SWODY1
SPC AC 171954
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CDT WED SEP 17 2008
VALID 172000Z - 181200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
IN MID-UPPER LEVELS...NRN STREAM PATTERN FEATURES ERN TROUGH AND WRN
RIDGE...WITH QUASISTATIONARY TROUGHING S OF RIDGE FROM GREAT BASIN
ESEWD ACROSS S-CENTRAL TX TO MS DELTA REGION AND NERN GULF...NEWD
INTO SHORTWAVE TROUGH ANALYZED OVER GA AND FL PANHANDLE. GA/FL
SEGMENT OF TROUGH IS FCST TO MOVE EWD -- OFFSHORE GA AND SC BY END
OF PERIOD. TRAILING PORTION WILL BECOME QUASISTATIONARY ACROSS NRN
FL WHILE STILL LINKED TO CYCLONIC SHEAR ZONE OVER NRN GULF.
SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER FAR
NRN CA -- IS FCST TO EJECT NEWD ACROSS ORE AS UPPER LOW OVER NERN
PACIFIC MOVES EWD TOWARD REGION.
AT SFC...COLD FRONT INITIALLY ANALYZED FROM SWRN QUE SWWD ACROSS
S-CENTRAL LOWER MI AND SRN WI...BECOMING QUASISTATIONARY OVER
IA...THEN WARM FRONT WNWWD ACROSS SRN SD. COLD FRONT IS EXPECTED TO
MOVE ESEWD ACROSS REMAINDER LH AND ST LAWRENCE VALLEY...MOVING OVER
NEW ENGLAND...PORTIONS MID-ATLANTIC AND MID-UPPER OH VALLEY BY
18/12Z. WHILE VERY BRIEF/ISOLATED TSTM CANNOT BE RULED OUT OVER MI
PORTION OF THIS FRONT...LACK OF MORE ROBUST
MOISTURE/INSTABILITY/CONVERGENCE INDICATES TSTM POTENTIAL TOO
CONDITIONAL/MRGL FOR GEN THUNDER OUTLOOK. MEANWHILE...WARM FRONT
SHOULD DRIFT NWD ACROSS N-CENTRAL PLAINS. SEPARATE FRONTAL ZONE
CONTINUES TO DRIFT SWD ACROSS NRN FL...WITH ENHANCEMENT FROM OUTFLOW
PRODUCED BY ONGOING CONVECTION.
...FL...
SCATTERED/LOCALLY NUMEROUS TSTMS FCST TO CONTINUE FORMING ALONG AND
S OF FRONT...INCLUDING INVOF SEA/LAKE BREEZE AND OUTFLOW
BOUNDARIES...AND THEIR INTERSECTIONS WITH EACH OTHER AND WITH FRONT.
STG-DAMAGING GUSTS AND MRGL SVR HAIL MAY OCCUR BRIEFLY WITH
BEST-ORGANIZED CONVECTION. EXPECT MLCAPES COMMONLY 1500-2000 J/KG
THROUGH AROUND 23Z IN RELATIVELY CLOUD-FREE AREAS AND AWAY FROM
CONVECTIVE OUTFLOWS. LOW-MIDLEVEL FLOW AND SHEAR GENERALLY WILL
REMAIN WEAK...ALTHOUGH SMALL AREA OF EFFECTIVE SHEAR MAGNITUDES
30-35 KT OVER PORTIONS NRN FL MAY AID IN MULTICELLULAR ORGANIZATION.
THREAT WILL DIMINISH AFTER SUNSET WITH COMBINED STABILIZING EFFECTS
OF OUTFLOW AND SFC DIABATIC COOLING.
..EDWARDS/KIS.. 09/17/2008
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