DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 041253
SWODY1
SPC AC 041251

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0651 AM CST TUE DEC 04 2012

VALID 041300Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MORNING WATER VAPOR DATA INDICATE A MID-LEVEL CYCLONE OVER NRN
ONTARIO THAT IS PROJECTED TO TRACK NEWD INTO QUEBEC. THIS FEATURE IS
ACCOMPANIED BY A SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE UPPER
MIDWEST AND GREAT LAKES BEFORE EVENTUALLY REACHING THE NERN STATES
BY EARLY WED MORNING. A SEPARATE SRN SHORTWAVE TROUGH WILL PROGRESS
ESEWD ACROSS THE SRN PLAINS...LOWER MS VALLEY...AND NRN GULF. A SFC
FRONT ASSOCIATED WITH THE COMPOSITE ERN/S-CNTRL-CONUS SHORTWAVE
TROUGHS WILL CONTINUE TO ADVANCE EWD/SWD THROUGH TONIGHT...AND
EXTEND FROM COASTAL NEW ENGLAND TO THE LOWER MS VALLEY TO THE NW
GULF BY EARLY WED MORNING.

...PORTIONS OF ERN/SRN TX...NRN/WRN LA...SRN AR...WRN MS THIS
AFTERNOON AND THIS EVENING...
ONGOING CONVECTION INVOF THE FRONT OVER NRN AR WILL LIKELY BE
STEERED ACROSS THE MID-SOUTH WHERE LOW-LEVEL MOISTURE/INSTABILITY
WILL BE RELATIVELY SMALLER IN MAGNITUDE COMPARED TO LOCATIONS
FARTHER SOUTH. THROUGH MID-DAY...ADDITIONAL STORMS WILL LIKELY
DEVELOP ACROSS THE LOWER MS VALLEY OVER THE SRN FLANKS OF THE
ONGOING CONVECTION...AND WITHIN A ZONE OF WEAK LOW-LEVEL
WAA/CONFLUENCE THAT LEADS THE FRONT. THIS AFTERNOON...STRONGER
STORMS WILL LIKELY DEVELOP ALONG THE FRONT FROM SRN AR INTO SRN TX.
THIS WILL OCCURS AS DIURNAL HEATING COMBINES WITH MODESTLY STEEP
MID-LEVEL LAPSE RATES OVERSPREADING PREFRONTAL DEWPOINTS IN THE
LOWER AND MIDDLE 60S. FORECAST SOUNDINGS SUGGEST THAT 500-1500 J/KG
OF MLCAPE WILL BE COMMON ACROSS THE AREA.

WITH 20-30 KT OF 500-MB FLOW...DEEP SHEAR IS NOT EXPECTED TO BE
STRONG...WITH CLUSTERS OF MULTICELL STORMS LIKELY BEING THE
PREDOMINANT CONVECTIVE MODE. ISOLATED INSTANCES OF SVR WINDS/HAIL
WILL BE POSSIBLE WITH THE MOST INTENSE STORMS. WEAK LOW-LEVEL FLOW
WILL ALSO PREVENT A MORE SUBSTANTIAL SVR THREAT FROM EVOLVING.

STORMS WILL LIKELY BE MOVING OFF THE TX COAST DURING THE EVENING
HOURS...WITH STORMS ACROSS THE LOWER MS VALLEY MOVING EWD/SEWD WHILE
WEAKENING DURING THE MID/LATE EVENING.

..COHEN/CORFIDI.. 12/04/2012

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