DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 231243
SWODY1
SPC AC 231241

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0641 AM CST SUN FEB 23 2014

VALID 231300Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
IN MID-UPPER LEVELS...BROADLY CYCLONIC FLOW WILL CHARACTERIZE
PATTERN OVER MOST OF CONUS...EXCEPT FOR RIDGING FCST ALONG W COAST
NEAR END OF PERIOD. SEVERAL INITIALLY LOW-AMPLITUDE PERTURBATIONS
AND VORTICITY MAXIMA WILL PHASE SUFFICIENTLY TO YIELD WELL-DEFINED
SHORTWAVE TROUGH OVER OH/LOWER MI/SERN ONT VICINITY BY END OF
PERIOD.

AT SFC...WEAK/FRONTAL-WAVE CYCLONE -- INITIALLY OVER RED RIVER
REGION OF SRN OK/N TX -- SHOULD MIGRATE EWD ACROSS ARKLATEX REGION
THROUGH EARLY EVENING BEFORE WEAKENING TONIGHT. ATTACHED COLD FRONT
WILL ACCELERATE SEWD/SWD...REACHING MID-ATLC REGION...MID TN...AND
S-CENTRAL TX BY 00Z. FRONT SHOULD REACH COASTAL SC AND SERN LA BY
12Z...WHILE DECELERATING OVER S TX AND NERN MEX. OLDER FRONTAL ZONE
-- ANALYZED INITIALLY FROM CENTRAL/SRN FL WNWWD ACROSS NRN GULF JUST
OFFSHORE LA/UPPER TX COAST...IS EXPECTED TO CONTINUE MOVING NWD AS
INCREASINGLY DIFFUSE WARM FRONT. THIS BOUNDARY THEN WILL BE
OVERTAKEN BY AFOREMENTIONED COLD FRONT FROM W-E OVERNIGHT.

...SERN CONUS...DELTA TO SRN GA/FL...
EPISODES OF SCATTERED TO WIDELY SCATTERED TSTMS IN CLUSTERS AND
BANDS ARE EXPECTED TO SHIFT EWD ACROSS OUTLOOK AREA...BEGINNING WITH
BKN SWATH OF CONVECTION NOW UNDERWAY FROM LA TO SRN AL AND FL
PANHANDLE. SUBSTANTIAL CONVECTION AS WELL AS MRGL SVR RISKS WILL
END FROM W-E ACROSS THIS AREA. MOST VIGOROUS CELLS MAY OFFER HAIL
NEAR SVR LIMITS FOR A FEW MORE HOURS...THOUGH WEAKENING OF LAPSE
RATES WITH TIME SHOULD KEEP REMAINING POTENTIAL TOO MRGL FOR
CATEGORICAL-THRESHOLD SVR PROBABILITIES.

INITIAL CONVECTIVE REGIME WILL REMAIN SUPPORTED BY EWD SHIFT IN
COUPLING OF
1. RIGHT ENTRANCE REGION OF BROAD UPPER-JET CORE CENTERED OVER TN
VALLEY AND CENTRAL/SRN APPALACHIANS...AND
2. BROAD BUT NOT PARTICULARLY INTENSE CONVEYOR OF LOW-LEVEL
WAA/ISENTROPIC LIFT/MOISTURE TRANSPORT...CHARACTERIZED BY 25-35 KT
SWLY LOW-LEVEL FLOW ATOP RELATIVELY STABLE BOUNDARY LAYER.
THIS REGIME SHOULD MODIFY AWAY RESIDUAL EML EVIDENT IN 12Z JAX RAOB.

BY AFTN...SRN EDGE OF THAT CLOUD/PRECIP PLUME MAY YIELD WELL-DEFINED
DIFFERENTIAL-HEATING/OUTFLOW BOUNDARY...WHILE CONVERGENCE ZONE
DEVELOPS OVER ERN FL PENINSULA SWD PAST LAKE OKEECHOBEE. LIFT
ASSOCIATED WITH THESE BOUNDARIES...ALONG WITH DIABATIC HEATING...MAY
ALLOW SFC-BASED EFFECTIVE INFLOW PARCELS IN SUPPORT OF
ADDITIONAL...WIDELY SCATTERED TO SCATTERED TSTM DEVELOPMENT.
POCKETS OF MID-UPPER 60S F SFC DEW POINTS SHOULD CONTRIBUTE TO
1000-1500 J/KG MLCAPE...WITH AROUND 40-45 KT EFFECTIVE SHEAR
MAGNITUDES EVIDENT IN FCST SOUNDINGS OVER E-CENTRAL/NERN FL S OF
ELEVATED WAA PLUME. ORGANIZED MULTICELLS OR TRANSIENT SUPERCELL
CHARACTERISTICS ARE POSSIBLE...THEREFORE MRGL SVR HAIL/GUST
PROBABILITIES ARE BEING INTRODUCED ATTM.

..EDWARDS/BOTHWELL.. 02/23/2014

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