SPC AC 230530
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 PM CST SUN NOV 22 2009
VALID 231200Z - 241200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A BROAD...CYCLONIC FLOW REGIME WILL BE MAINTAINED OVER MUCH OF THE
CONUS THROUGH THE DAY ONE PERIOD. THE PRIMARY FEATURE OF INTEREST
WITHIN THIS LARGER-SCALE PATTERN IS SHORT WAVE TROUGH WHICH WILL
INTENSIFY AND EVOLVE INTO A CLOSED SYSTEM WHILE TRANSLATING SEWD
FROM THE GREAT BASIN AND NRN INTERMOUNTAIN REGION INTO THE CNTRL
CONUS. ELSEWHERE...VORTICITY MAXIMUM CURRENTLY OVER THE CNTRL
APPALACHIANS WILL CONTINUE NEWD TO OFF THE MID ATLANTIC COAST.
AT THE SURFACE...LOW PRESSURE INITIALLY OVER THE SRN HIGH PLAINS IS
FORECAST TO DEEPEN SLIGHTLY WHILE DEVELOPING NEWD INTO THE LOWER MO
VALLEY. MEANWHILE...TRAILING COLD FRONT WILL SURGE SWD THROUGH THE
CNTRL AND SRN PLAINS. FARTHER E...SURFACE LOW WILL DEVELOP NNEWD
JUST OFF THE ATLANTIC COAST IN CONJUNCTION WITH LATTER MIDLEVEL
SYSTEM MENTIONED ABOVE.
...NC OUTER BANKS...
TSTMS NOW ONGOING OFF THE SC COAST ARE EXPECTED TO MOVE/DEVELOP
NNEWD ACROSS AREA TODAY IN CONCERT WITH MIGRATORY SURFACE LOW.
WHILE SOME WEAK SURFACE-BASED DESTABILIZATION IS FORECAST ALONG THE
COAST...ANY SEVERE WEATHER THREAT SHOULD REMAIN OFFSHORE.
...FL...
SCATTERED...DIURNAL STORMS WILL BE POSSIBLE ALONG/S OF SURFACE FRONT
WHICH IS FORECAST TO STALL OVER THE CNTRL PENINSULA TODAY. WEAK
LAPSE RATES AND VERTICAL SHEAR WILL PRECLUDE ANY SEVERE WEATHER
POTENTIAL.
...MID MO VALLEY...
ISOLATED TSTM DEVELOPMENT WILL BE POSSIBLE ALONG SURFACE FRONT LATER
TODAY INTO TONIGHT AS HEIGHT FALLS/DYNAMIC COOLING EFFECTIVELY
STEEPEN LAPSE RATES AND CONTRIBUTE TO A SMALL AMOUNT OF CONVECTIVE
INSTABILITY.
...CNTRL/SRN TX...
A MODIFIED CONTINENTAL AIR MASS WILL RETURN NWD IN ADVANCE OF
SWD-MOVING COLD FRONT WITH DEWPOINTS INCREASING THROUGH THE 50S OVER
THE HILL COUNTRY...TO MID 60S OVER DEEP S TX. THIS MOISTURE
INCREASE COUPLED WITH STEEPENING LAPSE RATES AHEAD OF AMPLIFYING
UPPER SYSTEM WILL RESULT IN A WEAKLY UNSTABLE ENVIRONMENT...
SUPPORTIVE OF SCATTERED TSTM DEVELOPMENT LATE TONIGHT INTO TUESDAY
MORNING.
..MEAD/GRAMS.. 11/23/2009
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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