Thursday, December 31, 2015

MikJournal January 2016 Prediction

Welcome to a special edition of my MikJournal page. If you are not familiar with the winter page, I will be posting a monthly report for each of the winter months December, January, and February.

In Review

December 2015 was a warm one, into the record books for one of the warmest Decembers on record. Also, it was a wet month, ranking again in the top ten wettest Decembers.

El Nino has had its footprint in a few locations nationwide but did not line up with what one would normally expect from a typical El Nino. But, we are just beginning, right?

Record warmth was also noted across Florida, where below normal temperatures are expected along with above normal precipitation for the winter. It's going to take quite a reversal to offset the anomalous warmth of December.

In fact, other areas of the south that are expecting overall below normal temperatures and above normal precipitation were very balmy, even by their standards. Mobile AL, Baton Rough LA, and Houston TX averaged between 5 and 9 degrees above normal for temperatures and well above normal for precipitation.

Overall, I was pleased with my December prediction, which highlighted no Arctic outbreaks, balmy temperatures, and severe weather chances. However, I think it was a little too warm and wet than even I had anticipated. But, what about going forward into the month of January?

January Prediction

The month of January appears to offer a major dose of reality. After an unusually warm start to the winter, January is offering a plate of at least typical winter fare.

One of my biggest arguments in favor of colder air is the alignment of the teleconnections AO, NAO, EPO, and the PNA. During the month of December, the Keeper of the Cold', the AO, stubbornly refused to dip much below neutral for the entire month; therefore, the coldest air remained locked in place in the Arctic region for the most part though spilling modified Arctic air into the western U.S. However, the eastern part of the United States enjoyed warmth, the typical trough west /ridge east pattern formed by the -PNA teleconnection working in conjunction with a positive AO, NAO, and largely EPO.

Now, the PNA has reversed for the time being. +PNA, or a ridge west/trough east will be working in harmony with the reversal of the negative AO, NAO, and EPO. However, the jury is still out on how the NAO will perform over the longer time frame.

Nevertheless, transport of cold, Arctic air will be available for much of the eastern part of the United States. Any long term cold will depend on how negative the NAO can become. We need a blocking pattern near Greenland to help pave the way for the Siberian Express and keep the cold train well oiled.

Otherwise, I am expecting cold shots of Arctic or modified Arctic air to be interspersed with some nice, seasonal weather with some above average readings. Now, I am not talking about the same kind of air we had in December, so let me be clear about that.

Well, if there is going to be cold air in place, what about snow chances?

The chances are higher that we will be looking at wintry weather for January, especially in comparison with December, right?

A persistent northwest flow will at times cut off the Gulf's moisture supply. But, remember, El Nino is notorious for affecting jet streams, most notably, the southern or subtropical jet. An active southern jet working in harmony with another teleconnection called the Madden Julian Oscillation (MJO) is expected, especially around the middle of the month.

In fact some of the maps I have been studying show a split flow regime where the polar jet and the southern jet are separated initially but then come close enough (or phase) to form a blockbuster storm. I am predicting at least 2 of these systems for the month, primarily near and after the middle of the month.

Right now, I cannot say what the dominant air mass will be when these 2 systems approach our region. You know how it is if you live in Kentucky. It seemingly appears to be a constant battleground between the precipitation types. There are 3 scenarios I foresee if these systems do try and phase the two jet streams.

First, cold air in place, phasing just west: This would not be good. Cold air with overrunning warm air can only spell trouble for the region, ice to rain back to rain/snow and all snow.

Second, mild air in place with low pressure tracking nearby or phasing just north: A rain or rain/snow mix transitioning to all snow after frontal passage.

Third, cold air in place, phase just south: This would result in greatest snow chances for our region but perhaps a bad ice storm for parts of the unprepared south.

Unfortunately, due to El Nino's warm influence and an indecisive NAO, I cannot fully support #3 at this time.

Therefore, I am leaning more toward the second solution, mild air in place with a rain or rain/snow mix transitioning to rain then rapidly changing to all snow after cold air infiltration with some accumulations..

I am not saying that if both systems do evolve, they will be twins of one another thereby producing the same kind of weather for the region. I do expect one system to offer a warmer solution than the other.

Now, if the NAO can stay mostly negative, that could alter this forecast. The second solution above still looks good though, because we do not want a phasing to occur too far south or else our region will mostly miss out on the biggest snows. However, it is more probable for parts of the state (south to southeast) to see significant snowfall than the northern half.

Conclusion:

January's temperatures should range between near normal to below normal, despite what the CPC says about an above normal temperature pattern.

Precipitation will depend on types. Right now, I am leaning toward below normal, no matter what types of precipitation we have. A colder air mass will yield much below normal precipitation while a milder air mass will yield a better result though still below normal.

MS

Monday, December 28, 2015

MikJournal Monday 12/28/15

Just a few days left in this record-setting year of 2015. Right now, I am trying to come up with as many words that start with the letter 'W' to describe the year's 'W'eather.... Let's see.

'W'et
'W'arm
'W'ild
'W'eird
'W'ashout
'W'acky
'W'affle
'W'intry
'W'onderful
'W'ambunctious...Okay, how did he get in here?


www.thecoasterguy.com

Well, anyway, this looks to be a memorable year, with all of the cold and snow we had...mostly late in the season, though. Still, February finished at #7 in the top ten coldest February's on record in Louisville. In fact, while there are no records for this category, February has also been the windiest month of the year, coming in at an average  speed of 9.9 mph. A few of those windy days came when the surface temperatures were already bone-chilling. Here are a few examples...

On Valentine's Day, Louisville had a wind gust of 44 mph when the high temperature was 38 and the low was 12.

On February 18, the high temperature was 24 and the low was 4. There was a recorded wind gust of 36 mph and an average speed of about 15 mph.

The very next day, we only reached 11 degrees while the bottom dropped out at -3 for an overnight low. Still, there was a 25 mph wind gust along with an average speed of 10.4 mph.

On March 5 in Louisville, we had a  top ten record snow depth of 10". March 4th was also the 5th snowiest March day on record at 8.3".

February had its 10th snowiest month on record at 10.9" and March had its 6th snowiest month of March at 11.9". In addition, that amount would prove to be Louisville's 7th heaviest snowfall on record, covering the March 4-5 time frame.

Thanks to that snowy March, the Spring of 2015 went into the record books as the 6th snowiest Spring on record at 11.9".

On the other hand, Louisville looks to finish in the top half of the top ten warmest December's on record, to go along with November's #5 ranking.

The autumn of 2015 finished #6 in the warmest Autumn season on record category.

Believe it or not, despite February's record cold and a ho-hum summer, with only 38 days in the 90's for Louisville, we should still see a top ten finish in the warmest years on record category.

How about wet? Was it wet or was it wet?

In Louisville, we recorded our 4th wettest day on record and the wettest April day ever on April 3 with 5.64".

Louisville also achieved a top ten wettest month in April (#3)  and July (#7). As of this morning, we have moved into the top ten wettest month for December, with more rain projected to come.

We have yet more top ten earners....The Spring season of 2015 came in at #7 wettest on record and the Summer season of 2015 came in at #5.

Also, as of this morning, and not surprisingly, we are at #4 in  the wettest years on record category.

As far as this year in review, at least for now, in the words of Porky Pig, "That's all folks."

MS

Friday, December 25, 2015

MikJournal Holiday Post 12/25/15

Record warmth continues to dominate the eastern part of the U.S.
Temperatures for the month have averaged 10-15 degrees above normal for the upper Great Plains, Midwest, Northeast, and our part of the world.
Snow Nazi says "No snow for you, come back...er, in a few days or so." Okay. So no white Christmas for many of us in eastern North America. But, changes are coming, soon.

Currently, U.S. snow cover is at 37.2%. Despite all of the warmth for the east, there is more snow cover this December 25 than last year at this time when it was 35.5%.

When was the last time over 50% of the country had snow on the ground?

You gotta go back to 2012, yes, the warmest year on record for Louisville and definitely a top ten favorite for others in this great state. Some 51.1% of real estate was covered in white. There were a slew of other years in that general time period of December 25 when over 50% of the country saw white.

2010 - 50.2%
2009 - 63.0%
2008 - 52.7%

Believe it or not, the last time we in Louisville and Lexington saw a white Christmas, with measurable snow on the ground, was 2010. Now, in 2012, we did not have a white Christmas, but it did snow a few days later as we approached the end of the year.

My December Prediction I made during the last week of November included balmy weather and also severe weather chances for the end of the month. The MikJournal January Prediction comes out later around the 29th or 30th. It's looking like a colder month (about time!) but what about snow chances? Find out that along with my thoughts about how the overall winter season could be progressing with El Nino's footprint seemingly everywhere.

MS

Thursday, December 24, 2015

MikJournal Case for Top Ten Warmest Year on Record for Louisville 2015

Yes, it has been a wet year, definitely a top ten earner. This December will be among the warmest on record, something a few are beginning to talk about now.

But, I have not heard or read anyone mentioning that this could be a top ten warmest year on record for Louisville. We should not only break into the top ten but may register as high as #5 on the list.

Perhaps it should not surprise you that 2015 could become a top ten inductee for warmest year on record, because 2007, 2010, 2011, and 2012 are among past inductees, 2012 having the distinction of warmest year ever.

But, here's what may surprise you....

#1 - 2012  60 days with temperatures >=90 for the year.
                 10 of those days >=100 degrees

#2 - 2007  67 days >=90 degrees
                   5 days >= 100 degrees

#5 - 2011  56 days >=90 degrees
                   5 days >=100 degrees

#6 - 2010   85 days >=90 degrees
                    4 days >=100 degrees

2015 has recorded only 38 days at or above 90 degrees. Guess how many days were above 100 degrees?

Zilch, nada, the big goose egg.

Yet, my current projection has 2015 beating out the #6 spot held by the year 2010 and will pose a strong challenge for #5 shared by 2011 and 1990.

Currently, the 2015's average temperature ranks #5. However, we still have a week to go. Yet, temperatures are expected to range well above average for December during the short term before attempting to return to slightly elevated values by year's end.

MS

Wednesday, December 23, 2015

Tornado Watch for Western Kentucky

Storm Prediction Center says two lines of strong to severe storms should impact the shaded areas. The Watch goes through 6pm est.

Currently, there have been a few reports of wind damage near St Louis.

We, who are east of this Watch box, need to pay special attention to this setup of two lines. If, and I do mean if, we are able to develop some instability, the first line could have impacts, possibly related to isolated tornadoes. Otherwise, the first line could just have pockets of heavy rain that may preclude severe weather along the second line.

This looks to be a complicated storm system as far as severe weather chances. Best chances reside west and south of our region of central Kentucky.

Timing the storms' arrival so far is poor. Models slow the whole line now. But a vigorous squall line may speed things along. The earlier that storms can arrive, higher severe weather risks.

Nowcast event underway.

MS

More Records Possible

I cannot remember too many Decembers in my lifetime that has been this warm overall. I am not talking about a day here or there that set a record high. I am not even talking about a regional thing with a few days in record high territory. This has been nearly a month-long event.

Fargo ND - over 13 degrees above average for the month.
International Falls MN - over 15 degrees above average with not a single day below zero yet this month. And they are supposed to be the Icebox Capital of the United States (there is still debates raging over that one).
Sault Ste Marie MI - over 12 degrees above average with just over an inch of snow for the month.
Buffalo NY - almost 11 degrees above average. With barely a flinch, the lake-effect snow machine has basically been shut down eeking out a robust 0.1".

In addition to a top ten wettest years on record, Louisville will be flirting with at least top ten warmest Decembers and a shot at a top ten warmest year on record. Oh forgot to mention, but Louisville will possibly break more local daily records as well before the month is over.

MS

Tuesday, December 15, 2015

Projection Time: Louisville's Winter Temperatures

Ok. Try and follow me here. The logic and numbers may seem distorted, so you might need a pencil and paper to help. Remember, though, these are just projections, not anything set in stone.

My winter outlook simply says that Louisville and surrounding region would be milder than the previous two winters.

In Louisville, the last two winters of December through February averaged at least 3 degrees below normal. Right now, or as of December 14, Louisville is averaging over 10 degrees above normal.

Today and tomorrow we should see readings at least 10 degrees above normal. Even though below normal temperatures are expected for 2 or 3 days later this week, we're only talking about 3-4, 5 degrees maximum of below normal values. Then, we go right back up from there, averaging more than 5 degrees above normal for a stretch of a few days.

As you can see, I am highlighting more higher 'above normal' readings than 'below normal' readings. In other words, we don't have 10 degrees above normal one day and 10 degrees below normal the next day. But, we might have days of 10 and 12 degrees above normal versus a couple of days of 4 or 5 degrees below normal. The 10 and 12 quite simply overwhelm the 4 or 5  so that the average remains above normal.

Now, for the sake of argument, let's assume that after today and tomorrow with double-digit temperatures above normal, the rest of the month, every day, the high temperature and low temperature met its normal value. What would be the result?

December would still finish 5-6 degrees above normal, not too far from top ten warmest Decembers on record status.

That means January and February would need to average about 8 degrees below normal per month for my outlook to be wrong.

I guess it could still happen, but I am already expecting a concession speech from Old Man Winter already.

MS

Monday, December 14, 2015

MikJournal Monday 12/14/15

Well, we're just about to the halfway point of the month. Wow. What a month! I really like this warmer than usual air. Don't get me wrong, because I'm a snow lover. But, I also enjoy outdoor activities while basking in a measure of the comfort of spring. Bonus weather, right? Don't fret, winter's coming, right?

Ok, yes it is finally looking like we will see some December weather by the end of the week...briefly.

My winter overview and December Prediction highlighted the balmy weather mixed with a cold shot here and there, though not of Arctic origin.

Looking forward to the rest of the month, I am still expecting average to above average temperature readings just like I said late last month.

But, I also mentioned severe weather chances for the end of the year. The jury is still out on that one, but with above average temperatures, a colder air mass is bound to collide with that one, possibly causing some stormy issues.

I have been harping on teleconnections for a while. The AO, NAO, and EPO need to be negative for true lasting cold air to take place. Currently, there are no signals yet showing this alignment.

In addition, the current CPC 8-14 day outlook has the entire U.S. in a higher probability for above average temperatures, again.
This takes us through the 27th.

As far as wintry weather worth talking about, honestly I don't foresee any serious contender until either side closest to the 2nd week of January...I guess around the 7th -12th. But, that's for another post. My January Prediction comes out later this month.

MS

Saturday, December 12, 2015

Rare Cooling Degree Days in December

Cooling Degree Days? Perhaps you have heard of it. Heating Degree Days and Cooling Degree Days are useful in helping to determine energy demands along with other factors when moving to another location.

It is based on a standard numerical value of 65 degrees. A high temperature and low temperature are added together and divided by two for the day's average temperature. If the average temperature is < 65, then a heating degree day is computed based on the difference between the standard and the actual average.

For example, if the day's high temperature is 60 and the day's low temperature is 40, then the average is 50 (60 + 40 = 100; divide by 2 = 50). Since the average temperature of 50 is less than 65, heating degree days are applied, in this case, 15 Heating Degree Days.

But, in Louisville, the day's high temperature was 73 degrees. Let's assume that the low temperature for today will be 65 degrees, since today has not officially ended until midnight. It was actually 66 early this morning but may push slightly lower just before midnight soon.

If we add 73 and 65, this equals 138; divide by 2 and we get a 69 degree average. Since the average value is higher than 65, cooling degree days are applied, in this case, 4 Cooling Degree Days.

It is very rare to obtain an average temperature of greater than 65 degrees in Kentucky during the month of December. Louisville typically averages 1 Cooling Degree Day for the month. But most years, we simply record zero.

The last December we recorded Cooling Degree Days was in 2012, also 4 CDD's. Since 2000, including the year 2012, during the past 15 years, we in Louisville have recorded a total of 5 CDD's, not counting any CDD's that will be computed by tomorrow morning.

Sunday, it is possible we may record a very rare second consecutive day of Cooling Degree Days for the month of December.

The record for CDD's in Louisville for December is 8, set in 1982, yes another El Nino year. Two consecutive days of average temperatures greater than 65 degrees were achieved.

I do not know if Louisville will be able to tie or break the mark set in 1982, but it will be close.

Another record that may be in jeopardy is the all-time high temperature for December here in Louisville, which is 76. It would be quite coincidental if Louisville should tie the all-time high temperature and the all-time Cooling Degree Days records on the same day in December.

MS

Wednesday, December 9, 2015

Winter is Coming...Sure It Is, Uh Huh

We keep hearing about cold air poised to invade our region of Kentucky soon. While the coldest air continues to dance to our north and expected to penetrate into the western part of the U.S., it sure appears likely that it will overtake us very soon.

Then, just when it seems like this is the cold front to do it, forecast temperatures are now expected not to be that cold, yes cooler than the 15-25 degrees above average we'll be experiencing this week, but not THE cold front to usher in wintertime cold.

What's going on? I have not read or heard too many meteorologists out there talk about the Arctic Oscillation lately, a familiar teleconnection that gave name recognition to the overhyped Polar Vortex from a couple of years ago.

Instead I read about EPO's, which by itself cannot guarantee the cold air we need. It needs to be used in conjunction with PNA and AO and the closely related NAO.

Once these teleconnections align themselves, then we can start talking about cold air. Right now, as one should surmise by now, these teleconnections are not quite aligned yet.

This is the time of year I turn my attention to the Arctic Oscillation index. Because the stormy low pressure area has been centered over the Arctic region somewhat persistently as of late, a rather mild stretch of weather has occurred here while the Arctic cold has been confined to its home base.

But signals are beginning to show a possible flip in that pattern. At the very least, the Arctic region will begin to see higher heights in terms of the average geostrophic 500mb reading. Think of it as high pressure in the Arctic. But a troughy pattern will begin to ensue for the middle latitudes where we are.

Therefore, the strong, stormy winds that were keeping the coldest air locked up in the Arctic will ease thereby allowing chunks of cold air to sink south. Then when the troughy conditions in the middle latitudes come to be, the interaction will help transport more of the real cold stuff toward the northern US.

In addition, a familiar pattern we have seen before will happen again. The Greenland Block is expected to develop and strengthen by the end of the year. This will make cold air transport even easier.

The ideal teleconnection combination involving the EPO, AO, and NAO would be -EPO, -AO, -NAO if you like really cold air here.

Nevertheless, I strongly caution that this is a strong El Nino winter. It is possible that such blocks will not be able to be sustained over a prolonged period of time. I am still expecting much variability in our winter weather.

MS

* The term geopotential should have been used instead of geostrophic.
(12/13/15 - MS)


Monday, December 7, 2015

...Where Two Oceans Meet???

Have you ever seen the picture below?





It's a picture taken in the Gulf of Alaska. The picture is said to represent where two bodies of water merge but not actually mix.

Actually, the lighter-shade of blue represents glacial sediment containing iron that is flowing from one of Alaska's rivers into the Gulf of Alaska. While the snapshot seems to depict a boundary or demarcation separating the two, they eventually do mix and the sediment line is not stationary.

There are actually several of these 'where two oceans meet' phenomena. Here is another...


Confluence-of-the-Jialing-and-Yangtze-Rivers-in-Chongqing,-China

In this case above, we call this a confluence of two rivers. Also, the confluence of the Ohio and Mississippi rivers results in a similar phenomenon...


Confluence of Ohio and Mississippi Rivers at Cairo, IL
taken from Earth Observatory

MS

MikJournal Monday 12/07/15

Good morning. The first week of December is coming to an end. Our region has experienced 1-2 degrees above average temperatures and near average precipitation.

The rest of this week features a warmer than average scenario resembling late October or early November readings. That translates to temperatures running at least 10-15 degrees above average!

However, by the end of the week, signs of change will already be looming. A shock to the senses with a heavy dose of meteorological reality is expected to overcome this sweet pattern.

The gatekeeper of the Arctic, the Arctic Oscillation teleconnection, is expected to trend toward neutral and slightly negative after a tremendous run of positive readings. What does that mean for us?

Well, recently, some in our region dealt with low temperatures in the teens. This was modified Arctic air, since the AO was still neutral to slightly positive during that time. In addition, some saw their first snowflakes of the season.

With a neutral to slightly negative AO, a taste of true Arctic air will make a run at the United States. How far south that air mass can make it remains to be seen.

At the very least, temperatures returning to the 30's for highs may be possible. But, I think the coldest air will not quite reach us yet. Ahead of a another storm system, temperatures should recover enough to preclude any significant snowfall for most of us. But, I am still hoping that additional data may help enhance our chances while the air could still be cold enough to support snow. Hopefully no ice.

According to my prediction for the rest of the month as noted in my December Prediction, near average to above average temperatures is still expected. But, as more data comes in this week, the AO index could help me fine tune this outlook.

A popular study has linked an above average Eurasian October snowfall will lead to a decisively negative AO winter, which means more shots of cold air for us and the Eastern United States.

Interpreting the study along with their current data, the second half of December would be below average in terms of temperatures.

But the models, at least some, are not in agreement with this happening in December, perhaps because of El Nino's influence.

Right now, I am in that boat. But, if I'm wrong, someone throw me a line and pull me into the other boat please.

MS

MikJournal Monday 09/18/2017...Remembering Hurricane Hugo and Maria Looming

Welcome to another installment of MikJournal Monday. It looks like a pretty quiet week in terms of weather. Yes, there will be a few showers...