Flash Flooding and Hail in South Carolina, July 10, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1018 AM EDT TUE JUL 10 2012

.SYNOPSIS...
A STALLING FRONTAL BOUNDARY AND A SURFACE TROUGH WILL BE A FOCUS
FOR SHOWERS AND THUNDERSTORMS THROUGH THE WEEK. HEAVY RAIN WILL
ACCOMPANY STRONGER STORMS. TEMPERATURES WILL COOL THROUGH THE WEEK
PROVIDING NEEDED RELIEF FROM THE RECENT HOT TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR ECHOS HAVE DISSIPATED ACROSS THE AREA THIS MORNING. BEST
CHANCE OF PRECIPITATION SHOULD BE THIS AFTERNOON...SO REMOVED POPS
UNTIL 16Z...NOON WHEN HEATING WILL INCREASE INSTABILITY PLUS
INTERACTION WITH THE FRONT ALONG THE NORTH CAROLINA AND SOUTH
CAROLINA BORDER. MADE MINOR CHANGES TO SKY...WIND AND DEW POINT
GRIDS FOR THE REST OF THIS MORNING.

LITTLE CHANGE IN THE OVERALL WEATHER PATTERN WITH A STRONG UPPER
HIGH CENTERED OVER UTAH AND ANOTHER OFF THE SOUTHEAST COAST WITH
THE UPPER RIDGE BEING SPLIT BY AN UPPER TROUGH AXIS EXTENDING FROM
THE GREAT LAKES SOUTHWARD INTO THE LOWER MISSISSIPPI VALLEY. THIS
CONFIGURATION YIELDS DEEP MOIST SOUTHWESTERLY FLOW ACROSS THE
FORECAST AREA. AT THE SURFACE THE FRONT IS NOW ANALYZED TO BE
ACROSS THE SOUTH CAROLINA/NORTH CAROLINA BORDER WITH A TROUGH OF
LOW PRESSURE EXTENDING FROM AUGUSTA TO MYRTLE BEACH.

ATMOSPHERE WILL AGAIN BE MODERATELY UNSTABLE WITH CAPE VALUES
EXCEEDING 2500 J/KG WITH A WEAKLY SHEARED ENVIRONMENT SUPPORTING
PULSE TYPE STORMS THAT COULD FORM INTO CLUSTERS AND WILL BE SLOW
MOVING AND POSE A HEAVY RAIN THREAT. DIFFERENTIAL HEATING
BOUNDARIES CREATED BY THE LINGERING THICK DEBRIS CLOUDS COULD ALSO
BECOME A FOCUS FOR CONVECTION AND COULD ALTER THE FORECAST LEADING
TO LOWER THAN NORMAL CONFIDENCE IN LOCATION OF STORMS. WILL CARRY
LIKELY POPS ACROSS THE NORTHERN HALF OF THE FORECAST AREA THIS
AFTERNOON WHERE PRECIP WATER VALUES WILL EXCEED 2 INCHES AND
MOISTURE ADVECTION INTO THE SURFACE TROUGH AND FRONTAL ZONE WILL
BE MAXIMIZED...AND HIGH CHANCE POPS ELSEWHERE. SIMILAR TO
MONDAY...EXPECT CONVECTION TO LINGER INTO THE OVERNIGHT HOURS AND
HAVE KEPT POPS HIGHER THROUGHOUT THE NIGHT TO ACCOUNT FOR
LINGERING CONVECTION.

TEMPERATURES TODAY SHOULD BE SLIGHTLY COOLER TODAY THAN MONDAY
WITH MORE CLOUDS AND SLIGHTLY COOLER 850 MB TEMPERATURES EXPECTED.
OVERNIGHT LOWS TONIGHT WILL BE DICTATED BY WHERE STORMS DEVELOP
BUT IN GENERAL WILL FALL INTO THE 70S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE UPPER TROUGH AXIS REMAINS TO THE WEST OF THE FORECAST AREA ON
WEDNESDAY WITH THE SURFACE FRONT AND TROUGH IN THE VICINITY
PROVIDING A FOCUS FOR DIURNAL CONVECTION ONCE AGAIN. ADDITIONAL
UPPER SUPPORT WILL COME IN THE FORM OF UPPER DIVERGENCE ASSOCIATED
WITH THE RIGHT ENTRANCE REGION OF AN UPPER JET AND THIS WILL
FURTHER ENHANCE LIFTING GENERATED BY A BUOYANT ATMOSPHERE. WILL
AGAIN CARRY LIKELY POPS ACROSS THE NORTHERN HALF OF THE FORECAST
AREA LATE AFTERNOON INTO THE EVENING HOURS WITH THE EXPECTATION
THAT STORMS WILL LINGER WELL INTO THE OVERNIGHT HOURS. BY
THURSDAY...THE UPPER RIDGE OVER THE WESTERN ATLANTIC BUILDS BACK
WESTWARD ACROSS THE SOUTHEASTERN STATES AND RISES 500 MB HEIGHTS
ACROSS THE REGION. PLENTY OF MOISTURE WILL REMAIN PLACE BUT THE
BUILDING RIDGE SHOULD SUPPRESS CONVECTION A BIT AND WILL CARRY
SOLID CHANCE POPS. MAX TEMPERATURES DURING THIS PERIOD WILL NEAR
TO SLIGHTLY BELOW NORMAL GIVEN CLOUDS AND PRECIPITATION WHILE MIN
TEMPERATURES WILL LIKELY BE ABOVE NORMAL DUE TO CLOUDS AND
INCREASED MOISTURE IN THE ATMOSPHERE.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
THE UPPER RIDGE OVER THE WESTERN ATLANTIC WILL CONTINUE TO BUILD
WESTWARD ACROSS THE SOUTHEASTERN AND GULF COAST STATES THROUGH
SUNDAY BEFORE FLATTENING OUT AS AN UPPER TROUGH DIGS ACROSS THE
GREAT LAKES INTO THE MID ATLANTIC ON MONDAY. THE AXIS HIGH PRECIP
WATER VALUES SHIFTS WEST OF THE FORECAST AREA WHICH WILL LOWER
OVERALL PRECIP CHANCES...BUT WILL CONTINUE TO ADVERTISE CHANCE
POPS GIVEN INSTABILITY AND PRESENCE OF A WELL INLAND PENETRATING
SEA BREEZE BOUNDARY AS A FOCUS FOR CONVECTION. TEMPERATURES DURING
THE PERIOD WILL BE NEAR NORMAL.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
FEW CHANGES MADE TO TERMINAL FORECASTS EXCEPT TO DELAY THE ONSET
OF CU FORMATION UNTIL 16Z AT ALL TERMINALS. WINDS WILL CONTINUE TO
BE LIGHT AS THE AREA IS IN A WIDE TROUGH WHICH INCLUDES THE FRONT
WHICH HAS BEEN ANALYZED TO BE ACROSS THE SOUTH CAROLINA/NORTH
CAROLINA BORDER. MOISTURE AND CONVERGENCE ASSOCIATED WITH THE
FRONT NEAR THE AREA WILL SUPPORT SHOWERS AND THUNDERSTORMS DURING
THE TAF PERIOD ESPECIALLY LATE THIS AFTERNOON WITH AFTERNOON
HEATING AND COPIOUS AMOUNTS OF MOISTURE.

CURRENT RADAR INDICATES ONLY SOME SHOWERS OVER SOUTHEAST NORTH
CAROLINA AT THIS TIME. THUNDERSTORMS WERE NOT INCLUDED DURING
MOST OF THE TAF PERIOD BECAUSE OF TIMING UNCERTAINTY AND WERE
BASED ON THE HIGH RESOLUTION WRF WITH THE BEST CHANCE BEING FROM THE
00Z TO 04Z TIME FRAME. INCLUDED THUNDERSTORMS IN THE FORECAST
DURING THAT TIME. STRONG AND GUSTY WINDS MAY OCCUR WITH A FEW OF
THE THUNDERSTORMS BECAUSE OF MODERATE INSTABILITY AND
PRECIPITATION LOADING. AWAY FROM SHOWERS...INSTABILITY SHOULD
GENERALLY LIMIT FOG DURING THE EARLY MORNING HOURS.

EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS MAY OCCUR IN
MAINLY AFTERNOON AND EVENING THUNDERSTORMS THROUGH SATURDAY. LOW
CLOUDINESS AND FOG MAY OCCUR...MAINLY DURING THE EARLY MORNING HOURS.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE COLUMBIA SC
423 AM EDT TUE JUL 10 2012

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-110830-
LINCOLN-MCDUFFIE-COLUMBIA-RICHMOND-BURKE-LANCASTER-CHESTERFIELD-
MCCORMICK-NEWBERRY-FAIRFIELD-KERSHAW-EDGEFIELD-SALUDA-LEXINGTON-
RICHLAND-LEE-AIKEN-SUMTER-BARNWELL-ORANGEBURG-CALHOUN-CLARENDON-
BAMBERG-
423 AM EDT TUE JUL 10 2012

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

.DAY ONE...TODAY AND TONIGHT.

ISOLATED TO SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE WITH
DAMAGING WIND GUSTS AND LARGE HAIL POSSIBLE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

ISOLATED TO SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE AGAIN ON
WEDNESDAY WITH DAMAGING WIND GUSTS AND LARGE HAIL POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.