SPC AC 210548

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1248 AM CDT WED AUG 21 2013

   VALID 221200Z - 231200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SYNOPSIS...
   AN UPPER-LEVEL SHORTWAVE TROUGH WILL MOVE ACROSS THE SAINT LAWRENCE
   RIVER VALLEY ON THURSDAY...WITH A BROADER SCALE WAVE LAGGING WWD
   FROM THIS FEATURE INTO THE UPPER GREAT LAKES REGION. SURFACE COLD
   FRONT ASSOCIATED WITH THE LEADING IMPULSE WILL MOVE SEWD ACROSS NEW
   ENGLAND AND SWD TOWARD THE OH VALLEY...WHILE ITS FAR WRN EXTENSION
   BECOMES QUASI-STATIONARY OVER THE CNTRL HIGH PLAINS. MEANWHILE OVER
   THE WRN CONUS...CLOSED LOW OVER NRN CA WILL BECOME AN OPEN WAVE AS
   IT EJECTS NEWD INTO ORE.

   ...CNTRL HIGH PLAINS...
   ISOLATED THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE CNTRL HIGH
   PLAINS DURING THURSDAY AFTERNOON/EVENING. DEWPOINTS IN THE 50S
   APPEAR REASONABLE GIVEN THE PRESENCE OF LOW-LEVEL ESELY WINDS...AND
   WITH 700-500 MB LAPSE RATES NEAR 7.0 C/KM...WILL SUPPORT MLCAPE
   VALUES AROUND 1000 J/KG. MID/UPPER-LEVEL FLOW WILL NOT BE STRONG
   OVER THE AREA /AOB 30 KT/...BUT WINDS WILL VEER WITH HEIGHT...WHICH
   COULD SUPPORT TRANSIENT SUPERCELL STRUCTURES AND A RISK FOR ISOLATED
   LARGE HAIL.

   ...NRN CA...NWRN NV...SRN ORE...
   AN UPPER-LEVEL SHORTWAVE TROUGH WILL LIFT NWD ALONG THE NRN CA COAST
   AND INTO SWRN ORE DURING THE AFTERNOON/EVENING. AS THIS
   OCCURS...LARGE-SCALE ASCENT ACCOMPANIED BY A SLY 60 KT UPPER-LEVEL
   SPEED MAX WILL SPREAD ACROSS THE AREA. LARGE-SCALE VERTICAL MOTION
   COMBINED WITH HEATED ELEVATED TERRAIN WILL FOSTER AN ENVIRONMENT
   FAVORABLE FOR SCATTERED THUNDERSTORM DEVELOPMENT. STEEP LAPSE RATES
   AND MLCAPE VALUES RANGING FROM 500-1000 J/KG...COMBINED WITH
   EFFECTIVE BULK SHEAR EXCEEDING 30 KT INVOF THE UPPER SPEED MAX...MAY
   RESULT IN A FEW ORGANIZED THUNDERSTORMS POSING A THREAT FOR
   HAIL/WIND GUSTS NEAR SEVERE LEVELS.

   ...WRN NY INTO NEW ENGLAND...
   A COLD FRONT IS FORECAST TO ENTER THE AREA BY AFTERNOON/EVENING AND
   WILL SERVE TO FOCUS ISOLATED/SCATTERED THUNDERSTORM DEVELOPMENT.
   DEEP-LAYER MID/UPPER-LEVEL WLYS AOA 30 KT MAY YIELD BRIEFLY
   ORGANIZED MULTICELL CLUSTERS/SMALL LINES POSING A THREAT FOR HAIL
   AND GUSTY WINDS. HOWEVER...WEAK MIDLEVEL LAPSE RATES WILL LIMIT
   MLCAPE TO LESS THAN 1000 J/KG...AND PRECLUDE A MORE SIGNIFICANT
   SEVERE WEATHER THREAT.

   ..GARNER.. 08/21/2013

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z