000
FXUS62 KCAE 070746
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
346 AM EDT TUE OCT 7 2008
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY ENSURING ANOTHER
FAIR DAY. MOISTURE WILL BE ON THE INCREASE WEDNESDAY AHEAD OF THE
NEXT WEATHER SYSTEM THAT WILL SLOWLY MOVE THROUGH.
&&
.NEAR TERM /THROUGH TONIGHT/...
FAIR AND DRY WEATHER WILL CONTINUE WITH HIGH PRESSURE ALONG THE EAST
COAST. EXPECT GRADUALLY INCREASING HIGH LEVEL CLOUDINESS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
UPPER TROUGH OVER THE CENTRAL CONUS TO SHIFT EAST INTO THE MISS
VALLEY WED. MODELS AGREE ON DEVELOPING A CLOSED UPPER LOW SOMEWHERE
IN THE VICINITY OF THE LOWER MISS VALLEY/DEEP SOUTH/SE US WED/WED
NT. THERE ARE DISAGREEMENTS AMONG THE MODELS WITH REGARDS TO
POSITION AND TIMING. 00Z GFS ENSEMBLE MOS INDICATING A WIDE RANGE OF
POPS AND HIGH STANDARD DEVIATIONS. THEREFORE...UNCERTAINTY IS
CONSIDERABLE. NAM KEEPS THE UPPER LOW TO OUR SW THU NT/FRI. THE GFS
MOVES IT SLOWLY EAST ACROSS OUR REGION THROUGH FRIDAY. 00Z NAM AND
GFS MOS BOTH PROVIDE CATEGORICAL POPS FOR WED NT. HOWEVER...SHORT
RANGE ENSEMBLE POPS AND QPF PROBABILITIES DO NOT EXCEED 50 PCT.
HPC PREFERS A GFS/ECMWF COMPROMISE. GOING FORECAST HAS LIKELY POPS
FOR WED NT. AT THIS TIME GIVEN UNCERTAINITY...WOULD RATHER NOT GO
CATEGORICAL POPS OR MAKE CONSIDERABLE CHANGES TO THE GOING
FORECAST. WILL MAINTAIN LIKELY POPS WED NT/THU.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
CONSIDERABLE UNCERTAINTY CONTINUES REGARDING THE AFOREMENTIONED
SYSTEM. GFS STALLS THE UPPER AND SURFACE LOWS JUST TO OUR
EAST THROUGH SUNDAY. THE ECMWF SHIFTS IT SOUTH. THE CANADIAN MODEL
KEEPS IT MOVING E/NE. THE GOING FORECAST IS DRY. AFTER COLLABORATION
WITH ADJACENT WFO...DECIDED A SMALL POP WAS IN ORDER THROUGH
SUNDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
THE FOG POTENTIAL APPEARS LESS LATE TONIGHT COMPARED TO LAST NIGHT.
EXPECT AN INCREASE IN BOUNDARY LAYER WINDS TOWARD DAYBREAK.
THE NAM AND GFS SHOW THE PRESSURE GRADIENT BECOMING TIGHTER DURING
THE EARLY MORNING HOURS AS THE RIDGE BUILDS INTO THE AREA FROM
THE NORTH. THE SREF GUIDANCE PLUS THE MET AND MAV MOS
TEMPERATURE-DEW POINT TEMPERATURE SPREADS SUPPORT VFR CONDITIONS
EARLY THIS MORNING. VSBYS ALREADY AROUND 6 MILES AT MOST TAF SITES.
COULD SEE VSBYS LOWER TO 2 OR 3 MILES BEFORE BOUNDARY LAYER WINDS
INCREASE. SHOULD SEE PATCHES OF MID AND HIGH LEVEL CLOUD MOVE
THROUGH THE AREA THIS MORNING. AFTER 13Z...THE DRY RIDGING SHOULD
MAINTAIN VFR CONDITIONS THROUGH THE DAY TUESDAY.
EXTENDED OUTLOOK...WIDESPREAD MVFR OR IFR CONDITIONS MAY OCCUR
WEDNESDAY NIGHT THROUGH FRIDAY ASSOCIATED WITH LOW PRESSURE MOVING
INTO THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
