Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 270550
SWODY1
SPC AC 270548

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1148 PM CST FRI DEC 26 2014

VALID 271200Z - 281200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE WRN GULF
COAST STATES...

...SUMMARY...
SCATTERED THUNDERSTORMS ARE EXPECTED TODAY ACROSS PARTS OF THE
WESTERN GULF COAST STATES. LOCALLY DAMAGING WINDS...MARGINALLY
SEVERE HAIL...AND A BRIEF TORNADO WILL BE POSSIBLE...MAINLY DURING
THE AFTERNOON.

...SYNOPSIS...
LONGWAVE TROUGH CENTERED OVER THE N-CNTRL TO SW CONUS WILL FEATURE
TWO EMBEDDED SHORTWAVE IMPULSES. THE LEAD IMPULSE WILL PROGRESS NE
ACROSS THE UPPER MIDWEST AND GREAT LAKES TODAY...WHILE THE UPSTREAM
IMPULSE ACCELERATES E REACHING CHIHUAHUA AND THE TX TRANS-PECOS
EARLY SUN. SURFACE COLD FRONT ASSOCIATED WITH THE LEAD FEATURE WILL
REACH THE MID-SOUTH TO TX COASTAL PLAIN BY AFTERNOON...WHILE A WEAK
WARM FRONT BECOMES ESTABLISHED ACROSS NRN/CNTRL LA INTO FAR SRN MS.

...WRN GULF COAST...
DESPITE NEUTRAL MID-LEVEL HEIGHT CHANGE THROUGH EARLY EVENING...A
WARM CONVEYOR BELT WILL PERSIST AHEAD OF THE SRN GREAT PLAINS COLD
FRONT. GOES PW DATA ALONG WITH OBSERVATIONS OF MIDDLE 60S TO LOWER
70S SURFACE DEW POINTS CONFIRM A SEASONABLY RICH MOISTURE PLUME
EMANATING N FROM THE WRN GULF. NEVERTHELESS...INITIAL LINGERING OF A
SURFACE RIDGE OVER THE LOWER MS VALLEY...WIDESPREAD
CLOUDINESS/SCATTERED WAA-DRIVEN SHOWERS...AND MODEST MID-LEVEL LAPSE
RATES OF AROUND 6-6.5 DEG C/KM FROM 700-500 MB WILL LIMIT THE
EXTENT/DEGREE OF INLAND WARM SECTOR DESTABILIZATION. BUT WHERE WEAK
DIABATIC HEATING CAN OCCUR /MOST LIKELY ALONG THE IMMEDIATE COASTAL
PLAIN/...THE COMBINATION OF LOW-LEVEL WAA AND FRONTAL/PRE-FRONTAL
CONFLUENCE SHOULD RESULT IN SCATTERED TSTMS FORMING BY EARLY
AFTERNOON. ALTHOUGH LOW-LEVEL FLOW WILL BE MODERATE...STRONG
DEEP-LAYER SHEAR WILL BE SUFFICIENT FOR UPDRAFT ROTATION. AMIDST A
PROBABLE CLUSTER-TYPE MODE...A FEW WEAK/TRANSIENT SUPERCELLS MAY
DEVELOP AND YIELD A MARGINAL SEVERE RISK.

..GRAMS/MOSIER.. 12/27/2014



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