322
FXUS61 KRNK 091054
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
654 AM EDT WED JUL 9 2008
SYNOPSIS
A WEAK COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT. THE FRONT
WILL STALL AND THEN DISSIPATE OVER THE CAROLINAS ON THURSDAY AND
THURSDAY NIGHT. WIDESPREAD THUNDERSTORMS CAN BE EXPECTED ACROSS THE
REGION WITH THE FRONTAL PASSAGE.
NEAR TERM /THROUGH TONIGHT/
FIRST BATCH OF SHOWERS AND THUNDERSTORMS CONTINUED TO MOVE EAST
ACROSS THE FORECAST AREA NORTH OF RTE 460 THIS MORNING. TOPS ARE
WARMING ON THE IR LOOP AND INTENSITY OF THE STORMS IS DIMINISHING
BUT ALL GUIDANCE HAS THIS AREA HOLDING TOGETHER AND CROSSING THE
REST OF THE WAY THROUGH THE FORECAST AREA...REACHING THE EASTERN
COUNTIES BETWEEN 09-12Z. MORE SHOWERS AND THUNDERSTORMS NOW IN
SOUTHERN WEST VIRGINIA WILL BE REACHING THE WESTERN COUNTIES BY THAT
TIME.
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
TIMING OF WEAK COLD FRONT REMAINS SIMILAR ON MODELS...BUT AT SOME
POINT THURSDAY OR THURSDAY NIGHT FRONT WILL STALL OUT AS IT
BECOMES PARALLEL WITH ZONAL FLOW ALOFT. BOTH GFS AND NAM ARE NOT
SHOWING ANY PRESSURE RISES AND HAVE A HINT OF A WAVE AT 850 MB
COMING OUT OF THE TENNESSEE VALLEY. LOW LEVEL WINDS BELOW 850 MB
MAY HAVE A LIGHT COMPONENT OUT OF THE EAST WHICH WOULD KEEP LOW
LEVEL MOISTURE HIGH. NAM WAS ALSO KEEPING DEEP MOISTURE IN THROUGH
FRIDAY MORNING. WILL SLIGHTLY INCREASE CHANCE OF PRECIPITATION
THURSDAY AND THURSDAY NIGHT ALONG THE VIRGINIA/NORTH CAROLINA
BORDER.
WITH ALL THE CLOUD COVER THIS MORNING HAVE LOWERED THE MAXIMUM
TEMPERATURES FOR TODAY A COUPLE OF DEGREES IN MOST LOCATIONS.
LONG TERM /FRIDAY THROUGH TUESDAY/
WEAK SLOW MOVING FRONT AFFECTING WX TODAY WILL STILL BE CAUSING
PROBLEMS ON FRIDAY. STOPPING ALONG THE NC/VA BORDER OR SOMEWHAT
FARTHER SOUTH...H5 LOW MOVING INTO SOUTH CENTRAL CANADA...AND
STRENGTHENING UPPER HIGH OVER THE GULF OF MEXICO MAY NUDGE THIS
BOUNDARY SLIGHTLY BACK NORTH. SOUPY AIRMASS WILL HAVE NEVER REALLY
LEFT...EXCEPT IN THE EXTREME NW CWA. WITH EVEN A WEAK ONSHORE FLOW
PERHAPS DEVELOPING IN THE SE CWA...FELT THE NEED TO INC POPS ALONG
THE SOUTHERN PERIPHERY...ESPECIALLY CONSIDERING THAT GFS/NAM ARE
MUCH MORE PESSIMISTIC THAN EARLIER RUNS FOR PRECIP ON FRIDAY.
SURFACE HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVER THE
WEEKEND. THIS WILL BRING SOUTHERLY FLOW ACROSS THE AREA WITH A
RETURN OF HEAT AND HUMIDITY BY THE END OF THE WEEKEND. MODELS ARE
SHOWING A WEAK FRONT AND/OR OVER RUNNING MOISTURE ON SUNDAY TO
INCREASE THE THREAT FOR RAIN OVER THE MOUNTAINS. MODELS HAVE NOT
BEEN CONSISTENT WITH LOCAL LONG TERM FORECAST. THEREFORE...WILL
KEEP POPS LOW (20/30) FOR THIS FORECAST PACKAGE.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
THE VISIBILITY WAS STILL GOING DOWN AT LWB SO HAVE ADDED A TEMPO
PERIOD FOR LIFR VISIBILITY EARLY IN THE FORECAST PERIOD. ONCE THE
FOG BURNS OFF THIS MORNING AND HEATING STARTS VFR CONDITIONS ARE
EXPECTED THROUGH ABOUT 18Z.
NUMEROUS THUNDERSTORMS WILL DEVELOP AGAIN THIS AFTERNOON AHEAD OF
AN APPROACHING COLD FRONT. WITH THE FRONT MOVING FROM WEST TO EAST
THE STORMS WILL DEVELOP IN THE MOUNTAINS FIRST AND EAST OF THE
BLUE RIDGE A LITTLE LATER IN THE DAY.
HAVE ALSO ADDED MVFR FOG IN AGAIN FOR OVERNIGHT AT LWB/DAN/LYH.
FRONT WILL NOT BE THROUGH THESE STATIONS UNTIL EARLY THURSDAY
MORNING SO DEW POINTS OVERNIGHT WILL STILL BE IN THE 60S.
FRONT MAY STALL ACROSS NC THU...SO THERE WILL BE A THREAT FOR TSTMS
MAINLY AT DANVILLE. SLIGHTLY DRIER AIR WILL WORK INTO MOST OF THE
AREA FOR THE END OF THE WEEK.
RNK WATCHES/WARNINGS/ADVISORIES
VA...NONE.
NC...NONE.
WV...NONE.
SYNOPSIS...AMS/RCS
NEAR TERM...AMS
SHORT TERM...AMS
LONG TERM...KM/RCS
AVIATION...AMS/KM
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