SPC AC 160812
DAY 2 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0212 AM CST FRI NOV 16 2007
VALID 171200Z - 181200Z
...NO SVR TSTM AREAS FORECAST...
CORRECTED TO ADD SEE TEXT LABEL TO CATEGORICAL GRAPHIC
...SYNOPSIS...
LARGE UPPER TROUGH -- COMPRISED OF SMALLER-SCALE FEATURES IN THE NRN
AND SRN STREAMS -- WILL MOVE EWD ACROSS THE ERN HALF OF THE CONUS
THIS PERIOD...WHILE FAST WSWLY FLOW PREVAILS ACROSS THE W AHEAD OF
AN OFFSHORE TROUGH OVER THE ERN PACIFIC.
AT THE SURFACE...A COLD FRONT IS EXPECTED TO MOVE SLOWLY SEWD ACROSS
THE NORTHEAST/GREAT LAKES/OH VALLEY...AND MORE SLOWLY SWD ACROSS THE
CENTRAL AND INTO THE SRN PLAINS.
...TX EWD INTO SWRN AR/WRN LA...
MID-LEVEL SHORT-WAVE TROUGH IS FORECAST TO MOVE SLOWLY EWD ACROSS
THE SRN PLAINS THIS PERIOD...ALONG WITH A PERSISTENT/BROAD AREA OF
WEAK LOW PRESSURE EXPECTED AT THE SURFACE. SLY LOW-LEVEL FLOW IS
FORECAST TO GRADUALLY ADVECT A FAIRLY MOIST BOUNDARY LAYER NWD INTO
TX...WHICH COMBINED WITH DAYTIME HEATING AND COOLING MID-LEVEL
TEMPERATURES SHOULD YIELD MARGINAL INSTABILITY /AROUND 500 J/KG
MIXED-LAYER CAPE./
THOUGH BOUNDARY LAYER SHOULD REMAIN CAPPED THROUGH MUCH OF THE
AFTERNOON...PERSISTENT UVV AHEAD OF APPROACHING TROUGH MAY
EVENTUALLY SUPPORT LOCAL STORM DEVELOPMENT. WEAK SURFACE PATTERN
SUGGESTS THAT STORM COVERAGE SHOULD REMAIN LIMITED THROUGH EARLY
EVENING...THOUGH THE DEVELOPMENT OF A WEAK LOW-LEVEL JET AND
ASSOCIATED WARM ADVECTION MAY ALLOW SOME INCREASE IN CONVECTIVE
COVERAGE INTO THE OVERNIGHT PERIOD.
WHILE LOW-LEVEL FLOW SHOULD REMAIN RELATIVELY WEAK...40 KT SWLYS AT
MID LEVELS SHOULD SPREAD ATOP THE WARM SECTOR AHEAD OF THE
APPROACHING TROUGH. RESULTING SHEAR MAY SUPPORT A FEW STRONGER
STORMS...POSSIBLY CAPABLE OF PRODUCING MARGINAL HAIL OR
LOCALLY-GUSTY WINDS. THUS...WILL INTRODUCE A SMALL AREA OF 5%
SEVERE PROBABILITY OVER CENTRAL TX AND VICINITY.
..GOSS.. 11/16/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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