Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 210811
SWODY3
SPC AC 210810

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0210 AM CST FRI NOV 21 2014

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF GULF COAST
STATES AND CAROLINAS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE GULF COAST
STATES...TN VALLEY AND CAROLINAS...

...SUMMARY...
STRONG TO SEVERE THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE FROM THE
LOWER MISSISSIPPI VALLEY EASTWARD ACROSS THE GULF COAST STATES AND
NORTHEASTWARD INTO THE EASTERN CAROLINAS ON SUNDAY. DAMAGING WIND
GUSTS AND PERHAPS A TORNADO OR TWO ARE EXPECTED TO BE THE PRIMARY
THREATS.

...GULF COAST STATES...
A NEGATIVELY-TILTED UPPER-LEVEL TROUGH IS FORECAST TO MOVE NEWD
ACROSS THE LOWER MS VALLEY INTO THE OH AND TN VALLEYS ON SUNDAY. AN
MCS MAY ONGOING IN THE LOWER MS VALLEY JUST AHEAD OF THE UPPER-LEVEL
TROUGH AT DAYBREAK ON SUNDAY. THE NAM AND GFS ARE IN REASONABLY GOOD
AGREEMENT...APPEARING TO MOVE A CONVECTIVE SYSTEM FROM THE NEW
ORLEANS AREA SUNDAY MORNING EWD INTO NRN FL SUNDAY AFTERNOON. NAM
FORECAST SOUNDINGS AT 21Z/SUN ALONG THIS CORRIDOR SHOW SFC DEWPOINTS
IN THE MID TO UPPER 60S F...MLCAPE OF 1000 TO 1500 J/KG AND 0-6 KM
SHEAR NEAR 60 KT. THIS COMBINED WITH STRONG LOW-LEVEL SHEAR WITH 0-3
KM STORM RELATIVE HELICITY OF 300 TO 350 M2/S2...SHOULD BE ENOUGH
FOR SUPERCELLS AND POSSIBLE A TORNADO OR TWO. THE TORNADO THREAT MAY
DEPEND UPON HOW MANY DISCRETE CELLS CAN FORM AHEAD OF THE MAIN MCS.
IF AN MCS CAN REMAIN SUSTAINED OR REDEVELOP IN THE CNTRL GULF COAST
STATES SUNDAY AFTERNOON...THEN THERE COULD BE A SUBSTANTIAL WIND
DAMAGE THREAT AS WELL.

...ERN CAROLINAS...
A NEGATIVELY-TILTED UPPER-LEVEL TROUGH WILL MOVE NEWD ACROSS THE OH
AND TN VALLEYS ON SUNDAY. AHEAD OF THE SYSTEM...LOW-LEVEL FLOW WILL
MARKEDLY INCREASE ACROSS THE CAROLINAS DURING THE DAY. AS A
RESULT...SFC DEWPOINTS ARE FORECAST TO REACH THE MID 60S F ACROSS
THE COASTAL PLAINS OF THE CAROLINAS BY AFTERNOON. MODEL FORECASTS
SUGGEST THAT CONVECTION WILL DEVELOP ACROSS THE ERN GULF COAST
STATES SUNDAY AFTERNOON AND MOVE NEWD ACROSS THE ERN CAROLINAS
DURING THE LATE AFTERNOON AND EARLY EVENING. FORECAST SOUNDINGS AT
00Z/MON FOR CHARLESTON SC SHOW MLCAPE AROUND 750 J/KG WITH 50 KT OF
0-6 KM SHEAR. THIS ENVIRONMENT WOULD BE ENOUGH TO SUPPORT STORM
ORGANIZATION AS A LINE OR CLUSTER OF STRONG STORMS MOVES INTO THE
REGION FROM THE SOUTHWEST. WIND DAMAGE MAY BE THE PRIMARY THREAT
WITH THE GREATEST POTENTIAL REMAINING CLOSE TO THE SC-NC COAST WHERE
LOW-LEVEL MOISTURE IS FORECAST TO BE MOST FAVORABLE.

..BROYLES.. 11/21/2014



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