Sunday, January 24, 2010

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 241952
SWODY1
SPC AC 241951

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0151 PM CST SUN JAN 24 2010

VALID 242000Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SOUTHEAST
AND THE CAROLINAS...

...THE SOUTHEAST/CAROLINAS...
INTENSE WIND SHEAR BUT MEAGER INSTABILITY CONTINUES TO CHARACTERIZE
THE PRE-FRONTAL ENVIRONMENT ACROSS THE SERN U.S. ATTM...AHEAD OF THE
EXPANSIVE UPPER TROUGH PROGRESSING STEADILY EWD INTO THE ERN CONUS.

A BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS PERSISTS ATTM FROM NWRN
GA SWWD TO THE MOUTH OF THE MISSISSIPPI...WITH CELLULAR LOW-TOPPED
CONVECTION NOW INCREASING AHEAD OF THE MAIN CONVECTIVE BAND OVER
SERN AL/WRN GA/THE FL PANHANDLE.

THE LACK OF APPRECIABLE CAPE WILL CONTINUE TO SUPPRESS THE POTENTIAL
FOR MORE ROBUST STORMS THROUGH THE PERIOD. HOWEVER...WITH STRONG
LARGE-SCALE ASCENT PROVIDING A FAVORABLE BACKDROP FOR SUSTAINED
CONVECTIVE DEVELOPMENT...A FEW ORGANIZED/ROTATING STORMS WILL REMAIN
LIKELY THROUGH THE PERIOD -- AIDED BY VEERING/STRENGTHENING WIND
FIELD WITH HEIGHT. WITH POTENTIAL FOR LOCALLY-DAMAGING
WINDS/ISOLATED TORNADOES TO PERSIST THROUGH THE PERIOD...WILL
MAINTAIN SLIGHT RISK ACROSS A SIZEABLE PORTION OF THE
SOUTHEAST/CAROLINAS.

..GOSS.. 01/24/2010

.PREV DISCUSSION... /ISSUED 1021 AM CST SUN JAN 24 2010/

...SOUTHEAST STATES...
A LARGE UPPER TROUGH IS IN PLACE OVER THE CENTRAL UNITED
STATES...WITH A 100+ KNOT 500MB JET ROTATING AROUND THE BASE OF THE
TROUGH AND INTO THE SOUTHEAST STATES. A LINE OF CONVECTION HAS
DEVELOPED ALONG THE SURFACE COLD FRONT OVER AL. THESE STORMS ARE
EXPECTED TO PERSIST THROUGH THE FORECAST PERIOD AND TRACK ACROSS
PORTIONS OF GA/FL AND INTO THE CAROLINAS TONIGHT. VERY STRONG
SOUTHERLY LOW LEVEL WINDS AHEAD OF THE STORMS /850 MB WIND SPEEDS
OVER 60 KNOTS/ WILL MAINTAIN VERY FAVORABLE LOW LEVEL VERTICAL SHEAR
PROFILES FOR BOWS/SUPERCELLS AND THE RISK OF DAMAGING WINDS AND
TORNADOES.

THE PRIMARY LIMITING FACTOR FOR SEVERE STORMS TODAY IS WEAK
INSTABILITY. LOW LEVEL MOISTURE IS BEING TRANSPORTED NORTHWARD IN
THE WARM SECTOR...WITH 60S DEWPOINTS LIKELY OVERSPREADING MUCH OF
CENTRAL GA AND SOUTHERN SC PRIOR TO FRONTAL PASSAGE. FORECAST
SOUNDINGS IN THESE AREAS SUGGEST MARGINAL BUT POTENTIALLY SUFFICIENT
CAPE FOR SURFACE-BASED STORMS. THEREFORE...WILL MAINTAIN SLIGHT
RISK AND TORNADO/WIND PROBABILITIES ACROSS THIS REGION. BY LATE
TONIGHT...THE SQUALL LINE WILL SAG INTO NORTHERN AND CENTRAL FL WITH
A CONTINUED RISK OF LOCALLY DAMAGING WINDS.

...LOWER/MID MS VALLEY THIS AFTERNOON...
WATER VAPOR IMAGERY SHOWS A MID LEVEL VORT MAX OVER NORTH CENTRAL
TX. THIS FEATURE WILL TRACK EASTWARD AND INTO PARTS OF AR/TN/MS
LATER THIS AFTERNOON AND EARLY EVENING. RELATIVELY STEEP LAPSE
RATES AND COLD TEMPERATURES ALOFT MAY RESULT IN A CLUSTER OF SHOWERS
AND THUNDERSTORMS. THERMODYNAMIC PARAMETERS SUGGEST A LOW-END RISK
OF HAIL IN THE STRONGEST CELLS AROUND PEAK HEATING BEFORE
DIMINISHING AFTER DARK.

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