FXUS62 KCAE 081201
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
701 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 /12Z TUESDAY THROUGH SUNDAY/...
CLOUDS WELL AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM NEAR THE FOUR
CORNERS REGION WILL CONTINUE TO SPREAD ACROSS THE FORECAST AREA
TODAY INTO TONIGHT. CIGS WILL CONTINUE TO LOWER TODAY TO IFR LEVEL
LATER THIS AFTERNOON WITH SOME LIGHT RAIN DEVELOPING. CONDITIONS
WILL BECOME IFR/LIFR FOR MOST LOCATIONS DURING THE OVERNIGHT HOURS
AS RAIN BECOMES MORE WIDESPREAD WITH SOME PATCHY FOG. SFC WINDS WILL
SHIFT FROM THE NE-E TODAY...BECOME MORE SOUTHERLY OVERNIGHT AND
INCREASING TO 10 KTS BY AROUND 06Z WEDNESDAY. NOT MUCH IMPROVEMENT
TOWARDS THE END OF THE 24 HR TAF PERIOD.
EXTENDED AVIATION OUTLOOK...IFR CONDITIONS WILL CONTINUE OVER OUR
AREA INTO EARLY WEDNESDAY AS THE LOW PRESSUE SYSTEM LIFTS INTO THE
GREAT LAKES REGION. CONDITIONS SHOULD IMPROVE BY LATE WEDNESDAY AS A
COLD FRONT SWEEPS THROUGH. HIGH PRESSURE WILL DOMINATE THE AREA FOR
THU/FRI. ANOTHER SYSTEM TO BEGIN TO AFFECT THE AREA BY SAT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
