Flash Flood Warning 7, NWS Columbia, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
153 PM EST WED NOV 15 2006

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
THE MAIN FORECAST PROBLEM CONTINUES TO BE THE SEVERE WEATHER THREAT
TONIGHT. STRONG SHEAR HAS ALREADY BEGUN TO DEVELOP. THE LATEST
ANALYSIS SHOWS H85 WIND HAS INCREASED TO NEAR 40 KTS. BOTH THE NAM
AND GFS PLUS WINDS WEST OF THE REGION SUPPORT THESE WINDS INCREASING
TO AROUND 60 KNOTS OVERNIGHT. THE NAM AND GFS ARE IN BETTER
AGREEMENT WITH THE INSTABILITY FORECAST AND INDICATE SURFACE-BASED
LI/S 0 TO -2. THUNDERSTORMS CURRENTLY ALONG THE GULF COAST SHOULD
LIMIT THE TRANSPORT OF MOISTURE AND INSTABILITY NORTHWARD SO THE WEAK
INSTABILITY FORECAST APPEARS REASONABLE AND IS THE LIMITING FACTOR
FOR SEVERE WEATHER. HOWEVER...WITH THE STRONG SHEAR AND SOME
INSTABILITY EXPECT SOME OF THE THUNDERSTORMS TONIGHT WILL CONTAIN
DAMAGING WIND. THE STRONG SHEAR AND WARM FRONTAL BOUNDARY WITH LOW
LIFTING CONDENSATION LEVELS SUPPORT A POSSIBILITY OF TORNADOES AS
WELL.

THE GFS IS A LITTLE FASTER COMPARED TO THE NAM WITH THE WEST TO EAST
TIMING. BELIEVE THE GFS IS BETTER BASED ON CURRENT RADAR. BASED ON
THE GFS TIMING THE RISK APPEARS GREATEST IN THE CENTRAL SAVANNAH
RIVER AREA FROM 1000 PM TO 400 AM TONIGHT...THE COLUMBIA AREA
MIDNIGHT TO 600 AM...AND CHERAW AREA 200 AM TO 800 AM.

AVERAGED THE GFS AND NAM FOR THE QPF FORECAST. EXPECT ABOUT 1
INCH.

THE FORECAST AREA SHOULD BE IN THE DRY SLOT FOR THURSDAY. EXPECT ANY
LINGERING SHOWERS WILL END EARLY. THE MODELS HAVE BEEN CONSISTENT
SHOWING SHALLOW LOW-LEVEL MOISTURE THURSDAY...SO EXPECT CONSIDERABLE
CLOUDINESS AND LITTLE TEMPERATURE RECOVERY. FURTHER LOW-LEVEL DRYING
SHOULD OCCUR FOR THURSDAY NIGHT AND FRIDAY WITH THE PRESSURE RIDGE
SOUTH OF THE REGION.

WILL USE THE MAV WIND GUIDANCE. WILL CONTINUE THE LAKE WIND ADVISORY
FOR TONIGHT AND THURSDAY.

PLAN TO USE THE WARMER GUIDANCE TEMPERATURES TONIGHT BECAUSE OF
CLOUDINESS AND STRONG MIXING. THE WARMER GUIDANCE ALSO APPEARS
BETTER FOR THURSDAY BECAUSE OF A WARM START.

&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE EXTENDED PERIOD APPEARS DRY. THE LATEST GFS SHOWS SURFACE HIGH
PRESSURE DOMINATING DURING THE PERIOD. SHARPENING 5H TROUGHING ALONG
THE COAST APPEARS TO OCCUR MONDAY...WITH MOST MOISTURE STAYING
OFFSHORE. THE ENSEMBLE MEAN POPS ARE LESS THAN 20 PERCENT DURING THE
PERIOD.
&&

.AVIATION...
THE MAIN ISSUE IS THE THREAT OF SEVERE THUNDERSTORMS LATE TONIGHT.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF A COLD
FRONT...WHICH WILL MOVE THROUGH TONIGHT AND EARLY THURSDAY MORNING.
STRONG ATMOSPHERIC WIND SPEEDS AND STRONG SHEAR ARE EXPECTED. THIS
WILL LEAD TO THE POSSIBILITY THAT SOME OF THE STRONGER STORMS WILL
PRODUCE STRONG DAMAGING WIND GUSTS AND POSSIBLY TORNADOES. SURFACE
WINDS WILL GRADUALLY PICK UP LATE THIS AFTERNOON AND EVENING...AND
BREEZY TO WINDY CONDITIONS ARE EXPECTED TONIGHT AND THURSDAY. LOW
LEVEL NON CONVECTIVE WIND SHEAR IS ALSO EXPECTED OVERNIGHT AS STRONG
LOW LEVEL JET AXIS MOVES ACROSS THE REGION. MOST OF THE
PRECIPITATION WILL MOVE EAST OF THE TAF SITES THURSDAY MORNING.
&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FOR SCZ015-016-018-020>022-025>031-035>038-
     041 FROM 7 PM WEDNESDAY TO 7 PM THURSDAY.
GA...LAKE WIND ADVISORY FOR GAZ040-063>065-077 FROM 7 PM WEDNESDAY
     TO 7 PM THURSDAY.
&&

SHORT TERM...05
LONG TERM...05
AVIATION...31

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE COLUMBIA SC
115 PM EST WED NOV 15 2006

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-
160900-
LINCOLN-MCDUFFIE-COLUMBIA-RICHMOND-BURKE-LANCASTER-CHESTERFIELD-
MCCORMICK-NEWBERRY-FAIRFIELD-KERSHAW-EDGEFIELD-SALUDA-LEXINGTON-
RICHLAND-LEE-AIKEN-SUMTER-BARNWELL-ORANGEBURG-CALHOUN-CLARENDON-
BAMBERG-
115 PM EST WED NOV 15 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MIDLANDS OF SOUTH
CAROLINA AND THE CENTRAL SAVANNAH RIVER AREA..

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TONIGHT AND EARLY
THURSDAY MORNING. SOME OF THE STRONGER STORMS WILL BE CAPABLE OF
PRODUCING STRONG DAMAGING WINDS...AND POSSIBLY TORNADOES. WINDY
CONDITIONS ARE ALSO EXPECTED. A LAKE WIND ADVISORY IS IN EFFECT FROM
7PM TONIGHT TO 7PM THURSDAY.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH MONDAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EARLY THURSDAY
MORNING. A LAKE WIND ADVISORY IS IN EFFECT FOR THURSDAY.
OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED FOR THE REMAINDER OF
THE PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY TONIGHT AND EARLY THURSDAY
MORNING.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE COLUMBIA SC
1020 PM EST WED NOV 15 2006

SCZ020-021-027-028-160415-
FAIRFIELD-LEXINGTON-NEWBERRY-RICHLAND-
1020 PM EST WED NOV 15 2006

...STRONG THUNDERSTORMS WERE AFFECTING FAIRFIELD...LEXINGTON...
NEWBERRY AND RICHLAND COUNTIES...

AT 1013 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 6 MILES NORTH OF
IRMO TO 12 MILES SOUTHWEST OF GASTON...OR ALONG A LINE EXTENDING FROM
6 MILES NORTH OF IRMO TO 17 MILES SOUTH OF RED BANK. THESE STORMS
WERE MOVING TO THE EAST ABOUT 30 MILES PER HOUR. THE COLUMBIA
METROPOLITAN AREA WILL BE IN THE PATH OF THESE STORMS. LOCALLY HEAVY
RAINFALL AMOUNTS OF ONE HALF TO 1 INCH PER HOUR WILL CAUSE SOME
PONDING OF WATER ON ROADWAYS.

BC

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE COLUMBIA SC
1135 PM EST WED NOV 15 2006

SCZ020-021-027-028-160530-
FAIRFIELD-LEXINGTON-NEWBERRY-RICHLAND-
1135 PM EST WED NOV 15 2006

...STRONG THUNDERSTORMS WERE AFFECTING PARTS OF
FAIRFIELD...LEXINGTON...NEWBERRY AND RICHLAND COUNTIES...

AT 1133 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING SOUTHERN FAIRFIELD
COUNTY TO SOUTHERN LEXINGTON COUNTY. THESE STORMS WERE MOVING TO THE
EAST ABOUT 30 MILES PER HOUR. THE COLUMBIA METROPOLITAN AREA WILL
CONTINUE TO BE IN THE PATH OF THESE STORMS. LOCALLY HEAVY RAINFALL
AMOUNTS OF ONE HALF TO 1 INCH PER HOUR WILL CAUSE SOME PONDING OF
WATER ON ROADWAYS. WIND GUSTS OF 25 TO 35 MILES PER HOUR ARE
POSSIBLE.

BC

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE COLUMBIA SC
1144 PM EST WED NOV 15 2006

SCZ035>037-041-160545-
BAMBERG-BARNWELL-CALHOUN-ORANGEBURG-
1144 PM EST WED NOV 15 2006

...STRONG THUNDERSTORMS WERE AFFECTING BAMBERG...BARNWELL...CALHOUN
AND ORANGEBURG COUNTIES...

AT 1139 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 13 MILES NORTH OF
BLACKVILLE TO BOWMAN...OR ALONG A LINE EXTENDING FROM 17 MILES
NORTHWEST OF DENMARK TO 13 MILES SOUTHEAST OF BROOKDALE...MOVING
EAST AROUND 30 MPH. THESE STORMS WILL AFFECT THE CITIES OF
ORANGEBURG AND BAMBURG THROUGH 1245 AM. LOCALLY HEAVY RAINFALL
AMOUNTS UP TO ONE INCH PER HOUR WILL CREATE PONDING OF WATER ON
ROADWAYS. WIND GUSTS OF 25 TO 35 MILES PER HOUR ARE POSSIBLE.

BC