FXUS62 KCAE 080753
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
253 AM EST TUE DEC 8 2009
.SYNOPSIS...
A WARM FRONT WILL REMAIN SOUTH AND EAST OF THE FORECAST AREA THROUGH
TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT. THE FRONT
WILL MOVE THROUGH THE AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
THE NAM AND GFS SHOW ISENTROPIC LIFT WILL BE ON THE INCREASE TODAY.
THE NAM AND GFS MOS INDICATE RAIN WILL DEVELOP AROUND MIDDAY OR
DURING THE AFTERNOON. THIS IS SUPPORTED BY RADAR TRENDS WITH RAIN IN
THE LOWER MISSISSIPPI RIVER VALLEY SPREADING NORTHEASTWARD AND
TOWARD THE FORECAST AREA. PLAN TO FORECAST CATEGORICAL POPS. LEANED
TOWARD THE IN-HOUSE WEDGE SCHEME FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
PLAN TO CONTINUE CATEGORICAL POPS TONIGHT. THE MODELS SHOW THE H85
JET MOVING INTO THE REGION SO EXPECT CONTINUED RAIN OR SHOWERS.
SHEAR WILL BE STRONG. THE MODELS SHOW H85 WINDS 50 TO 70 KNOTS.
SEVERE THUNDERSTORM CANNOT BE RULED OUT BECAUSE OF THE VERY STRONG
SHEAR...BUT THE THREAT APPEARS LOW BECAUSE OF A LACK OF
SURFACE-BASED INSTABILITY. THE NAM LI PATTERN INDICATES THE WEDGE
PATTERN WILL CONTINUE THROUGH TONIGHT. INSTABILITY WILL ALSO BE
LIMITED BECAUSE OF THE FLAT UPPER-LEVEL PATTERN. SHOWERS ASSOCIATED
WITH THE H85 JET MAY LINGER INTO WEDNESDAY MORNING. THE MODELS SHOW
DRYING BY MIDDAY. EXPECT BREAKS IN THE CLOUDINESS OR THE ERODING
WEDGE RIDGE WILL RESULT IN MIXING WEDNESDAY. IT SHOULD BECOME
BREEZY BECAUSE OF CONTINUED STRONG WINDS ALOFT. A LAKE WIND ADVISORY
WILL LIKELY BE NEEDED WEDNESDAY. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE GFS AND ECMWF INDICATE WEDNESDAY NIGHT THROUGH FRIDAY MORNING
SHOULD BE DRY WITH HIGH PRESSURE DOMINATING. LIGHT WIND WITH
STRONG RADIATIONAL COOLING SHOULD RESULT IN COLD CONDITIONS
THURSDAY NIGHT. THE GFS ENSEMBLES SUPPORT LOWS IN THE MID TO
UPPER 20S. THE GFS SHOWS INCREASING MOISTURE AND ISENTROPIC LIFT
FRIDAY WITH DEEP MOISTURE FRIDAY NIGHT INTO SATURDAY. THE
OPERATIONAL GFS INDICATES TEMPERATURES COLD ENOUGH FOR SNOW OR
SLEET IN THE NORTH PART FRIDAY NIGHT. THE GFS ENSEMBLE MEAN
TEMPERATURES WERE WARMER AND THE ECMWF WAS DRY SO BELIEVE THE
CHANCE OF FROZEN PRECIPITATION IS TOO LOW TO ADD TO THE FORECAST
AT THIS TIME. THE GFS SHOWS DRY RIDGING DOMINATING SUNDAY WITH A
RETURN TO ISENTROPIC LIFT MONDAY. THE ECMWF IS MORE FOCUSED AND
HAS DEEP MOISTURE AND ISENTROPIC LIFT CONFINED TO SATURDAY. PLAN
LITTLE CHANGE TO THE PREVIOUS FORECAST WITH THE BEST RAIN CHANCE
SATURDAY.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE CENTERED FROM THE GREAT LAKES TO THE MID ATLANTIC
REGION WILL GRADUALLY MOVE OFFSHORE. EXPECT CLOUDINESS ASSOCIATED
WITH ISENTROPIC LIFT WITH MVFR CONDITIONS BECOMING IFR.
EXTENDED AVIATION OUTLOOK...EXPECT WIDESPREAD IFR CONDITIONS
TONIGHT INTO WEDNESDAY MORNING ASSOCIATED WITH A COLD FRONT.
WIDESPREAD IFR CONDITIONS MAY OCCUR SATURDAY ASSOCIATED WITH LOW
PRESSURE MOVING INTO THE AREA.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...JL
NEAR TERM...JL
SHORT TERM...JL
LONG TERM...JL
AVIATION...BC
