DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 190600
SWODY2
SPC AC 190559

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT WED SEP 19 2012

VALID 201200Z - 211200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
IN MID-UPPER LEVELS...MEAN TROUGH WILL BE MAINTAINED FROM HUDSON BAY
TO UPPER GREAT LAKES...MS VALLEY AND CENTRAL/WRN GULF. MOISTURE
CHANNEL IMAGERY SHOWS NW-FLOW SHORTWAVE NOW APCHG ND/CANADA
BORDER...WHICH IS FCST TO MOVE THROUGH MEAN TROUGH POSITION OVER MS
THEN EJECT NEWD ACROSS NERN ONT AND ERN HUDSON BAY THIS PERIOD.
MEANWHILE...UPSTREAM VORTICITY/SPEED MAXIMA ALOFT WILL DIG SEWD AND
PIVOT ACROSS MN...WI...LS AND UPPER MI. AS THIS OCCURS...BELT OF
STRONGEST CYCLONIC FLOW ALOFT WILL ARC FROM DAKOTAS ACROSS
IA...IL...LOWER MI...AND SRN ONT. MEANWHILE...LOW-AMPLITUDE
SHORTWAVE TROUGH NOW APPARENT OVER ARKLATEX REGION SHOULD ELONGATE
IN POSITIVELY TILTED FASHION AND REACH PORTIONS MS...AL...AND SERN
LA BY 20/12Z...PERHAPS WITH EMBEDDED/WEAK 500-MB LOW OVER SRN MS OR
SERN LA.

AT SFC...COLD FRONT NOW OVER NRN PLAINS IS FCST TO MOVE SEWD ACROSS
UPPER MS VALLEY AND CENTRAL PLAINS DAY-1...REACHING LM...SRN
IL...OZARKS...SWRN OK AND NW TX BY START OF PERIOD. SRN-PLAINS
SEGMENT OF FRONT SHOULD STALL...WITH SOME NWD RETREAT POSSIBLE OVER
TX PANHANDLE AND ERN NM. DIFFUSE DRYLINE SHOULD DEVELOP FROM NW TX
SWD INTO MTNS OF NRN MEX AS MODEST MOISTURE -- DEW POINTS 50S TO LOW
60S F -- RETURNS NWD FOLLOWING RECENT MAJOR FROPA.

...SRN PLAINS TO OZARKS...
TWO CONVECTIVE EPISODES ARE POSSIBLE THAT MAY BE CONNECTED
TRANSITIONALLY...
1. ISOLATED TO WIDELY SCATTERED TSTMS INVOF FRONTAL ZONE DURING
AFTERNOON AND EARLY EVENING. THIS ACTIVITY WOULD BE
SFC-BASED...WITH DEEPLY MIXED SUBCLOUD LAYERS. SVR POTENTIAL
APPEARS MINIMAL ATTM DUE TO LACK OF MORE ROBUST MOISTURE/CAPE...AND
TO WEAKNESS OF WINDS AND SHEAR FROM LOW THROUGH MIDDLE LEVELS.
HOWEVER...A FEW STG GUSTS ARE POSSIBLE.
2. WIDELY SCATTERED TO SCATTERED TSTMS SHIFTING EWD ACROSS PORTIONS
OK/KS AND PERHAPS SERN MO OVERNIGHT. THIS ACTIVITY SHOULD BE ROOTED
IN ELEVATED INFLOW LAYER...WITH ENOUGH VENTILATING FLOW IN UPPER
LEVELS FOR SOME ORGANIZED MULTICELLULAR MODES. SOME HAIL NEAR SVR
LEVELS MAY OCCUR...BUT MUCAPE SHOULD BE BELOW 1000 J/KG OVER MOST
AREAS BECAUSE OF WEAK MOISTURE.

...SERN CONUS...
WIDELY SCATTERED TO SCATTERED TSTMS SHOULD FORM THROUGHOUT PERIOD
ALONG AND S OF RESIDUAL FRONTAL ZONE...AMIDST RICH LOW-LEVEL
MOISTURE BUT WEAKNESS OF DEEP-LAYER SHEAR AND LAPSE RATES. GREATEST
COVERAGE IS EXPECTED TO BE DIURNAL...WITH INSOLATION AUGMENTING LIFT
NEAR FRONT AND MESOSCALE BOUNDARIES TO ITS S. AS SUCH...SVR
POTENTIAL APPEARS TOO MINIMAL FOR UNCONDITIONAL PROBABILITIES ATTM.

..EDWARDS.. 09/19/2012

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