last night, UL lost to Villanova at Villanova and UK lost to Alabama at Tuscaloosa. Could this be deja vu? Well, if history repeats itself, then two days or so later, Louisville and Lexington should be looking at possibly 3" of snow on the ground.

Hey, this model makes just as much sense as the ones we hear about on a daily basis from our weather heroes. Take care and I'll give the NAM a few more chances to catch up with the NCAA model.

MS



Snow Chances 01/23/13

Ah, I said beware of the 'snow job' fallacy during a prior post. Data for our upcoming storm system comes in weaker mainly because the phasing aspect may not materialize as assumed. Nevertheless, my low end conservative guidance remains in play (2-3"). And things can still change. I'll be taking a look at the NAM model throughout the day. It is perhaps the main driver in my MrHP (Mid-range Highest Probability) snow forecast. The other factors include the timing (24-36 hours out), upper air forecasts, surface temperature forecasts, and to a limited extent (and I do mean limited) my personal expectations based on observed data.

Even if this forecast does not favor snow enthusiasts' expectations, winter is not over yet. So far, the CPC has put out these mid-range forecasts that have been surprisingly accurate, at least for our region. They predicted the above average warmth and wetness just before the middle of the month. They predicted the below normal cold and below normal precipitation for this period, again some 6-14 days out.

Mark this on your calendars. The January 28 - February 03 time frame is expecting above normal precipitation. Interestingly, the first part of February could be looking at below normal temperatures. Coincide the cold with the precipitation and we could be looking at the elusive 'big one' for our region. Or at the very least, our biggest snowfall of the winter season is in store.

You can check out their predictions at the link below...

CPC Outlook and Information Page

MS

Tuesday, January 22, 2013

Another 'Snow Job'?

Snow Job - "an attempt to deceive or persuade by using flattery or exaggeration" (Dictionary.com)

For at least a couple of days now, NWS offices and other mets have been advertising an 'impactful' winter storm for the Jan 24-26 time frame.

The NWS Louisville office reminds us that despite high confidence for a storm system to affect the region, precipitation types are still 'up in the air'. At this time, a southern track remains the preferred choice.

If the southern track should verify, then sizable snow amounts can be expected, generally north of a line from Beaver Dam to Richmond. However, as usual, Kentucky seems to be the battleground for transitional precipitation.

Any shift in the storm track will impact snow and ice amounts significantly. However, there seems to be growing confidence that a wintry scenario will unfold across the state due to the presence of a retreating yet still present Arctic air mass by Thursday.

Since this type of cold air is difficult to budge at the surface, how thin will the Arctic layer become? If precipitation falls later than expected, warmer air will nudge in from the south in the upper layers of the atmosphere, possibly falling as rain for some of us. The problem then becomes, if temperatures are below freezing, perhaps 3-5 degrees below freezing, any liquid rain that falls will freeze on contact with surfaces and other objects (thus freezing rain).

I'm not here to exaggerate precipitation amounts and types. The storm system is still just offshore. Remember, as I know from personal experience, Arctic air masses are typically stubborn. Cold air likes to hang around, especially near snow-packed areas. There's not much snow out there. Also, these air masses have a great deal of dry air with them. Any precipitation that falls generally have a difficult time making it to the surface.

Depending on the speed, strength, and track of the storm system, it will be interesting to forecast how a developing winter storm will fare against a retreating yet somewhat strong Arctic air mass.

Nevertheless, 2-6" looks like a conservative guesstimate for those who get mostly snow. Although this sounds like an appreciable amount, any mixing of precipitation will reduce those totals in a hurry.

The main concern that I have with this upcoming system is the ice potential. It could become a widespread issue, not like the last storm where only a relatively few locations were significantly impacted.

If the current track remains, ice accumulations for Campbellsville to Corbin  appear possible, at least somewhere in that region, maybe even more locations of eastern KY as well.

For now, let's just wait and see as the storm system comes ashore. Upper air data can then be calculated and storm track along with p-types will become a little clearer.

Looks like another tough snow job to forecast, or should I say, beware of those snow job forecasts that persuade you this will be an easy storm to forecast.

MS


Thursday, January 17, 2013

January Mid-Month Report

A good time to look at what has and what will happen.

Overall, it's been wet and mild...thru 1/16
Louisville  234% of normal precip
Louisville 4.8 degrees above normal

Lexington 181% of normal precip
Lexington 5.3 degrees above normal

Bowling Green 203% of normal precip
Bowling Green 5.8 degrees above  normal

Jackson 179% of normal precip
Jackson 5.5 degrees above normal

The CPC says for the time frame of Jan 22-26, temps retreating from below normal readings. In fact, Jan 24-30 time frame shows above normal readings across much of the south, including KY.
I'll be interested in seeing how this unfolds as some are pointing toward a very cold period during this latter period.

Here is what the CPC says for the month of February...

February Temps
February Precip

MS

MikJournal Midweek 11/16/2017... A Lot of Data

Good afternoon. My expected midweek post was a little bit delayed. I had an influx of data to pore over and did not have time to write ...