Winter is Not Over Yet!

Posted on: 10:50 am, February 7, 2013, by

If you have not heard by now, there is a tremendous winter storm/blizzard forecast for the Northeast late this week. February blizzards in that part of the country are not unheard of; in fact, two of the benchmark storms in the Northeast in modern history occurred around Valentine’s Day and President’s Day in 1979 and again in 2003.

This is from the NWS Taunton, Mass. (Boston):

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE TAUNTON MA
425 AM EST THU FEB 7 2013

...A POTENTIAL HISTORIC WINTER STORM AND BLIZZARD IS EXPECTED TO
DROP 1 TO 2 FEET OF SNOW ACROSS MUCH OF THE REGION FRIDAY INTO
SATURDAY...

Here’s the chance of heavy snow for the Northeast Friday night:
Screen Shot 2013-02-07 at 10.10.49 AM

So that’s the Northeast. Alabama and Tennessee are enjoying, well, anything but that kind of weather right now! Light rain is possible again early Friday along a cool front, but even as a slightly cooler air mass arrives for Saturday, it will still be pleasant with a high close to 60 degrees.

A heavy, soaking rain event develops over the South (including the Tennessee Valley) on Sunday. Severe weather is unlikely around here, but we could get a real frog-strangler kind of rain at times. Three to five inches of rain are possible, but there may be some locally higher totals near US 278 and I-59 through North and Central Alabama Sunday through Tuesday.

What happens after the rain makes snow-lovers (and haters) sit up and take notice. There are no definite threats of snow or ice in the Tennessee Valley in our near future; however, there are some suspicious looks to the long-range guidance. There is a big cool-down coming for sure; below you see the probability of temperatures staying under 40º F as a “high” for a 6-hour period. Anything above 20-30% is a good enough chance for us to have decent confidence in colder weather. It does not scream “arctic outbreak,” just below-average temperatures. The neutral/slightly negative NAO backs that idea:

Screen Shot 2013-02-07 at 10.05.04 AM

So we have colder weather and an active subtropical jet stream. That can be a recipe for winter weather in the South even in February and March; in fact, February is the second “snowiest” month in the Tennessee Valley. Huntsville averages 0.7″ of snow in February; Muscle Shoals averages 0.9″ this month. We have had some historic ice storms in February, and the greatest multi-day snowfall (5 consecutive days with snowfall) occurred in February 1966 when Red Bay totaled up 8.0″ of snow over a 5-day period.

Could it happen again? Sure. Is it likely to happen again? Probably not, but like I said earlier, there are some suspicious storm systems on the horizon.

Warning: This is pure model guidance and should be treated as such. A forecast beyond 5 to 7 days that tries to be specific on a chance of snow probably going to be dead wrong; this is a look behind the curtain at what we see in long-term trends. Anything specific would be pure speculation at this point!

There are three opportunities for wintry weather in the region this month based on our current guidance. The first comes in on Wednesday behind the heavy rain threat. That one does not have the earmarks of being a “storm;” it looks more like a brief change from rain to a mixture or a few snowflakes. It’s a better chance of all snow in Arkansas and West Tennessee.

The second comes in around the 17th with a strong signature of something wintry over a wide area in the South. If that pans out exactly like the model suggests (very unlikely that it’s 100% accurate), it would mean another blizzard for the Northeast. The third chance is so far out there that the GFS is in flip-flop mode over the position of the system. Here are some of the morning GFS charts for the three possibilities.

Screen Shot 2013-02-07 at 10.40.37 AM

So what do you take from this? First of all, don’t change any plans based on these maps. There is very low confidence that any particular storm will produce significant snow in the Tennessee Valley in our near future. There is enough uncertainty to be watchful and vigilant in keeping track of these suspicious systems, but there is no reason to “expect” a big snow yet.

A specific forecast right now is like a half-court shot in a basketball game; it could go in, but it’s a very low-percentage shot:

-Jason
Connect with me!
Google+: Jason Simpson
Facebook: Jason Simpson’s Fan Page
Twitter: @simpsonwhnt

July-Aug-Milkshake-170x65
Jack’s