FXUS62 KILM 021123
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
620 AM EST WED DEC 2 2009
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL BRING RAIN...WIND...LARGE WAVES
OFFSHORE...AND POSSIBLY SEVERE WEATHER TO THE CAROLINAS TODAY.
HIGH PRESSURE WILL BUILD IN THURSDAY AND FRIDAY BRINGING COLDER
AIR. AN UPPER LEVEL DISTURBANCE WILL BRING RAIN CHANCES LATE
FRIDAY NIGHT INTO SATURDAY. CHILLY HIGH PRESSURE WILL RETURN
SUNDAY THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...PRECIP SHIELD STEADILY ADVANCING FROM THE SW
AND EXPECT THE FIRST PATCHES OF DRIZZLE TO ARRIVE IN OUR SOUTH
CAROLINA COUNTIES IN THE NEXT HOUR OR SO. SUBSTANTIAL RAIN EVENT
STILL ON TRACK FOR TODAY WITH THE POTENTIAL FOR SEVERE WEATHER
DURING THE AFTERNOON AND EVENING. WITH IMPRESSIVE VERTICAL SHEAR AND
STRONG WINDS JUST OFF THE DECK THE MAIN THREATS WILL BE DAMAGING
WINDS MIXING DOWN AND TORNADOES...ESPECIALLY LATER THIS AFTERNOON
AND WELL INTO THE EVENING. SYSTEM RESPONSIBLE FOR ALL THIS NOW
RAPIDLY EVOLVING OVER THE GULF COAST STATES. LOW CENTER WILL LIFT
RAPIDLY NE ALONG THE MISSISSIPPI RIVER VALLEY AS ASSOCIATED WARM
FRONT MOVES NORTH UP THE COAST...PUTTING US IN THE WARM SECTOR THIS
EVENING. COLD FRONT WILL SWEEP EAST AND OFFSHORE BY AROUND
MIDNIGHT...AFTER WHICH THREAT FOR SEVERE WEATHER WILL RAPIDLY
DECLINE. QPFS LOOK IMPRESSIVE...COULD SEE 2 TO 3 INCHES TOTAL FOR
THIS EVENT AND WILL HAVE TO KEEP AN EYE OUT FOR FLOODING ISSUES.
STRONG SLY WINDS THIS AFTERNOON WILL KEEP MAX TEMPS WELL ABOVE
NORMAL...ESPECIALLY ALONG THE COAST. MAX TEMPS WILL RANGE FROM MID
60S INLAND TO AROUND 70 AT THE COAST. STRONG ONSHORE WINDS ALONG THE
COAST THIS AFTERNOON INTO TONIGHT. AT THIS POINT DO NOT SEE NEED FOR
WIND ADVISORY AS GRADIENT WINDS SHOULD STAY JUST BELOW ADVISORY
CRITERIA.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...WILL BEGIN THE PERIOD IN BETWEEN THE PRE-
FRONTAL TROUGH AND THE ACTUAL COLD FRONT. DEEP MOISTURE WILL BE
SHUNTED OFFSHORE BY 12Z THU...ALLOWING FOR A DRY FORECAST EVEN
WITH THE LATE-DAY FROPA. COOL AND DRY HIGH PRESSURE WILL BUILD IN
FROM THE OHIO VALLEY THU NIGHT AND FRI. HOWEVER...CLOUDS WILL
INCREASE FRI AFTERNOON AS SW FLOW MOISTENS THE MID LEVELS. BY FRI
NIGHT...EXPECT A WAVE TO RIDE NORTHEAST ALONG THE FRONT STILL
PARKED WELL OFFSHORE. BIGGEST QUESTION IS WHETHER THE FRONT WILL
BE CLOSE ENOUGH OR THE DISTURBANCE STRONG ENOUGH TO PUSH PRECIP
ONSHORE. WILL GO WITH CHANCE POPS ALONG THE COAST...BUT JUST
SLIGHT CHANCE INLAND. DECENT AGREEMENT AMONG VARIOUS GUIDANCE
TEMPS AND CONSENSUS SEEMS THE PATH OF LEAST REGRET.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...FORECAST CONFIDENCE IS FAIRLY LOW FOR
SATURDAY...AS LOW PRESSURE WILL MOVE NORTHEAST ALONG THE
STATIONARY FRONT OFFSHORE. THE QUESTION IS HOW FAR ONSHORE THIS
SYSTEM WILL BE ABLE TO FLING MOISTURE. LATEST GFS CAME IN A LOT
WETTER THAN THE PREVIOUS RUN...WITH LIKELY TO CATEGORICAL POPS IN
THE GUIDANCE. NOT READY TO BITE ON THAT YET...SO WILL CARRY HIGH
CHANCE POPS FOR SATURDAY...AND SLIGHT OR LOW CHANCE INTO SAT
NIGHT.
COLD HIGH PRESSURE WILL WIN THE BATTLE AFTER THAT...RESULTING IN
TEMPS WELL BELOW NORMAL ESPECIALLY BY DAY. MAX TEMPS SUNDAY AND
MONDAY WILL STRUGGLE TO REACH EVEN MID-JANUARY NORMALS. ANOTHER
SOUTHERN STREAM SYSTEM COULD COME INTO PLAY BY LATE TUESDAY...BUT
WILL KEEP THE FORECAST DRY UNTIL BETTER CONSISTENCY CAN BE
ESTABLISHED.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
CUT OFF LOW OPENS UP TODAY AND TRACKS NORTHEAST AS A NEGATIVELY
TILTED 500 MB TROUGH. SURFACE LOW PRESSURE IS WELL WEST OF THE
REGION...WITH WEAK CYCLOGENESIS ALONG THE WARM FRONT. LOOK FOR
MOSTLY STRATIFORM PRECIPITATION EARLY ON...WITH HEAVIER SHOWERS
EMBEDDED BY MID MORNING AS THE WARM FRONT WAVES NORTHWARD. WINDS
WILL INCREASE AT VEER TO THE EAST SOUTHEAST BY MIDDAY. AS THE WARM
FRONT MOVES NORTH OF THE CWA...THERE MAY BE A LULL IN THE
PRECIPITATION...BUT MVFR CEILINGS WILL REMAIN. WITH THE DEWPOINTS
APPROACHING THE MID SIXTIES BY THIS AFTERNOON...THERE IS A SLIGHT
CHANCE OF SOME IFR STRATUS ALONG THE COAST...BUT WILL STAY CLEAR OF
THIS SCENARIO FOR NOW. LATE THIS AFTERNOON...THE COLD FRONT
APPROACHES. A NARROW BAND OF STRONG OMEGA SUGGESTS THAT A SQUALL
LINE WILL FORM NEAR FLO BY 20Z...PUSHING TO THE COAST BY 00Z. TIMING
IS STILL A BIT IN QUESTION AND WILL BE REFINED ON THE NEXT SET OF
TAFS. WINDS WITH THE NARROW BAND OF CONVECTION WILL BE STRONG...WITH
WINDS AT 850 MB APPROACHING 60 KTS. AFTER THE STORMS
PASS...CONDITIONS WILL IMPROVE TO VFR. WINDS WILL SHIFT TO THE
SOUTHWEST AND WILL CONTINUE TO BE GUSTY THROUGH THE END OF THE
FORECAST PERIOD.
EXTENDED OUTLOOK...VFR THURSDAY AND FRIDAY. RAIN AND IFR CEILINGS
LIKELY SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...MAINTAINING CURRENT GALE WARNING FOR STRONG
GUSTY WINDS AND HIGH SEAS TODAY INTO TONIGHT. SYSTEM RESPONSIBLE FOR
THESE CONDITIONS NOW RAPIDLY EVOLVING OVER THE GULF COAST STATES.
DEVELOPING LOW CENTER WILL LIFT RAPIDLY NE ALONG THE MISSISSIPPI
RIVER VALLEY AS ASSOCIATED WARM FRONT MOVES NORTH UP THE COAST AND
OVER THE FORECAST AREA THIS EVENING. STRONG SELY WINDS THIS MORNING
WILL VEER SOUTH THIS AFTERNOON AND THEN SW THIS EVENING AS LOW MOVES
NORTHEAST AND DEEPENS. SEAS PRESENTLY IN THE 4 FT RANGE WILL EXCEED
6 FT MOST PLACES BY SUNRISE...FURTHER BUILDING TO AS HIGH AS 13 FT
THIS EVENING. WIND GUSTS WILL FREQUENTLY EXCEED 35 KTS STARTING
THIS MORNING...WITH SUSTAINED WINDS IN THE 25 TO 30 KT RANGE FOR
MUCH OF THE FORECAST PERIOD. COULD BRIEFLY SEE MUCH STRONGER WINDS
LATE THIS AFTERNOON AND EVENING IN SQUALLS.
SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM WEDNESDAY...WINDS WILL BE ON A DIMINISHING TREND BY
DAYBREAK THURSDAY AS THE LOW-LEVEL JET SHOULD BE OFFSHORE. STILL A
DECENT GRADIENT SO SCA CONDITIONS SHOULD PERSIST FOR MUCH OF THE
DAY. FROPA LATE THURSDAY WILL CAUSE WINDS TO SHIFT TO NW AND DROP
OFF TO 10-15 KT IN PRETTY SHORT ORDER. ONLY THEN WILL SEAS BE ABLE
TO SUBSIDE...ESPECIALLY ALONG FRYING PAN SHOALS.
THE VEERING TREND WILL CONTINUE THU NIGHT AS HIGH PRESSURE BUILDS
IN FROM THE OHIO VALLEY...WITH MODEST NE WINDS EXPECTED DURING THE
DAY ON FRIDAY.
LONG TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...WILL MAINTAIN A DECENT NORTHERLY GRADIENT
THRU THE PERIOD AS LOW PRESSURE MOVES ALONG THE FRONT
OFFSHORE...AND HIGH PRESSURE REMAINS TO OUR NORTH AND WEST.
TIGHTEST GRADIENT WILL BE NEAR OR JUST AFTER THE CLOSEST APPROACH
OF THE LOW ON SATURDAY AFTERNOON...AND COULD PUT WINDS CLOSE TO
SCA THRESHOLDS. TRAJECTORY IS SLIGHTLY OFFSHORE SO SEAS WILL BE
HELD IN CHECK...NO MORE THAN 4 OR 5 FT WITHIN THE COASTAL WATERS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING UNTIL 7 AM EST THURSDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...REK
SHORT TERM...RAS
LONG TERM...RAS
AVIATION...43
