SWODY1
SPC AC 100538
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1138 PM CST THU FEB 09 2012
VALID 101200Z - 111200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
BLOCKING PATTERN WILL PERSIST FRIDAY AS SERIES OF IMPULSES ROTATE
AROUND HUDSON BAY VORTEX INTO ERN HALF OF THE U.S. CONTRIBUTING TO
AMPLIFICATION OF ERN U.S. UPPER TROUGH. ONE SUCH IMPULSE WILL DROP
SEWD THROUGH THE GREAT LAKES AND OH VALLEY...WHILE SRN STREAM
SHORTWAVE TROUGH NOW OVER TX/OK ADVANCES THROUGH THE SERN STATES.
STRONG POLAR FRONT WILL MOVE SEWD THROUGH THE GREAT LAKES AND INTO
THE SRN PLAINS IN ASSOCIATION WITH THE NRN STREAM SHORTWAVE TROUGH.
FARTHER EAST A WEAK SFC WAVE IS FORECAST TO DEVELOP IN VCNTY OF THE
FL PENINSULA WITH ATTENDANT WEAK FRONTOGENESIS IN ASSOCIATION WITH
EJECTING LEAD SRN STREAM IMPULSE CURRENTLY MOVING THROUGH THE LOWER
MS VALLEY. A WARM FRONT WILL DEVELOP NWD THROUGH FL AND THE GULF
STREAM AHEAD OF THE EJECTING WAVE.
...FL THROUGH GA AND SC COASTS...
RICHER MOISTURE WITH LOW-MID 60S DEWPOINTS WILL RETURN THROUGH THE
FL PENINSULA AND GULF STREAM AS WARM FRONT DEVELOPS NWD. THE NWD
ADVECTION OF MOISTURE AND POTENTIAL FOR DIABATIC WARMING WILL
CONTRIBUTE TO DESTABILIZATION WITH 500-800 J/KG MLCAPE POSSIBLE. AS
BOUNDARY LAYER WINDS BECOME MORE SLY...A ZONE OF ISENTROPIC ASCENT
WILL DEVELOP NWD WHICH ALONG WITH LOW LEVEL CONVERGENCE BANDS AND
POTENTIAL SEA-BREEZE CIRCULATIONS WILL CONTRIBUTE TO THUNDERSTORM
DEVELOPMENT AS THE ATMOSPHERE DESTABILIZES. UPPER FLOW WILL
STRENGTHEN WITH APPROACH OF THE SRN STREAM SHORTWAVE TROUGH
CONTRIBUTING TO 45+ KT EFFECTIVE SHEAR...BUT WINDS IN THE SFC-700 MB
LAYER ARE FORECAST TO REMAIN MODEST OWING TO ONLY WEAK SFC WAVE
DEVELOPMENT. WHILE WEAK ROTATING UPDRAFTS AND ISOLATED STRONG
DOWNDRAFTS CANNOT BE RULED OUT...OVERALL SEVERE THREAT IS EXPECTED
TO REMAIN LIMITED DUE TO A MARGINAL THERMODYNAMIC ENVIRONMENT AND
RELATIVELY WEAK FLOW AOB 700 MB.
...ERN TX THROUGH LA...
FORCING FOR ASCENT ASSOCIATED WITH PROGRESSIVE SRN LATITUDE
SHORTWAVE TROUGH WILL MAINTAIN BANDS OF FORCED CONVECTION THROUGH
THE REMAINDER OF ERN TX INTO THE LOWER MS VALLEY FRIDAY MORNING AND
INTO THE AFTERNOON. MOISTURE RETURN AHEAD OF THIS FEATURE IS LIMITED
AND WILL CONTRIBUTE TO ONLY MARGINAL MUCAPE AS IT IS ADVECTED
BENEATH 6.5-7 C/KM MID LEVEL LAPSE RATES RESULTING IN MUCAPE AOB 300
J/KG. A FEW LIGHTNING STRIKES WILL BE POSSIBLE WITH THIS
ACTIVITY...BUT COVERAGE WILL LIKELY REMAIN SPARSE DUE TO WEAK
INSTABILITY.
..DIAL.. 02/10/2012
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