FXUS62 KCAE 011943
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
243 PM EST TUE DEC 1 2009
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. RAIN ILL DEVELOP BY
LATER TONIGHT AS LOW PRESSURE MOVES NORTHEAST FROM THE GULF OF
MEXICO. RAIN WILL CONTINUE WEDNESDAY...WITH THUNDERSTORMS ALSO
POSSIBLE...UNTIL A COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. FAIR
WEATHER EXPECTED THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL MOVE OFFSHORE THIS
EVENING AND TONIGHT. HIGH CLOUDS ALREADY BEGINNING TO STREAM IN
FROM THE WEST. CLOSED UPPER LOW OVER NORTHERN MEXICO/TEXAS REGION
WILL PUSH EAST. UPPER LEVEL IMPULSES AHEAD OF IT IN A SW UPPER
FLOW WILL ALLOW SURFACE LOW PRESSURE TO DEVELOP NEAR THE WESTERN
GULF TODAY...PUSHING NE TOWARDS THE LOWER MISSISSIPPI VALLEY OR
NORTHERN GULF COAST TONIGHT. A WARM FRONT TYPE FEATURE WILL
APPROACH OUR FA WITH ISENTROPIC LIFT INDUCED RAINFALL EXPECTED TO
DEVELOP AND PUSH INTO OUR FA FROM THE SW LATE TONIGHT. LOW
TEMPERATURES TONIGHT COULD BE REACHED EARLY WITH LIGHT WINDS AND
JUST SOME UPPER LEVEL CLOUDINESS. BY LATE TONIGHT...CLOUD BASES
WILL BE LOWERING AND WIND WILL BE INCREASING WHICH MAY ALLOW TEMPS
TO REMAIN STEADY OR RISE SOME...THOUGH THAT COULD BE TEMPERED LATE
BY RAINFALL.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
WARM FRONT TYPE FEATURE EXPECTED TO MOVE THROUGH EARLY WEDNESDAY.
WITH TRACK OF SURFACE LOW REMAINING TO OUR WEST...AND WITHOUT A
STRONG PARENT HIGH TO OUR NE...ANY IN SITU WEDGE THAT COULD DEVELOP
SHOULD BE WEAK AND SHORT LIVED FOR OUR FA. IT APPEARS THAT OUR FA
WILL BE IN A WARM SECTOR WEDNESDAY AFTERNOON AND INTO THE EVENING
HOURS. NAM APPEARS TO BE FASTER AND A BIT MORE UNSTABLE THAN THE
GFS SOLUTION. SPC INDICATES A SLIGHT RISK OF SEVERE THUNDERSTORMS
ACROSS OUR FA. MODELS ARE SHOWING IMPRESSIVE LOW-LEVEL SHEAR WITH
STRONG STORM RELATIVE HELICITY VALUES. HOWEVER...THIS IS
GENERALLY A CLIMATOLOGICALLY UNFAVORABLE TIME OF YEAR FOR
SIGNIFICANT SEVERE WEATHER FOR OUR FA. THERE IS ALSO A QUESTION
HOW MUCH CONVECTIVE ACTIVITY WE MAY GET. IF SIGNIFICANT CONVECTION
DEVELOPS WELL SOUTH OF OUR FA ALONG THE FL PANHANDLE...THAT MAY
LIMITED THE DEVELOPMENT OF CONVECTION IN OUR AREA TO SOME DEGREE.
SREF ENSEMBLES SEEM TO GIVE AN AVERAGE OF AROUND 1.6 INCHES OF
RAIN THROUGH THURSDAY MORNING. WILL NOT ISSUE A FLOOD WATCH FOR
OUR AREA AT THIS TIME. FRONT TO MOVE THROUGH LATE WEDNESDAY NIGHT.
MODELS INDICATE UPPER FLOW TO REMAIN SW...WHICH WOULD NOT ALLOW
THE FRONT TO GET A GOOD PUSH. IT APPEARS IT MAY STALL
OFFSHORE BY EARLY THURSDAY.
WILL ISSUE A LAKE WIND ADVISORY FOR THE ENTIRE AREA FROM 18Z
WEDNESDAY TO 12 THURSDAY AS THE LOW-LEVEL WINDS INCREASE AHEAD OF
THE LOW PRESSURE SYSTEM.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
DRY HIGH PRESSURE TO BUILD IN FROM THE WEST THURSDAY AFTERNOON
INTO FRIDAY. MODELS IN GENERAL SEEM TO SUGGEST A LOW DEVELOPING
AND MOVING ACROSS SOUTHERN FLORIDA IN VARYING DEGREES SATURDAY AND
MOVING NE...WITH THE MAIN MOISTURE PLUME REMAINING TO OUR SOUTH.
HOWEVER...LIFT FROM THE UPPER TROUGH ALONG WITH ANY MOISTURE COULD
TRANSLATE TO A CHANCE OF PRECIP FOR OUR REGION. FOR NOW WILL GO
WITH A SLIGHT CHANCE OF RAIN SATURDAY. GFS/ECMWF BRING IN SURFACE
HIGH PRESSURE FOR SUN/MON...BUT REDEVELOPS A WSW UPPER FLOW WHICH
PROVIDES FOR UNCERTAINTY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS TODAY INTO THIS EVENING WILL BEGIN DETERIORATING AFTER
02/05Z. INCREASING MOISTURE AHEAD OF A LOW PRESSURE SYSTEM COMING
OUT OF THE GULF OF MEXICO WILL SPREAD CLOUDS AND RAIN ACROSS THE TAF
SITES AFTER 02/05Z. CIGS EXPECTED TO LOWER TO MVFR BY THE END OF THE
TAF PERIOD. NORTHEAST WINDS WINDS 5 TO 10 KNOTS TODAY...BECOMING
EAST AROUND 10 KNOTS AFTER 06Z. MAY SEE WIND GUSTS NEAR 20 KNOTS
TOWARD DAYBREAK WEDNESDAY.
EXTENDED AVIATION OUTLOOK...MVFR TO IFR CONDITIONS EXPECTED WEDNESDAY
INTO THURSDAY MORNING AS A LOW PRESSURE SYSTEM AFFECTS THE AREA.
ANOTHER LOW PRESSURE AREA ALONG THE COAST COULD BRING RESTRICTED
CONDITIONS ON SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 1 PM WEDNESDAY TO 7 AM EST THURSDAY
FOR SCZ015-016-018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY FROM 1 PM WEDNESDAY TO 7 AM EST THURSDAY
FOR GAZ040-063>065-077.
&&
$$
