Tornado Warning 1, NWS Columbia, SC

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE COLUMBIA SC
1028 AM EDT THU AUG 12 2004

.UPDATE...
FLOOD WATCH FOR THIS AFTERNOON/TONIGHT...ON TRACK. TROPICAL STORM
PRECIP GUIDANCE TOOLS SUGGEST 2 TO 4 INCHES WITH A FEW AREAS UP TO 5
INCHES. TROPICAL STORM BONNIE NEAR THE FLORIDA PAN-HANDLE COAST AT
14Z MOVING NORTHEAST AND INCREASING FORWARD SPEED. HURRICANE CENTER
TRACK A LITTLE FURTHER EAST THAN PREVIOUS ADVISORY...BUT STILL EXPECT
CENTER TO MOVE THROUGH THE MIDLANDS THIS EVENING. MODEL BOUNDARY
LAYER WINDS SUPPORT WIND GUST TO 35 MPH...ESPECIALLY IN THE EASTERN
MIDLANDS. NUMEROUS SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP IN
THE CSRA AND WEST MIDLANDS THIS MORNING. SURFACE BOUNDARY HAS MOVED
INTO THE UPSTATE AREA. AIRMASS BECOMING MODERATELY UNSTABLE. VAD WIND
PROFILE INDICATING LOW LEVEL SHEAR INCREASING AS EXPECTED. POTENTIAL
FOR SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING...TORNADO MAIN
THREAT. SPC INDICATING A SEVERE WEATHER WATCH MAY BE REQUIRED THIS
AFTERNOON. PLAN ON RAISING WIND SPEEDS TO LAKE WIND ADVISORY CRITERIA
FOR THE EVENING PERIOD...15 TO 25 MPH WITH GUSTS TO 35 MPH.
&&

.PREV DISCUSSION...
THE MAIN FORECAST PROBLEMS ARE THE FLOOD AND TORNADO THREAT
ASSOCIATED WITH THE INTERACTION OF BONNIE WITH THE STALLED FRONT.
THE REMNANTS OF BONNIE SHOULD MOVE THROUGH THE FORECAST AREA
TONIGHT. THE ETA AND GFS INDICATE AROUND 1.5 INCHES OF RAIN WILL
OCCUR. THE 100 DIVIDED BY THE EXPECTED STORM SPEED RULE OF THUMB
INDICATES A MAXIMUM AROUND 3 INCHES. HOWEVER...BECAUSE OF THE
STALLED FRONT BELIEVE THERE IS ENOUGH OF A THREAT OF TRAINING FOR
HIGHER AMOUNTS SO PLAN TO ISSUE A FLOOD WATCH FOR LATE THIS
AFTERNOON AND TONIGHT.

THE GFS SHOWS H85 WINDS INCREASING TO AROUND 40 KNOTS THIS AFTERNOON
AHEAD OF BONNIE. THIS SHEAR AND AFTERNOON HEATING SUPPORTS A
POSSIBILITY OF TORNADOES. THE TORNADO THREAT SHOULD CONTINUE THIS
EVENING BECAUSE OF THE CONTINUED HIGH SHEAR ASSOCIATED WITH THE
WEAKENING STORM.

STILL DO NOT EXPECT SUSTAINED TROPICAL STORM FORCE WIND. WINDS OF 25
TO 35 WITH GUSTS NEAR 40 STILL APPEAR ON TRACK. A WIND ADVISORY WILL
PROBABLY BE NEEDED FOR TONIGHT.

THE LINGERING TROUGH BEHIND BONNIE SUPPORTS A CONTINUED POP FOR
FRIDAY. ADDITIONAL HEAVY RAIN MAY OCCUR FRIDAY NIGHT INTO SATURDAY
DEPENDING ON THE UNCERTAIN PATH OF CHARLIE. EXPECT LITTLE
THUNDERSTORM COVERAGE MONDAY THROUGH WEDNESDAY WITH SURFACE RIDGING
DOMINATING.

RADAR CURRENTLY SHOWING SCATTERED SHOWERS APPROACHING CENTRAL
SAVANNAH RIVER AREA. MID TO HIGH LEVEL CEILINGS WILL PREVAIL DURING
THE MORNING HOURS. SOME LOW CLOUDS WITH BASES AROUND 2000 FT NEAR
AREAS OF RAIN. SOME PATCHY MORNING FOG IN LOW-LYING AREAS AND NEAR
RIVERS. SCATTERED SHOWERS WILL BE A THREAT THIS MORNING WITH
SCATTERED THUNDERSTORMS DEVELOPING DURING THE AFTERNOON IN ADVANCE
OF TROPICAL STORM BONNIE. SOME LOW-LEVEL WIND SHEAR MAY DEVELOP BY
LATE AFTERNOON OR EARLY EVENING AS THE REMNANTS OF BONNIE APPROACH
THE AREA FROM THE SOUTHWEST.
&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH LATE THIS AFTERNOON AND TONIGHT SCZ015-016-018-
     020>022-025>031-035>038-041.
     LAKE WIND ADVISORY ALL CWA TONIGHT SCZ015-016-018-
     020>022-025>031-035>038-041.
GA...FLOOD WATCH LATE THIS AFTERNOON AND TONIGHT GAZ040-063>065-077.
     LAKE WIND ADVISORY TONIGHT GAZ040-063>065-077.
&&

AWP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE COLUMBIA SC
440 AM EDT THU AUG 12 2004

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-130900-
AIKEN SC-BAMBERG SC-BARNWELL SC-BURKE GA-CALHOUN SC-CHESTERFIELD SC-
CLARENDON SC-COLUMBIA GA-EDGEFIELD SC-FAIRFIELD SC-KERSHAW SC-
LANCASTER SC-LEE SC-LEXINGTON SC-LINCOLN GA-MCCORMICK SC-MCDUFFIE GA-
NEWBERRY SC-ORANGEBURG SC-RICHLAND SC-RICHMOND GA-SALUDA SC-
SUMTER SC-
440 AM EDT THU AUG 12 2004

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

.DAY ONE...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY MAINLY DURING
THE AFTERNOON AND EVENING HOURS. TROPICAL STORM BONNIE WILL MAKE
LANDFALL TODAY ALONG THE FLORIDA PANHANDLE. AS BONNIE ADVANCES
INLAND TOWARDS THE NORTHEAST...SCATTERED THUNDERSTORMS WILL DEVELOP
ACROSS THE AREA LATER TODAY. SOME OF THE STORMS WILL PRODUCE LOCALLY
HEAVY RAINFALL OF 2-4 INCHES SO LOCALIZED FLOODING WILL BE A THREAT.
ISOLATED TORNADOES ARE POSSIBLE LATE THIS AFTERNOON INTO THIS
EVENING. FOR FURTHER UPDATES ON BONNIE...REFER TO THE LATEST
ADVISORIES ISSUED BY THE NATIONAL HURRICANE CENTER.

.DAYS TWO THROUGH SEVEN...
HURRICANE CHARLEY WILL AFFECT PORTIONS OF THE SOUTHEASTERN STATES
FRIDAY NIGHT INTO SATURDAY. FOR FURTHER UPDATES ON CHARLEY...REFER
TO THE LATEST ADVISORIES ISSUED BY THE NATIONAL HURRICANE CENTER.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND THIS
EVENING.