Saturday, September 24, 2011

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 241619
SWODY1
SPC AC 241617

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1117 AM CDT SAT SEP 24 2011

VALID 241630Z - 251200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
THE CLOSED LOW OVER NRN IL WILL DRIFT WWD TO ABOUT THE IA BORDER BY
EARLY SUNDAY...AND A SHORTWAVE TROUGH CENTERED NEAR 42 N AND 136 W
WILL APPROACH THE ORE/WA COASTS OVERNIGHT. OTHERWISE...LITTLE
CHANGE IS EXPECTED IN THE LARGE SCALE REGIME ACROSS THE CONUS FOR
THE NEXT COUPLE OF DAYS. EMBEDDED SPEED MAXIMA ROTATING AROUND THE
LOW AND A WEAK SURFACE FRONTAL SEGMENT ACROSS ERN IL/INDIANA WILL
MAINTAIN A FOCUS FOR THUNDERSTORM DEVELOPMENT TODAY. ADDITIONAL
CONVECTION IS EXPECTED OVERNIGHT ALONG THE BOUNDARY IN SRN MO/NRN AR
WHERE LOW-LEVEL FRONTOGENESIS/WAA WILL BE FOCUSED. VERTICAL SHEAR
WILL BE SUFFICIENT FOR ORGANIZED STORMS S THRU E OF THE MIDLEVEL LOW
THROUGH THE PERIOD...BUT EXPECT ONLY WEAK INSTABILITY AND NO
APPRECIABLE RISK FOR STRONG/SEVERE STORMS AS A RESULT OF COOL
SURFACE TEMPERATURES AND POOR LOW-LEVEL MOISTURE.

A SEPARATE FRONTAL SEGMENT WILL REMAIN QUASI-STATIONARY FROM N FL TO
ERN NC. CLOUDS/RAIN WITHIN THE MOISTURE PLUME EXTENDING NWD FROM
THE BAHAMAS WILL TEND TO LIMIT THE POTENTIAL FOR SURFACE
HEATING/DESTABILIZATION INLAND THIS AFTERNOON /ESPECIALLY NC/...AND
LOW-LEVEL FLOW IS EXPECTED TO REMAIN WEAK INLAND THROUGH THE PERIOD.
THUS...WHILE AN ISOLATED ROTATING STORM OR BOWING SEGMENT CANNOT BE
RULED OUT ACROSS THE CENTRAL/ERN CAROLINAS AS A RESULT OF THE
INSTABILITY AND DEEP-LAYER SHEAR NOTED IN 12Z SOUNDINGS...THE
OVERALL SEVERE STORM THREAT SHOULD REMAIN MARGINAL AT BEST.

..THOMPSON/HURLBUT.. 09/24/2011

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