1/29/13

Arctic Front to Slam into the Region Late Wednesday!

Mother Nature will put the kabosh on yet another prelude to spring as the air mass that froze us just last weekend; aggressively comes back home to roost. After snow, sleet, freezing rain, heavy rains and thunderstorms; Mom Nature will leave us where she found us...in the deep freeze; a flash deep freeze!

The Arctic cold will slam into the region late Wednesday and change any rain showers to light snow and snow showers. Latest indications now indicate enough moisture and energy will remain on the backside of the front (as waves of low pressure move along it) to generate a light accumulation of snow Wednesday night into Thursday. This, along with sharply falling temperatures from the 50s to near 60 early in the day to the 30s by the evening and teens on Thursday morning, will result in residual water on untreated roads and walkways to flash freeze causing slippery driving and walking conditions. Undoubtedly; "walking like a penguin conditions" will become common-place Wednesday night into Thursday. 

Overnight into Wednesday: 

In the meantime; Hang on, 'cause it's gonna be a bumpy ride!

It not hard to see with a 250 MB /35000 Ft/ jet core where our spring warmth is coming from on the second map below; note the strong sub-tropical wind max across northern Mexico and Texas arched northeastward into the Lakes! Meanwhile; the foreboding of Arctic air is just beginning to get entrained into this mammoth system over the Pacific Northwest aloft.

On the third map; the surface reflection of this strong jet is in the form of a stationary from draped from Michigan, south southwest into a deepening storm/low pressure center over Illinois. As the jet core races northeast it will accelerate the front as an Arctic cold front Wednesday. Ahead of the front, a line of strong to some severe thunderstorms area expected overnight well northeast into the Mid- Mississippi and Ohio Valleys (see insert first map; severe wx outlook for the overnight hours).

While the bulk of the severe weather should remain south of Southeast Lower Michigan, some thunderstorms and strong shifting winds are likely as the apex of the instability moves across the region overnight and then again; as the Arctic front roars through during Wednesday afternoon and evening. Gusts of winds during these periods may be as high as 35 - 50 mph considering the winds just aloft. With the instability and convective nature of the beast; it is quite possible some of that wind will make it to the surface; irrespective of a shallow stable lower layer! Extra-ordinary forceful winds of near hurricane speeds /75 mph/ are projected to cross the region aloft /5000ft/ toward sunrise. Hang on; that 12Z weather balloon release at DTX should track out like a bat out of hell as she lifts north - northeast into the jet!  LOL
      
With the rest of the snow melt and still mainly frozen ground; the heavy showers and scattered thunderstorms will continue lowland flooding into Wednesday before the freeze.


                                                                 SVR WX OUTLOOK OVERNGHT-WEDNESDAY MORNING





By Wednesday evening (fourth map); the balmy air for January will be rudely shunted eastward and Mom Nature reminds us what season it truly is! A second re-enforce of Arctic air (fifth map) will be overspreading the region.



 Look for below normal temperatures and periods of snow showers Thursday into into Sunday. Highs will be in the teens and 20s; while lows fall into the single digits to teens.


Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian




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