Friday, March 14, 2014

A Soaker To Snow?


1:30 PM Friday Update... Yes, some of the models continues to indicate a change over to wet snow Sunday afternoon and evening, especially across northern Arkansas.  Like I have been saying, this is a completely different set up compared to most this winter. I still think the majority of the precip will fall in the form of rain.  This forecast can and still will change.




I have had to say the "S" word and it isn't "spring".  You have to remember, this time of the year can bring some of the wildest weather.  Remember last March?  Heavy snow fell across northern Arkansas during spring break.  Up to 9'' piled up in Fulton county if my memory is correct.  So this is nothing unusual, but I think there's many of you tired of it this winter.

I want to make it crystal clear, the bulk of the precipitation will fall as rain and it could be heavy at times, especially late Saturday.  We should get a break early Sunday, then moisture and cold air will pour back in Sunday afternoon and evening.  High temperatures will be set early in the day.  This set up is very different from what we have seen over the past 3 months, but very typical for late winter and early spring.  During this past winter, low level arctic air has undercut a warm and moist flow aloft and this has resulted in lots of ice and sleet.   IF there's any frozen precipitation late Sunday, it would likely fall in the form of snow due to the development of a strong area of low pressure aloft.  So while temperatures at the surface could be just above freezing, aloft it will be cold.  This is very different than past set ups this winter.  Instead of the cold building from the surface up, the cold will build from the top, down.  I hope that makes sense.

With all that said, there are major differences between the North American Model (NAM) and the Global Forecasting System (GFS).  Both indicate significant rainfall, but differ in the strength and amount of moisture associated with the upper low late Sunday.  If you love snow, you're rooting for the NAM, and if you don't, you're rooting for the GFS.  However, the GFS even indicates a change over late Sunday over the far north.

Check out the maps below courtesy of weatherbell.com

This is the Friday overnight run of the NAM.  The surface low is in southern Kentucky with plenty of moisture wrapping around and a strong area of low pressure aloft.  This changes the rain to snow over a LARGE chunk of Arkansas.  The black lines are isobars and they are closely space together.  This means a strong northerly wind bringing in the cold air.  The red line is the freezing line and the blue line is the 35 degree line.
This is the GFS at the same time.  The surface low is further south, but the upper low is not as strong as the NAM.  There is a change over to snow, but it's over far northern Arkansas,
IN SUMMARY... USUALLY NEITHER MODEL IS CORRECT AND THERE'S A COMPROMISE.  I CAN'T STRESS THIS ENOUGH, MOST OF THE PRECIP WILL FALL AS RAIN.  IF THERE'S A CHANGE TO SNOW, THE NORTH WOULD BE FAVORED AND ANY CHANCE FOR A LASTING IMPACT WOULD BE MINIMAL.  IT'S ONLY FRIDAY AND THIS FORECAST CAN AND LIKELY WILL CHANGE SO STAY TUNED!

4 comments:

Anonymous said...

Come on I hope the models trend more snow!

jimmylee42 said...

A snowfall record for Harrison would be tough to break on St. Patrick's Day. The record is 13 inches set on that day in 1988.

Anonymous said...

Imagine if all that rain fell in the form of wintry precipitation! I wish...

Anonymous said...

Imagine if all that rain fell in the form of wintry precipitation! I wish...

Octo-BRRR