Severe Thunderstorm Warning 209, NWS Columbia, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
254 PM EDT SAT JUL 22 2006

.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...

SURFACE BOUNDARY CURRENTLY SITUATED FROM SOUTHWEST PENNSYLVANIA
THROUGH EASTERN KENTUCKY INTO NORTHERN ALABAMA. REGIONAL RADAR
SHOWING SOME CONVECTION DEVELOPING DEVELOPING ACROSS SOUTHEAST
GEORGIA...AND A LINE DEVELOPING JUST WEST OF CHS.

UPPER TROUGH EXTENDING FROM THE GREAT LAKES THROUGH THE OHIO
VALLEY WILL SWING EAST INTO NEW ENGLAND AND THE MID ATLANTIC LATER
TONIGHT AND SUNDAY...WHICH WILL PUSH THE FRONTAL BOUNDARY INTO THE
AREA. HAVE DECIDED TO BUMP UP POPS TO LOW LIKELY OVERNIGHT AND
CONTINUE THEM INTO SUNDAY WITH THE BOUNDARY APPROACHING AND
SHORTWAVE ENERGY NEARBY. MODEST INSTABILITY SHOULD ALLOW
CONVECTIVE ACTIVITY TO LINGER INTO THE OVERNIGHT HOURS...HOWEVER THERE
IS A POTENTIAL FLY IN THE OINTMENT FOR TONIGHT. THE EXPANDING
CONVECTION ACROSS ALABAMA INTO GEORGIA COULD ROB SOME OF THE
MOISTURE FROM THE SOUTHWESTERLY FLOW. THE FRONTAL BOUNDARY REMAINS
IN THE VICINITY FOR MONDAY AND THEN BASICALLY DISSOLVES BY MID
WEEK. WILL KEEP CHANCE POPS RUNNING FOR MONDAY AND TUESDAY WITH
DEEP ATMOSPHERIC MOISTURE IN PLACE.

TEMPERATURES WILL RUN AT OR BELOW NORMAL DURING THIS PERIOD WITH
PLENTY OF MOISTURE IN PLACE. STAYED PRETTY CLOSE TO GUIDANCE
NUMBERS WHICH WERE CLUSTERED.

&&

.LONG TERM (WEDNESDAY THROUGH SATURDAY)...

UPPER PATTERN REFLECTS WEAK TROUGH ALOFT AND NEAR THE SURFACE FOR
MUCH OF NEXT WEEK. THIS PATTERN COMBINED WITH PLENTY OF DEEP
MOISTURE WILL PROVIDE DIURNALLY DRIVEN CONVECTIVE ACTIVITY DURING
THE EXTENDED PERIOD. WILL KEEP CHANCE POPS THROUGHOUT DURING THE
PERIOD...WHILE TEMPERATURES WILL REMAIN IN THE UPPER 80S TO LOWER 90S.

&&

.AVIATION...

MAINLY VFR CONDITIONS BUT ATMOSPHERE UNSTABLE THIS AFTERNOON AND
EVENING WITH LIS -5/-6 AND CAPES 2000-3000. SEA BREEZE HAS FORMED
ALL THE WAY FROM SOUTHWEST GEORGIA INTO SOUTHEAST SOUTH CAROLINA
AND THUNDERSTORMS HAVE DEVELOPED ALONG THIS FEATURE. THIS MAY LIMIT
CONVECTION OVER THE CAE CWA BUT BRIEF MVFR-IFR CONDITIONS POSSIBLE
IN SHOWERS AND FEW THUNDERSTORMS STILL POSSIBLE. THUNDERSTORM
ACTIVITY STILL WELL WEST AND SOUTH OF THE AREA AT 18Z. WEAK SHORT
WAVE MOVING OVER AREA LATE TONIGHT A GOOD CHANCE OF SHOWERS AND A
FEW THUNDERSTORMS. STILL A POSSIBILITY OF SEVERE STORMS BUT
POTENTIAL APPEARS TO HAVE DIMINISHED OVER THE EARLY AFTERNOON HOURS.
OTHERWISE...BOUNDARY LAYER WINDS LATE TONIGHT AND SUNDAY MORNING
LOOK LIKE THEY WILL BE STRONG ENOUGH TO INHIBIT THE DEVELOPMENT OF
MUCH FOG NEAR SUNRISE SUNDAY.

&&

.PREVIOUS DISCUSSION...
(ISSUED 328 AM EDT SAT JUL 22 2006)

SHORT TERM (TODAY THROUGH SUNDAY NIGHT)...

STRONG UPPER RIDGE CENTERED OVER THE WESTERN US...WITH RIDGE AXIS
STILL EXTENDING EASTWARD INTO THE SE US. CONVECTION HAS BEEN FLARING
UP OVER THE UPSTATE AND NE GA OVER THE PAST COUPLE OF HOURS...APPEARS
TO BE THE RESULT OF BOUNDARY COLLISIONS. OTHER ISOLATED ACTIVITY
POPPING UP ACROSS THE CENTRAL FA. WITH RIDGE AXIS STILL EXTENDING
ROUGHLY ACROSS OUR CENTRAL FA...AND WITH DIURNAL TREND TOWARDS
MORE STABILITY...WILL EXPECT SCATTERED CONVECTION TO AFFECT
PRIMARILY THE NORTHERN HALF OF OUR FA THIS MORNING. THE RIDGE
WEST/TROUGH EAST UPPER PATTERN TO AMPLIFY FOR TODAY/SUNDAY...
THOUGH STRONGEST UPPER ENERGY TO REMAIN TO OUR NORTH. FRONTAL
BOUNDARY STILL ON COURSE TO MOVE IN LATE TODAY/TONIGHT...AND STALL
OVER THE REGION SUNDAY. THIS ALONG WITH INCREASED ATMOSPHERIC
MOISTURE TO RESULT IN INCREASED PRECIP CHANCES.

LONG TERM (MONDAY THROUGH FRIDAY)...

MADE NO CHANGES. FRONTAL BOUNDARY MAY STILL BE STALLED OVER THE
REGION MONDAY. UPPER PATTERN TO DEAMPLIFY...WITH WEAK TROFINESS
REMAINING OVER THE EAST INTO MID WEEK. APPEARANCE OF BERMUDA
RIDGE TRYING TO BUILD WESTWARD BY LATE WEEK.

AVIATION...

EXPECT MAINLY VFR CONDITIONS. THE LOW-LEVEL JET SHOULD LIMIT FOG
DEVELOPMENT EARLY THIS MORNING. LINGERING UPPER-LEVEL RIDGING SHOULD
LIMIT THUNDERSTORM COVERAGE EARLY IN THE TAF PERIOD. EXPECT COVERAGE
WILL INCREASE LATER IN THE PERIOD ASSOCIATED WITH STRONG HEATING AND
CONVERGENCE ASSOCIATED WITH THE APPROACHING FRONT. HAVE NOT
EXPLICITLY FORECASTED THUNDERSTORMS AT THE TERMINALS AT THIS TIME
BECAUSE OF TIMING UNCERTAINTY.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

HC/HC/TTH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE COLUMBIA SC
513 AM EDT SAT JUL 22 2006

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-230913-
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-
513 AM EDT SAT JUL 22 2006

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

.DAY ONE...TODAY AND TONIGHT
A FRONTAL SYSTEM MOVING INTO THE REGION PLUS STRONG HEATING AND HIGH
MOISTURE WILL LEAD TO SCATTERED THUNDERSTORMS TODAY AND TONIGHT.
A FEW OF THE THUNDERSTORMS MAY BECOME SEVERE WITH WIND GUSTS
AROUND 60 MPH. THE SEVERE WEATHER THREAT WILL BE MAINLY LATE THIS
AFTERNOON AND THIS EVENING.

HEAVIER RAINFALL AMOUNTS WILL ALSO OCCUR WITH SOME OF THE
THUNDERSTORMS...WITH PONDING OF WATER IN POOR-DRAINAGE AREAS.

SEVERE THUNDERSTORM AND FLOOD WATCHES OR WARNINGS MAY BE NEEDED LATER
TODAY OR TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
EMERGENCY MANAGEMENT AND SPOTTER ACTIVATION MAY BE REQUIRED THIS
AFTERNOON OR TONIGHT.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
1043 AM EDT SAT JUL 22 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0420 PM     DOWNBURST        6 SE EUTAWVILLE         33.34N 80.27W
07/21/2006                   ORANGEBURG         SC   NWS STORM SURVEY

            1 MOBILE HOME OVERTURNED. HALF ROOF TORN OFF...2 OTHER
            MOBILE HOMES DAMAGED. LOCATION...ADDIAS ROAD. ROOF
            SHINGLES OFF 1 HOME...PORCH DAMAGE ON OTHER HOME. MANY
            TREES DOWN. PATH WAS 1 TO 1.5 MILES WIDE. ESTMTD 75 MPH.

&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE COLUMBIA SC
320 PM EDT SAT JUL 22 2006

GAZ063>065-077-SCZ025-030-035-036-041-222015-

AIKEN-BAMBERG-BARNWELL-BURKE-COLUMBIA-EDGEFIELD-MCDUFFIE-ORANGEBURG-
RICHMOND-
320 PM EDT SAT JUL 22 2006

...STRONG THUNDERSTORMS WILL IMPACT BURKE COUNTY...RICHMOND COUNTY...
MCDUFFIE COUNTY...COLUMBIA COUNTY...EDGEFIELD COUNTY...AIKEN
COUNTY...ORANGEBURG COUNTY...BARNWELL COUNTY AND BAMBERG COUNTY
THROUGH 415 PM EDT...

AT 320 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
CLUSTER OF STRONG THUNDERSTORMS DEVELOPING IN RICHMOND...BURKE AND
AIKEN COUNTIES. THESE STORMS WERE MOVING EAST 10 TO 15 MPH. THIS
CLUSTER OF STRONG THUNDERSTORMS WILL AFFECT AREAS IN AND AROUND
MARTINEZ...KEYSVILLE...HEPHZIBAH...GROVETOWN...FORT GORDON...EVANS
...WAYNESBORO AND THE AUGUSTA AREA THROUGH 415 PM EDT.

THESE STORMS MAY PRODUCE SURFACE WINDS OF 35 TO 45 MPH AND EXCESSIVE
LIGHTNING.  MOVE INSIDE IF STORMS APPROACH YOUR LOCATION.

TTH