Flash Flood in North Carolina, July 25, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
259 PM EDT SUN JUL 25 2004

.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...
THE SURFACE PATTERN THIS AFTN IS DOMINATED BY TROUGHS ALONG THE COAST
AND JUST WEST OF THE APPALACHIANS...WHILE RIDGING CONT EAST OF THE
MTN CHAIN WITH A PERSISTENT NE FLOW. KGSP VAD WIND PROFILE SHOWS
THREE GATES OF EASTERLY FLOW NEAR THE GROUND...BUT SHORT RANGE MODELS
INDICATE ONLY SLIGHT IMPROVEMENT IN THE UPSLOPE COMPONENT THROUGH THE
OVERNIGHT HOURS. THUS...BEST COVERAGE THROUGH THE TONIGHT PERIOD
SHOULD COME TOGETHER OVER THE HIGHER TERRAIN WITH CONVECTION STEERED
TOWARD THE MTN CHAIN FROM ERN TN...AND THEN WEAK UPSLOPE TRIGGERING
ALONG THE ERN ESCARPMENT. PRECIPITATION AMOUNTS SHOULD BE GREATEST
NEAR THE TN BORDER THIS EVENING WHERE HIGHER INSTABILITY WILL YIELD
GREATER PRECIP RATES.

FLOW VEERS SRLY TOMORROW THROUGH TUESDAY NIGHT AHEAD OF LOW PRESSURE
RIDING NORTHWARD ALONG THE FRONT TOWARD THE OH VALLEY. THIS WILL
RESULT IN AN INCREASED FLOW OF GULF MOISTURE INTO THE REGION AND
IMPROVING S TO SW UPSLOPE FLOW. THE PROXIMITY OF THE UPPER JET
STREAK MAY FINALLY START TO LEND SOME UPPER DIVERGENCE TO THE MIX BY
MONDAY NIGHT...BUT A STRONG WEST TO EAST GRADIENT OF POPS IS STILL
EXPECTED WITH THE HEAVY RAINFALL THREAT CONFINED MAINLY TO THE
MTNS. WILL ADJUST THE ESF TO INCLUDE ONLY THE MTN COUNTIES AND ONE
TIER OF ADJACENT FOOTHILL COUNTIES THROUGH TUESDAY.

FROPA IS TENTATIVELY SLATED FOR TUE NIGHT. THE DEGREE OF DRYING
THROUGH WED IS QUESTIONABLE AS BOUNDARY COULD STALL IN...OR JUST
EAST OF THE FORECAST AREA.
&&

.LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)...
SFC BNDRY IS FORECAST TO DISSIPATE ACRS THE CAROLINAS ON DAY 4 AND
MODEL CONSENSUS IS FOR ATLANTIC RIDGING TO BEGIN BUILDING WESTWARD
INTO THE MID-ATLANTIC AND SOUTHEAST U.S. AT THE END OF THE WORK WEEK.
FOR NEXT WEEKEND...THIS RIDGE WILL BECOME THE DOMINANT WX FEATURE
WITH THE CWFA ASSUMING A FAIRLY TYPICAL SUMMERTIME ORIENTATION...
COMING UNDER IT/S WESTWARD EXTENDING NOSE. MOIST SOUTHEAST FLOW LOOKS
TO  EVOLVE INTO AN INCREASINGLY DEEP AND MOIST SOUTHERLY FLOW
HEADING INTO THE WEEKEND...WHICH USUALLY RESULTS IN ABOVE NORMAL
CONVECTIVE ACTIVITY. MAX TEMPS FOR DAY 4-7 ARE EXPECTED TO BE NEAR
IF NOT JUST A TOUCH BELOW NORMAL.
&&

.AVIATION...
LACK OF OBVIOUS TRIGGERING MECHANISM THIS AFTERNOON AND EVENING WILL
RESULT IN A LIMITING OF ANY THUNDER CHANCES TO JUST KAVL. HAVE
DELAYED ONSET OF NOCTURNAL STRATCU CIGS FOR THE UPSTATE TAFS UNTIL
THE OVERNIGHT WITH ETA MODEL TIMEHEIGHT CROSS SECTIONS DELAYING
NOTABLE MOISTENING WITHIN 1000-850 MB LAYER UNTIL GENERALLY AFTER
06Z. CONSENSUS AMONG 12Z SHORT RANGE MODELS THAT THREAT OF IFR CIGS
BECOMING MORE PROBABLE...SO HAVE ADDED AT LEAST A PERIOD OF LOW CIGS
ADVECTING IN FROM NNE TO AS FAR SOUTHWEST AS KGSP THRU DAYBREAK.
NOMINAL CHANGES TO EARLIER VSBY RESTRICTIONS SINCE CONFIDENCE
REMAINS LOW FOR ADDITIONAL PCPN AT ANY TERMINALS THIS AFTERNOON OR
EVENING.
&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&

SHORT TERM...HG
LONG TERM/AVIATION...CSH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
515 AM EDT SUN JUL 25 2004

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-SCZ001>014-
019-260906-
ABBEVILLE SC-ALEXANDER NC-ANDERSON SC-AVERY NC-BUNCOMBE NC-BURKE NC-
CABARRUS NC-CALDWELL NC-CATAWBA NC-CHEROKEE SC-CHESTER SC-
CLEVELAND NC-DAVIE NC-ELBERT GA-FRANKLIN GA-GASTON NC-GRAHAM NC-
GREATER GREENVILLE SC-GREATER OCONEE SC-GREATER PICKENS SC-
GREENVILLE MOUNTAINS SC-GREENWOOD SC-HABERSHAM GA-HART GA-HAYWOOD NC-
HENDERSON NC-IREDELL NC-LAURENS SC-LINCOLN NC-MACON NC-MADISON NC-
MCDOWELL NC-MECKLENBURG NC-MITCHELL NC-NORTHERN JACKSON NC-
OCONEE MOUNTAINS SC-PICKENS MOUNTAINS SC-POLK NC-RABUN GA-ROWAN NC-
RUTHERFORD NC-SOUTHERN JACKSON NC-SPARTANBURG SC-STEPHENS GA-
SWAIN NC-TRANSYLVANIA NC-UNION SC-UNION NC-YANCEY NC-YORK SC-
515 AM EDT SUN JUL 25 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA...
UPSTATE SOUTH CAROLINA...AND EXTREME NORTHEAST GEORGIA.

.DAY ONE...
SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER THE MOUNTAINS
AND FOOTHILLS OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS
AFTERNOON. THE THUNDERSTORMS WILL BE VERY SLOW MOVING...AND SOME
LOCATIONS WILL SEE LOCALLY VERY HEAVY RAIN. THE SCATTERED
THUNDERSTORMS WILL CONTINUE OVER THE MOUNTAINS FOOTHILLS MUCH OF THE
NIGHT.

.DAYS TWO THROUGH SEVEN...
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE REGION
MONDAY THROUGH TUESDAY. WITH A MOIST ATMOSPHERE AND WEAK WINDS
ALOFT...THE STORMS WILL BE VERY SLOW MOVING. A FEW AREAS WILL LIKELY
SEE SEVERAL INCHES OF RAIN...AND SOME ISOLATED FLOODING AND FLASH
FLOODING MAY DEVELOP.

THERE WILL BE A CHANCE OF THUNDERSTORMS AGAIN ACROSS THE REGION ON
THURSDAY AND FRIDAY...AND IN THE MOUNTAINS ON SATURDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON...MAINLY TO REPORT
RAINFALL AMOUNTS AND MONITOR STREAM LEVELS.

MCAVOY