Tornado and Damaging Winds in South Carolina, September 5, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
443 PM EDT MON SEP 5 2011

.SYNOPSIS...
A COLD FRONT WILL APPROACH TODAY INTO TONIGHT AND STALL OUT AS IT
INTERACTS WITH THE REMNANTS OF LEE. THIS WILL BRING TROPICAL
MOISTURE TO THE REGION THROUGH TUESDAY WITH SOME LOCALLY HEAVY
RAIN POSSIBLE. THERE MAY ALSO BE THE POSSIBILITY OF SEVERE WEATHER
TONIGHT INTO TUESDAY. THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL
LINGER ON INTO WEDNESDAY AS WELL.

&&

.NEAR TERM /TONIGHT/...
CAE RADAR SHOWING SCATTERED SHOWERS AND STORMS MOVING THROUGH THE
REGION. COVERAGE EXPECTED TO INCREASE THROUGH THE EVENING AND
OVERNIGHT.

THE REMNANTS OF TS LEE WILL MOVE TO THE NE WITH THE CENTER OF THE
SYSTEM JUST MOVING INTO NRN/CNTRL ALABAMA TONIGHT. MODEL TIME
SECTIONS ARE QUITE MOIST TONIGHT. WILL CONTINUE WITH INCREASING
POPS THROUGH THE NIGHT. MODELS INDICATE INCREASING ISENTROPIC
LIFT...WITH BEST LIFT ACROSS THE UPSTATE THROUGH TONIGHT. SPC HAS
PORTION OF THE SOUTHEAST INCLUDING THE CSRA UNDER A SLIGHT RISK
FOR SEVERE STORMS...MAINLY FOR THE EVENING/TONIGHT. THE LOW LEVEL
WIND FIELD WILL BE INCREASING THROUGH THE PERIOD...ESPECIALLY
LATER TONIGHT WITH INCREASING SHEAR AND MODERATE INSTABILITY.
THERE IS A RISK OF SEVERE WEATHER THIS EVENING.  MAY BE ENOUGH
SHEAR FOR AN ISOLATED TORNADO. THERE IS ALSO THE POSSIBILITY OF
LOCALLY HEAVY RAIN WITH SHRA/TSRA AS PW VALUES WILL BE INCREASING
TO ABOVE 2.0 INCHES. AS FOR TEMPERATURES...GUIDANCE AND LOCAL
MODELS SHOWING A BIT OF A SPREAD...BUT WILL STAY NEAR CONSENSUS
FOR TEMPERATURES...BUT ABOVE CONSENSUS FOR POPS.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE NAM CONTINUES TO BE THE FASTEST OF THE MODELS WITH THE
MOVEMENT OF THE REMNANTS OF LEE. THE SLOWER ECMWF/GFS ARE
PREFERRED. THE FORECAST FOR THE REMNANTS OF LEE ARE EXPECTED TO
CONTINUE TO MOVE NORTHEAST AND BE LOCATED NEAR THE GA/TN LINE THEN
CONTINUING TO WEAKEN AND MOVE SLOWLY NORTHEAST ALONG THE SRN
APPALACHIANS. MAIN FORECAST ISSUE WILL BE AT THE BEGINNING OF THE
SHORT TERM WITH THE POSSIBILITY OF SEVERE WEATHER ACROSS THE
REGION ON TUESDAY...ESPECIALLY TUESDAY MORNING INTO THE EARLY
AFTERNOON HOURS. SPC HAS AREA OUTLOOKED FOR A SLIGHT RISK. BUFKIT
SOUNDINGS INDICATING PRETTY GOOD WIND PROFILES WITH H8 WINDS FROM
35 TO 45 KTS EARLY TUESDAY WITH AROUND 40 KTS OF SHEAR AND
HELICITY VALUES APPROACHING 200 AFTER SUNRISE TUESDAY. AS THE
REMNANTS OF LEE MOVE WEST OF THE AREA ON TUESDAY...CWA WILL BE IN
THE WARM SECTOR AND THE AIRMASS IS EXPECTED TO BECOME MODERATELY
UNSTABLE. THE FORECAST IS FOR CLOUDY SKIES BUT ANY BREAKS COULD
PROVIDE ADDITIONAL HEATING FOR INCREASED INSTABILITY. LOCAL
ANALYSIS INDICATES THE POTENTIAL FOR SUPERCELL DEVELOPMENT WITH
THE POSSIBILITY OF TORNADOES OF THE TROPICAL
VARIETY...WEAKER/SHORTER LIVED. THIS SITUATION WILL NEED TO BE
MONITORED FOR ANY CHANGES IN THE TRACK OF LEE AND ANY CHANGES IN
THE WIND FIELD FROM EARLY TUESDAY MORNING INTO THE AFTERNOON
HOURS. THERE REMAINS A THREAT FOR POSSIBLE LOCALLY HEAVY RAIN ON
TUESDAY WITH PW VALUES WELL ABOVE 2.0 INCHES. SEVERE THREAT AS
WELL AS HEAVY RAIN THREAT WILL DIMINISH WITH THE PASSAGE OF
FRONTAL BOUNDARY THROUGH THE AREA TUESDAY NIGHT. BY
WEDNESDAY...MODELS INDICATE MID/UPPER LEVEL CLOSED LOW TO OUR WEST
THAT WILL MOVE SLOWLY NORTHWARD THROUGH WED NIGHT. THIS WILL KEEP
DAYTIME TEMPERATURES COOLER THAN NORMAL FOR WEDNESDAY. WILL
CONTINUE SMALL CHANCE POPS WEDNESDAY AND WEDNESDAY NIGHT AS UPPER
LOW MEANDERS OVER OH VALLEY WITH PIECES OF ENERGY ROTATING INTO
THE AREA. TEMPS GENERALLY CLOSE TO MODEL CONSENSUS.

LAKE WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 6 PM TUESDAY.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
MODELS SLOWLY PULL OUT MOISTURE FROM THE REMNANTS OF TROPICAL
DEPRESSION LEE TO THE NORTHEAST THURSDAY WITH CLOSED LOW TO OUR
NORTHWEST OVER THE TN VALLEY. THIS SYSTEM WILL GRADUALLY
WEAKEN...BUT CONTINUE TO DRIFT OVER THE OH VALLEY/MID MS VALLEY
THROUGH THE PERIOD. AS FOR HURRICANE KATIA...ITS EXPECTED TO
CONTINUE WESTWARD...BUT GRADUALLY TURN TO THE NORTH/NORTHEAST AS
THE TROFINESS ALONG THE EASTERN PORTION OF THE COUNTRY WILL
PREVENT KATIA FROM GETTING TOO CLOSE TO THE EAST COAST. LOW
CONFIDENCE WITH CHANCES FOR PRECIPITATION LATER IN THE PERIOD AS
UPPER LOW BECOMING A BROAD UPPER TROUGH EXTENDING FROM THE GREAT
LAKES TO THE MID-MS VALLEY. FORECAST MAX TEMPS GENERALLY A COUPLE
OF DEGREES BELOW NORMAL...AND FORECAST MINS NEAR NORMAL THROUGH
THE PERIOD.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
CLOUDS ARE FILLING BACK IN ACROSS THE FORECAST AREA AS THE DEEPER
TROPICAL MOISTURE APPROACHES. PREVIOUSLY THERE WOULD BE A
POSSIBILITY OF IFR CIGS MOVING IN BUT AS SOUTHERLY SURFACE WINDS
HAVE INCREASED TO 10-20 KNOTS...NOT THINK CIGS SHOULD REMAIN MVFR
OR HIGHER. SO WILL GO MAINLY VFR THROUGH AROUND MIDNIGHT...THEN
MVFR FOR THE REST OF THE PERIOD.

EXTENDED AVIATION OUTLOOK...TROPICAL MOISTURE OVER THE REGION IS
EXPECTED TO RESULT IN CONTINUED HIGH CHANCES FOR PRECIPITATION AND
ASSOCIATED RESTRICTIONS TO CIGS/VSBYS AT LEAST THROUGH WEDNESDAY.
IMPROVING TREND POSSIBLE THURSDAY INTO FRIDAY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 6 PM EDT TUESDAY FOR SCZ015-016-018-
     020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 6 PM EDT TUESDAY FOR GAZ040-063>065-
     077.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE COLUMBIA SC
351 PM EDT MON SEP 5 2011

GAZ040-063-064-SCZ015-018-020-021-025-026-062000-
LINCOLN-MCDUFFIE-COLUMBIA-LANCASTER-MCCORMICK-NEWBERRY-FAIRFIELD-
EDGEFIELD-SALUDA-
351 PM EDT MON SEP 5 2011

...TORNADO WATCH 840 IN EFFECT UNTIL 11 PM EDT THIS EVENING...
...LAKE WIND ADVISORY IN EFFECT UNTIL 6 PM EDT TUESDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL GEORGIA AND
CENTRAL SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   TORNADO WATCH.
   LAKE WIND ADVISORY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   LAKE WIND ADVISORY.

THERE WILL STILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS
TUESDAY...ISOLATED TORNADO THREAT AS TROPICAL DEPRESSION LEE
APPROACHES FROM THE WEST.

THERE WILL ALSO BE AN INCREASING THREAT OF RIVER FLOODING AS
RAINFALL FROM THE TROPICAL SYSTEM ENTERS STREAMS AND RIVERS ACROSS
THE REGION THE NEXT SEVERAL DAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER TONIGHT.

GAZ065-077-SCZ016-022-027>031-035>038-041-062000-
RICHMOND-BURKE-CHESTERFIELD-KERSHAW-LEXINGTON-RICHLAND-LEE-AIKEN-
SUMTER-BARNWELL-ORANGEBURG-CALHOUN-CLARENDON-BAMBERG-
351 PM EDT MON SEP 5 2011

...LAKE WIND ADVISORY IN EFFECT UNTIL 6 PM EDT TUESDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL GEORGIA AND
CENTRAL SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   LAKE WIND ADVISORY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   LAKE WIND ADVISORY.

THERE WILL STILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS
TUESDAY...ISOLATED TORNADO THREAT AS TROPICAL DEPRESSION LEE
APPROACHES FROM THE WEST.

THERE WILL ALSO BE AN INCREASING THREAT OF RIVER FLOODING AS
RAINFALL FROM THE TROPICAL SYSTEM ENTERS STREAMS AND RIVERS ACROSS
THE REGION THE NEXT SEVERAL DAYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER TONIGHT.