SWODY1
SPC AC 071252
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0652 AM CST SAT JAN 07 2012
VALID 071300Z - 081200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
THE SSEWD PROGRESSION OF AN UPPER-LEVEL JET STREAK FROM THE PACIFIC
NW AND GREAT BASIN WILL SUPPORT THE AMPLIFICATION OF A
POSITIVELY-TILTED MIDLEVEL TROUGH FROM THE CNTRL ROCKIES INTO SWRN
DESERTS DURING THE D1 PERIOD. DOWNSTREAM FROM THIS FEATURE...
VORTICITY MAXIMA OVER THE OZARK PLATEAU AND CNTRL GULF OF MEXICO
WILL FURTHER WEAKEN WHILE PROGRESSING EWD TO OFF THE ATLANTIC COAST
BY 08/12Z. IN THE LOW LEVELS...A COLD FRONT CURRENTLY EXTENDING
FROM THE UPPER OH VALLEY SWWD TO AN AREA OF LOW PRESSURE OVER NERN
TX WILL ADVANCE EWD TO OFF THE NEW ENGLAND AND MID-ATLANTIC
COASTS...WHILE SETTLING MORE SLOWLY SWD THROUGH THE TN VALLEY INTO
GULF COAST STATES. MEANWHILE...THE SWRN EXTENSION OF THE FRONT WILL
BECOME QUASI-STATIONARY ACROSS ERN AND SRN PARTS OF TX.
...LOWER MS VALLEY/CNTRL GULF STATES...
ELEVATED CONVECTION WITH EMBEDDED TSTMS HAS GRADUALLY INCREASED IN
AREAL COVERAGE EARLY THIS MORNING FROM NRN MS/WRN TN EWD INTO NRN AL
AND SRN MIDDLE TN. WEAK ISENTROPIC ASCENT COUPLED WITH INCREASING
DCVA DOWNSTREAM FROM THE OZARK PLATEAU IMPULSE APPEAR TO BE THE
PRIMARY MECHANISMS FORCING THIS ACTIVITY. 12Z REGIONAL SOUNDINGS
INDICATE THAT THE AMBIENT AIR MASS IS MODESTLY MOIST WITH PW VALUES
OF .85-1.0 INCH AND RESULTANT MUCAPE VALUES OF 500-1000 J/KG.
MOREOVER...THESE DATA SUGGEST THAT THE ONSET OF DAYTIME HEATING AND
DEEPER PBL MIXING SHOULD RESULT IN AN INCREASE IN DEWPOINTS
INLAND...SUPPORTING AFTERNOON SBCAPE VALUES OF 500-1000 J/KG.
EXPECT ONGOING ELEVATED TSTMS TO PERSIST THIS MORNING ACROSS THE
SAME GENERAL AREAS AS DCVA FURTHER INCREASES AHEAD OF OZARK PLATEAU
VORTICITY MAXIMUM. BY AFTERNOON...SUFFICIENT HEATING/MOISTENING OF
THE BOUNDARY LAYER SHOULD OCCUR TO SUPPORT THE DEVELOPMENT OF
SURFACE-BASED TSTMS OVER PORTIONS OF LA...MS AND AL. SOME
LONGER-LIVED...WEAKLY ROTATING UPDRAFTS WILL BE POSSIBLE GIVEN THE
PRESENCE OF A VERTICALLY VEERING WIND PROFILE AND AROUND 30 KT OF
EFFECTIVE BULK SHEAR. HOWEVER...IT APPEARS THAT ANY MEANINGFUL
SEVERE WEATHER THREAT WILL BE LIMITED BY WEAK LAPSE RATES AND THE
MARGINALLY STRONG VERTICAL SHEAR.
..MEAD/DEAN.. 01/07/2012
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