Flood Watch 4, NWS Charleston, WV

Boyd County, KY, Carter County, KY, Greenup County, KY, Lawrence County, KY, Gallia County, OH, Lawrence County, OH, Meigs County, OH, Washington County, OH, Barbour County, WV, Boone County, WV, Braxton County, WV, Cabell County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Gilmer County, WV, Harrison County, WV, Jackson County, WV, Kanawha County, WV, Lewis County, WV, Lincoln County, WV, Logan County, WV, Mason County, WV, McDowell County, WV, Mingo County, WV, Pleasants County, WV, Putnam County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tyler County, WV, Upshur County, WV, Wayne County, WV, Wirt County, WV, Wood County, WV, Wyoming County, WV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
749 PM EDT MON MAY 4 2009

.SYNOPSIS...
STATIONARY FRONT REMAINS IN THE AREA OVER THE NEXT SEVERAL DAYS.
WAVES OF LOW PRESSURE ON FRONT WILL CROSS AREA WEDNESDAY NIGHT
INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
ONLY MINOR TWEAKS MADE TO THE FORECAST THIS EVENING. LIGHT SHOWERS
CONTINUE THIS EVENING IN SOUTHERN WEST VIRGINIA FROM A WEAK WAVE
OVER EASTERN KENTUCKY. THESE SHOWERS SHOULD DISSIPATE LATER THIS
EVENING AS INSTABILITY WEAKENS. BRIEF BREAK IN PRECIPITATION IS
STILL EXPECTED FOR MUCH OF THE FORECAST AREA THIS EVENING...BUT WILL
INCREASE IN COVERAGE AGAIN AS A SECONDARY SHORTWAVE...CURRENTLY
LOCATED ALONG THE AR/OK BORDER MOVES NORTHEAST INTO THE REGION. AT
THIS TIME...ONLY LIGHT AMOUNTS OF PRECIPITATION ARE EXPECTED FROM
THIS WAVE.

PREVIOUS DISCUSSION FOLLOWS...
THE PRIMARY AREA OF PRECIPITATION IS MOVING OUT TO THE NORTHEAST AS
THE WAVE PROGRESSES EASTWARD. A WAVE OVER CENTRAL KENTUCKY IS
GENERATING PRECIPITATION THERE.  THE NAM KEEPS THE QPF TO THE WEST
BUT SHOWS SOME UPPER LEVEL DIVERGENCE AS WELL AS SOME 700
DEFORMATION PROTRUDING INTO THE WESTERN PORTION OF THE FORECAST AREA
THIS EVENING BEFORE WEAKENING AND MOVING NORTH.  AS A RESULT HAVE
BROUGHT SOME SHOWERS INTO THE SOUTHWEST PORTION OF THE FORECAST AREA
THIS EVENING.

TUESDAY BOTH THE NAM AND GFS SHOW THE WAVE BRINGING PRECIPITATION
INTO THE REGION.  THIS IS THE FIRST APPEARANCE OF PRECIPITATION WITH
THIS SYSTEM.  QPF AMOUNTS ARE LIGHT AND THE WESTWARD EXTENSION IS
IN QUESTION SO HAVE GONE WITH CHANCE.  THE MID SHIFT SHOULD BE
BETTER ABLE TO SORT THIS OUT WITH THE 00Z RUN.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
ANOTHER SHORTWAVE MOVES EASTWARD FROM LOWER MISSISSIPPI VALLEY
LATE TUESDAY NIGHT/WEDNESDAY AND WILL MOVE THROUGH VIRGINIA WEDNESDAY
NIGHT. POTENTIAL FOR ANOTHER INCH OF RAIN SOUTH AND EAST OF A
WILLIAMSON TO CHARLESTON TO ELKINS LINE WITH MUCH LESS RAINFALL TO
THE NORTH AND WEST.

FLOOD POTENTIAL IS SLIGHT AT BEST AT THIS POINT. GROUND WILL HAVE
HAD A COUPLE DAYS TO RECOVER FROM RAINS THIS PAST WEEKEND...AND
RIVERS IN THIS AREA SHOULD BE ABLE TO HANDLE ABOUT AN INCH OF RAIN
WITH LITTLE IF ANY PROBLEMS.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
UNCERTAINTY ABOUNDS IN THE EXTENDED RANGE AS THE MODELS ARE
SHOWING LITTLE CONSISTENCY WITH EACH OTHER. THE GFS IS RUNNING 12
TO 24 HOURS FASTER WITH FEATURES AND IS BY FAR QUICKER TO MOVE
SYSTEMS THROUGH. THE ECMWF IS THE SLOWEST MODELS AND ALSO THE MOST
AMPLIFIED WHEN IT COMES TO THE SYSTEM THAT DEVELOPS FRIDAY INTO
SATURDAY. THE CANADIAN IS MORE LIKE THE ECMWF BUT A LITTLE FASTER.
WITH THE SPREAD IN THE SCENARIOS...DO NOT HAVE MUCH CONFIDENCE ON
THE TIMING OR STRENGTH OF THE FEATURES IN THIS TIME PERIOD.

ON THURSDAY...THE WAVE THAT MOVES IN LAST WED INTO WED NIGHT
SHOULD BE EXITING WITH THE PCPN TAPERING OFF. SO ALLOW FOR SOME
DRY WEATHER IN THE MID DAY TO AFTERNOON HOURS. THE SURFACE FRONT
REMAINS STALLED TO THE SOUTH...BUT WITH THE UPPER TROUGH STILL IN
PLACE OVER THE GREAT LAKES AND EASTERN US...WILL CONTINUE TO SEE
IMPULSES MOVING THROUGH THE TROUGH. THE NEXT WAVE LOOKS TO ARRIVE
SOME TIME THURSDAY NIGHT INTO FRIDAY. THE GFS WOULD HAVE IT
EARLIER...WHICH THE ECMWF DOES NOT BRING IT IN UNTIL LATE ON
FRIDAY. FOR NOW HAVE GONE WITH SOME LOWER POPS THURSDAY NIGHT WITH
HIGHER POPS ON FRIDAY AS THIS IS THE MOSTLY LIKELY TIME AT THIS
POINT FOR ANOTHER SLUG OF RAIN TO DEVELOP.

AFTER THIS WAVE PASSES THE QUESTION WILL BE HOW STRONG WILL THE
NEXT WAVE BE ON SATURDAY AND WILL IT DEVELOP A STRONG SURFACE LOW.
THE ECMWF DEVELOPS A STRONGER MORE AMPLIFIED TROUGH AND STRONGER
SURFACE LOW. THE CANADIAN AND GFS ARE WEAKER AND MORE PROGRESSIVE
WITH THIS WAVE. THE 00Z GFS ENSEMBLE IS MORE IN LINE WITH THE
ECMWF...BUT NOT AS STRONG. HPC GUIDANCE WAS A BLEND OF THE
GUIDANCE WITH THE FRONT SWEEPING ACROSS EARLY ON SATURDAY. SO HAVE
FOLLOWED ALONG ON THAT BLEND OF TIMING. THIS SHOULD ALLOW FOR MORE
SHOWERS FRIDAY NIGHT INTO EARLY SATURDAY BEFORE CLEARING SATURDAY
AFTERNOON AS HIGH PRESSURE FINALLY ARRIVES.

HAVE ALLOWED DRY WEATHER TO RETURN SAT NIGHT INTO MONDAY AS HIGH
PRESSURE SETTLES OVER THE AREA. THE GFS ALLOWS THE HIGH TO COME IN
BRIEFLY BUT THAN BEGINS TO ALLOW WARM ADVECTION TO OVERRIDE AND
PUSH CLOUDS AND MOISTURE BACK EAST MUCH QUICKER. FOR NOW IT LOOKS
TOO FAST SO HAVE FOLLOWED MORE TOWARD THE SLOWER ECMWF.

FOR TEMPERATURES...GENERALLY BLENDED THE NUMBERS BETWEEN THE HPC
GUIDANCE AND THE 12Z MEX AS THE 12Z GFS BEGAN TRENDING TOWARD THE
ECMWF AND CANADIAN RUNS.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
00Z TUESDAY THROUGH 00Z WEDNESDAY...
WITH DEPARTURE OF THE FRONT TO THE EAST CEILINGS OVER THE WESTERN
PORTION OF THE FORECAST AREA WILL RUN AT VFR THIS EVENING WITH MVFR
CIGS OVER THE SOUTH AND EASTERN PORTIONS OF THE FORECAST AREA. RIVER
VALLEY FOG WILL DEVELOP AFTER 06Z...PRODUCING LOCAL IFR AND ISOLATED
LIFR CEILINGS AND VISIBILITIES...IMPROVING AFTER 12Z. ANOTHER
SHORTWAVE WILL MOVE INTO THE REGION TOMORROW...CREATING SHOWERS AND
ISOLATED THUNDERSTORMS AFTER 18Z. LIGHT SURFACE WINDS WITH LIGHT TO
MODERATE SW WINDS ALOFT.

AVIATION OUTLOOK /BEYOND 12Z TUESDAY/...
IFR CONDITIONS POSSIBLE IN RAIN WEDNESDAY NIGHT.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLOOD WATCH UNTIL 4 PM EDT THIS AFTERNOON FOR WVZ030>032-039-
     040.
OH...NONE.
KY...NONE.
VA...NONE.

&&

SYNOPSIS...JKF/AAR/ESS
NEAR TERM...SL/AAR
SHORT TERM...JKF
LONG TERM...ESS
AVIATION...SL