Sunday, April 19, 2009

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 200049
SWODY1
SPC AC 200046

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT SUN APR 19 2009

VALID 200100Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS TONIGHT OVER AL/FL PNHDL/WRN
GA...

...AL/GA/FL PNHDL...

SCATTERED TSTMS WHICH FORMED EARLIER TODAY ALONG PRE-FRONTAL TROUGH
REMAIN IN PROGRESS THIS EVENING OVER AL...SEVERAL OF WHICH HAVE
EXHIBITED SUPERCELL CHARACTERISTICS OVER THE PAST SEVERAL HOURS.
00Z MESOANALYSIS INDICATES THAT THIS ACTIVITY IS CURRENTLY NEAR OR
E/NE OF PRIMARY LOW-LEVEL THETA-E/MOISTURE AXIS IN PLACE FROM SERN
MS INTO W-CNTRL AL...WITH BOUNDARY LAYER BECOMING PROGRESSIVELY
DRIER WITH EWD EXTENT INTO WRN GA. WHILE DEEP-LAYER SHEAR REMAINS
RATHER UNIFORM /I.E. 40-50 KT/ ACROSS REGION...INSPECTION OF LOCAL
VWPS INDICATES AN NOTABLE INCREASE IN LOW-LEVEL SHEAR FROM ERN MS
EWD ACROSS AL OWING TO BACKED/STRONGER SURFACE WINDS AND COLLOCATION
OF 35-45 KT LLJ AXIS.

INFLUX OF WARMER/MORE MOIST AIR FROM THE SW /REF. 00Z LIX SOUNDING/
COUPLED WITH GLANCING INFLUENCE OF STRONG VORTICITY MAXIMUM LIFTING
ENEWD THROUGH THE TN VALLEY SHOULD BE SUFFICIENT TO MAINTAIN ONGOING
STORMS FOR THE NEXT FEW HOURS WITH A CONTINUED THREAT FOR
HAIL...DAMAGING WINDS AND PERHAPS A TORNADO OR TWO. THE EWD EXTENT
OF A MORE ORGANIZED SEVERE WEATHER THREAT REMAINS SOMEWHAT UNCERTAIN
AND LARGELY DEPENDENT ON THE DEGREE OF BOUNDARY LAYER
MOISTENING/DESTABILIZATION THAT CAN TAKE PLACE IN ADVANCE OF ONGOING
STORMS. GIVEN THE RELATIVELY STRONG WIND FIELDS IN PLACE AND
INCREASED LARGE-SCALE FORCING WITH APPROACH OF MIDLEVEL
IMPULSE...HIGHER SEVERE PROBABILITIES AND CATEGORICAL SLIGHT RISK
HAVE BEEN SHIFTED SLIGHTLY EWD OVER WRN GA.

..MEAD.. 04/20/2009

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