SWODY2
SPC AC 130555
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1155 PM CST THU NOV 12 2009
VALID 141200Z - 151200Z
...NO TSTM AREAS FORECAST...
...SYNOPSIS...
UPPER AIR PATTERN TRANSITION WILL FAVOR RISING HEIGHTS OVER MUCH OF
ERN CONUS...IN WAKE OF DEPARTING DEEP-LAYER CYCLONE NOW JUST
OFFSHORE OUTER BANKS...AND MORE WIDESPREAD TROUGHING ACROSS WRN
CONUS. INITIALLY SEPARATE SHORTWAVE TROUGHS -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER ORE/ID BORDER AND OVER N-CENTRAL MT TO
S-CENTRAL SK -- ARE EXPECTED TO PHASE TOGETHER...MOVE EWD... AND
DEVELOP NEARLY CLOSED 500 MB LOW OVER ND BY 14/12Z. THIS CYCLONE
THEN SHOULD CONTRACT AND MOVE ENEWD ACROSS NRN SHORE OF LS IN
ONT...BY END OF PERIOD. UPSTREAM PERTURBATION IS AMPLIFYING ATTM W
OF VANCOUVER ISLAND...AND SHOULD DIG SEWD ACROSS GREAT BASIN EARLY
IN PERIOD. BY 15/00Z...TROUGH SHOULD EXTEND FROM CENTRAL AZ NWD TO
NRN ROCKIES..ANCHORED BY SMALL/CLOSED 500 MB LOW OVER UT. AT END OF
PERIOD...POSITIVELY TILTED AND HIGH-AMPLITUDE TROUGH SHOULD EXTEND
FROM NRN HIGH PLAINS TO NWRN MEX...WITH EMBEDDED/MID-UPPER LOW
BETWEEN 4-CORNERS AREA AND SRN ROCKIES.
SFC COLD FRONT -- NOW ANALYZED FROM NWRN MN SWWD ACROSS CENTRAL NEB
TO FRONTAL-WAVE LOW OVER NRN CO -- IS FCST TO EXTEND FROM UPPER MS
VALLEY LOW SWWD ACROSS NWRN MO AND NWRN OK BY 14/12Z. SFC CYCLONE
WILL MOVE NEWD ACROSS LS REGION BY 15/12Z...IN RESPONSE TO NRN
STREAM SHORTWAVE TROUGH...COLD FRONT WILL REACH TO NEAR CENTRAL
INDIANA...OZARKS...RED RIVER REGION AND PORTIONS WRN/NWRN TX.
STG LOW-LEVEL WAA REGIME IS EXPECTED ACROSS CENTRAL/SRN PLAINS AHEAD
OF MID-UPPER TROUGHING...AND S OF FRONTAL ZONE.
HOWEVER...LOW LEVEL MOISTURE RETURN IS FCST TO BE RATHER
FEEBLE...GIVEN PERSISTENCE/SIZE OF CYCLONE MOVING OFFSHORE E
COAST...AND LONGEVITY OF RELATIVELY LOW-THETAE TRAJECTORIES IN ITS
WAKE. AS SUCH...SVR POTENTIAL APPEARS MINIMAL. POTENTIAL FOR TSTMS
WILL BE VERY CONDITIONAL...MRGL AND ISOLATED AT BEST.
LATE IN PERIOD...MIDLEVEL CONVECTION MAY DEVELOP BEHIND SFC
FRONT...DEEPLY ENOUGH TO POSE SOME CONCERN FOR THUNDER BETWEEN SRN
ROCKIES AND NRN OK...RELATED LARGELY TO STG DYNAMICALLY DRIVEN
DESTABILIZATION ALOFT. ATTM IT APPEARS LACK OF DEEPER BUOYANT LAYER
AND OF MORE ROBUST MOISTURE WILL PRECLUDE ENOUGH UNCONDITIONAL TSTM
POTENTIAL FOR CATEGORICAL GEN THUNDER OUTLOOK.
..EDWARDS.. 11/13/2009
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