SPC AC 210656
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CST WED NOV 21 2007
VALID 221200Z - 231200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
LARGE UPPER TROUGH IS FORECAST TO PREVAIL ACROSS THE CONUS THIS
PERIOD...WITH THE TROUGH EXPECTED TO SEPARATE INTO TWO DISTINCT
SMALLER-SCALE FEATURES -- ONE MOVING SLOWLY EWD ACROSS THE NORTHEAST
AND THE SECOND DIGGING SWD INTO THE DESERT SW.
AT THE SURFACE...COLD FRONT INITIALLY ALIGNED ROUGHLY ALONG THE W
SLOPES OF THE APPALACHIANS IS FORECAST TO MAKE STEADY PROGRESS
EWD/SEWD...EXITING THE ATLANTIC AND GULF COASTS DURING THE SECOND
HALF OF THE PERIOD.
...SERN VA SWD INTO FL...
SHOWERS AND THUNDERSTORMS ARE FORECAST TO BE ONGOING AT THE START OF
THE PERIOD INVOF FRONT...AND SHOULD SPREAD E OF THE APPALACHIANS
THROUGH THE PERIOD AS FRONT ADVANCES TOWARD THE ATLANTIC COAST.
MODESTLY-MOIST BOUNDARY LAYER /GENERALLY UPPER 50S TO LOW 60S
DEWPOINTS/ IS EXPECTED AHEAD OF THE FRONT FROM THE MID-ATLANTIC
REGION SWD...BUT WEAK LAPSE RATES AND CLOUD COVER/LIMITED HEATING
SUGGEST ONLY MARGINAL DESTABILIZATION /GENERALLY LESS THAN 500 J/KG
MIXED-LAYER CAPE/.
ROUGHLY UNIDIRECTIONAL 25 TO 40 KT WSWLY FLOW WITH HEIGHT FORECAST
ACROSS THE WARM SECTOR FROM VA SWD SUPPORTS SOME POTENTIAL FOR
ORGANIZED STORMS -- OVERALL SEVERE THREAT SHOULD REMAIN LIMITED DUE
TO LACK OF INSTABILITY. LOCALLY GUSTY WINDS OR AN ISOLATED TORNADO
WILL BE POSSIBLE WITH A COUPLE OF STRONGER STORMS/LINE
SEGMENTS...BUT DEGREE OF THREAT APPEARS ATTM TO BE BELOW SLIGHT RISK
THRESHOLDS.
..GOSS.. 11/21/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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