Friday, October 31, 2014

First Measurable Snow Possible...Find Out Where

It's only October. Okay, it's the end of October, but we are already talking winter time. Unfortunately, for those who want October Snowfall records to fall by the wayside may be disappointed as the bulk of any accumulation would not happen till after midnight, which takes us into November 1.

Nevertheless, snowfall accumulations do look possible, especially in the favored higher locations of eastern Kentucky.

What makes this system so interesting is that the track of this low and the cold air associated around it could produce a quick burst of heavy snow to the tune of at least 2". And if this energy happens over the mountains, one could be looking at more than that.

Dynamic cooling...what a fancy term. This storm system will be generating its own precipitation via upsloping and cooling of the air column at the same time so that snow will begin breaking out seemingly prematurely. But, surface temperatures will quickly follow suit and fall rapidly.

While ground temperatures are still too warm to support significant snow accumulations, enough heavy snow bursts will allow for some accumulations.

Right now, I'm looking at 2-4" for the eastern parts of Kentucky and the higher elevations, especially above 2,000 feet. But, don't be too disappointed if it does not stick around very long.

For the rest of us, especially from I-65 eastward, heavier snow showers may actually whiten the ground for a time before surrendering to the warmer ground.

MS

Friday, October 17, 2014

*SPECIAL* - A Look at the Discrepancies Between the NWS Official Reporting Sites and Nearby Mesonet Sites

Subjects: Kentucky NWS Official Reporting Sites
                Adjacent Kentucky Mesonet Sites
Time Period: June - September 2014
Topic: Number of 90 degree days

First, let me throw several sets of numbers at you. The data you are about to see is a sampling of the number of this year's 90 degree days for adjacent or nearby Mesonet sites compared to that of the 'official' National Weather Service sites.

Ky Mesonet Caldwell County 12 days
Ky Mesonet Graves County 19 days
Ky Mesonet Marshall County 19 days
NWS Paducah   43 days

Ky Mesonet Oldham County 4 days
Ky Mesonet Shelby County 1 day
NWS Louisville  35 days

Ky Mesonet McCreary County 1 day
Ky Mesonet Casey County 2 days
NWS London  17 days

Ky Mesonet Fayette County 1 day
Ky Mesonet Madison County 1 day
Ky Mesonet Clark County 6 days
Ky Mesonet Nicholas County 12 days
Ky Mesonet Lincoln County 10
NWS Lexington  21 days

Ky Mesonet Barren County 16 days
Ky Mesonet Warren County(1) 27 days
Ky Mesonet Warren County(2) 36 days
NWS Bowling Green  41 days

Ky Mesonet Owsley County 5 days
Ky Mesonet Knott County 4 days
Ky Mesonet Breathitt County 7 days
NWS Jackson  7 days

Ky Mesonet Franklin County 4 days
NWS Frankfort  13 days

Remember, these numbers are for adjacent counties, sometimes within the same county, and nearest Mesonet sites in relation to the 'official' NWS sites. Except for the NWS at Jackson, all of the other 'official' NWS sites show large variations in the number of 90 degree days compared to other reporting stations of the Kentucky Mesonet.

I think you would agree that we need good continuity of data to provide fair representation for the state of Kentucky's climatological record. Of course, this does not have to pertain to the number of 90 degree days only.

Most, if not all, of Kentucky's NWS official reporting stations are located at airports. Now, each site must follow stringent guidelines about siting and exposure of equipment.

For example, the siting of temperature sensors should include locating them at least 100 feet from any extensive concrete or paved areas, or 500 feet from any building or area that might influence readings. Avoid swampy locations where water collects or artificial irrigation areas. Keep grass or vegetation within 100 feet of the site cut to less than 10" in height and provide unobstructed flow of air.

Special attention is to be given to any changes made in the station sensor that could affect data and necessitate the requirement for a temperature comparison routine.

Recently, complaints about the Lexington temperature sensor had technicians busy. I corresponded with one of the engineers and he told me they had conducted numerous tests and that the sensor met quality standards. Local media were invited to have their cameras rolling as to demonstrate the calibration process and show that the equipment was within appropriate quality assurance standards.

Yet, Lexington's sensor has altered things a little bit. But not as much as one thinks. Comparing data from this year to the same time last year (when the old sensor was still in play) Lexington NWS 2014 average high temperatures were 3.05 degrees higher than the nearby Mesonet site versus 2.65 degrees higher last year under the old sensor. But, this is compared to the Mesonet site a few miles away. Keep in mind,  the Lexington NWS recorded 21 days in the 90's. The Mesonet site recorded just 1 during the year 2014. Last year, Lexington NWS saw 17 days in the 90's. The Mesonet site again only recorded 1 day.

As a side thought, I do not understand why 'official' records should be kept at an airport, as this is not climatologically indicative or reflective of the surrounding area, which includes much more grass, trees, and a lot less concrete (attention NWS Louisville @ the Airport).

Well, what about the Mesonet sites? By analyzing the data above, it seems apparent that their data and means of collecting that data follow a different set of standards or guidelines. But, do they?

At least three times a year, technicians visit and perform required tasks to make sure the equipment still meets manufacturer's specifications. Any faulty sensor or equipment is sent back to the laboratory to be either recalibrated or decommissioned.

I wonder about the sites themselves, though. Why is there so much of a temperature variation from site to site, especially those in close proximity to one another?

For example, in Warren County, one site registered 36 days of at least 90 degrees. A few miles away, another site registered 27 days. For me, that's significant. One has to wonder if the site is not right for the equipment or the methods being followed for the equipment's data monitoring is substandard.

If the equipment's sensors fall within the range of quality standards, then there has to be either a site issue or a methodology issue when it comes to the various Mesonet sites across the commonwealth.

I do not know what it's going to take to get someone's attention to make sure that the data collected is fairly representative and contributes to the overall homogeneity reflecting the current affairs of our climate. But when one sees the wide discrepancy between each of the sites I presented to you, would you accept these numbers as legitimate?

And this is just one aspect that I'm looking at, the number of 90 degree days. What about the other measurements that are taken? Wind, precipitation, dewpoint readings? Are these fairly representative when we compare the official data versus the Mesonet sites. Well, I may investigate those as well. But, I think this will do for now.

References:
http://www.nws.noaa.gov/directives/sym/pd01013002curr.pdf
http://www.nws.noaa.gov/wsom/manual/archives/NB118209.HTML#5.3
http://www.kymesonet.org/instrument.html#!instrument
http://www.kymesonet.org/instrument.html#!sitemaint
http://www.kymesonet.org/historical_data.php
http://www.nws.noaa.gov/climate/index.php?wfo=lmk

MS

Monday, October 13, 2014

Following Severe Storm Reports...and a Blizzard?

8:30pm Update
Extensive line of thunderstorm warnings west of Louisville. At this time, the supercell with a history of funnel and touchdowns is showing signs of dissipating. This was the same cell that started pretty far south and tracked through Clarksville TN into southwest KY and produced amazing tornado signatures. Latest radar image shows no signature. I would not let my guard down if I were you.
------------------------------

Damage reports are coming in from western KY. Paducah is reporting a roof off of a building.
In addition, other communities such as La Center in Ballard County have downed trees and lines.
Check out the following storm report below....

Wickliffe actually reported thunderstorm damage with fallen trees, even some blocking roadways. That was a separate report. No reports of tornadoes yet. However, Watch boxes are lined up all the way to the I-65 corridor.

More updates later..

 
PRELIMINARY LOCAL STORM REPORT

NATIONAL WEATHER SERVICE PADUCAH KY

327 PM CDT MON OCT 13 2014

 

..TIME......EVENT...  ...CITY LOCATION...  ...LAT.LON...

..DATE.......MAG....   ..COUNTY LOCATION..ST....SOURCE....

            ..REMARKS..

 

0325 PM     BLIZZARD     4 E WICKLIFFE      36.97N 89.01W

10/13/2014               BALLARD       KY   TRAINED SPOTTER

 

     TREES DOWN AND ROAD BLOCKAGE REPORTED EAST OF COMMUNITY.

Sunday, October 12, 2014

Updated Severe Weather Forecast

Both the GFS and the NAM are displaying severe weather breaking out along a squall impacting Arkansas, southeast Missouri, western Tennessee, western Mississippi, and possibly far western Kentucky tomorrow afternoon and evening.

Widespread destructive winds exceeding 70mph at times along with possible brief spin-ups are expected anywhere along this line.

It is still indeterminable if central and eastern parts of Kentucky will be affected by the strength of this line, as it appears it will lose some of its high energy punch after 10pm eastern daylight time as the entire line becomes more of a flooding threat with 2" amounts common in several locations. Amounts of up to 4" are possible and may give way to high water issues along creeks and streams.

Still, I cannot rule out isolated wind damage/brief tornadoes along this line for central and eastern Kentucky. The longer we get into the night, though, the lesser the danger of destructive winds and tornadoes.

This is just a preliminary outlook based on my opinion and does not reflect the views of the National Weather Service or other AMS Meteorologist.

Updates likely tomorrow....

MS

Storm Weary Residents Brace For More Possible Severe Weather Monday-Tuesday

The current, prolonged active weather pattern is about to come to a climactic conclusion. Following a week of quick-hitting tornadoes and damaging microburst winds along with very heavy rainfall, a vigorous storm system appears to be taking shape and aiming for us in the Ohio Valley.

What does that mean for many of us? At least another round of possible severe weather. Indications are pointing to a widespread severe weather event at least for western KY. At this time, there has been no official mention of a widespread event for central and eastern parts yet, but a real possibility exists. You know the song and dance. We will have to wait for computer models to chew on the data and spit out some possibilities.

In a situation like this, I like to look at analogs, or past similar weather patterns/systems that align with the current thinking of the approaching storm system.

The NAM analogs for the period showed a few solutions.

One was confining the widespread severe weather south of the region, say, from Tennessee into Alabama and Mississippi.

Another showed the bulk of the severe weather hitting parts of southern Indiana.

Then, there was a particular troubling analog that showed central Kentucky getting hammered with widespread wind damage. This analog was November 9-10, 2000. Numerous reports of winds exceeding 70 mph and isolated tornadoes occurred along the main squall as it raced across Kentucky.

Let's see how the models digest the data. But be prepared for another round of severe weather. This has the look of a potentially widespread event that, in my opinion, combines all three solutions above, from Indiana through Kentucky and into the south. Timing, instability, upper level winds need to be fine-tuned yet.

Here's one look of the NAM model currently...

















 
MS

Thursday, October 9, 2014

Wet Consecutive Days Coming For Louisville KY

Didn't it seem like last month we were talking about the driest stretch of days in a very long time for Louisville? I think we ended up with at least 20 consecutive days without measurable precipitation.

Now, all of the forecasters are talking about a stretch of days where we could see several inches before all is said and done.

I do not know what the record for most consecutive days of measurable precipitation is, at least here in Louisville. I would have to dig and do a bit more research. However, just looking back a few years yielded at least one impressive result.

A stretch of 7 consecutive days in April 2011, from the 22nd through the 28th, produced over 7.73".

The current forecast calls for a likely chance of rain for the next 6 days with expected rainfall amounts of 4-6" during that time period.

MS

Monday, October 6, 2014

News About Space Weather and Upcoming Eclipses

Get those cameras ready. Charge the batteries the night before. Weather permitting, a total lunar eclipse will commence early Wednesday morning, October 8.

Along with a low moon in the sky will come a variety of color shades that should prove spectacular for videos and snapshots, especially as twilight emerges from the east and interacts with a lightening western sky.

In addition, a very rare event with this upcoming lunar eclipse will occur. Some locations might have a chance to view the shadow of the earth across the western-setting moon while simultaneously catching a glimpse of the first slither of the sunrise in the east.

I do not expect this to happen here in Louisville. Sunrise will be at 7:45am while moonset will be at 7:52. Nevertheless, a good show is expected. Again, hopefully skies will clear.

The coppery-red color and totality will occur around 6:30am. Get out there and enjoy!


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 












  
Don't worry if you miss this event. Later this month, a partial solar eclipse will happen on the 23rd of this month. For Louisville, that show will begin near 6pm with the maximum eclipse occurring just before sunset.
 
Next, as far as space weather is concerned, sunspot activity has been rather low lately. On July 17, 2014, the sun's face was spot free. Why was that significant? It marked the first time since August 14, 2011 - that's nearly 3 years - that at least one sunspot had not been observed on the face of the sun.
 
Since January 1, 2011 until now, there have only been 3 days when no sunspots have been observed.
 
Therefore, while sunspot activity has been slowing down, we still have observable sunspots almost on a daily basis.
 
MS
 
 
 
 
 
 
 
 
 
 
 
 
 
 


Friday, October 3, 2014

Carbon Dioxide Levels Atop Mauna Loa Hawaii

Did you know on May 9, 2013 the Mauna Loa CO2 level breached 400 parts per million for the first time?

The CO2 level has been rising continuously on a year over year basis for several decades now.

Typically, the levels reach a maximum during the late Spring season and begin to decrease as vegetation absorbs the carbon dioxide.

Then, by September and October, levels begin increasing again as deciduous trees and other vegetation lose their foliage.

Carbon dioxide has long been looked at as the primary greenhouse gas contributing to the global warming episode during these past decades.

Below is a snapshot of the most recent year over year chart of the daily and weekly average CO2 values.









MS

Wednesday, October 1, 2014

Models Differ From Oct 2-9

Okay. My last forecast based on the GFS and ECMWF was a bust. But, even the NWS office in Louisville could not get those high temperatures right for the week either. The dry ground made it difficult even one day in advance much less several days out.

Now, for the upcoming forecast period. Instead of the GFS and the ECMWF agreeing like this past week, there are significant differences by the time we get into the beginning of the work week.

Both models agree that after a balmy Thursday, temperatures will be quite cool come Friday night through Sunday morning. The GFS is actually colder for its highs on Saturday than the ECMWF.

Granted, cold air advection can make a mess of a computer model's idea of what surface temperatures will be like. Cyclonic flow will advect colder air into the region on the heels of stiff northwest winds by Friday night as temperatures will fall throughout the day on Friday.

Saturday looks very cool, cold compared to the 80's. GFS shows 52 degrees for Louisville while the ECMWF shows 56. I think those numbers sound reasonable as we will not be under the influence of high pressure but continued cyclonic flow around low pressure. That means more clouds than sun during the heat of the afternoon, putting a lid on rising temperatures.

Saturday night into Sunday morning raises a question mark. Will the winds relax enough and skies clear enough for patchy frost formation?

Generally, under cyclonic flow, there is normally a measure of some wind and some clouds. However, I have seen when winds relax and skies clear a couple of hours before sunrise. And I think that will happen in this instance for many locations.

Look for several areas with readings in the mid and upper 30's. With calm conditions, expect patchy frost confined mainly to rooftops, windshields, and iron rails. Some tender vegetation may be impacted, but this should not be a killing frost ending the growing season for many of us. But, I would not be surprised in valley areas or higher elevations of the Bluegrass and eastern KY that widespread frost may potentially damage plants.

If clearing should occur, expect the NWS offices to put out Frost advisories for areas generally east of I-65 for the Sunday morning time frame.

By the beginning of next week, the models differ on how things will progress for the rest of the time period through Thursday.

The Euro shows a reinforcing shot of cooler air arriving by early next week while the GFS maintains that temperatures will be steady and slowly rise throughout the forecast period.

According to the Euro, Louisville's temperatures would slowly recover from highs in the lower 60's on Monday to possibly mid 70's by next Thursday while the GFS has upper 60's rising to the mid 70's during the same time. I am siding with the ECMWF.

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 ...