FXUS61 KRLX 290545
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1239 AM EST SUN NOV 29 2009
.SYNOPSIS...
HIGH PRESSURE IS EXODUS SUNDAY BUT CLOSE ENOUGH FOR ONE MORE DRY
DAY. RAIN ARRIVES WITH A COLD FRONT LATE SUNDAY NIGHT AND LASTS
INTO MONDAY. HIGH PRESSURE RETURNS TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE IN CONTROL...WITH FLATTENING H500 RIDGE AXIS MOVING
THROUGH TONIGHT. NARY A CLOUD TO BE SEEN OVERNIGHT WITH A VERY DRY
COLUMN. SHOULD SEE A SILENT WARM FRONTAL PASSAGE OVERNIGHT THAT
WILL ONLY SERVE TO INCREASE DEWPOINTS A BIT. CONSIDERING DRY
AIRMASS AND LACK OF CLOUDS...ELECTED TO GO A BIT BELOW MET/MAV
NUMBERS TONIGHT /UPDATED TO LOWER LOWS IN THE VALLEYS AND RAISE LOWS
A BIT ON THE RIDGE TOPS/.
SUNDAY WILL FEATURE INCREASING SOUTHWEST FLOW. H500 HEIGHTS
CONTINUE TO FALL AS DIGGING SHORTWAVE OVER THE UPPER MISSISSIPPI
VALLEY HELPS TO FLATTEN THE EAST COAST RIDGE. THE MORE ZONAL FLOW
SHOULD HELP TO PUSH CIRRUS INTO THE CWA BY LATE MORNING...WITH SLOW
LOWERING/THICKENING CLOUDS THROUGH THE AFTERNOON. H850 TEMPS ARE
ONLY ABLE TO CLIMB TOWARDS +6 TO +8C...MAKING THE MOS TEMPERATURES
SEEM TOO WARM. UNDERCUT MET/MAV BY AT LEAST A COUPLE OF DEGREES
ACROSS THE BOARD.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
A COLD FRONT...AND ASSOCIATED PRECIPITATION WILL MOVE THROUGH THE
REGION SUNDAY NIGHT THROUGH MONDAY. COLD FRONT WILL BEGIN TO ENTER
THE WESTERN EDGE OF THE CWA AROUND 06Z MONDAY...AND EXIT THE CWA
AROUND 15Z...WITH MUCH OF THE PRECIPITATION BEGINNING TO TAPER OFF
BEHIND THE FRONT AS DRIER AIR MOVES INTO THE FORECAST AREA. MUCH
COOLER AIR WILL ALSO MOVE INTO THE CWA BEHIND THE FRONT. BY MONDAY
EVENING...LIGHT SNOW SHOWERS CAN BE EXPECTED ABOVE 2500 FEET...WITH
A RAIN SNOW MIX AROUND 2000 FEET...CHANGING TO ALL SNOW OVERNIGHT.
ANY ACCUMULATIONS WILL BE LIGHT...DUE TO WARM GROUND AND DECREASE IN
MOISTURE AS THE FRONT CONTINUES TO PUSH EAST. HIGH PRESSURE WILL
BUILD IN FROM THE WEST FOR TUESDAY...FOR DRIER AND GRADUALLY WARMER
CONDITIONS. A FEW LIGHT SNOW SHOWERS WILL CONTINUE TO LINGER EARLY
TUESDAY IN THE NW FLOW...BUT THESE WILL TAPER OFF BY LATE TUESDAY
MORNING AS THE FLOW TURNS MORE WESTERLY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
SOUTHERN STREAM WAVE TO RIDE NORTH ALONG THE APPALACHIAN MOUNTAINS
LATE TUESDAY NIGHT INTO THURSDAY. BOTH GFS AND EUROPEAN MODELS STILL
SHOW SOME DIFFERENCES IN HANDLING THIS WAVE...WITH LATEST RUNS OF
THE GFS SHOWING SIGNS THAT IT WILL SHIFT ITS SOLUTION TO WHAT
PREVIOUS EUROPEAN RUNS WERE SHOWING. HOWEVER..IT STILL IS A LITTLE
TO0 PROGRESSIVE WITH NRN STREAM ENERGY DROPPING INTO THE NRN NORTH
CENTRAL US.
THE STORM TRACK OF THIS SRN STREAM ENERGY WILL PLAY A BIG ROLE IN
HOW OUR FORECAST PLAYS OUT...AND CURRENT THOUGHT IS THAT FOLLOWING
THE ECMWF AND ENSEMBLE SOLUTIONS AS ARE HPC GRIDS...WILL BE THE BEST
COURSE OF ACTION. ONLY CHANGE WAS TO WARM TEMPS SLIGHTLY AHEAD OF
SRN STREAM FEATURE...AND THIS MAY DELAY ANY SWITCH OVER TO SNOW WITH
AS CAA OCCURS THURSDAY. WRAP AROUND MOISTURE COUPLED WITH AN 850H
THERMAL TROUGH WILL LINGER FRIDAY FOR A CONTINUATION OF MOUNTAIN
SNOW SHOWERS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL PREVAIL AS HIGH PRESSURE REMAINS IN CONTROL WITH
LIGHT SOUTHERLY FLOW OVERNIGHT. HOWEVER...MODERATE SOUTHWEST FLOW
ALOFT WILL BE A BIT STRONGER 8-14Z OVERNIGHT INTO SUNDAY MORNING AS
THE NOCTURNAL LOW LEVEL JET DEVELOPS. THIS MAY GIVE RISE TO LOW
LEVEL WIND SHEAR DURING THIS TIME...WITH WINDS OF 30-35 KNOTS JUST
ABOVE DECOUPLED BOUNDARY LAYER.
HIGH CLOUDS ARRIVING FROM THE WEST SUNDAY MORNING WILL LOWER AND
THICKEN DURING THE AFTERNOON BUT REMAIN ABOVE 10KFT FROM THE OHIO
RIVER EAST THROUGH 23Z SUNDAY.
A COLD FRONT WILL APPROACH FROM THE WEST SUNDAY EVENING
STRENGTHENING THE SOUTHWEST FLOW.
AFTER 06Z MONDAY...
BRIEF PERIODS OF IFR IN RAIN ALONG COLD FRONT LATER SUNDAY NIGHT
INTO MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KMC/CL/SL
NEAR TERM...CL/TRM
SHORT TERM...SL
LONG TERM...KMC
AVIATION...ARJ
