SWODY1
SPC AC 280600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT SAT AUG 28 2010
VALID 281200Z - 291200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER TROUGH WILL AMPLIFY OVER THE WRN STATES AS A STRONG VORT MAX
DROPS SWD INTO CA BEFORE TURNING EWD INTO THE GREAT BASIN SATURDAY
AFTERNOON AND EVENING. BAROCLINIC ZONE EXTENDS FROM THE NRN PLAINS
SWWD INTO NRN CA. THE NERN EXTENSION OF THIS BOUNDARY WILL BECOME
QUASISTATIONARY FROM THE NRN ROCKIES THROUGH NRN PLAINS...WHILE SRN
EXTENSION DROPS SWD THROUGH THE GREAT BASIN AND CA. AREA OF LOW
PRESSURE OVER THE NRN GULF IS FORECAST TO DRIFT SLOWLY NORTH AS
UPPER RIDGE AXIS BUILDS AND SHIFTS EWD TOWARD THE ATLANTIC SEABOARD.
...NRN ROCKIES AREA...
PRIMARY UNCERTAINTY REGARDING EXTENT OF SEVERE POTENTIAL IN THIS
REGION IS EVOLUTION OF MOISTURE PROFILES. THE 00Z UPPER AIR DATA
INDICATE A RESERVOIR OF RICHER MOISTURE ACROSS AZ INTO SRN NM. SWLY
FLOW ALOFT DOWNSTREAM FROM AMPLIFYING UPPER TROUGH WILL RESULT IN A
GRADUAL EWD SHIFTING OF DEEPER MOISTURE PLUME. HOWEVER...FLOW MAY
REMAIN MORE SLY EAST OF SURFACE LOW THAT IS FORECAST TO LIFT NEWD
ALONG BAROCLINIC ZONE THROUGH SERN ID INTO SWRN MT DURING THE
DAY...AND COULD HELP TO TRANSPORT MOISTURE NWD. CURRENT THINKING IS
THAT BOUNDARY LAYER DEWPOINTS IN THE LOW TO MID 40S WILL BE
REPRESENTATIVE OF THE MEAN MIXED LAYER WHICH WILL YIELD MLCAPE AOB
500 J/KG. AN EXCEPTION MAY BE ACROSS ERN SERN ID AND SWRN MT IN
VICINITY OF THE BAROCLINIC ZONE AND EAST OF SURFACE LOW WHERE THE
EFFECTS OF MIXING COULD BE SUBDUED. STORMS SHOULD REDEVELOP DURING
THE AFTERNOON WITHIN ZONE OF INCREASING UPPER DIVERGENCE ASSOCIATED
WITH UPPER JET STREAK ROTATING THROUGH BASE OF TROUGH. ACTIVITY WILL
SPREAD NEWD WITH INCREASING COVERAGE ALONG AND NORTH OF BAROCLINIC
ZONE ACROSS SWRN THROUGH CNTRL MT. VERTICAL SHEAR OF 50+ KT WILL
SUPPORT THE POTENTIAL FOR ORGANIZED STORMS INCLUDING SUPERCELLS.
ISOLATED DAMAGING WIND AND HAIL WILL BE THE MAIN THREATS. WILL
MAINTAIN 5% SEVERE PROBABILITIES THIS OUTLOOK...BUT AN UPGRADE TO
SLIGHT RISK MIGHT EVENTUALLY BE NEEDED IF IT BECOMES MORE CERTAIN
THAT MOISTURE AND INSTABILITY WILL BE SUFFICIENT FOR A MORE ROBUST
THREAT.
...GULF COASTAL AREA...
LOW LEVEL SHEAR COULD UNDERGO SOME INCREASE AS AN AREA OF LOW
PRESSURE OVER THE NRN GULF DRIFTS NWD. LOW LEVEL HODOGRAPHS COULD
BECOME SUFFICIENT FOR THE THREAT FOR AN ISOLATED TORNADO OR TWO.
HOWEVER...UNCERTAINTY REGARDING THE FUTURE EVOLUTION OF THIS FEATURE
PRECLUDES A CATEGORICAL RISK AT THIS TIME.
..DIAL/GRAMS.. 08/28/2010
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