Bring out the Guillotines

There has been a lot of chatter about the "blown" forecast for snow the day after Christmas.  Unfortunately, it was not a blown forecast.  The feast or famine scenario was realized (described in my last post), and we experienced famine.  An image of snow totals in the area can be found below.

It's important to note the STEEP drop of snowfall totals away from the area sometimes referred to as the deformation zone.  The deformation zone is the area of diverging winds, cold air, and abundant moisture on the northwest side of a low pressure system where heavy wet snow occurs.  25 miles separated areas from 0 to 8in of snow.  That's an incredible snowfall drop-off.  The snowfall totals were diminished in the Effingham area by a slight shift of the storm system to the southeast.  You can observe the overall picture of snowfall totals below. 

Who's to blame?

Before you lynch your local meteorologist, consider the steep snowfall drop-off.  What about the opposite scenario?  What if we had received 6-10in of snow and the meteorologist forecasted a dusting or no snow?  He'd be wrong again right? Yeah, but in that circumstance people's lives would be at stake as city crews and schools would be unprepared.  So, a meteorologist will always side with caution to protect you and at times, save your life. 

The Sky Started it

When I awoke to no snowfall accumulation at 6am on Wednesday morning. I didn't curse my local meteorologist.  I cursed the sky. The one who's to blame. Weather is highly variable and rapidly changing, if you choose not to believe that, you're going to hate a lot of meteorologists in your lifetime. The meteorologist nailed this forecast. Minor details of a particular storm cannot be predicted with accuracy.  The public needs to understand the variability of weather and the fact that the tools do not exist to predict the future with 100% accuracy.  Weather is a game of probabilities, and sometimes you lose.

Feast or Famine

What is perhaps the greatest uncertainty when forecasting snow in Southern Illinois is the temperature.  Will the temperature fall low enough to snow? Well, for once, the concern is not will it snow, but how much it will snow. It has been a rather long time since portions of Southern Illinois have seen a winter storm forecasted of this magnitude.  In fact, the National Weather Service in Paducah, KY has issued a rather rare Blizzard Watch for areas south of I-64 (featured in lime-green). 

Winds are expected to be quite tame compared to what the area experienced last week (gusts reached 53+ mph as Blizzard conditions occurred from Springfield to northwest Illinois and Iowa).  Winds are expected to be from the north in the 25-30mph range and shift northwest as the area of low pressure passes to the southeast.  While, the winds will not be as fierce as last week, the winds are still strong enough to cause white-out conditions while traveling.

Deformation Zone

Perhaps what is of more interest are snowfall amounts.  It's what I often refer to as a feast or famine scenario. Areas located just northwest of the area of low pressure will experience snowfall totals not seen in a decade or more for portions of Southern Illinois.  However, this is a small area often referred to as the deformation zone.  Where gulf moisture, cold air, and diverging winds create incredible snowfall rates.


A small shift in the track of the winter storm can move the area of heaviest snowfall northwest or farther southeast.  Essentially, a small shift can drastically change the snowfall amounts seen in the Effingham area.  Recent forecast model runs show a southeast trend, which is bad news for snowfall totals in Effingham and areas northwest of Effingham.  However, we WILL see snow.  How much is the only factor at stake.

Snowfall Amounts

From this graphic, it's easy to see how a shift to the southeast can drastically hinder snowfall totals northwest of the area of low pressure.  As Springfield is only expected to receive half an inch.  If the trend continues, the snowfall rates in the Effingham area may be diminished. The National Weather Service in Lincoln, Illinois is still predicting rather modest snowfall rates for portions of southeast Illinois.  Including 5-6 inches for the Effingham area. 

Timing

Timing of the storm is always a variable.  However, it appears snow will begin to fall in our area around the 9pm mark and tapper off around 10am to noon on Wednesday.

Travel

Travel? Are you nuts?  Spend the late, white christmas with those who mean the most to you.  Take your favorite board game out of the cupboard, and force your family members to play it with you.  Even though you mop the floor with them on a yearly basis and laugh in their faces.  More importantly, don't forget the hot chocolate.  Merry Christmas Everyone.