FXUS62 KCAE 242035
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
335 PM EST THU DEC 24 2009
.SYNOPSIS...
A STORM SYSTEM OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL MOVE
NORTH TONIGHT AND FRIDAY. ITS ASSOCIATED COLD FRONT WILL CROSS
OUR AREA FRIDAY. RAIN WILL OVERSPREAD THE AREA TONIGHT INTO
FRIDAY. DRY HIGH PRESSURE WILL THEN RETURN OVER THE WEEKEND AND
INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN UPPER LEVEL SHORTWAVE OVER TX WILL MOVE NORTH OVERNIGHT AND
FRIDAY...AND MERGE WITH A SHORT WAVE OVER THE HIGH PLAINS...TO
DEVELOP A LARGE VORTEX OVER THE CENTRAL PART OF THE COUNTRY.
SURFACE HIGH PRESSURE ALONG THE EAST COAST WILL SLIDE OFF THE
COAST TONIGHT AS A LOW PRESSURE SYSTEM IN THE LOWER MISSISSIPPI
RIVER VALLEY MOVES NORTH. CLOUDS OVERSPREADING THE AREA THIS
EVENING.
RETREATING SURFACE HIGH ALONG THE EAST COAST WILL ALLOW FOR A
WARM FRONT TO DEVELOP LATE TONIGHT OVER SOUTHERN GA...AND MOVE
NORTHWARD THROUGH OUR REGION FRIDAY. GOOD INSENTROPIC LIFT LATE
TONIGHT INTO FRIDAY IN ADVANCE OF THE WARM FRONT. KEPT CATEGORICAL
POPS OVERNIGHT AND INTO FRIDAY OVER THE ENTIRE CWA. RAINFALL
AMOUNTS BETWEEN 1.00 AND 1.5 INCHES.
GFS AND NAM STILL INDICATING AIR MASS TO BECOME UNSTABLE AHEAD OF
THE COLD FRONT FRIDAY AFTERNOON. WHILE LAPSE RATES REMAIN RATHER
WEAK...MOISTURE COUPLED WITH DIABATIC HEATING SUPPORT CHANCE FOR
CONVECTION. MENTION CHANCE OF TSTMS FRIDAY AFTERNOON.
STRONG LOW LEVEL JET CROSSING THE REGION TONIGHT INTO FRIDAY. ANY
MIXING WILL BRING STRONGER WINDS TO THE SURFACE. HAVE ISSUED A
LAKE WIND ADVISORY FROM MIDNIGHT THROUGH FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
RAIN MOVES EAST OF THE REGION BY FRIDAY NIGHT. HIGH PRESSURE
RIDGING IN FROM THE WEST. DRY FORECAST FRIDAY NIGHT INTO SATURDAY
NIGHT. HIGHS IN THE 50S AND LOWS IN THE 30S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
LARGE MID/UPPER LEVEL VORTEX OVER THE UPPER MID-WEST/GREAT LAKES
REGION LIFTS NORTHEAST AND OPENS UP EARLY NEXT WEEK. SURFACE HIGH
PRESSURE BUILDING IN FROM THE WEST SUNDAY THROUGH TUESDAY.
WEST/NORTHWEST FLOW AT H850 WILL KEEP THE GULF CLOSED. DRY AND
COOL PERIOD THROUGH WEDNESDAY.
NEXT MID LEVEL DISTURBANCE ALONG THE CA COAST WILL MOVE THROUGH
THE SOUTHWEST TUESDAY...AND DEVELOP ANOTHER AREA OF LOW PRESSURE
IN THE WESTERN GULF OF MEX THURSDAY. LOW PRESSURE IS FORECAST TO
MOVE/REFORM OFF THE SOUTHEAST SEABOARD LATE THURSDAY OR FRIDAY.
UNCERTAINTY STILL WITH THIS SYSTEM. ECMWF IS WARMER AND WETTER
THAN THE DRY AND COOL GFS. FOR NOW WILL INTRODUCE A CHANCE OF
LIQUID PRECIP THURSDAY.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS QUICKLY GIVING WAY TO MVFR AND IFR. HIGH PRESSURE
WILL SLIDE FURTHER AWAY FROM THE AREA AS LOW PRESSURE AND AN
ASSOCIATED COLD FRONT MARCH INTO THE REGION. SATELLITE IMAGERY
SHOWS LOW LEVEL CLOUDS DEVELOPING AROUND THE TAF SITES AS EASTERLY
WINDS PUSH INCREASING MOISTURE INLAND. THIS TREND WILL BE AIDED BY
SOUTHERLY LOW LEVEL JET THIS EVENING PUSHING GULF MOISTURE
NORTHWARD. BY 25/06Z EXPECT RAIN TO BEGIN AT THE TAF SITES WITH
THE COLD FRONT NOT ARRIVING UNTIL VERY LATE IN THE TAF PERIOD.
HEAVIEST RAIN WILL ARRIVE AROUND 25/14Z WITH CIGS AND VSBYS
EXPECTED IN THE IFR RANGE. WINDS WILL INCREASE THROUGH THE PERIOD
WITH AROUND 15 KNOTS BY 25/06Z WITH GUSTS TO AROUND 22 KNOTS.
EXTENDED AVIATION OUTLOOK...IFR/MVFR CONDITIONS POSSIBLE FRIDAY AS A
COLD FRONT MOVES THROUGH THE REGION. HIGH PRESSURE WILL BUILD INTO
THE REGION FOR FRIDAY NIGHT THROUGH TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EST FRIDAY
FOR SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EST FRIDAY
FOR GAZ040-063>065-077.
&&
$$
SYNOPSIS...10
NEAR TERM...10
SHORT TERM...10
LONG TERM...10
AVIATION...MP
