FXUS62 KILM 081142
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
642 AM EST TUE DEC 8 2009

.SYNOPSIS...
INTENSE LOW PRESSURE OVER THE SOUTHERN PLAINS WILL LIFT NORTHEAST
THROUGH THE GREAT LAKES BY WEDNESDAY NIGHT. THIS WILL RESULT IN A
WARM FRONT MOVING NORTH ACROSS THE REGION TUESDAY NIGHT...FOLLOWED
BY A STRONG COLD FRONT LATE WEDNESDAY. HIGH PRESSURE WILL BUILD
THURSDAY AND FRIDAY. THE NEXT LOW PRESSURE SYSTEM WILL BRING
UNSETTLED CONDITIONS ON SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM MONDAY...LOW PRESSURE DEVELOPING OVER THE PLAINS WILL 
HELP BRING COASTAL TROF ONSHORE AS A WARM FRONT LATE TONIGHT. 
SURFACE HIGH BUILDING IN FROM THE NORTH TODAY COMBINED WITH 
SOUTHERLY MID LEVEL FLOW WILL RESULT IN ANOTHER DAY WITH PLENTY OF 
LOW TO MID STRATUS ACROSS THE CAPE FEAR REGION. CLOUD DECK WILL 
LOWER THROUGH THE DAY AS MOISTURE ALOFT INCREASES/LOWERS...BUT LOW 
LEVEL DRY AIR WILL HOLD ON INTO THE EVENING. DO EXPECT TO SEE A FEW 
SPRINKLES POP UP ACROSS PARTS OF SC LATE IN THE AFTERNOON...BUT LOW 
AFOREMENTIONED DRY AIR WILL KEEP MEASURABLE PRECIP AT BAY UNTIL 
CLOSER TO 00Z. BEST ISENTROPIC LIFT OCCURS IN THE 00Z TO 06Z TIME 
FRAME AS WEAK SURFACE WAVE DEVELOPS ALONG THE BOUNDARY AND MOVES 
NORTH ACROSS THE AREA. HEAVIEST PRECIP WILL BE ASSOCIATED WITH THIS 
FEATURE AND WILL PROBABLY DEVELOP SOME ELEVATED CONVECTION. DID NOT 
INCLUDE MENTION OF CONVECTION/THUNDER WITHIN THE WX GRIDS...MAINLY 
BECAUSE IT SHOULD BE MINIMAL IN SCOPE. PRECIP DOES BECOME NEARLY ALL 
CONVECTIVE CLOSER TO THE END OF THE PERIOD...AS WARM PUSHES INLAND 
AND NORTH WITH COVERAGE DECREASING SIGNIFICANTLY.

LATEST DAY 1 OUTLOOK HAS THE FORECAST AREA IN SLIGHT RISK FOR THE
EVENING/OVERNIGHT HOURS. MAIN THREAT WOULD BE DAMAGING WIND FROM
50 KT LOW LEVEL JET. SEVERE WEATHER THREAT WILL BE IN THE STRONG
WARM ADVECTION BEHIND THE WARM FRONT. FOR NOW WILL CARRY MENTION
OF SEVERE WEATHER IN HWO...BUT NOT IN ANY TEXT/GRIDS GIVEN THE
AMOUNT OF UNCERTAINTY.

TEMPERATURE FORECAST IS ALSO GOING TO BE VERY TRICKY WITH A LOT OF 
POTENTIAL FOR IT TO GO VERY WRONG VERY QUICKLY. I AM PRETTY 
CONFIDENT AT LEAST 1 OF MY HIGH OR LOW TEMPERATURES WILL BE OFF BY 
10 DEGREES OR MORE WHEN ALL IS SAID AND DONE. CLOSER TO THE COAST 
HIGHS TODAY WILL LIKELY BE WITHIN A DEGREE OF THE TONIGHTS LOW...MOS 
IS EVEN SUGGESTING THAT CRE/ILM/MYR WILL ALL HAVE HIGHS/LOWS BEING 
THE SAME NUMBER. THAT BEING SAID...HIGHS TODAY EXPECTED NEAR TO 
BELOW CLIMO WITH WARMEST NUMBERS ALONG THE COAST. TEMPERATURES WILL 
HOLD STEADY THIS EVENING BEFORE SLOWLY RISING OVERNIGHT. ONLY A 
SLIGHT RISE IS EXPECTED INLAND...BUT WARMER TEMPS ARE POSSIBLE 
DEPENDING ON HOW FAR INLAND/FAST THE FRONT MOVES. OF COURSE THE 
REVERSE IS ALSO POSSIBLE...IF THE FRONT HANGS UP ALONG THE COAST 
LOWS ACROSS THE AREA WOULD END UP MUCH COOLER.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...UNSEASONABLY WARM AND BREEZY CONDITIONS IN
STORE ON WEDNESDAY AS THE EASTERN CAROLINAS WILL BE SOLIDLY IN THE
WARM SECTOR OF A VIGOROUS MIDWESTERN CYCLONE. PRECIP CHANCES WILL
BE LIMITED BY MID AND UPPER-LEVEL DRY SLOT AND RELATIVE LACK OF
CONVERGENCE WITH A DIFFUSE COLD FRONT. WILL CARRY CHANCE
POPS...HIGHEST INLAND AND NORTH. MARGINAL INSTABILITY AND THE LACK
OF MOISTURE WILL LIMIT THE POTENTIAL FOR ORGANIZED SVR...BUT AN
IMPRESSIVE AND UNI DIRECTIONALLY SHEARED WIND FIELD WILL MEAN THAT
DAMAGING WINDS CANNOT BE COMPLETELY DISCOUNTED.  

ONCE THE FRONT CROSSES THE AREA WED NIGHT THE WINDS SHOULD
DIMINISH...BUT FAIRLY MILD TEMPS WILL REMAIN AS WESTERLY FLOW IS
NOT TOO CONDUCIVE FOR BRINGING THE COLD AIR IN. WED NIGHT TEMPS
STILL WELL ABOVE NORMAL. HAVE LEANED TOWARD THE HIGH END OF
GUIDANCE FOR THURSDAY EVEN IN THE FACE OF CAA...DUE TO DOWN SLOPE
TRAJECTORY AND A MILD START.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 3 AM TUESDAY...HIGH PRESSURE FINALLY BUILDS IN EARNEST AND
WILL MAKE FOR A DRY BUT CHILLY PERIOD THU NIGHT INTO FRI. TEMPS
CLOSE TO 10 DEGREES BELOW NORMAL...WITH LOWS JUST BELOW FREEZING
AND HIGHS STRUGGLING TO CRACK 50 DEGREES.  

BIGGEST QUESTION IS THE INFLUENCE OF A SOUTHERN STREAM SYSTEM THAT
WILL ORGANIZE ALONG THE GULF COAST FRI NIGHT AND PARALLEL THE
CAROLINA COAST SATURDAY INTO SATURDAY NIGHT. GFS IS A GOOD BIT
QUICKER AND STRONGER WITH THIS SYSTEM THAN THE ECMWF...AND FOR NOW
WE WILL GO WITH IT. THIS WILL PROVIDE A CHILLY RAIN SAT INTO SAT
NIGHT...WITH TEMPS STUCK SOLIDLY IN THE 40S.   

DRY HIGH PRESSURE RETURNS SUN-MON WITH TEMPS ON THE LOW SIDE OF
CLIMO.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z MVFR CEILINGS ARE OCCURRING AT ALL TERMINALS EXCEPT LBT AS 
EAST NORTHEAST WINDS BELOW AN INVERSION AT 2-3K CONTINUE TO ADVECT 
MOISTURE IN OFF THE ATLANTIC AT THAT LEVEL. CURRENT GFS/MET MOS
GUIDANCE IS NOT HANDLING THESE CEILINGS WELL. AT LBT WHERE
SCATTERED TO BROKEN MID LEVEL CEILINGS ARE OCCURRING...THE
VISIBILITY HAS DECREASED TO 3-5 MILES AT TIMES THIS MORNING.

LOOK FOR A COASTAL TROUGH TO REMAIN OFFSHORE TODAY AS A WARM FRONT 
APPROACHES FROM THE SOUTH THIS EVENING. LIGHT RAIN WILL OVERSPREAD 
THE TERMINALS TODAY BUT THINK SIGNIFICANT RAINS WILL HOLD OFF UNTIL 
LATE AFTERNOON AT FLO/LBT AND EARLY EVENING AT ILM AND LBT.

CLIMO AND LATEST LAMP GUIDANCE INDICATE A 50/50 CHANCE OF CEILINGS 
IMPROVING TO LOW VFR BY MID TO LATE MORNING. ALTHOUGH SOME DIURNAL 
RISE COULD OCCUR...AM EXPECTING MOISTURE TO REMAIN TRAPPED NEAR THE 
INVERSION TODAY RESULTING IN MVFR CEILINGS FOR THE MOST PART. 
MOISTURE AT THIS LEVEL WILL ONLY BE REINFORCED FURTHER ONCE RAINS 
BEGIN LATER TODAY.

A WARM FRONT WILL MOVE THROUGH LATE THIS EVENING. SHOULD BE A GOOD 
CHANCE OF HEAVIER RAINFALL/IFR CEILINGS AND VISIBILITIES/LLWS/AND
POSSIBLY ELEVATED CONVECTION NEAR THE COASTAL TERMINALS PRIOR TO
WARM FROPA. IFR CEILINGS AND VISIBILITIES SHOULD BEGIN AT FLO/LBT
LATE THIS AFTERNOON AND EARLY THIS EVENING...AND AT THE COASTAL
TERMINALS THIS EVENING. ONCE THE WARM FRONT MOVES THROUGH AROUND
05Z-07Z TERMINALS WILL BE IN THE WARM SECTOR. EXPECT SCATTERED TO
BROKEN MVFR CEILINGS...ISOLATED SHOWERS AND GUSTY SOUTH TO
SOUTHWEST WINDS. WIND GUSTS COULD EXCEED 30 KNOTS AS A STRONG LOW-
LEVEL JET MOVES ACROSS THE TERMINALS. THE COLD FRONT WILL BE JUST
WEST OF FLO/LBT IN THE PRE-DAWN HOURS WITH SHOWERS AND ISOLATED
THUNDERSTORMS AHEAD OF IT...THUS SOME OF THESE WILL LIKELY AFFECT
THE FLO/LBT TERMINALS FROM 08Z-12Z.
 
EXTENDED OUTLOOK...IFR/ISOLATED THUNDERSTORMS WEDNESDAY. CHANCE IFR 
LATE FRIDAY AND SATURDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/... 
AS OF 3 AM MONDAY...NORTHEAST FLOW OVER THE WATERS TODAY WILL
BECOME ONSHORE LATE THIS AFTERNOON AS COASTAL TROF/WARM FRONT
MOVES WEST ACROSS THE WATERS. STRONG LOW LEVEL JETTING TUE
EVENING/NIGHT...50-60 KT BETWEEN 900 AND 850 MB...WILL ENSURE
STRONG ONSHORE FLOW ONCE THE BOUNDARY PASSES. COOLER SSTS SHOULD
LIMIT AMOUNT OF MIXING...BUT SPEEDS SHOULD STILL END UP EXCEEDING
SCA THRESHOLDS BY MIDNIGHT. STRONG ONSHORE FLOW WILL ALSO HELP
PUSH SEAS ABOVE 6 FT INTO THE NEAR SHORE WATERS PRETTY QUICKLY.
HAVE RAISED SCA FOR ALL ZONES...STARTING AT 23Z FOR NC WATERS AND
06Z FOR SC WATERS...THOUGH THE END OF THE PERIOD.

SHORT TERM /WEDNESDAY THROUGH THURSDAY/... 
AS OF 3 AM TUESDAY...EXPECT VERY FRISKY SW WINDS ON WEDNESDAY
AHEAD OF A STRONG COLD FRONT. LOW-LEVEL JET CRANKS UP TO 50-60 KT
THRU THE 925-850MB LAYER. HOWEVER DO NOT EXPECT MUCH MIXING IN
THIS WAA REGIME...SO THIS WILL TRANSLATE TO A SOLID 25 KT AT THE
SURFACE. COULD SEE GUSTS TO GALE FORCE BUT IN THE ABSENCE OF
WIDESPREAD CONVECTION OVER THE WATERS...DO NOT THINK GUSTS WILL BE
FREQUENT ENOUGH TO MERIT A WARNING. PERSISTENT AND WIDE OPEN
FETCH WILL ALLOW SEAS TO REALLY CRANK UP ON WED AFTERNOON...WITH
6-8 FT BEING FAIRLY COMMON AND 10 FOOTERS IMPACTING FRYING PAN
SHOALS.

FROPA WILL BE LATE WED NIGHT...WITH WINDS DIMINISHING BEHIND THE
FRONT AS THE LOW-LEVEL JET IS SHUNTED OFFSHORE AND ANY COLD AIR
STILL LAGS BEHIND.LOOK FOR DIMINISHING W-NW WINDS ON
THURSDAY...AND SEAS CONTINUING TO SUBSIDE IN THE OFFSHORE FLOW.

LONG TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...GRADIENT BECOMES MORE NORTHERLY THU NIGHT AND
REMAINS SO INTO FRIDAY AS A CHILLY HIGH BUILDS TO OUR NORTH. COULD
SEE A WEDGE SETTING UP FRIDAY NIGHT...WITH WINDS SHIFTING TO THE
NE AND THE GRADIENT MAYBE GETTING PINCHED. LOOKS LIKE A SOUTHERN
STREAM SYSTEM PASSING OFFSHORE COULD MAKE THINGS INTERESTING ON
SATURDAY BUT STILL NOT TOO CONFIDENT IN THE TIMING OR STRENGTH OF
THIS SYSTEM. WILL SHOW A VEERING TO ENE AND KEEP WINDS AT 15-20
KT. THAT DOES PROVIDE ENOUGH FETCH FOR A LONG ENOUGH PERIOD TO
BUILD SEAS BACK TO MARGINAL ADVISORY THRESHOLDS.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM WEDNESDAY TO 7 AM EST THURSDAY 
     FOR AMZ254-256.

     SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST 
     THURSDAY FOR AMZ250-252.

&&

$$

NEAR TERM...III
SHORT TERM...RAS
LONG TERM...RAS
AVIATION...MRR