DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161245
SWODY1
SPC AC 161243

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT SUN MAR 16 2014

VALID 161300Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/ERN GULF
COASTAL PLAIN...

...SYNOPSIS...
MID-UPPER LEVEL PATTERN FEATURES HIGH-AMPLITUDE RIDGE WITH BROADLY
ANTICYCLONIC FLOW FIELD COVERING MUCH OF WRN CONUS.
DOWNSTREAM...COMPLEX SERIES OF SHORTWAVES IS CONTRIBUTING TO
POSITIVELY TILTED SYNOPTIC-SCALE TROUGHING THAT EXTENDS FROM JAMES
BAY VORTEX SWWD ACROSS UPPER GREAT LAKES...MO...TX...AND NRN MEX.
LEADING SHORTWAVE TROUGH -- CURRENTLY LOCATED INVOF OK/AR BORDER --
IS FCST TO DEAMPLIFY TODAY WHILE MOVING EWD ACROSS AR...DISSIPATING
TONIGHT OVER TN. WEAKER PERTURBATION -- NOW EVIDENT IN
MOISTURE-CHANNEL IMAGERY OVER COAHUILA -- IS EXPECTED TO EJECT ENEWD
ACROSS TX COAST BY 00Z BEFORE WEAKENING.

MAIN SHORTWAVE TROUGH IS PIVOTING SEWD OVER FAR W TX AND CHIHUAHUA
ATTM...AND WILL PHASE WITH STILL ANOTHER PERTURBATION NOW DIGGING
SSEWD OVER CENTRAL PLAINS. BY 00Z...COMBINED 500-MB TROUGH SHOULD
EXTEND FROM CENTRAL OK SSWWD ACROSS W-CENTRAL TX AND N-CENTRAL MEX.
BY 12Z...THIS FEATURE IS FCST NEAR MEM-VCT-LRD LINE.

AT SFC...11Z CHART LOCATED PRIMARY LOW 30 W HOT. LOW SHOULD SHIFT
EWD TOWARD EXTREME NRN AL BY 00Z. LOW WILL ENCOUNTER DAMMING FRONT
OVER NRN GA OVERNIGHT...BECOMING DIFFUSE WHILE ANOTHER WEAK LOW
DEVELOPS ALONG THAT FRONT OFFSHORE SRN NC. COLD FRONT -- ANALYZED
AT 11Z FROM NRN LA SWWD ACROSS SAT AREA -- IS FCST TO MOVE OFF
MID-UPPER TX COAST AND THROUGH MOST OF DEEP S TX BY EARLY
AFTN...REACHING SRN MS AND EXTREME SERN LA BY 00Z. FRONT SHOULD
REACH CENTRAL/SRN GA AND CENTRAL FL PANHANDLE BY END OF PERIOD.
MARINE/WARM FRONT WAS MOVING SLOWLY NEWD ACROSS EXTREME SERN MS AND
SWRN AL...WHILE BEING OVERTAKEN FROM W-E BY CONVECTION.

...CENTRAL/ERN GULF COASTAL PLAIN...
STG-SVR TSTMS WILL CONTINUE TO SHIFT EWD ACROSS THIS REGION TODAY.
ACTIVITY WILL OFFER DAMAGING WIND THREAT AND RISK FOR A FEW
TORNADOES...FROM BOTH QLCS-EMBEDDED CIRCULATIONS AND WARM-SECTOR
SUPERCELLS.

REF WW 30 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST NEAR-TERM
GUIDANCE ON MORNING SVR THREAT. PRECONVECTIVE AIR MASS FARTHER E
ACROSS CENTRAL/ERN FL PANHANDLE IS EXPECTED TO DESTABILIZE LATER
THIS MORNING AND INTO AFTN BECAUSE OF...
1. LIMITED INSOLATION BENEATH CLOUD CANOPY GENERATED BY CONVECTION
AND
2. BOUNDARY-LAYER WAA AND MOISTENING ACCOMPANYING WARM FRONT...WITH
MID-UPPER 60S F SFC DEW POINTS OFFSETTING WEAK MID-UPPER LEVEL LAPSE
RATES. RESULT SHOULD BE 500-1000 J/KG MLCAPE NEAR
COAST...DIMINISHING NWD/INLAND.

LOW-LEVEL HODOGRAPHS AND DEEP SHEAR WILL REMAIN FAVORABLE FOR SVR AS
THIS REGIME SHIFTS EWD ALONG GULF COAST THROUGH AFTN. SFC-850 MB
WINDS MAY VEER PRIOR TO ARRIVAL OF PRIMARY QLCS...AS IS EVIDENT IN
12Z LIX RAOB. THIS SUGGESTS MAINTENANCE OF DOMINANT LINEAR
MODE...THOUGH TRANSIENT SUPERCELLS MAY OCCUR AHEAD OF QLCS.

...INTERIOR MS/AL...
WIDELY SCATTERED TSTMS MAY DEVELOP THIS AFTN AND MOVE GENERALLY EWD
ACROSS THIS REGION...OFFERING MRGL HAIL THREAT AND STG GUSTS. LAPSE
RATES ALOFT ARE EXPECTED TO STEEPEN ACROSS THIS REGION DURING AFTN
BEHIND INITIAL PRECIP AREA...AS SUBTLE LARGE-SCALE ASCENT AND
COOLING MID-UPPER LEVEL TEMPS PRECEDE SHORTWAVE TROUGH. RESIDUAL
LOW-LEVEL MOISTURE AND POCKETS OF SFC DIABATIC HEATING MAY SUPPORT
300-800 J/KG MLCAPE FOR BRIEF PERIOD. CONVECTION SHOULD DIMINISH
AFTER 00Z AS MID-UPPER WAVE WEAKENS AND NEAR-SFC LAPSE RATES
STABILIZE.

..EDWARDS/MOSIER.. 03/16/2014

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