Remembering January/February 1994: Winter’s TKO

If you’ve watched our weathercasts over the past several days, you’ve probably heard 1994 mentioned a time or two.  Monday featured some of the coldest daytime readings South-Central KY has experienced since then.  It’s been frigid, no doubt, but readings from the past two days don’t even hold a candle to the kind of temperatures and wind chills this state dealt with 20 years ago!  Not to mention, the kind of snow and ice that preceded that cold.  And that event was followed by another crippling ice storm just a few weeks later in February.  Some of you may have better recollections of the second one, and for good reason.  Back to that in a moment.

The night of January 16, 1994 was one of those times when all the right ingredients for a major winter storm came together for the lower Ohio Valley.  Arctic cold was already in place.  Bowling Green woke up to a reading of -1, which is the last time we had subzero with no snow on the ground.  The temperature climbed into the upper 20s late that afternoon and evening as clouds rapidly increased.  Winter Storm Warnings had been hoisted for the entire region. By nightfall, a messy mix of freezing rain and sleet had developed across Western KY, spreading eastward as the evening wore on. With the ground already very cold, roads quickly became icy and treacherous.  To the north along the Ohio River, the mix changed to a very heavy snow in Paducah, Owensboro, and Louisville. “Thunder” snow was reported in some spots, with snowfall rates near 3″ per hour at the height of the event! 

The change from a mix to snow worked southeastward through the night, reaching Bowling Green before daybreak on January 17th.  While the city didn’t get in on the really huge snow totals seen over the northern half of the state, about a half a foot of snow fell on top of a 1/2-1″ of ice in the city before the snow moved out early that afternoon.  The heavy snow/ice accumulations weighed down trees and power lines, causing electricity to go out for thousands.  As temperatures tumbled from an early morning high in the lower 30s down into the teens by evening, all travel came to a halt!  In fact, then Governor Bererton Jones declared a State of Emergency for the entire Commonwealth.  All interstates and parkways were shut down so they could be cleared.  But clearing the ice and snow was easier said then done.

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Things went from just plain cold on the 17th to INCREDIBLY cold on the 18th and 19th!  The core of a frigid arctic air mass settled into the region on the 18th.  Daytime temperatures hovered near 0 in Bowling Green, with wind chills near -20.  As skies cleared and winds relaxed on the morning of the 19th, record low after record low went by the wayside.  Most reporting stations across South-Central KY dropped into the teens below 0, some even into the -20s! 

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With readings so cold, salt was rendered useless on Kentucky roads for several days after the early week winter storm.  This kept a lot of roads impassible, especially rural routes.  Some places were only reachable by helicopter.  And that wasn’t the only problem the cold caused.  Natural gas explosions took out several homes near downtown Bowling Green during the height of this arctic outbreak.  The extreme cold made putting out the large fires that ensued very difficult for firefighters.

By Thursday the 20th, a slow warmup and gradual improvements were underway.  At least one lane of I-65 and the Natcher Parkway were opened, with both thoroughfares reopen by Friday as the State of Emergency was finally lifted.

Old Man Winter’s one-two punch had come and gone. The next few weeks saw generally milder weather for Kentucky.  Then came the “TKO”: February 1994.

Few could have believed a paralyzing ice storm was just hours away from developing on Tuesday, Feb. 8th. The high that day reached a near record warm 72 degrees!  A sharp cold front came through that night, bringing thunderstorms along with falling temperatures.  By 6:00 the next morning, the mercury had fallen to 32, with rain changing to freezing rain then to snow as readings continued to fall into the 20s.  Travel became hazardous on the afternoon and evening of the 9th. 

Snow and ice stopped falling for awhile on the night of the 9th into the morning of the 10th…perhaps leading some to believe the worst was over.  That was far from the case.  A renewed round of moisture moved in from out of Arkansas and West Tennessee that afternoon.  The air aloft had warmed while surface temperatures were still in the mid 20s.  This was a recipe for trouble.  Rain began falling in Bowling Green around mid-afternoon, freezing on contact.  That rain continued all the way into the afternoon of the 11th before it finally tapered off to drizzle and ended that night.  But the damage had been done.

Bowling Green’s total for precipitation at the airport for the 10th & 11th: 1.61″, ALL of that coming as freezing rain!!  Up to 2″ of ice was reported in nearby Barren and Allen Cos, with up to 3″ of ice to the east in London.  Just as we’d seen a few weeks prior, most South-Central KY counties were back under States of Emergency.  Power substations froze, and at one point nearly 200,000 people in the state had lost electricity. Utility lines and trees were draped across roadways with travel virtually impossible during and immediately after the event.  For some homes and businesses, power was out as much as two weeks after the event.  Below is a shot from Cave City taken 2/11/94:

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That, my friends, was the TKO. January and February 1994 truly were a couple of ROUGH months for winter weather in South-Central KY…the kind we have not seen the likes of since!

Update on Sunday Snow and Bitter Cold That Follows

First of all, for anyone hoping for a BIG snow in South-Central KY, it looks like any shot for that is out the window.  Morning computer model runs have been trending warmer tomorrow. This is due to a more northwesterly track depicted by the low pressure system responsible for the rain and snow chances.  If you’re a lover of snow, a track right over Bowling Green – much less one to the west – is not what you want to see.  To get a really good snow here, you would want to see a track to the south over the Tennessee Valley. Such a track does not appear likely now.

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With most guidance trending this way, it now appears our precipitation will fall mainly as rain before a changeover to *some* snow late tomorrow afternoon.  With the snow’s duration looking shorter now, it’s looking like 1-2″ totals will be more common than the 2-4″ we were thinking yesterday, and 2″ may be a stretch. Models often fluctuate with the ultimate track of storm systems, and that’s a BIG reason why we always stress things can and often DO change with regard to projected snowfall amounts from winter storms.  

This is NOT to say we will not have any issues with hazardous travel tomorrow evening.  I fully expect we will.  Much of those issues could come from “flash freezing” of water/slush on the roadways as temperatures quickly dive into the 20s and teens tomorrow night. Gusty winds could blow around any snow that accumulates.  Icing in roads won’t go away easily since temperatures are forecast to dive into the single numbers late Sunday night.  When it gets that cold, salt is of little use.  Glazed roads are likely to persist through Monday, as well.  And speaking of the cold…

Sunday night and Monday continue to look AWFULLY frigid for us!  We’ll likely wake up to readings around 0 Monday morning with daytime readings only in the single digits.  Combine that with gusty NW winds 20-30 mph and you get wind chills that will bottom out in the -15 to -25 range!  We could see Wind Chill Advisories issued at some point late tomorrow into Monday. Be prepared!

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That deep trough has BITTER cold written all over it!

The National Weather Service will hold a conference call soon.  We’ll keep you updated as to their thoughts, and Stephanie Midgett will have the very latest on snow amounts and how cold temps and wind chills will get tonight on WBKO @ 10!

 

 

Still Dreaming of a White Christmas??

Well, if you are…as they say in New York City:  “Fahgettaboudit”!  (translation: forget about it).  Allow me to explain why.

On my last post here, I mentioned that models were honing in on a major storm system affecting the Ohio Valley the weekend leading up to Christmas.  That much is still on the table, though it will be a rain and thunderstorm producer for us Friday through Sunday.  There’s even potential for minor flooding and strong storms to go with it.

Once that system sweeps out of here Sunday night, a cooler but quiet weather pattern takes shape through Christmas Day.  It’s worth noting the models have really backed off what once looked like brutally cold air plunging into Kentucky next week.  The newest runs keep the coldest of arctic air confined to Canada, the Northern Plains, and the Upper Midwest.  It still appears chilly, but it now appears likely our temperatures will moderate on Christmas after a quick cold shot Monday into Tuesday (Christmas Eve).

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Even with colder air present Monday and Tuesday, it takes moisture to create snow, and that won’t be present in our area, either.  High pressure is expected to move over our region during that time.  Here’s one model’s take on forecast snow depth through Christmas Eve.  While this could change a bit, notice how far northwest of the Blue Grass state one has to travel before finding at least 1″ of snow on the ground.

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So as far as our chances for seeing a White Christmas in South-Central KY, it’s 4th and long, and the punting unit is coming out on the field.  Maybe next year.

Shane

Is the “Dream” Alive?

“…where the treetops glisten, and children listen…to hear sleigh bells in the snow…”

So here we are, just two weeks away from Christmas Day.  It’s that time some of you may start wondering, “is there ANY shot for a White Christmas in South-Central KY this year?”  History tells us that chance is very small, but we can never say never!

In order for a Christmas to be “white”, a couple of pieces of criteria must be met:  1.) At least 1″ of snow observed on the ground on Christmas morning, or 2.)  At least 1″ of new snow falling on Christmas Day.  Sounds simple, but if you’ve lived here long enough, you know meeting that criteria is easier said than done.

Here’s a list of “official” White Christmases for Bowling Green dating back to the 1800s (data courtesy of Louisville’s National Weather Service):

1880:  4″*

1899: 1.2″

1909: 4″

1912: 2″*

1914: 3″*

1935: 4.5″

1962: 2″*

1963: 6″* (most snow observed in BG on Christmas)

1966: 3″*

1969: 3.4″

1989: 1″*

1992: 3.5″

1993: 1″

2010: 1.1″ (4″ on ground)

*observed snow depth

When you count them up, you find that an “official” White Christmas has only happened 14 times in the last 134 years for Bowling Green.  Not very good odds for “snow birds”, that’s for sure.  BUT…I think it’s worth noting that when we do see White Christmases here, they tend to come in “bunches”.  Note there were three between 1909-1914, four in the 1960s, and three between 1989-1993.  Our most recent, and it was a quite memorable, happened just three years ago.  That’s when nearly 4″ of the white stuff fell on Bowling Green on Christmas Eve with an additional inch falling from snow showers on Christmas Day.

Speaking of the odds, here they are for the nation as a whole based on climatology (courtesy of NOAA): 

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 For a sure bet of seeing 1″ of snow on the ground on Christmas Day, one usually has to go north – sometimes WAY up north – to see a mantle of white covering the ground.  Every year is different, though. 

So what about this year?  Well, it’s still far too soon to say with great confidence whether or not Bowling Green will experience a White Christmas.  But the long range models do offer some clues as to what may transpire between now and the 25th. 

Of course, this is NOT a forecast and the details are fuzzy this far in advance, but a couple of models are converging on a strong storm system affecting the Ohio/Tennessee Valley region toward the end of the next week (around the 20th/21st). 

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This could be a heavy rain or even thunderstorm producer for us before a blast of VERY cold air arrives in its wake late next weekend and early the following week (22nd and after).  Below is one model’s projection for temperatures relative to averages for Christmas week.

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It looks mighty chilly for much of the country!

If that cold air verifies, the question turns to moisture and the availability of it.  Does the system potentially affecting us on the 20th-22nd deliver a shot of at least some snow as it departs?  Or will there be another weathermaker in its wake closer to Christmas itself?  It is simply too soon to answer those questions right now.  But the moral of the story…our chance for a White Christmas is NOT at zero yet!

Shane

Shane’s 2013-2014 Winter Weather Outlook for South-Central KY

             Leaves are falling, the days are getting shorter, and the nights are getting colder.  Yes indeed, winter is just around the corner.  With that in mind, it is time for me to make my annual stab at a forecast for the upcoming season.  I know winter has been on the minds of many even since late summer.  That’s understandable, especially since our summer was a wet and relatively cool one.  I’ve had MANY a person ask me, “Does this cool summer mean we’re going to have a harsh winter?”  My answer to that: “Not necessarily”.  While it’s true the winter that followed our last really cool summer (2009) was quite cold and snowy, the winter that followed 2004 (another cool summer) was quite mild, especially after Christmas.  I think mid-autumn patterns (October/early November) have more bearing on how the upcoming winter plays out.  That’s a big reason why I never bite on these forecasts until November.

              I should remind everyone there is SO MUCH to consider when comprising these forecasts.  Having them verify when all is said and done is even more difficult.  In fact, that part is out of my hands completely!  One thing that makes the challenge enormous is that no two winters in South-Central KY are exactly the same.  Remember, it was just a few years back when Bowling  Green experienced back-to-back double digit snowfall seasons (2009-’10: 15” and 2010-’11: 21”).  On the other hand, the last two seasons have been duds for “snow hounds”.  The average annual snowfall for BG is 9” (based on 1981-2010 data). 

              I think it’s also important to keep average monthly temperatures in perspective.  January is typically our coldest month, with an average temp of 35.7° (that’s all the highs/lows combined).  It’s closely followed by December (38.6°) and February (39.8°).  Although the onset of Spring falls in March, not to mention the month is excluded from what is known as “meteorological winter”, it can be chilly (March 2013 was!), with 48.4° being the month’s average reading.

              Now, let’s discuss the factors or atmospheric “players” that I took in consideration for this forecast.  The language gets a little “weatherese”, so bear with me.

1   *El Nino-Southern Oscillation (ENSO):  In a nutshell, this refers to the warming or cooling of the Pacific Ocean waters just north of the equator.  If abnormal cooling is taking place, then we have “La Nina”.  If warming is happening, it’s “El Nino”.  So what about this year?  Well, it appears neither condition is likely to be present since water temperatures in the Central Pacific are forecast to remain close to normal.  That’s what we call an “ENSO Neutral” condition.  There’s some suggestion we could see a weak El Nino try to develop late this winter.  That could throw a monkey wrench in my outlook down the road.  For now, though, I am of the belief that ENSO will NOT be a big player this season.                            

* NAO/AO (North Atlantic Oscillation/Arctic Oscillation):   These two are the wild cards, especially the NAO.  The North Atlantic Oscillation refers to a blocking pattern that exists in the North Atlantic Ocean.  A “positive” NAO happens when an upper low situates itself between Greenland and Iceland while a strong upper high is parked near the Azores off the coast of Spain and Portugal.  When that low in the North Atlantic breaks down and higher pressure builds there, blocking of the polar jet stream can occur (aka a “negative” NAO). This can send the jet plunging deep into the eastern United States, bringing colder air our way.  This is especially true if the AO works in tandem with it.  Basically, a “positive” AO means pressures over the Arctic Circle are low, which tends to cause cold air to sit and “well up” near the North Pole.  A “negative” AO, on the other hand, means pressures are rising in the arctic, often forcing cold air southward. 

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         In the last several winters, these AO and NAO have arguably been the biggest players in terms of the overall pattern.  But trying to predict how these two will interact and behave over the course of a three month period is darn-near impossible!  That’s because there is very little skill when it comes to computer model projections with these indices beyond two weeks out.  These are highly variable pressure patterns, unlike El Nino or La Nina, which are driven by sea surface temperatures that change more slowly with time.  My gut feeling is that we probably won’t see a blocking pattern establish itself over the North Atlantic for too long a period this winter, which leads me to believe this could be a “see-saw season” for us.

3.  *Pacific-North American Pattern (PNA):  The PNA deals with the relationship between the circulation pattern over the northern Pacific Ocean and the existing pattern over North America. A “positive” phase of the PNA results when high pressure sits close to Hawaii and over the western part of the lower 48, while low pressure resides just south of Alaska and over the southeastern part of the lower 48.  When combined with a negative NAO/AO, it can make for very chilly temperatures in the Blue Grass state, sometimes setting us up for big snows IF an active subtropical jet is present.

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4.  *Snow Cover/Arctic Sea Ice:  Not much has been said about it, but there’s actually been an uptick in the amount of real estate near the North Pole covered by sea ice vs. this time last year.  In theory, cold begets cold, and the more ice there is over the arctic, the more cold air can develop and sustain itself.  It remains to be seen whether or not this increase in sea ice can extend for another couple of years or if the overall decline in it over the long haul continues.  I do think it has some bearing on how cold our temperatures get when arctic outbreaks occur, though.  

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 5.   *Other Factors (Sunspots, AMO):  It’s worth noting the increasing sunspot activity over the past three years.  Exactly what impacts these sunspots have on Earth’s overall global temperature is very much up for debate.  It is interesting, though, that some of our coldest, snowiest winters coincide with downticks in solar activity (i.e. 1917-1918 and the late 1970s). 

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            On a different yet somewhat related subject, the AMO (Atlantic Multidecadal Oscillation), MAY be one reason – along with sunspot cycles – so many recent winters have been fairly mild.  The AMO deals with sea surface temperature trends over the North Atlantic Ocean.  The chart below shows how these temperatures have fluctuated over the past 150 years or so.  Note the areas in blue (1900-1920s with another in the late 1960s-early 1980s).  These coincide with some of the most brutal winters Kentucky has ever seen.  Right now, however, we are in a “warm” cycle of the AMO.  But the AMO has trended a bit cooler since the mid 2000s. 

Will this trend continue?  I don’t think anyone has a definitive answer to that question.  Some believe the AMO could go into a “cold” cycle within the next decade or so.  Should that happen, it may increase the chances for us to experience more of the kind of harsh winters we had back in the 1960s and ‘70s. 

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ANALOG YEARS:  Listed below are winters that had atmospheric patterns and ENSO conditions closest to those expected for this season.  These are what we call “analog years”.  Total snowfall amounts for those seasons are listed in parentheses.

1980-’81 (9”)

1989-’90 (7”)

2001-’02 (3”)

2003-’04 (5”)

Month-to-Month Outlook

              If you’ve reached this far without your head spinning too much, kudos to you!  Now that I have discussed the “players” I took into account when making this forecast, let’s dive into the forecast itself.  I will focus on the three months that make up “meteorological winter” (December, January, and February), though I would not be surprised if measurable snow takes place in March once again, as it did this past season.

              First, allow me to get the obligatory annual disclaimer out of the way:  This is NOT an official First Alert Storm Team forecast!!  It is simply my take on how I think the season plays out.

DECEMBER:  This is a month that could prove to be a microcosm for how the rest of winter shakes out.  There’s a lot of indication in the long range models that November could end very cold with the chill lingering into the first week to ten days of December.  We’ve been spoiled with mild days on our first rounds of Christmas parades these past couple of years.  It could be a different story this time, though.  It does not appear as if the cold will persist through the entire month, though.  There are indications that a large ridge of high pressure may anchor itself over the Southeast during the month.  If so, a flip to a milder pattern will take place, one that could hold even through Christmas.  Our last White Christmas was in 2010.  Since history tells us White Christmases seem to come closely together for Bowling Green, the chance at seeing one can’t be ruled completely out.  But with the way I see the month unfolding, the late Bing Crosby would probably cry rather than croon.  Maybe more of a Jimmy Buffett “Christmas in the Carribean” (you may have known I would go there).

Forecast average temperature:  (39°-41°, one to three degrees above normal)

Forecast precip:  Slightly below normal

Forecast snowfall: Trace to ½” (Below normal)

JANUARY:  In most years, this month is the coldest of the bunch.  This one could start fairly mild, however, especially if the Southeast high pressure ridge holds its own.  There is some indication that much colder air could return by the second half of the month.  This could make for a volatile setup at some point.  Kentucky will often be right in the battle zone between frigid air just north and warm, moist air to the south.  We had to deal with severe weather during the early morning of January 30th last season, and it would not surprise me if a similar scenario unfolds again this January (always be prepared!).  If you’re a fan of the white stuff, some patience may be in order.  I don’t think we’ll be shut out completely in the snowfall department in January, but our best chances at a decent snowfall may wait until later in the season.

Forecast temperature: (35°-37°, near to slightly above normal)

Forecast precip: Near normal

Forecast snowfall: 1-2” (below normal)

FEBRUARY:  I believe it’s here where winter may finally show its hand.  If the Southeast ridge breaks down and more blocking develops over the North Atlantic, then there could be more opportunity for colder air to dive southward into Kentucky.  Also, IF a very weak El Nino tries to get going toward season’s end, it could result in a slightly more active subtropical jet.  This increases the chances for a wetter pattern, and if colder air is present, some snow.  One word of caution:  ENSO Neutral winters are infamous for ice storms in South-Central KY.  Remember the short-lived but nasty one we had in late January?  I think it’s highly likely we could see another significant icing episode this season.

Forecast temperature:  (36°-38°, one to three degrees below normal)

Forecast precip:  Slightly Above normal

Forecast snowfall:  5-7” (above normal)

OTHER NOTES/PREDICTIONS:

Chances for seeing at least one or two significant severe weather outbreaks and/or flooding events:  60% with best chance coming during the first half of winter

Chances for seeing at least one icing event of a quarter inch or more:  40%

Chances for seeing a 4” snowfall from one system: 40%

Chances for seeing a 6” snowfall from one system: 10%

Total snowfall for the season: 7-10” (near to slightly below normal)

Chances for seeing a White Christmas: (historically 10%, this year, I give it 5%)

Coldest temperature:  Between 5° and 10°, most likely in February

So there you have it.  I think in the end, Winter 2013-2014 does not go down as ranking among our coldest or snowiest of all-time, but I do like our chances of seeing at least a little more snow than in the past two seasons.  I think most of the wintry weather comes from two or three systems, with many bringing just plain old rain or a mixed bag of precip quickly changing to rain.  There’s a CHANCE for one really decent snowfall (the kind that brings us at least 4”).  Otherwise, look for a “see-saw season” with no real dominant pattern.  It would not shock me if we hit 70° and 7° within the same week; that’s the kind of season I think it will be.  I hope you’ve had your flu shots and have cold medications stocked up and ready!

Remember, as with any forecast, there is ALWAYS bust potential!  For example, if the Southeast high pressure ridge builds more strongly than anticipated, then winter could wind up warmer with even less snow.  By the same token, if blocking patterns develop and the subtropical jet is active when/if they do, then we could wind up with a little more snow than I think.  I’m just calling it as I see it right now.

Thanks for reading! Let the games begin!

Shane’s 2013-2014 Winter Weather Outlook for South-Central KY

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              Leaves are falling, the days are getting shorter, and the nights are getting colder.  Yes indeed, winter is just around the corner.  With that in mind, it is time for me to make my annual stab at a forecast for the upcoming season.  I know winter has been on the minds of many even since late summer.  That’s understandable, especially since our summer was a wet and relatively cool one.  I’ve had MANY a person ask me, “Does this cool summer mean we’re going to have a harsh winter?”  My answer to that: “Not necessarily”.  While it’s true the winter that followed our last really cool summer (2009) was quite cold and snowy, the winter that followed 2004 (another cool summer) was quite mild, especially after Christmas.  I think mid-autumn patterns (October/early November) have more bearing on how the upcoming winter plays out.  That’s a big reason why I never bite on these forecasts until November.

              I should remind everyone there is SO MUCH to consider when comprising these forecasts.  Having them verify when all is said and done is even more difficult.  In fact, that part is out of my hands completely!  One thing that makes the challenge enormous is that no two winters in South-Central KY are exactly the same.  Remember, it was just a few years back when Bowling  Green experienced back-to-back double digit snowfall seasons (2009-’10: 15” and 2010-’11: 21”).  On the other hand, the last two seasons have been duds for “snow hounds”.  The average annual snowfall for BG is 9” (based on 1981-2010 data). 

              I think it’s also important to keep average monthly temperatures in perspective.  January is typically our coldest month, with an average temp of 35.7° (that’s all the highs/lows combined).  It’s closely followed by December (38.6°) and February (39.8°).  Although the onset of Spring falls in March, not to mention the month is excluded from what is known as “meteorological winter”, it can be chilly (March 2013 was!), with 48.4° being the month’s average reading.

              Now, let’s discuss the factors or atmospheric “players” that I took in consideration for this forecast.  The language gets a little “weatherese”, so bear with me.

1   *El Nino-Southern Oscillation (ENSO):  In a nutshell, this refers to the warming or cooling of the Pacific Ocean waters just north of the equator.  If abnormal cooling is taking place, then we have “La Nina”.  If warming is happening, it’s “El Nino”.  So what about this year?  Well, it appears neither condition is likely to be present since water temperatures in the Central Pacific are forecast to remain close to normal.  That’s what we call an “ENSO Neutral” condition.  There’s some suggestion we could see a weak El Nino try to develop late this winter.  That could throw a monkey wrench in my outlook down the road.  For now, though, I am of the belief that ENSO will NOT be a big player this season.                            

* NAO/AO (North Atlantic Oscillation/Arctic Oscillation):   These two are the wild cards, especially the NAO.  The North Atlantic Oscillation refers to a blocking pattern that exists in the North Atlantic Ocean.  A “positive” NAO happens when an upper low situates itself between Greenland and Iceland while a strong upper high is parked near the Azores off the coast of Spain and Portugal.  When that low in the North Atlantic breaks down and higher pressure builds there, blocking of the polar jet stream can occur (aka a “negative” NAO). This can send the jet plunging deep into the eastern United States, bringing colder air our way.  This is especially true if the AO works in tandem with it.  Basically, a “positive” AO means pressures over the Arctic Circle are low, which tends to cause cold air to sit and “well up” near the North Pole.  A “negative” AO, on the other hand, means pressures are rising in the arctic, often forcing cold air southward. 

Image

 Image           

 

         In the last several winters, these AO and NAO have arguably been the biggest players in terms of the overall pattern.  But trying to predict how these two will interact and behave over the course of a three month period is darn-near impossible!  That’s because there is very little skill when it comes to computer model projections with these indices beyond two weeks out.  These are highly variable pressure patterns, unlike El Nino or La Nina, which are driven by sea surface temperatures that change more slowly with time.  My gut feeling is that we probably won’t see a blocking pattern establish itself over the North Atlantic for too long a period this winter, which leads me to believe this could be a “see-saw season” for us.

3.  *Pacific-North American Pattern (PNA):  The PNA deals with the relationship between the circulation pattern over the northern Pacific Ocean and the existing pattern over North America. A “positive” phase of the PNA results when high pressure sits close to Hawaii and over the western part of the lower 48, while low pressure resides just south of Alaska and over the southeastern part of the lower 48.  When combined with a negative NAO/AO, it can make for very chilly temperatures in the Blue Grass state, sometimes setting us up for big snows IF an active subtropical jet is present.

Image

4.  *Snow Cover/Arctic Sea Ice:  Not much has been said about it, but there’s actually been an uptick in the amount of real estate near the North Pole covered by sea ice vs. this time last year.  In theory, cold begets cold, and the more ice there is over the arctic, the more cold air can develop and sustain itself.  It remains to be seen whether or not this increase in sea ice can extend for another couple of years or if the overall decline in it over the long haul continues.  I do think it has some bearing on how cold our temperatures get when arctic outbreaks occur, though.  

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 5.   *Other Factors (Sunspots, AMO):  It’s worth noting the increasing sunspot activity over the past three years.  Exactly what impacts these sunspots have on Earth’s overall global temperature is very much up for debate.  It is interesting, though, that some of our coldest, snowiest winters coincide with downticks in solar activity (i.e. 1917-1918 and the late 1970s). 

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            On a different yet somewhat related subject, the AMO (Atlantic Multidecadal Oscillation), MAY be one reason – along with sunspot cycles – so many recent winters have been fairly mild.  The AMO deals with sea surface temperature trends over the North Atlantic Ocean.  The chart below shows how these temperatures have fluctuated over the past 150 years or so.  Note the areas in blue (1900-1920s with another in the late 1960s-early 1980s).  These coincide with some of the most brutal winters Kentucky has ever seen.  Right now, however, we are in a “warm” cycle of the AMO.  But the AMO has trended a bit cooler since the mid 2000s. 

Will this trend continue?  I don’t think anyone has a definitive answer to that question.  Some believe the AMO could go into a “cold” cycle within the next decade or so.  Should that happen, it may increase the chances for us to experience more of the kind of harsh winters we had back in the 1960s and ‘70s. 

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ANALOG YEARS:  Listed below are winters that had atmospheric patterns and ENSO conditions closest to those expected for this season.  These are what we call “analog years”.  Total snowfall amounts for those seasons are listed in parentheses.

1980-’81 (9”)

1989-’90 (7”)

2001-’02 (3”)

2003-’04 (5”)

Month-to-Month Outlook

              If you’ve reached this far without your head spinning too much, kudos to you!  Now that I have discussed the “players” I took into account when making this forecast, let’s dive into the forecast itself.  I will focus on the three months that make up “meteorological winter” (December, January, and February), though I would not be surprised if measurable snow takes place in March once again, as it did this past season.

              First, allow me to get the obligatory annual disclaimer out of the way:  This is NOT an official First Alert Storm Team forecast!!  It is simply my take on how I think the season plays out.

DECEMBER:  This is a month that could prove to be a microcosm for how the rest of winter shakes out.  There’s a lot of indication in the long range models that November could end very cold with the chill lingering into the first week to ten days of December.  We’ve been spoiled with mild days on our first rounds of Christmas parades these past couple of years.  It could be a different story this time, though.  It does not appear as if the cold will persist through the entire month, though.  There are indications that a large ridge of high pressure may anchor itself over the Southeast during the month.  If so, a flip to a milder pattern will take place, one that could hold even through Christmas.  Our last White Christmas was in 2010.  Since history tells us White Christmases seem to come closely together for Bowling Green, the chance at seeing one can’t be ruled completely out.  But with the way I see the month unfolding, the late Bing Crosby would probably cry rather than croon.  Maybe more of a Jimmy Buffett “Christmas in the Carribean” (you may have known I would go there).

Forecast average temperature:  (39°-41°, one to three degrees above normal)

Forecast precip:  Slightly below normal

Forecast snowfall: Trace to ½” (Below normal)

JANUARY:  In most years, this month is the coldest of the bunch.  This one could start fairly mild, however, especially if the Southeast high pressure ridge holds its own.  There is some indication that much colder air could return by the second half of the month.  This could make for a volatile setup at some point.  Kentucky will often be right in the battle zone between frigid air just north and warm, moist air to the south.  We had to deal with severe weather during the early morning of January 30th last season, and it would not surprise me if a similar scenario unfolds again this January (always be prepared!).  If you’re a fan of the white stuff, some patience may be in order.  I don’t think we’ll be shut out completely in the snowfall department in January, but our best chances at a decent snowfall may wait until later in the season.

Forecast temperature: (35°-37°, near to slightly above normal)

Forecast precip: Near normal

Forecast snowfall: 1-2” (below normal)

FEBRUARY:  I believe it’s here where winter may finally show its hand.  If the Southeast ridge breaks down and more blocking develops over the North Atlantic, then there could be more opportunity for colder air to dive southward into Kentucky.  Also, IF a very weak El Nino tries to get going toward season’s end, it could result in a slightly more active subtropical jet.  This increases the chances for a wetter pattern, and if colder air is present, some snow.  One word of caution:  ENSO Neutral winters are infamous for ice storms in South-Central KY.  Remember the short-lived but nasty one we had in late January?  I think it’s highly likely we could see another significant icing episode this season.

Forecast temperature:  (36°-38°, one to three degrees below normal)

Forecast precip:  Slightly Above normal

Forecast snowfall:  5-7” (above normal)

OTHER NOTES/PREDICTIONS:

Chances for seeing at least one or two significant severe weather outbreaks and/or flooding events:  60% with best chance coming during the first half of winter

Chances for seeing at least one icing event of a quarter inch or more:  40%

Chances for seeing a 4” snowfall from one system: 40%

Chances for seeing a 6” snowfall from one system: 10%

Total snowfall for the season: 7-10” (near to slightly below normal)

Chances for seeing a White Christmas: (historically 10%, this year, I give it 5%)

Coldest temperature:  Between 5° and 10°, most likely in February

So there you have it.  I think in the end, Winter 2013-2014 does not go down as ranking among our coldest or snowiest of all-time, but I do like our chances of seeing at least a little more snow than in the past two seasons.  I think most of the wintry weather comes from two or three systems, with many bringing just plain old rain or a mixed bag of precip quickly changing to rain.  There’s a CHANCE for one really decent snowfall (the kind that brings us at least 4”).  Otherwise, look for a “see-saw season” with no real dominant pattern.  It would not shock me if we hit 70° and 7° within the same week; that’s the kind of season I think it will be.  I hope you’ve had your flu shots and have cold medications stocked up and ready!

Remember, as with any forecast, there is ALWAYS bust potential!  For example, if the Southeast high pressure ridge builds more strongly than anticipated, then winter could wind up warmer with even less snow.  By the same token, if blocking patterns develop and the subtropical jet is active when/if they do, then we could wind up with a little more snow than I think.  I’m just calling it as I see it right now.

Thanks for reading! Let the games begin!

Stranger Things Have Happened

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Snow sculpture from March 2008

Legendary sports figure Yogi Berra once said, “It ain’t over til it’s over.”  The same holds true with Winter in South-Central Kentucky.  And sometimes even when it’s over, it’s still not over!  We’ve had measurable snowfall as late as the final day of April in Bowling Green.

I was browsing through some of the biggest/most infamous late season snowfalls in Bowling Green.  Here are a few, some of which you might recall:

March 1, 1980:  5″

March 8, 2008:  5″ (Up to 10″ in parts of the WBKO viewing area)

March 30-31, 1987:  8″

March 22, 1968:  11″

March 13, 1993:  1″ (up to 6″ in eastern sections near Lake Cumberland, this from “SuperStorm ’93″)

March 19-20, 1996:  7″ (up to a foot in some parts of the WBKO viewing area)

April 1, 1996 (less than two weeks after the snowstorm listed above):  1.5″

April 18, 1983:  2.1″

And the granddaddy of all snowstorms for Bowling Green:  23.7″ on March 8-9, 1960!!

Do I think we’ll see a repeat of that blockbuster winter storm our area experienced more than a half century ago?  Probably not.  But as we close out the winter season, we often have more moisture available for storm systems even through the depth of cold air in March or April is typically not all that great.  Of course, accumulating snow has been almost non-existent this winter (shades of last year), and many of us probably lose the mood for seeing flakes fly once the calendar rolls over into the third month of the year.  But don’t be surprised if we see a sneaky kind of system (one that models don’t often latch onto until almost the last minute) give us one more round of the white stuff before we can finally bid Winter farewell.

This could be one of those seasons where a Yogi-ism applies.

Shane