Flash Flood Warning 20, NWS Charleston, WV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
150 AM EDT SUN AUG 2 2009

.SYNOPSIS...
STRONG UPPER LEVEL DISTURBANCE OVERNIGHT INTO SUNDAY...WITH PASSAGE
OF COLD FRONT. DRY MONDAY...FOLLOWED BY ANOTHER FRONT TUESDAY NIGHT
INTO WEDNESDAY.

&&

.NEAR TERM /THROUGH TODAY/...
FORECAST WAS UPDATED TO APPEND ANOTHER TIER OF COUNTIES NORTHWARD TO
CURRENT FLASH FLOOD WATCH...BASED ON RADAR TRENDS OF INCOMING SYSTEM
AS WELL AS WHERE HEAVY RAIN FELL DURING THE LAST ONE.

PREVIOUS DISCUSSION...
OVERALL THINKING REMAINS THE SAME AS THE SLOW MOVING COLD
FRONT...WHICH STRETCHES FORM WESTERN LOWER MICHIGAN SOUTHWARD
THROUGH EASTERN ILLINOIS INTO NERN ARKANSAS AT 00Z...WILL CONTINUE
TO MOVE EASTWARD OVERNIGHT. AHEAD OF THE FRONT...A MOISTURE LADEN
SOUTHERLY FLOW WILL PUSH PRECIPITABLE WATER VALUES BACK UP TO
AROUND 1.8 TO 2 INCHES. WITH SHORTWAVE ENERGY SLIDING INTO THE
REGION BETWEEN 6Z AND 12Z...EXPECT TO SEE SHOWERS WITH SOME
EMBEDDED THUNDER MOVE ACROSS THE REGION. WITH THE FFG GUIDANCE
AROUND 1.5 INCHES IN 3 HOURS...COULD SEE THE POTENTIAL FOR
FLOODING PROBLEMS SHOULD THE RAIN DEVELOP...SO WILL CONTINUE THE
WATCH. THE ONE CONCERN AT THIS TIME IS THE CONVECTION OVER THE
DEEP SOUTH...FROM TEXAS INTO ALABAMA. THE MODELS ARE NOT HANDLING
THIS VERY WELL AND IF THIS CONVECTION CONTINUES...IT WILL LESSEN
THE CHANCES OF SIGNIFICANT RAIN ACROSS THE OHIO VALLEY AS THE
MOISTURE FLOW WILL BE BLOCKED.

THE COLD FRONT SHOULD ARRIVE ALONG THE OHIO RIVER AROUND 15Z AND
WILL PUSH THROUGH THE MOUNTAINS BY 21Z. BEHIND THE FRONT...MUCH
DRIER AIR ALOFT PUSHES IN...ENDING THE SHOWERS...BUT SOME
AFTERNOON CU CAN STILL BE EXPECTED AS THE LOW LEVEL MOISTURE
LINGERS BRIEFLY.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
THE ACTUALLY COLD FRONT WILL PASS THRU THE AREA SUNDAY
NIGHT...KEEPING LINGERING SHOWERS IN THE MOUNTAINS INTO THE EVENING
HOURS. THE FRONT STALLS JUST SOUTH OF WV MONDAY.

BEHIND THE FRONT...MODELS TRY TO BRING RELATIVELY COOLER/DRIER AIR
INTO THE NORTHERN SECTIONS UNDER WEST...NORTHWEST FLOW AT
H8...BRINGING DRY WEATHER THROUGH MONDAY NIGHT. THEREFORE...ADJUSTED
POPS/WX GRIDS WITH CHANCE POPS OVER HIGHER ELEVATIONS...AND SLIGHT
CHANCE OVER WESTERN SLOPES.

WENT A DEGREE OR TWO HIGHER THAN GUIDANCE FOR LOWS SUNDAY NIGHT
COUNTING ON WET TERRAIN KEEPING HIGHER DEWPOINTS.
HOWEVER...SOUNDINGS SHOW DESCENT DRY COLUMN ALLOWING RADIATIONAL
COOLING TO FORM DENSE FOG ALONG RIVER VALLEYS AND AREAS THAT RECEIVE
RAIN...THROUGH MONDAY MORNING.

BY MONDAY MORNING...MODELS HAVE A WEAK RIDGE OF HIGH PRESSURE OVER
THE REGION THAT WILL HOLD THROUGH MONDAY NIGHT. AFTER ANY MORNING
FOG...INCREASED SUNSHINE MONDAY WILL REBOUND TEMPS WELL INTO THE
80S...ATMOSPHERE TOO CAPPED FOR ANYTHING BUT AN ISOLATED AFTERNOON
MOUNTAIN SHOWER OR THUNDERSTORM.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
ANOTHER COLD FRONT APPROACHES TUESDAY...WITH SHOWERS AND STORMS
AHEAD OF IT. MODELS IN GOOD AGREEMENT BRINGING THE ACTUALLY COLD
FRONT EARLY WEDNESDAY MORNING.

MODELS HAVE JUST ENOUGH PUSH ON THIS FRONT TO GET IT JUST SOUTH OF
OUR AREA BEFORE STALLING. THUS...KEPT CHANCE POPS ACROSS THE
SOUTHERN HALF OF OUR CWA AND SLIGHT CHANCES ELSEWHERE THRU WED.

AS THE STATIONARY FRONT WEAKENS...ITS VICINITY AND ABUNDANT LOW
LEVEL MOISTURE COULD REGENERATE SOME AFTERNOON CONVECTION MAINLY
ALONG THE MOUNTAINS THU AND THU NGT...WHERE KEPT SLIGHT CHANCE POPS.

ONLY THE ECMWF BRING ANOTHER COLD FRONT FOR FRIDAY. DECIDED TO GO
DRY...AS THE GFS FOR NOW.

HAVE GONE WITH BIAS CORRECTED GMOS FOR HIGHS AND LOWS FROM TUE AND
TUE NGT. GENERALLY MID 80S LOWLANDS RANGING TO MID 70S FOR
HIGHS...AND WARM LOWS IN THE MID 60S.

EXPECTING DESCENT CLOUD COVER FOR WED AND WED NGT WHICH PROMPTED
COOLER TEMPS DURING THE DAY...LOW 80S...AND WARMER NIGHT GENERALLY
IN THE MID 60S.  WENT CLOSER TO GFS TEMPS THROUGH THE END OF THE
PERIOD.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
STRONG UPPER WAVE MOVES THROUGH...QUICKLY FOLLOWED BY PASSAGE OF
COLD FRONT TODAY. RAIN WITH EMBEDDED THUNDERSTORMS LEADS TO MVFR
CIGS AND VIS FOR MOST AREAS DURING MUCH OF THE MORNING...WITH BRIEF
IFR CONDITIONS UNDER THE HEAVIER CELLS. BEHIND THE  FRONT...DRIER
AIR ARRIVES WITH A RETURN TO VFR CONDITIONS...THOUGH WITH DECENT
FIELD OF CUMULUS. HIGH PRESSURE MOVES IN TONIGHT WITH CLEARING SKY
AND DECOUPLING WINDS...WHICH WITH WET GROUND FROM TODAY WILL LEAD TO
A NIGHT OF GOOD VALLEY FOG DEVELOPMENT.

AFTER 06Z MONDAY...
LIKELY IFR TO LIFR VISIBILITIES IN VALLEY FOG DURING THE PREDAWN
HOURS MONDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR WVZ005>008-
     013>016-018-024>030-033>040-046-047.
OH...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR OHZ086-087.
KY...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR VAZ003-004.

&&

SYNOPSIS...26/ARJ
NEAR TERM...MDP/ESS
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...MDP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHARLESTON WV
151 AM EDT SUN AUG 2 2009

KYZ101>103-105-OHZ086-087-VAZ003-004-WVZ005>008-013>016-018-024>030-
033>040-046-047-030600-
GREENUP-CARTER-BOYD-LAWRENCE KY-GALLIA-LAWRENCE OH-DICKENSON-
BUCHANAN-WAYNE-CABELL-MASON-JACKSON WV-LINCOLN-PUTNAM-KANAWHA-ROANE-
CALHOUN-MINGO-LOGAN-BOONE-CLAY-BRAXTON-GILMER-LEWIS-MCDOWELL-WYOMING-
RALEIGH-FAYETTE-NICHOLAS-WEBSTER-UPSHUR-BARBOUR-POCAHONTAS-RANDOLPH-
151 AM EDT SUN AUG 2 2009

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST
KENTUCKY...SOUTHEAST OHIO...SOUTHWEST VIRGINIA AND WEST VIRGINIA.

.DAY ONE...TONIGHT.

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

   FLASH FLOOD WATCH.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED.

OHZ066-067-075-076-083>085-WVZ009>011-017-019-020-031-032-030600-
PERRY-MORGAN-ATHENS-WASHINGTON-JACKSON OH-VINTON-MEIGS-WOOD-
PLEASANTS-TYLER-WIRT-RITCHIE-DODDRIDGE-HARRISON-TAYLOR-
151 AM EDT SUN AUG 2 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST OHIO AND WEST
VIRGINIA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.