Wednesday, August 10, 2011

August 10 Severe Weather Discussion


VALID 101200Z - 111200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN KS/ERN OK EWD INTO
   THE SRN APPALACHIANS...
   
   ...SYNOPSIS...
   ONLY MINOR CHANGES EXPECTED IN THE LARGE SCALE UPPER PATTERN THIS
   PERIOD...WITH A FLAT RIDGE OVER THE S CENTRAL AND SWRN STATES...VERY
   WEAK TROUGHING OVER THE NW...AND TROUGHING OVER THE EAST.
   
   AT THE SURFACE...A BAROCLINIC ZONE IS FORECAST TO LIE NNW-SSE ALONG
   THE HIGH PLAINS...AND THEN MORE EWD ACROSS THE SRN PLAINS/MID LOWER
   MS VALLEY AND INTO THE SOUTHEAST.  THIS BOUNDARY WILL COINCIDE WITH
   A ZONE OF CONVECTIVE/LOW-END SEVERE POTENTIAL THROUGH THE PERIOD.
   
   ...SERN KS/ERN OK EWD INTO THE MID MS/TN VALLEYS...
   SOMEWHAT DIFFICULT FORECAST ACROSS THIS REGION IN TERMS OF
   DETAILS...AS WIDESPREAD CONVECTION ONGOING FROM NEB SWD INTO OK WILL
   BE SHIFTING INTO THE SLIGHT RISK AREA EARLY IN THE PERIOD. 
   PRESUMING AMPLE DESTABILIZATION CAN OCCUR AHEAD OF THE LINGERING
   CONVECTION...STORMS SHOULD REINTENSIFY DURING THE AFTERNOON -- AIDED
   BY MODERATE WLY/WNWLY FLOW ALOFT.  
   
   STORMS SHOULD SHIFT EWD/ESEWD WITH TIME...MOVING ACROSS THE
   MID/LOWER MS VALLEY INTO THE TN VALLEY...BEFORE WEAKENING DURING THE
   EVENING INTO THE SRN APPALACHIANS.  IN THE MEAN TIME...THREATS FOR
   HAIL AND LOCALLY DAMAGING WINDS CAN BE EXPECTED ACROSS THE SLIGHT
   RISK AREA.
   
   ...HIGH PLAINS...
   ISOLATED CONVECTIVE DEVELOPMENT IS FORECAST DURING THE EVENING FROM
   SWRN MT SEWD/SWD ALONG THE HIGH PLAINS/FRONT RANGE REGION...AS
   AIRMASS BECOMES MODESTLY UNSTABLE IN CONJUNCTION WITH DAYTIME
   HEATING.  WITH SHEAR SUFFICIENT FOR SOME DEGREE OF ORGANIZATION/WEAK
   ROTATION...EXPECT STRONGER CELLS TO BE CAPABLE OF PRODUCING GUSTY
   WINDS AND HAIL.  ATTM...LIMITED COVERAGE IS ANTICIPATED...WHICH
   PRECLUDES MORE THAN LOW SEVERE PROBABILITIES.
   
   ...THE NORTHEAST/NEW ENGLAND...
   COOL AIR ALOFT ASSOCIATED WITH THE UPPER TROUGH COMBINED WITH
   DAYTIME HEATING WILL YIELD MODEST AFTERNOON DESTABILIZATION...AND
   EVENTUAL DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED
   THUNDERSTORMS.  A FEW OF THE STRONGEST CELLS -- AIDED BY MODERATE
   FLOW ALOFT -- MAY PRODUCE LOCALLY GUSTY WINDS AND HAIL UNTIL STORMS
   WEAKEN DURING THE EVENING.

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