[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 022238
SWOMCD
SPC MCD 022238 
AZZ000-CAZ000-030115-

MESOSCALE DISCUSSION 1928
NWS STORM PREDICTION CENTER NORMAN OK
0538 PM CDT SAT SEP 02 2006

AREAS AFFECTED...SRN CA...SWRN/CNTRL AZ

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 022238Z - 030115Z

DOWNBURST WINDS AND HEAVY RAIN POTENTIAL EXPECTED TO CONTINUE WITH
SLOW MOVING AND POORLY ORGANIZED DEEP CONVECTION ACROSS THE SRN CA
AND CNTRL/SWRN AZ INTO THE EVENING. A WATCH IS NOT LIKELY AT THIS
TIME.

OVER THE PAST HOUR...SEVERAL INTENSE STORMS HAVE FORMED ACROSS THE
HIGHER ELEVATIONS OF RIVERSIDE AND SAN DIEGO COUNTIES IN SRN CA...AS
WELL AS YUMA AND MARICOPA COUNTIES IN SWRN AZ. DIURNAL HEATING AND
OROGRAPHIC FORCING WITHIN A VERY MOIST AND MODESTLY UNSTABLE AIR
MASS APPEAR TO BE THE PRIMARY FACTORS RESULTING IN THIS DEEP
CONVECTION. WHILE WEAK CLOUD-BEARING FLOW AND SHEAR WILL LIMIT
OVERALL STORM ORGANIZATION...RELATIVELY STRONGER FLOW IN THE 300MB
TO 250MB LAYER WAS CONTRIBUTING TO FAVORABLE BACKGROUND ASCENT AS
WELL AS EXHAUST FOR THE CONVECTION.

DESPITE WEAK STORM ORGANIZATION...LARGE SURFACE DEWPOINT DEPRESSIONS
AND DCAPE VALUES OVER 1000 J/KG SUGGEST THAT ISOLATED DOWNBURST
WINDS IN EXCESS OF 50KT...AND PERHAPS SOME HAIL...MAY BE PRODUCED BY
ONGOING ACTIVITY. STORM MERGERS AND UPSCALE DEVELOPMENT...EXPECTED
TO REMAIN LIMITED BY WEAK FORCING/FLOW...COULD ALSO RESULT IN
LOCALLY EXCESSIVE RAIN IN SOME AREAS AND BLOWING DUST AROUND THE
PERIPHERY OF SUCH MERGERS. LATEST DIAGNOSTIC DATA INDICATES A POOL
OF STRONGER INSTABILITY WAS SITUATED OVER THE LOWER CO RIVER VALLEY.
IT IS POSSIBLE THAT PULSE/MULTICELL ACTIVITY MAY PERSIST AROUND THIS
POOL OF INSTABILITY OVER THE NEXT SEVERAL HOURS.

..CARBIN.. 09/02/2006

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...TWC...FGZ...PSR...VEF...SGX...

33571174 33091155 32001282 32271377 32541525 32751604
33081636 33481630 33971561 34351468 34731343 34841282
34591248 34001200 

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