SWODY1
SPC AC 291623
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1123 AM CDT FRI AUG 29 2008
VALID 291630Z - 301200Z
...NO SVR TSTM AREAS FORECAST...
...CENTRAL AZ THIS AFTERNOON/EVENING...
THE LARGE SCALE REGIME IS SIMILAR TO YESTERDAY WITH A BAND OF 30-40
KT ELY MID LEVEL FLOW OVER AZ ON THE N SIDE OF AN ELONGATED MID
LEVEL LOW OVER NRN MEXICO. THE 12Z SOUNDING FROM TUS SHOWS SOME
STABILIZING IMPACTS FROM OVERNIGHT CONVECTION...WHILE THE PHOENIX
SOUNDING IS FAIRLY SIMILAR TO 12Z YESTERDAY...DESPITE THE PRIOR
CONVECTION. GIVEN THE RELATIVE LACK OF CLOUDS OVER AZ THIS
MORNING...SURFACE HEATING SHOULD ALLOW TEMPERATURES TO RISE TO THE
MID-UPPER 90S OVER THE LOWER DESERTS. THESE TEMPERATURES WILL TEND
TO REDUCE CONVECTIVE INHIBITION AND SUPPORT MLCAPE VALUES OF
1500-2500 J/KG. GIVEN THE MODERATE INSTABILITY AND SUBSTANTIAL ELY
MID LEVEL FLOW...ANY STORM CLUSTERS THAT FORM OVER THE HIGH TERRAIN
WILL MOVE WWD OVER THE LOWER DESERTS AND BE CAPABLE OF PRODUCING
DAMAGING WINDS AND ISOLATED HAIL. THUNDERSTORM COVERAGE IS SOMEWHAT
IN QUESTION SINCE THE PRIMARY EMBEDDED WAVES IN THE ELYS ARE NOW
OVER THE NRN GULF OF CA...AND FARTHER TO THE E OVER THE BIG BEND
REGION OF TX. STILL...THE CENTRAL AZ AREA WILL CONTINUED TO BE
MONITORED...AND A SLIGHT RISK MAY BECOME NEEDED IF EXPECTED STORM
COVERAGE INCREASES THIS AFTERNOON.
...KY/TN/AR/OK THIS AFTERNOON...
AN OUTFLOW BOUNDARY IS MOVING SEWD INTO WRN KY/MO BOOTHEEL/NRN AR/NE
OK...TO THE SE OF THE SYNOPTIC COLD FRONT. REGIONAL SOUNDINGS
REVEAL THE POTENTIAL FOR MODERATE-STRONG INSTABILITY THIS AFTERNOON
WITH DAYTIME HEATING AND BOUNDARY LAYER DEWPOINTS AOA 70 F.
HOWEVER...VERTICAL SHEAR WILL BE WEAK OVER THIS AREA...SUGGESTING
THAT ANY SEVERE STORM THREAT WILL LIKELY CONSIST OF ISOLATED
DOWNBURSTS AND/OR MARGINALLY SEVERE HAIL WITH PULSE-TYPE STORMS
ALONG THE SURFACE BOUNDARIES.
...S CENTRAL CO THIS AFTERNOON/EVENING...
BOUNDARY LAYER DEWPOINTS IN THE 40S AND 50S HAVE BACKED WWD TO THE
HIGH TERRAIN IN S CENTRAL CO...WHERE CLOUD BREAKS WILL ALLOW MODEST
DESTABILIZATION THIS AFTERNOON. MEANWHILE...THIS AREA REMAINS ON
THE SRN FRINGE OF A MID-UPPER CYCLONIC SHEAR AXIS OVER CENTRAL
CO...AND WITHIN A NARROW BELT OF 30-50 KT WNWLY FLOW ALOFT SAMPLED
BY THE GJT 12Z SOUNDING. GIVEN THE MODEST VERTICAL SHEAR AND
INSTABILITY...A FEW ORGANIZED STORMS MAY PRODUCE ISOLATED LARGE HAIL
AND DAMAGING GUSTS THIS AFTERNOON/EVENING.
..THOMPSON/GRAMS.. 08/29/2008
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