DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 201250
SWODY1
SPC AC 201248

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0748 AM CDT MON AUG 20 2012

VALID 201300Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE SRN RCKYS AND
SRN HI PLNS...

...SYNOPSIS...
AMPLIFIED WRN RIDGE/ERN TROUGH PATTERN WILL PERSIST THIS
PERIOD...WITH SLOW EWD PROGRESSION EXPECTED AS UPSTREAM TROUGH NOW
OVER THE ERN PACIFIC EDGES E TO THE WA/ORE CST. AT LWR LVLS...WEAK
HIGH PRESSURE WILL REMAIN DOMINANT FROM THE UPR MS VLY INTO MUCH OF
THE OH AND TN VLYS. FARTHER SE...A WEAK FRONTAL ZONE WILL PERSIST
FROM JUST OFF THE NC CST WSW TO THE CNTRL GULF CST. THIS BOUNDARY
WILL CONTINUE TO SERVE AS A FOCUS FOR DIURNALLY ENHANCED TSTMS.

MEANWHILE...UPR RIDGE WILL MAINTAIN NW FLOW OVER THE RCKYS AND PLNS.
SEVERAL WEAK DISTURBANCES IN THIS JET WILL MODULATE TSTM DEVELOPMENT
OVER PARTS OF CO/NM AND THE ADJACENT HIGH PLNS. SOME OF THESE STORMS
COULD BECOME SVR. A FEW STRONGER STORMS ALSO COULD OCCUR WITHIN UPR
TROUGH AXIS OVER THE UPR OH VLY.

...NE NM SEWD INTO THE WRN OK/TX PANHANDLES THIS AFTN/EVE...
VEERING WIND PROFILES...WITH WEAK SLY FLOW AT THE SFC AND NWLY FLOW
ALOFT WILL YIELD MODERATELY LONG...STRAIGHT HODOGRAPHS FAVORABLE FOR
SLOWLY MOVING AFTN SUPERCELLS WITH HAIL OVER NE NM. AMPLE MOISTURE
/PW AOA 1 INCH WITH AVERAGE SFC DEWPOINTS IN THE UPR 40S TO MID 50S
F/ WILL BE PRESENT FOR STORMS TO FORM OVER THE HIGHER TERRAIN. THESE
LIKELY WILL CONSOLIDATE INTO ONE OR TWO SE-MOVING CLUSTERS THAT
COULD ALSO POSE A DMGG WIND THREAT SEWD INTO PARTS OF TX AND WRN OK
BY EARLY TNGT. STRENGTHENING SSELY LLJ AHEAD OF UPR IMPULSES
APPROACHING FROM THE CNTRL RCKYS SUGGESTS THAT THE CLUSTERS COULD
PERSIST THROUGH EARLY TUE OVER NW/WCNTRL TX AND SW OK.

...SERN LA INTO NRN/CNTRL FL AND NEWD TO THE NC CST TODAY...
DEEP...UNIDIRECTIONAL SW FLOW WILL PREVAIL FROM THE NERN GULF TO THE
NC CST THROUGH THIS EVE...ON SE SIDE OF UPR TROUGH. MID LVL LAPSE
RATES WILL REMAIN WEAK. BUT GIVEN BACKGROUND WIND FIELD AND
CONTINUING PRESENCE OF HIGH PWS WITH NEARLY STNRY COLD FRONT...SETUP
MAY YIELD NUMEROUS CLUSTERS OF AFTN STORMS. SUCH ACTIVITY MAY BECOME
MOST CONCENTRATED OVER NRN AND PERHAPS CNTRL FL...WHERE HEATING WILL
BE GREATEST...AND SEA BREEZE BOUNDARY WILL FOCUS UPLIFT ON E SIDE OF
PENINSULA. SOME OF THE STORMS COULD CONTAIN OCCASIONAL BOWING
SEGMENTS WITH A RISK FOR LOCALLY DMGG WIND. HAIL ALSO MAY
OCCUR...ESPECIALLY OVER CNTRL FL...WHERE HEATING WILL BE GREATEST
AND 12Z TAMPA RAOB SHOWS 500 MB TEMP AROUND MINUS 8 C.

...ERN OH/WRN PA/WV THIS AFTN...
SFC HEATING OF ELEVATED TERRAIN BENEATH AXIS OF UPR TROUGH COULD
YIELD SCTD STRONG DIURNAL STORMS CAPABLE OF MARGINALLY SVR HAIL OVER
THE UPR OH VLY...WHERE SFC HEATING SHOULD BE GREATER THAN THAT WHICH
OCCURRED IN SIMILAR ENVIRONMENT YESTERDAY...AND ASCENT MAY BE
AUGMENTED BY WEAK IMPULSE DRIFTING NE FROM SRN IND.

..CORFIDI/HURLBUT.. 08/20/2012

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