SPC AC 280548
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1148 PM CST THU DEC 27 2007
VALID 291200Z - 301200Z
...NO SVR TSTM AREAS FORECAST...
...SERN U.S./CENTRAL GULF COAST...
SRN END OF LARGE SCALE FORCING/ASCENT WILL BRUSH THE MIDDLE ATLANTIC
REGION EARLY IN THE PERIOD AS STRONG MID LEVEL SPEED MAX/SHORTWAVE
TROUGH EJECT ACROSS SRN NEW ENGLAND. ASSOCIATED SFC FRONT WILL
TRAIL SWWD ACROSS SERN VA INTO CNTRL NC BEFORE THIS PORTION OF THE
FRONT IS FORCED OFFSHORE BY A SOMEWHAT BENIGN AND RELATIVELY WEAK
SFC HIGH THAT SHOULD SETTLE INTO THE APPALACHIANS BY THE END OF THE
PERIOD. PRIOR TO SFC FRONTAL PASSAGE...FORECAST SOUNDINGS SUGGEST
WEAK BUOYANCY IF LIFTING A PARCEL NEAR 850MB. THIS MAY PROVE
SUFFICIENT IN THE DEVELOPMENT OF ISOLATED THUNDERSTORMS BEFORE 18Z.
FARTHER SW AND DURING THE LATTER HALF OF THE PERIOD...LOW LEVEL WARM
ADVECTION SHOULD INCREASE ALONG/NORTH OF STALLED FRONTAL ZONE OVER
THE NRN GULF OF MEXICO. THIS ENHANCED WARM ADVECTION WILL BE DUE
LARGELY TO INCREASING SWLY 850MB FLOW IN ADVANCE OF APPROACHING
SHORTWAVE TROUGH OVER OK/TX. IT APPEARS ADEQUATE MOISTURE WILL
RETURN JUST ABOVE THE BOUNDARY LAYER AND WEAK ELEVATED CAPE SHOULD
PROVIDE ENOUGH INSTABILITY FOR SCATTERED THUNDERSTORMS AFTER
06Z...PERHAPS AS LATE AS 30/12Z ALONG A NARROW AXIS FROM SERN LA
INTO SRN AL/WRN FL PANHANDLE.
...PACIFIC NW...
THERMAL PROFILES WILL COOL NOTICEABLY IN THE WAKE OF FRONTAL PASSAGE
AFTER 30/00Z ALONG THE WA/NWRN ORE COAST. FORECAST SOUNDINGS WITHIN
POST FRONTAL MARINE BOUNDARY LAYER AIRMASS SUGGEST 100-200 J/KG
SBCAPE WITH SFC-3KM LAPSE RATES ON THE ORDER OF 8 C/KM. THIS SHOULD
PROVE MORE THAN ADEQUATE FOR SCATTERED THUNDERSTORMS ALONG/WEST OF
COASTAL RANGE...MAINLY AFTER 06Z.
..DARROW.. 12/28/2007
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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