SPC AC 200558
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT TUE MAR 20 2012
VALID 211200Z - 221200Z
...THERE IS A SLGT RISK OF SVR TSTMS SERN LA AND A SMALL PORTION OF
SWRN MS...
...SYNOPSIS...
LARGE UPPER LOW IS FORECAST TO REMAIN QUASI-STATIONARY INVOF WRN OK
THIS PERIOD...AND WILL REMAIN THE PRIMARY FEATURE WITH RESPECT TO
THE CONVECTIVE FORECAST THIS PERIOD. ELSEWHERE...HIGH PRESSURE WILL
REMAIN OVER THE ERN AND SWRN PORTIONS OF THE COUNTRY...WITH A
COMPLEX/LARGE-SCALE ERN PACIFIC TROUGH SLOWLY APPROACHING THE WRN
U.S. THROUGH THE PERIOD.
AT THE SURFACE...A COLD FRONT SHOULD CROSS OREGON AND PARTS OF NRN
CA WITH TIME AHEAD OF THE APPROACHING TROUGH...WHILE A WEAK COLD
FRONT MOVES SLOWLY EWD ACROSS THE LOWER MS VALLEY AHEAD OF THE MAIN
UPPER LOW.
...LOWER MS VALLEY...
A N-S BAND OF SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING AT THE
START OF THE PERIOD NEAR/JUST W OF THE SLIGHT RISK AREA -- I.E.
ACROSS AR AND WRN LA...WITH POSSIBLE ONGOING/LOW-END SEVERE THREAT.
LIMITED HEATING AHEAD OF THE FRONT AND ASSOCIATED CONVECTIVE BAND
WILL SUPPORT SOME INTENSIFICATION OF STORMS THROUGH THE
AFTERNOON...IN CONJUNCTION WITH A SHORT-WAVE TROUGH ROTATING AROUND
THE LARGER-SCALE LOW THAT IS PROGGED TO BRUSH THE LOWER MS VALLEY
AREA. STRONGER FLOW ALOFT SHOULD REMAIN W OF THE CONVECTION -- I.E.
NEARER THE UPPER SYSTEM. HOWEVER...WITH A VERY MOIST BOUNDARY LAYER
AND AMPLE SHEAR IN THE LOWEST KM EXPECTED...THIS SUPPORTS POTENTIAL
FOR A COUPLE OF TORNADOES -- ESPECIALLY WITH ANY STORMS WHICH CAN
INITIATE AHEAD OF THE MAIN/PERSISTENT CONVECTIVE BAND.
THREAT SHOULD GRADUALLY DIMINISH SOME THROUGH THE EVENING...THOUGH
LIMITED THREAT COULD CONTINUE WELL INTO THE OVERNIGHT HOURS AS
STORMS SHIFT SLOWLY EWD THROUGH THE PERIOD.
..GOSS.. 03/20/2012
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NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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