Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 181632
SWODY1
SPC AC 181630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT THU SEP 18 2014

VALID 181630Z - 191200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED DAMAGING WINDS AND LARGE HAIL WILL BE POSSIBLE THIS
AFTERNOON FROM NORTHEAST NEVADA TO SOUTH CENTRAL MONTANA.  OTHER
MARGINALLY SEVERE STORMS WITH GUSTY WINDS CAN BE EXPECTED THIS
AFTERNOON ALONG THE SOUTH CAROLINA COAST...AS WELL AS ACROSS
SOUTHEAST ARKANSAS AND ADJACENT AREAS OF NORTHWEST MISSISSIPPI AND
NORTHEAST LOUISIANA.

...NE NV TO SRN MT THIS AFTERNOON...
A MIDLEVEL TROUGH IS MOVING SLOWLY INLAND OVER THE PAC COAST...WITH
A BAND OF ENHANCED MID-UPPER SWLY FLOW PRECEDING THE TROUGH FROM THE
NW GREAT BASIN TO THE NRN ROCKIES.  SOME LOW-LEVEL MOISTURE IS BEING
DRAWN NWD ACROSS CENTRAL/ERN NV IN ADVANCE OF THE MIDLEVEL TROUGH
AND BAROCLINIC ZONE.  LINGERING CLOUDS WITH ONGOING CONVECTION FROM
ID INTO SRN MT COULD SLOW SURFACE HEATING...WHILE MODIFIED 12Z
SOUNDINGS FROM SLC AND LKN SHOW THE POTENTIAL FOR SBCAPE OF 300-500
J/KG WITH SURFACE TEMPERATURES NEAR 80 F AND DEWPOINTS IN THE MID
40S.  THOUGH BUOYANCY WILL BE LIMITED...DEEP-LAYER SHEAR WILL BE
FAVORABLE FOR ORGANIZED STORMS /INCLUDING SUPERCELLS/...SO WILL
MAINTAIN LOW PROBABILITIES FOR DAMAGING WINDS/LARGE HAIL.

...SC/GA COAST THIS AFTERNOON...
A WEAK SURFACE LOW AND REMNANT FRONTAL ZONE...ALONG WITH LOCAL SEA
BREEZE CIRCULATIONS...WILL HELP FOCUS THUNDERSTORM DEVELOPMENT THIS
AFTERNOON ALONG THE GA/SC COAST.  MLCAPE OF 1500-2000 J/KG AND
EFFECTIVE BULK SHEAR NEAR 30 KT WILL SUPPORT THE RISK FOR
SEMI-ORGANIZED CELLS WITH THE POTENTIAL TO PRODUCE ISOLATED STRONG
OUTFLOW GUSTS WITH WET MICROBURSTS.

...SE KS/ERN OK TO THE ARKLAMISS THIS AFTERNOON...
SEVERAL FACTORS ARE COMBINING TO REDUCE THE RISK FOR ISOLATED
DAMAGING WINDS AND HAIL TODAY.  AN EXTENSIVE COLD POOL WITH ONGOING
CONVECTION CONTINUES TO SURGE SWWD INTO WRN AND SRN OK...LOOSELY IN
ASSOCIATION WITH A SUBTLE SHORTWAVE TROUGH MOVING SEWD OVER NE OK.
THOUGH CONVECTION HAS WEAKENED IN OK SINCE EARLIER THIS
MORNING...LINGERING CLOUDS AND THE STABILIZING INFLUENCE OF THE COLD
POOL WILL ACT TO REDUCE BUOYANCY THROUGH THE AFTERNOON.  THE
STRONGER VERTICAL SHEAR WILL TEND TO REMAIN WELL ON THE COOL SIDE OF
THE OUTFLOW BOUNDARY...SUCH THAT ORGANIZED SEVERE STORMS APPEAR
UNLIKELY ALONG THE OUTFLOW ITSELF.  FARTHER S ALONG THE REMNANT
FRONT FROM NRN LA TO NE TX...VERTICAL SHEAR WILL REMAIN WEAK AND
EXTENSIVE HIGH CLOUDS /EMANATING FROM THE REMAINS OF TC ODILE/ WILL
TEND TO SLOW SURFACE HEATING AND LIMIT BUOYANCY.  ALL THINGS
CONSIDERED...THE RISK FOR DAMAGING WINDS AND LARGE HAIL APPEARS TO
BE TOO SMALL TO WARRANT KEEPING AN OUTLOOK AREA.
OTHERWISE...SOMEWHAT STRONGER BUOYANCY IS EXPECTED ALONG THE FRONT
FROM SE AR INTO NW MS WHERE STRONG SURFACE HEATING IS OCCURRING.
THERE WILL BE SOME POTENTIAL FOR GUSTY OUTFLOW WINDS WITH STORMS
EXPECTED TO FORM ALONG THE FRONT BY EARLY AFTERNOON.

..THOMPSON/LEITMAN.. 09/18/2014



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