Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 221731
SWODY2
SPC AC 221730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CST MON DEC 22 2014

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MS RIVER
VALLEY/GULF COAST STATES...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK
AREA...

...SUMMARY...
STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS SOUTHERN
PARTS OF THE LOWER MISSISSIPPI VALLEY AND THE GULF COAST
STATES...MAINLY TUESDAY AFTERNOON AND TUESDAY NIGHT. THE POTENTIAL
EXISTS FOR ISOLATED DAMAGING WIND GUSTS AND POSSIBLY A FEW
TORNADOES.

...SYNOPSIS...
A HIGHLY AMPLIFIED LARGE-SCALE PATTERN WILL EXIST OVER THE CONUS ON
TUESDAY. THIS SCENARIO WILL BE HIGHLIGHTED BY AN INITIALLY
POSITIVE-TILT TROUGH OVER THE LOWER MO VALLEY/SOUTHERN PLAINS...WITH
THE TROUGH EXPECTED TO TAKE ON A MORE NEUTRAL TILT LATE TUESDAY
NIGHT INTO WEDNESDAY AS IT SHIFTS EASTWARD TOWARD THE
OZARKS/ARKLATEX.

...LOWER MS VALLEY/CENTRAL GULF COAST REGION...
AS MENTIONED IN THE PRIOR OUTLOOK...EARLY DAY CONVECTION/WEAK
BUOYANCY REMAINS A COMPLICATING AND POSSIBLE...IF NOT
PROBABLE...LIMITING FACTOR /ESPECIALLY WITH NORTHWARD EXTENT/ FOR A
MORE CONSEQUENTIAL SEVERE RISK. EXTENSIVE CLOUDS AND SHOWERS INLAND
ARE LIKELY TO DETER THE INLAND ADVANCEMENT OF A RICHER MARITIME AIR
MASS...THUS POTENTIALLY KEEPING DESTABILIZATION VERY MARGINAL /ONLY
A FEW HUNDRED J PER KG MLCAPE/ ROUGHLY IN AREAS 100+ MILES AWAY FROM
THE GULF COAST.

GIVEN THE PREVIOUSLY DESCRIBED LARGE-SCALE EVOLUTION...OVERALL
FORCING/CONFLUENCE ACROSS THE WARM SECTOR WILL INITIALLY BE MODEST.
ALTHOUGH AT LEAST A CONDITIONAL SEVERE RISK WILL EXIST GIVEN GRADUAL
LOW-LEVEL MOISTENING AND AN INCREASINGLY STRONG LOW-LEVEL WIND FIELD
THROUGH THE AFTERNOON/NIGHT.

A SOMEWHAT MORE ORGANIZED SEVERE RISK COULD EVOLVE BY LATE AFTERNOON
INTO TUESDAY NIGHT...MAINLY ACROSS A CORRIDOR INTO SOUTHEAST
LA/SOUTHERN MS INTO SOUTHERN AL AND PARTS OF THE FL PANHANDLE. AN
INCREASINGLY STRONG CYCLONIC FLOW REGIME WILL CONTRIBUTE TO WEAK
SURFACE LOW/NORTHEASTWARD FRONTAL WAVE DEVELOPMENT OVER THE
NORTHWEST GULF OF MEXICO INTO PARTS OF LA/MS AND WESTERN/NORTHERN AL
LATE TUESDAY INTO WEDNESDAY. GIVEN ADEQUATE BUOYANCY /PARTICULARLY
WITHIN 100 MILES OR SO OF THE COAST/...EFFECTIVE SHEAR FROM 40-50 KT
WILL SUPPORT THE POTENTIAL FOR ORGANIZED STORMS INCLUDING BOTH
SUPERCELLS AND BOWING SEGMENTS CAPABLE OF DAMAGING WINDS AND
POSSIBLY A FEW TORNADOES.

..GUYER.. 12/22/2014




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