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Mesoscale Discussion 1961
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MD 1961 graphic

   MESOSCALE DISCUSSION 1961
   NWS STORM PREDICTION CENTER NORMAN OK
   1146 PM CST TUE DEC 02 2014

   AREAS AFFECTED...PORTIONS OF THE SAN FRANCISCO BAY AREA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 030546Z - 030745Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...STORMS HAVE INCREASED IN COVERAGE OVER THE PAST HOUR
   OFFSHORE THE W-CNTRL CA COAST. AS THESE STORMS MOVE ONSHORE NEAR THE
   SAN FRANCISCO BAY AREA...SMALL HAIL AND GUSTY WINDS MAY BE POSSIBLE.
   THE MARGINAL NATURE OF THE THREAT WILL PRECLUDE A WW ISSUANCE.

   DISCUSSION...AN UPPER LEVEL LOW AND ASSOCIATED SFC LOW PRESSURE AREA
   IS LOCATED OVER THE ERN PACIFIC...AND BOTH FEATURES WILL MOVE CLOSER
   TO THE NRN CA COAST OVERNIGHT. SOUTHERLY LOW LEVEL FLOW ACROSS THE
   BAY AREA HAS BROUGHT A MOIST AND WEAKLY UNSTABLE AIR MASS INLAND TO
   THE FOOTHILLS OF THE COASTAL RANGES. RAP BASED MESOANALYSIS SUGGESTS
   250-500 J/KG OF MLCAPE IS PRESENT ON THE COAST ALONG WITH GENERALLY
   25-35KT OF EFFECTIVE BULK SHEAR.

   LIGHTNING HAS INCREASED IN CONVECTION OFFSHORE OF W-CNTRL CA...AND
   RECENT RADAR IMAGERY FROM KMUX ALSO SHOWS AN UPTICK IN CONVECTIVE
   ORGANIZATION WITH THE STORMS THAT WILL MOVE ONSHORE OVER THE NEXT
   SEVERAL HOURS. CONVECTION-ALLOWING MODEL GUIDANCE SUGGESTS THAT
   STORMS WILL CONTINUE FORMING OFFSHORE AND THEN MOVE ENE TOWARDS THE
   BAY AREA FOR AT LEAST THE NEXT FEW HOURS. BUT...THE MARGINAL
   COMBINATION OF INSTABILITY AND SHEAR SHOULD GREATLY LIMIT ANY SEVERE
   WEATHER THREAT...ALTHOUGH SMALL HAIL AND GUSTY WINDS MAY BE POSSIBLE
   WITH ANY OF THE STRONGER CORES.

   ..GLEASON/CORFIDI.. 12/03/2014


   ATTN...WFO...MTR...

   LAT...LON   38302310 38432283 38172246 37482197 37082189 36982229
               37962304 38302310 

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Page last modified: December 03, 2014
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