DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 160510
SWODY1
SPC AC 160507

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1207 AM CDT MON MAR 16 2009

VALID 161200Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

LARGE-SCALE PATTERN WILL REMAIN PROGRESSIVE THROUGH THE PERIOD WITH
THE PRIMARY FEATURE OF INTEREST BEING A SRN STREAM SHORT WAVE TROUGH
WHICH WILL TRANSLATE EWD ACROSS THE SERN UNITED STATES.
ELSEWHERE...A POWERFUL POLAR JET WILL DEVELOP EWD FROM THE NRN
ROCKIES INTO THE UPPER GREAT LAKES ALONG SRN PERIPHERY OF BROAD
CYCLONE FLOW REGIME EXTENDING FROM THE GULF OF AK INTO CNTRL
CANADA.

IN THE LOW LEVELS...A WEAK SURFACE LOW INITIALLY OVER SRN AL WILL
DEVELOP EWD ALONG A QUASI-STATIONARY BOUNDARY TO OFF THE SERN
ATLANTIC COAST BY THIS EVENING. A TRAILING COLD FRONT WILL
CONCURRENTLY PUSH EWD AND THEN SEWD THROUGH SRN PARTS OF AL/GA AND
NRN FL.

...ERN GULF COAST...

CURRENT LAND/BUOY OBSERVATIONS AND GOES SOUNDER PW DATA INDICATE
THAT A RATHER MOIST AIR MASS RESIDES OVER THE N-CNTRL/NERN GULF
BASIN AND IMMEDIATE COAST WITH DEWPOINTS IN THE MID 60S TO LOWER 70S
AND PW VALUES ABOVE 1.5 INCHES. HOWEVER...16/00Z REGIONAL OBSERVED
SOUNDING DATA AND LATEST MODEL GUIDANCE INDICATE THAT LAPSE RATES
REMAIN QUITE WEAK ALONG AND AHEAD OF ABOVEMENTIONED SHORTWAVE TROUGH
WITH MLCAPE LIKELY REMAINING AOB 500 J/KG.

TSTMS ARE EXPECTED TO BE ONGOING AT 16/12Z ALONG AND AHEAD OF
SURFACE COLD FRONT OVER SRN AL AND THE FL PNHDL. THIS ACTIVITY IS
EXPECTED TO PROGRESSIVELY MOVE/DEVELOP EWD ACROSS SRN GA AND THE
REMAINDER OF NRN FL IN ADVANCE OF MIGRATORY UPPER TROUGH. WHILE WRN
EXTENSION OF 50-60 KT MIDLEVEL JET WILL RESIDE ACROSS THE WARM
SECTOR...STRONGER LOW-LEVEL FLOW ASSOCIATED WITH A SWLY LLJ WILL
RAPIDLY DEVELOP E OF THE REGION TODAY. THE NET RESULT WILL BE
LARGELY UNDIRECTIONAL WIND PROFILES WITH 30-40 KT DEEP LAYER SHEAR.
THIS KINEMATIC ENVIRONMENT IN CONJUNCTION WITH THE WEAK INSTABILITY
MAY BE SUPPORTIVE A FEW STRONGER STORMS CAPABLE OF GUSTY WINDS.
HOWEVER...A MORE SUBSTANTIAL SEVERE WEATHER THREAT WILL BE TEMPERED
BY THE POOR LAPSE RATES AND WEAK LOW-LEVEL WIND FIELDS.

..MEAD/SMITH.. 03/16/2009

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