Winter 2008-2009 Outlook

An overview of how Shane Holinde sees the upcoming winter season playing out for South-Central Kentucky.

Allright, it is time for me to roll up my sleeves and get down to business on making a call for this upcoming winter season.  I see this season being one that will have a tough time making up its mind in terms of whether or not it wants to "behave" like winter on occasion.  While I don't think it will be as wet or as stormy as last winter (one that gave us three big severe weather outbreaks in what's normally the dead of the season), it should provide us with some active weather that will yield to several shots at significant snow/ice.  Now, just so you don't think I'm flying blindly here, I must tell you there are MANY factors that I took into consideration when drawing up this forecast.  Past history is among the factors (this blog is titled a "History Lesson", after all).  Before I get into my reasoning though, here are just a couple of "FYI's":  1.) This forecast is NOT AN OFFICIAL First Alert Storm Team forecast.  It is simply one man's take (in this case, mine) on the upcoming season, and 2.) I will be focusing on the months that comprise "meteorological winter", which runs from December 1st through February 28th.  Of course, much of our area witnessed a big snow last March on the 8th day of the month, and it's worth noting that Bowling Green's snowiest month of all time was a March (1960).  However, uncertainty grows the farther out one ventures, so for the purposes of this blog, I'm sticking with the next three months. 

THE PLAYERS:

1. El Nino/Southern Oscillation (ENSO):  I know visions of the late Chris Farley on "Saturday Night Live" years ago may already be coming to some minds ("I'm the Big, Bad El Ninooooo!").  But it's true, this is a MAJOR player in North America's winter season.  Basically, the El Nino/Southern Oscillation (ENSO) refers to changes in water temperature along the equatorial waters of the Pacific Ocean, with El Nino conditions resulting from warmer-than-normal waters and La Nina being colder-than-normal.  "Oscillation" refers to the waffling back and forth of these conditions, which generally run on 3-6 year cycles. 

NOAA officials are declaring this season to be an "ENSO Neutral" year, which means neither a solid El Nino or La Nina is present.  However, there remains evidence of a very weak La Nina leftover from last year, as sea surface temps remain a bit colder-than-average across the central Pacific.  This kind of setup may reduce the amount of moisture drawn into the lower atmosphere, one reason why I think this winter will not be quite as wet for Kentucky as last (I'll get to the other reason in a bit).  With a "Neutral ENSO", the jet stream pattern tends to favor one with more shots of cold air coming south from Canada into the eastern U.S.  Some of our coldest arctic outbreaks have occured in "ENSO Neutral" years (Feb. 1951 and Dec. 1989, to name a couple).  I don't forsee too many brutally cold nights for South-Central KY this winter, but given the ENSO conditions in place, I think this season will be a little colder overall than last...POSSIBLY our coldest since Winter 2002-03 (which I know isn't saying a whole lot since recent winters have been relatively mild). 

2. Other Oscillations:  Here's where it gets more technical with all the acronyms, so bear with me!   Besides ENSO, there are several other oscillations/cycles with ocean currents and semi-permanent pressure systems that can have a HUGE bearing on winter weather in the United States.  The PNA (Pacific-North American Oscillation) is one of those.  The PNA is the result of the positioning of upper high pressure off the U.S. West Coast.  Often times if high pressure strengthens off the coast of California & Oregon, the jet stream is forced to ride up and over that ridge (considered a "positive" phase).  This setup can help propel cold, arctic air southward into the eastern U.S., however, several other factors come into that equation.  One is the NAO (North-Atlantic Oscillation), which along with the AO (Arctic Oscillation) is a relationship between upper high pressure in the northern lattitudes and upper low pressure in the lower (warmer) lattitudes.  When the NOA/AO are in a "negative" phase, the result is stronger high pressure in the North Atlantic over Greenland or just west of Iceland, a situation that favors outbreaks of cold, arctic air for Kentucky, especially when the PNA is "positive".  These stars don't align themselves in this manner all that often, not to mention it's very hard to predict what each oscillation will do beyond a few weeks out,  and that's part of what makes winter forecasting so challenging!  Yet another player is the Madden-Julian Oscillation (MJO).  This one refers to the general movements of storm systems in the tropical regions.  A strong MJO often means better potential for a wet season across the lower Ohio Valley and the southern U.S.  If you like snow, then your ideal oscillation setup is a positive PNA, a negative NAO/AO, and a strong MJO.  At this time, though, NOAA's outlook calls for a "weak" MJO, and that's another reason why I believe this winter will not be quite as wet or stormy as last.  We'll see how that goes!

3. Other Factors:  A couple of items that bore less weight but still played a role in the way I see this winter playing out are a.) Volcanic activity, and b.) Sea ice over the Arctic Ocean.  You may not have known of it, but there were a few volcanic eruptions in 2008 which ejected particulate matter into the lower atmosphere.  The most significant was the eruption of Mt. Kasatochi in Alaska back in August.  Something else you may not have known about (and you will likely NOT hear about it from mainstream media) is that arctic sea ice actually increased this year, and studies show the ice cap over the North Pole is now at its largest diameter since 2002!  This produces more of a "refrigeration" effect, as cold air masses feed better off areas with more ice vs. water. 

Now that you know more about my reasoning, let's get to the forecast specifics (note:  all averages are for Bowling Green and represent the period 1971-2000):

DECEMBER:

Based partly on the most recent long range climate models and partly on analog winter seasons (i.e. past seasons with oscillation patterns similar to those forecast for this one), I think this will be the coldest of the three winter months.  You've probably already taken note of the unseasonably cold air we've been dealing with leading up to the new month.  In my studies of past seasons, I recognized at least SOME coorelation between a cold second half of November and a very cold December.  This year certainly has potential to follow suit.  Earlier I mentioned December 1989.  It was a BITTERLY COLD month for the Commonwealth, with temperatures as low as the teens below zero for Bowling Green!   Now, I am not saying this December will be that cold--I don't think it will--but I think we'll see repeated shots of cold, arctic air enter the region during the month.  Something else we saw back in '89:  A White Christmas.  Our last "official" one in BG happened in 1993 (though I argue we had one in 2004 with all that ice on the ground from a major winter storm two days prior).  Could this be the year that streak ends?  Check back with me around mid-December!

December Mean Temp Average(High/Low Temps Combined): 38 degrees.  Forecast Mean Temp for this December: 33 Degrees (5 Below Avg).  Average December Snowfall: 1".  Forecast Snowfall for this December:  3.5" (2.5" Above Avg)

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

JANUARY: 

Historically, this is the coldest of the winter months, but I am going out on a limb to say it will NOT be our coldest this go round.  Why?  Well, there are indications that upper high pressure over the Carribean Sea may spread its influence northward into the southeast U.S. by this time.  This would result in arctic air either being bottled up north of us or shunted westward into the Rockies or Plains.  Incidentally, this is a big reason why last winter was SO mild until almost the very end in late February, when this ridge broke down.  Nevertheless, I think January will be an up and down month for temperatures, with some stretches of 50-60 degree weather (the kind that may make us wonder where winter went) along with some cold air making a comeback on occasion.  With warmer air involved, this month is likely to be a little wetter than December overall, and I wouldn't rule out the possibility of at least ONE "off season" episode with strong or severe thunderstorms.  I think we'll have several instances of winter storms that will offer us more rain than snow, but that's not to say we won't have stabs at significant wintry weather during this month, because I believe we will have at least a few. 

January Mean Temp Average: 34 degrees.  Forecast Mean Temp for this January: 37 degrees (3 Above Average).   Average January Snowfall: 4".  Forecast Snowfall for this January: 2.5" (1" Below Avg)

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

FEBRUARY:

Uncertainty abounds this far out, but I see another roller-coaster month here.  As alluded to earlier, Winter 2007-08 was quite mild until we reached the middle of February.  That's when snow and ice events started showing up with a little more frequency for our area, a pattern that persisted into early March.  Though I don't think we'll have to wait that long for our first measurable snow of the season (it took until the third week of February for us to see that last season), there's potential that we could have another extended late season comeback of cold weather before the season is out.  A similar situation happened in Winter 2005-06.  Coming into February that season, we had only 1.8" of snowfall, but we rallied with over 8" of the white stuff that month thanks to three consecutive weekends with significant snow.  Each season is different, of course, but it's my hunch we could have another late season rally similar to those in the last few seasons. 

February Mean Temp Average: 39 degrees.  Forecast Mean Temp for this February: 41 degrees (2 Above Average).  Average February Snowfall: 4"  Forecast Snowfall for this February: 3.5" (0.5" Below Normal)

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

So there you have it.  To sum it up, look for a cold--potentially VERY COLD--start to this winter season with spells of milder weather as we head into January and February.  I think when it all shakes out at the end of these three months, temperatures and precip will average near normal, and the same goes for snowfall.  It's important to keep in mind that average seasonal snowfall for Bowling Green is 10", a number that has not been exceeded since Winter 2002-03.  While it's not out of the realm we could surpass the average by a hair, I think we'll wind up close to that amount by the end of the season.  Not a record season on tap for snowfall, but enough that I think area "snow birds" will have some moments to crow about! 

Thanks for logging on, and may the games begin!

SH

 

 

 

 

 

 

 

 

 

 

 

 

 

Read More Blogs
WBKO.com is happy to provide a forum for commenting and discussion. Please respect and abide by the house rules:

Keep it clean, keep it civil, keep it truthful, stay on topic, be responsible, no links, share your knowledge, and please suggest removal of comments that violate these standards.

powered by Disqus
WBKO 2727 Russellville Road Bowling Green, KY 42101-3976 Phone: 270-781-1313 After Hours Hotline: 270-781-6397 Fax: 270-781-1814
Copyright © 2002-2014 - Designed by Gray Digital Media - Powered by Clickability
Gray Television, Inc.