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Cool and Dry in the East; Turning Stormy in the Northwest

Much cooler temperatures behind a cold front will bring a feeling of fall to the East Coast today. In addition, an active fall storm pattern developing in the Pacific Northwest this week will bring areas of heavy rain and high elevation snow. Northern California will benefit from rainfall this week that will aid firefighters given the recent large wildfires. Read More >

Mesoscale Discussion #0417 issued at 1438 UTC 15 March 2008
MESOSCALE DISCUSSION 0417
   NWS STORM PREDICTION CENTER NORMAN OK
   0938 AM CDT SAT MAR 15 2008
   
   AREAS AFFECTED...PORTIONS NRN AL...NRN GA.
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 118...
   
   VALID 151438Z - 151545Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 118
   CONTINUES.
   
   ORIGINAL WW -- SCHEDULED TO EXPIRE AT 15Z -- WILL BE EXTENDED
   LOCALLY FOR SOME NERN AL COUNTIES AHEAD OF SRN PORTION OF ONGOING
   CONVECTIVE BAND...WHERE DAMAGING WIND AND MRGL SVR HAIL THREAT
   REMAINS MOST CONCENTRATED IN NEAR TERM.  SVR POTENTIAL WILL INCREASE
   AS AREA OF LOW LEVEL ASCENT NOW REPRESENTING SRN PORTION MCS MOVES
   INTO DESTABILIZING AND FAVORABLY SHEARED AIR MASS OVER NRN GA. 
   THEREFORE ADDITIONAL/TORNADO WW MAY BE REQUIRED WITHIN NEXT 1-2
   HOURS.
   
   SFC MESOANALYSIS SHOWS PRIMARY LOW ELONGATED OVER ERN/SRN AR...BUT
   WITH SECONDARY MESOLOW OVER N-CENTRAL AL...COLLOCATED WITH ONGOING
   BAND OF CONVECTION.  WARM FRONT CURRENTLY HAS DOUBLE STRUCTURE WITH
   SRN MEMBER EXTENDING FROM BHM AREA SEWD ACROSS SWRN GA...AND NRN
   MEMBER BEING OUTFLOW-REINFORCED BOUNDARY THROUGH LGC-MCN-AGS AREAS. 
   MESOLOW IS EXPECTED TO CONSOLIDATE/PROPAGATE EWD ACROSS NRN GA INTO
   CAROLINAS THROUGH EARLY AFTERNOON...BECOMING PRIMARY SFC CYCLONE
   CENTER.  THIS PROGGED TREND IS SUPPORTED BY LAST TWO HOURS OF
   ISALLOBARIC FALL/RISE COUPLET DEVELOPMENT/MOTION ACROSS NRN AL. 
   THIS PROCESS WILL SUPPORT BACKED LOW LEVEL WINDS AND ENLARGED
   HODOGRAPHS ALONG OUTFLOW-REINFORCED SFC FRONT THAT SHOULD
   CONSOLIDATE ACROSS NRN GA DURING NEXT 2-3 HOURS.
   
   TORNADO AND DAMAGING WIND POTENTIAL ARE EXPECTED TO INCREASE FAIRLY
   QUICKLY FROM LATE MORNING INTO EARLY AFTERNOON INVOF SFC
   BOUNDARY...WHERE MOST FAVORABLE OVERLAP OF BUOYANCY AND SHEAR WILL
   SET UP.  VIS IMAGERY INDICATES SUBSTANTIAL CLOUD BREAKS ACROSS MUCH
   OF ERN/NERN GA...WHICH WILL AID IN DESTABILIZATION ALONG WITH SFC
   MOIST ADVECTION FROM REGION OF HIGHER DEW POINTS NOW OVER SERN
   AL/SWRN GA...S OF SRN WARM FRONTAL SEGMENT.  STG DEEP-LAYER SHEAR
   PROFILES ARE FCST WITH FRONTAL ZONE AS WELL.
   
   ..EDWARDS.. 03/15/2008