Thursday, December 10, 2015

Bumpy Transition To Colder Air

Don't forget to get your entries in for the winter weather contest.  Read the post below for more information.  The grand prize is a professional home weather station.

When temperatures get into the 70s in December, look out!  We have a strong storm system coming through Saturday night into Sunday.  The Storm Prediction Center has outlined much of western Arkansas for a severe weather risk late Saturday. While I can't rule out some strong winds, I really don't think severe weather is the main threat at this time as instability levels will be quite low.  If that changes, I'll let you know.

The main threat, IMO, will be heavy rainfall.  Some locations may see 2-3 inches with isolated higher amounts.

There appears to be a more significant push of colder air by the middle of next week.  Moisture return looks minimal as the front moves through Wednesday.  I expect highs only in the 30s and 40s by the end of next week across the state.  What about moisture?  The GFS says "yes" and the Euro says "no".  In the long range, I would place bets on the Euro.

The GFS valid Friday the 18th at midnight.  This model develops a significant wave of low pressure along a stalled front along the Gulf coast.  With the freezing line over northern Arkansas, it develops snow across the northern portions of the state with a cold rain elsewhere.
The Euro shows the cold air in place, but the wave of low pressure is weaker and moves quickly to the east

THE BOTTOM LINE...  While the SPC has a slight risk for severe weather across western Arkansas late Saturday, I have doubts.  Instability is limited.  If this came in during the day, I would have more concern.  At this time, I'm not dismissing the severe chances completely, but I think heavy rainfall will be the main threat.  I expect flash flood watches to be issued as 2-3'' + of rain will be possible.

Both models agree a strong cold front will move through Wednesday and introduce the coldest air of the season so far.  Sorry winter weather lovers (I'm one of them), winter weather chances do not look great.  The GFS says "yes" and the Euro says "no."  If this changes, I'll let you know.

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