SPC AC 050059

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0759 PM CDT THU JUL 04 2013

   VALID 050100Z - 051200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SYNOPSIS...
   HIGH-AMPLITUDE UPPER-AIR PATTERN CONTINUES OVER MOST OF
   CONUS...CHARACTERIZED BY STG ANTICYCLONES OVER AZ AND WRN ATLC. 
   THOSE...AS WELL AS NRN STREAM ZONAL FLOW BELT ACROSS SRN CANADA...
   BRACKET QUASISTATIONARY SYNOPTIC TROUGH THAT EXTENDS FROM UPPER MS
   VALLEY THROUGH WEAK/EMBEDDED CYCLONE OVER MO...TO NERN MEX AND
   ADJACENT WRN-MOST GULF.

   AT SFC...BROAD/WEAK CONFLUENCE ZONE AND EMBEDDED SFC TROUGH --
   REPRESENTING REMNANTS OF OLD BAROCLINIC ZONE -- WAS DRAWN AT 23Z
   FROM SRN QUE SSWWD ACROSS CENTRAL PA. THIS FEATURE BECAME
   ILL-DEFINED AMIDST CONVECTIVE ACTIVITY FROM THERE SWWD OVER
   AL...THEN APPEARED AGAIN FROM SRN PORTIONS MS/LA SWWD OVER DEEP S
   TX.  GREATEST LOW-LEVEL THETAE REMAINS NEAR AND E OF THAT FEATURE TO
   ATLC COAST.  COLD FRONT WAS ANALYZED FROM SRN MB ACROSS ERN
   ND...NRN/WRN SD AND EXTREME SERN MT...INTERSECTING CONVECTIVE
   OUTFLOW INVOF BIL.

   ...NRN GREAT BASIN/SIERRAS/ID REGION...
   WIDELY SCATTERED TO SCATTERED TSTMS SHOULD CONTINUE TO MOVE NEWD TO
   EWD ACROSS THIS REGION...WITH POTENTIAL FOR ISOLATED SVR HAIL/GUSTS.
    COMBINATION OF BUOYANCY AND DEEP SHEAR WILL REMAIN BEST JUXTAPOSED
   OVER NRN NV AND PORTIONS EXTREME SRN ID.  THERE...PRECONVECTIVE
   MLCAPE 1000-1500 J/KG WILL REMAIN COMMON FOR ANOTHER FEW
   HOURS...ALBEIT SHRINKING IN AREA DUE TO OUTFLOW EFFECTS.  RELATIVELY
   MAXIMIZED MID-UPPER LEVEL WINDS AROUND AZ HIGH CONTRIBUTE TO 35-40
   KT EFFECTIVE SHEAR MAGNITUDES.  OVERALL COVERAGE/INTENSITY OF TSTMS
   OVER THIS REGION SHOULD DIMINISH CONSIDERABLY AFTER ABOUT 04Z...AS
   AIR MASS STABILIZES FROM COMBINATION OF DIABATIC SFC COOLING AND
   AGGREGATED CONVECTIVE OUTFLOWS.

   ...ERN CONUS...
   DEEP FETCH OF MOISTURE TRANSPORT CONTINUES FROM CENTRAL-ERN GULF
   NNEWD ACROSS SRN APPALACHIANS REGION...THEN ARCHING NEWD OVER UPPER
   OH VALLEY...NRN APPALACHIANS AND NEW ENGLAND.  GREATER
   DESTABILIZATION HAS OCCURRED IN RELATIVELY CLOUD/PRECIP-FREE PART OF
   THIS BELT FROM WV/PA NEWD...WITH GREATER CONVECTIVE COVERAGE AND
   WEAKER BUOYANCY FARTHER S.  STRONGEST LOW-LEVEL SHEAR VALUES WILL
   SHIFT SOMEWHAT EWD THROUGH EVENING IN STEP WITH 30-40 KT LLJ...BUT
   STILL REMAINING REMAIN OVER GENERALLY WEAKER-CAPE AIR MASS FROM
   PORTIONS GA NWD OVER SRN/CENTRAL APPALACHIANS.  UNCONDITIONAL SVR
   POTENTIAL REMAINS TOO MRGL/ISOLATED FOR CATEGORICAL RISK....GIVEN
   1. NEBULOUS FOCI FOR ORGANIZED/SUSTAINED CONVECTION OVER WHOLE
   CORRIDOR...
   2. FRAGMENTED/MRGL NATURE OF INSTABILITY FARTHER S WHERE SHEAR IS
   MOST SUPPORTIVE OF SVR POTENTIAL...AND
   3. LOWER INITIAL TSTM COVERAGE PRIOR TO ONSET OF SUBSTANTIAL
   DIABATIC SFC COOLING.

   ...MT/WY...
   SVR THREAT OVER THIS REGION HAS BECOME VERY ISOLATED AND FRAGMENTED
   BY OUTFLOW POOL FROM EARLIER CENTRAL MT TSTMS.  HOWEVER...VERTICAL
   SHEAR REMAINS FAVORABLE WITH 40-50 KT EFFECTIVE SHEAR MAGNITUDES
   EVIDENT OVER NRN MT.  FARTHER S UNDER WEAKER FLOW ALOFT...SHEAR
   VALUES DIMINISH...BUT INITIAL TSTM COVERAGE IS MUCH GREATER.  MAIN
   OUTFLOW BOUNDARY WILL CONTINUE TO MOVE SWD ACROSS EXTREME SRN MT
   INTO NRN WY.  MEANWHILE...CONVECTION TO ITS S MAY PRODUCE ISOLATED
   HAIL/GUSTS NEAR SVR LEVELS BEFORE ITS OWN OUTFLOW AND THAT FROM
   EARLIER CONVECTION STABILIZES AIR MASS TOO MUCH.  IN ADDITION TO
   ISOLATED STG-SVR TSTMS ESE HVR...CONVECTION OVER PORTIONS SWRN
   SK/SERN AB MAY REACH NRN BORDER BEFORE DIMINISHING...WITH RISK OF
   HAIL AND STG/DAMAGING GUSTS.  TFX/GGW SOUNDINGS YIELD MRGL CAPE BUT
   SAMPLED DRIER ENVIRONMENTS THAN EVIDENT OVER N-CENTRAL MT....WHERE
   SFC DEW POINTS 60S F SHOULD CONTRIBUTE TO 1000-1500 J/KG MLCAPE FOR
   ANOTHER COUPLE OF HOURS.

   ..EDWARDS.. 07/05/2013

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