Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 060525
SWODY1
SPC AC 060524

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1124 PM CST MON DEC 05 2016

VALID 061200Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SOUTHERN
GEORGIA AND NORTHERN FLORIDA...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF SOUTHERN SOUTH
CAROLINA...GEORGIA AND NORTHERN FLORIDA...

...SUMMARY...
A FEW STRONG TO SEVERE STORMS WITH DAMAGING WIND AND POSSIBLY A
TORNADO WILL EXIST THIS MORNING ACROSS SOUTHERN GEORGIA AND NORTHERN
FLORIDA.

...EASTERN GULF COAST STATES/SOUTH CAROLINA...
A NEGATIVELY-TITLED UPPER-LEVEL TROUGH WILL BECOME LESS AMPLIFIED
TODAY AS THE SYSTEM MOVES EAST NORTHEASTWARD FROM THE CENTRAL GULF
COAST STATES THIS MORNING AND INTO THE CAROLINAS THIS AFTERNOON. AT
THE SURFACE...A LOW WILL MOVE NORTHEAST THROUGH THE TENNESSEE AND
OHIO VALLEYS AS A COLD FRONT ADVANCES EASTWARD ACROSS THE CENTRAL
GULF COAST STATES. AHEAD OF THE FRONT...A MOIST AIRMASS WILL BE IN
PLACE AT THE START OF THE PERIOD FROM SOUTHEAST ALABAMA EASTWARD TO
THE GEORGIA COAST WHERE SURFACE DEWPOINTS WILL RANGE FROM THE MID
60S TO THE LOWER 70S FAHRENHEIT. SCATTERED THUNDERSTORMS ACROSS THE
MOIST SECTOR SHOULD INHIBIT DESTABILIZATION.  TO COUNTER THIS
NEGATIVE...FORECAST SOUNDINGS ACROSS SOUTHERN GEORGIA AT 15Z SHOW A
STRONGLY SHEARED ENVIRONMENT WITH 0-6 KM SHEAR IN THE 50 TO 55 KT
RANGE. THIS COMBINED WITH 0-3 KM STORM RELATIVE HELICITIES IN THE
250 TO 350 M2/S2 WILL BE ENOUGH FOR STORM ROTATION AND POSSIBLY A
TORNADO NEAR THE CORE OF A 40 TO 55 KT LOW-LEVEL JET. IN ADDITION...
FORECAST SOUNDINGS SHOW STRONG SPEED SHEAR IN THE BOUNDARY LAYER
WITH 45 KT OF SOUTH SOUTHWESTERLY FLOW AT 1 KILOMETER.  THIS COULD
SUPPORT A WIND DAMAGE THREAT AS THE BETTER ORGANIZED DOWNDRAFTS
TRANSFER THE STRONG FLOW TO THE SURFACE.

THE MAIN UNCERTAINTY IS HOW MUCH THE AIRMASS CAN RECOVER AS THE
UPPER-LEVEL SYSTEM APPROACHES THE REGION THIS MORNING. THE CURRENT
THINKING IS THAT A FEW STRONG THUNDERSTORMS WILL MOVE ACROSS THE
SLIGHT RISK AREA BETWEEN 12Z AND 16Z AS IS SUGGESTED BY THE LATEST
HRRR. THE STRONG SHEAR ENVIRONMENT SHOULD BE ABLE TO OVERCOME THE
WEAKNESS IN INSTABILITY TO ENABLE A SEVERE THREAT. BUT THIS WILL
DEPEND UPON HOW MUCH ORGANIZATION CAN TAKE PLACE WITH THE CONVECTION
JUST PRIOR TO THE DAY 1 PERIOD. A REASSESSMENT OF THE SEVERE
POTENTIAL WILL TAKE PLACE FOR THE 13Z OUTLOOK AND THE SLIGHT RISK
COULD BE ADJUSTED OR EVEN DROPPED AT THAT TIME IF THE SEVERE THREAT
HAS NOT MATERIALIZED. AS THE UPPER-LEVEL TROUGH MOVES THROUGH THE
CAROLINAS THIS AFTERNOON...THE STRONGER LOW-LEVEL FLOW IS FORECAST TO
MOVE OFFSHORE OVER THE GULF STREAM...MAKING THE SEVERE THREAT
MARGINAL ACROSS SOUTHERN SOUTH CAROLINA AND LIMITING THE SEVERE
THREAT ACROSS EASTERN NORTH CAROLINA.

..BROYLES/GLEASON.. 12/06/2016

$$


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