Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 271937
SWODY1
SPC AC 271935

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0135 PM CST SAT DEC 27 2014

VALID 272000Z - 281200Z

...THERE IS A MRGL RISK OF SVR TSTMS FROM SERN TX INTO THE LOWER MS
VALLEY...

...SUMMARY...
ISOLATED SEVERE STORMS CAPABLE OF LOCALLY DAMAGING
WINDS...MARGINALLY SEVERE HAIL...AND A BRIEF TORNADO ARE POSSIBLE
THIS AFTERNOON INTO THIS EVENING FROM SOUTHEAST TEXAS INTO LOUISIANA
AND SOUTHWEST MISSISSIPPI.

HAVE MADE MINOR ADJUSTMENTS TO THE SEVERE THREAT ACROSS PORTIONS OF
SERN TX.  COLD FRONT IS SURGING SWD TOWARD THE UPPER TX COAST AND
POST-FRONTAL CONVECTION SHOULD REMAIN TOO WEAK TO WARRANT MORE THAN
MARGINALLY SEVERE HAIL.  OTHERWISE...EARLIER THOUGHTS REGARDING THE
SEVERE POTENTIAL DOWNSTREAM REMAIN.  REF SWOMCD1998 FOR MORE
MESOSCALE DETAILS ON THIS EVENT.

..DARROW.. 12/27/2014

.PREV DISCUSSION... /ISSUED 1028 AM CST SAT DEC 27 2014/

...SYNOPSIS...
AN INITIAL SHORTWAVE TROUGH IS TRANSLATING QUICKLY NEWD OVER THE
UPPER MS VALLEY...WHILE THE PRIMARY SHORTWAVE TROUGH IS DRIFTING EWD
OVER NM/AZ/NW MEXICO.  AT THE SURFACE...A COLD FRONT IS MOVING SEWD
INTO SE TX...WHILE THE SURFACE WARM SECTOR IS CONFINED TO A
RELATIVELY SMALL AREA OF S/SE TX TO NEAR THE LA COAST.  THE WARM
SECTOR /CHARACTERIZED BY BOUNDARY LAYER DEWPOINTS NEAR 70 F/ SHOULD
SPREAD A LITTLE FARTHER INLAND TODAY ACROSS S/SW LA PRIOR TO COLD
FRONTAL PASSAGE...BUT INLAND PROGRESS WILL BE SLOWED BY WIDESPREAD
CLOUDS TO INHIBIT HEATING/MIXING...AND MINIMAL CYCLOGENESIS WITH THE
PRIMARY WAVE WELL TO THE W.

REGIONAL 12Z SOUNDINGS SHOWED THE POTENTIAL FOR MLCAPE TO REACH
500-1000 J/KG WHERE THE NEAR 70 F BOUNDARY LAYER DEWPOINTS COINCIDE
WITH THE NE EDGE OF A SHALLOW EML NOTED AT BRO/CRP.  IT APPEARS THE
MORE WIDESPREAD CONVECTION WILL OCCUR TODAY IN TWO ZONES THAT ARE
ALREADY APPARENT...ONE ALONG THE SURFACE COLD FRONT FROM SE TX INTO
WRN LA...AND ANOTHER FROM SE LA INTO SRN MS ON THE N EDGE OF A SURGE
OF RICHER MOISTURE /PW VALUES NEAR 1.75 INCHES/.  THE BUOYANCY AND
DEEP-LAYER VERTICAL SHEAR WILL BE SUFFICIENT FOR SOME RISK OF
ORGANIZED/WEAKLY ROTATING STORMS WITH A MARGINAL SEVERE RISK.
HOWEVER...LOW-LEVEL SHEAR WILL REMAIN RATHER MODEST BY COOL SEASON
STANDARDS AS A RESULT OF ONLY MINIMAL CYCLOGENESIS...WHICH WILL
LIMIT THE OVERALL SUPERCELL/TORNADO RISK.




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