FXUS62 KILM 251949
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
249 PM EST FRI DEC 25 2009

.SYNOPSIS...
RAIN AND WINDS WILL DIMINISH THIS EVENING AS A LOW PRESSURE SYSTEM
LIFTS NORTHEAST ACROSS THE EASTERN CAROLINAS. DRY HIGH PRESSURE
WILL BUILD IN FROM THE GULF COAST SATURDAY AND SUNDAY...AND BE
REINFORCED BY A COLDER AIR MASS FROM THE NORTH MONDAY THROUGH
WEDNESDAY. THE NEXT STORM SYSTEM MAY AFFECT THE REGION THURSDAY
INTO FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...LEADING EDGE OF COLD FRONT...AS EVIDENCED BY 
WIND SHIFTS AND A LINE OF CONVECTION...HAS JUST MOVED INTO THE CWA 
FROM THE WEST AND IS MOVING QUICKLY ACROSS FLORENCE...DARLINGTON AND 
MARLBORO COUNTIES AT THIS TIME. PRECIP IS SHUTTING OFF RAPIDLY 
BEHIND THIS FRONT SO HAVE TRIED TO TIME LINE AS IT MOVES EAST. 
EXPECT BULK OF PRECIP TO MOVE OFFSHORE LATE THIS AFTERNOON OR THIS 
EVENING. ASSOCIATED TRIPLE POINT LOW IS ALSO CLOSE BY...JUST 
NORTHWEST OF ROCKINGHAM NC...AND THIS WILL JUST SKIRT BY THE 
FORECAST AREA. SO FAR LINE OF CONVECTION IS BEHAVING ITSELF...NO 
SUSPICIOUS SIGNATURES IN EVIDENCE. HOWEVER...AS WE ARE IN A SLIGHT 
RISK AREA FOR SEVERE THUNDERSTORMS AND REMAIN IN A HIGH SHEAR 
ENVIRONMENT WILL CONTINUE TO KEEP A CLOSE WATCH ON ANY CONVECTION IN 
THE AREA. SO FAR MAIN THREAT FROM THIS LINE IS FROM HEAVY RAIN AND 
SOME LIGHTNING. GRADIENT WIND REMAINS QUITE BREEZY AND GUSTS UP TO 
29 KTS HAVE BEEN NOTED INLAND. VAD WIND PROFILE SHOWS 45 KTS AT 1000 
FT SO ANY STRONG CONVECTION COULD TRANSLATE DOWN SOME HEFTIER GUSTS 
THAN THIS. GUIDANCE IN CLOSE AGREEMENT ON OVERNIGHT TEMPS. FAR WEST 
COUNTIES WILL SEE COLDEST TEMPS AS COLDER AIR BEGINS TO POUR IN FROM 
THE WEST...SO THEY WILL DROP DOWN TO AROUND 40 BY DAYBREAK. CAPE 
FEAR AREA WILL BE LAST TO SEE COLD SURGE SO TEMPS THERE WILL HOVER 
AROUND 50 FOR A MINIMUM. 

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...SFC HIGH PRESSURE ALONG THE GULF COAST WILL
BUILD INTO THE CAROLINAS SATURDAY INTO SUNDAY...MAKING FOR A DRY
AND MILD WEEKEND. ONLY COMPLICATING FACTOR IS CYCLONICALLY CURVED
SW UPPER FLOW THAT WILL PERSIST OVER THE SOUTHEAST THRU MUCH OF
THE PERIOD...AS THE CUTOFF LOW SITS AND SPINS OVER THE WESTERN GREAT
LAKES. THERE WILL BE DISTURBANCES IN THIS SW FLOW CROSSING THE
AREA...BUT LOW LEVELS SHOULD STILL BE WAY TOO DRY TO SUPPORT ANY
PRECIP.  

TEMP FORECAST IS PRETTY MUCH MOS CONSENSUS...WITH THE EXCEPTION OF
SAT NIGHT WHICH IS NEAR OR EVEN A BIT BELOW THE COOLER GFS MOS DUE
TO WEAK LOW-LEVEL WINDS. HOWEVER THERE IS STILL BUST POTENTIAL DUE
TO POSSIBLE MID-LEVEL CLOUDS ASSOCIATED WITH ANY DISTURBANCES
ALOFT THAT WOULD CROSS THE AREA. 

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...MID TO UPPER TROUGH FINALLY SWINGS THROUGH WITH 
TROUGH AXIS PUSHING THROUGH COASTAL CAROLINAS IN THE AFTERNOON AND 
MOVING OFF SHORE BY EVENING. THIS WILL SCOUR OUT THE MOISTURE IN THE 
MID TO UPPER LEVELS AND GIVE A DEEP LAYER NW FLOW OF DRIER AND 
COOLER AIR THROUGH MON NIGHT INTO TUES. SHOULD BE LONG ENOUGH TO 
PRODUCE A COUPLE OF COLD MORNINGS EARLY TUES AND WED WITH TEMPS 
AROUND FREEZING. BLAST OF VERY COLD AIR WILL BE BRIEF AS LOW TO MID 
LEVEL FLOW BEGINS TO BACK AROUND TO THE WEST AND THEN SOUTHWEST BY 
LATE TUES. THE HIGHER DEWPOINT AIR SHOULD HELP TO RAISE LOWS 
OVERNIGHT BY A FEW DEGREES BY THURS. IT LOOKS LIKE THE MAKING OF 
ANOTHER OVERRUNNING EVENT WITH THIS WARMER AIR OVERRIDING THE 
SHALLOW COLD AIR MASS IN PLACE. THEREFORE EXPECT LOW CLOUDS AND COOL 
DRIZZLE/RAIN FOR WED THROUGH FRI. NOT EXPECTING MUCH FOR QPF
DURING WED/THURS TIME FRAME...BUT GFS/ECMWF HINTING AT COASTAL
TROUGH DEVELOPING INTO LOW WED NIGHT INTO THURS. DEPENDING ON
STRENGTH AND TRACK OF THIS POSSIBLE LOW COULD SEE MORE IN TERMS OF
QPF. PCP WATER DOWN BELOW A QUARTER OF INCH MON AFTN THROUGH WED
WITH HIGH PRESSURE AT THE SURFACE AND RIDGING ALOFT SO EXPECTING
CLEAR AND COOL WEATHER...BUT BY WED AFTN RAIN CHANCES INCREASE AS
PCP WATER INCREASES UP NEAR AN INCH AS SOUTHERN STREAM BECOMES
MORE ACTIVE ONCE AGAIN. TEMPS RUNNING AT OR BELOW NORMAL THROUGH
THE PERIOD WITH HIGHS WITHIN A FEW DEGREES OF 50 AND LOWS IN THE
30S.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AS OF 18Z...WARM FRONT HAS MOVED NORTH THROUGH THE REGION LEAVING 
THE TERMINALS IN THE WARM SECTOR AND CREATING STRONG SE WINDS. RAIN 
AND AN ISOLATED THUNDERSTORM WILL OCCUR THIS EVENING AHEAD OF A COLD 
FRONT. 

HIGH CONFIDENCE IN CHARACTERISTICS OF EVENT TODAY...WITH LOW 
CONFIDENCE IN TIMING OF LOWERED CIGS AND VSBYS. LARGE AREA OF 
STRATIFORM RAIN WITH EMBEDDED CONVECTIVE ELEMENTS IS BEGINNING TO 
MOVE THROUGH THE TERMINALS AND WILL SLOWLY WORK ITS WAY EAST THROUGH 
THE AFTN. BELIEVE THE RISK OF ANY THUNDER HAS DIMINISHED DUE TO 
LACK OF INSTABILITY...BUT CANNOT ENTIRELY RULE OUT AN ISOLATED 
THUNDERSTORM AT ANY OF THE TERMINALS. HAVE NOT MENTIONED TS IN THE 
TAFS DUE TO LOW CHANCE OF OCCURRENCE. HAVE PREDOMINATE IFR CIGS AT 
FLO FOR THE NEXT FEW HOURS...WITH TEMPO IFR AT THE OTHER TERMINALS. 
DETERMINING TIMING OF IFR CIGS IS QUITE TRICKY IN THESE OVERRUNNING 
PRECIP EVENTS AS THE RAIN HAS TO SATURATE THE COLUMN FROM TOP DOWN 
AND ONLY IN THE MODERATE RAIN WILL IFR CIGS OCCUR. HENCE THE USE OF 
THE TEMPO GROUP...AS IFR IS MOST LIKELY IN THE EMBEDDED CONVECTIVE 
SHOWERS. OTHER ISSUE IS INCREASINGLY STRONG SE WIND. LLJ AT 850 MB 
IS 50 TO 60 KT AND SOME OF THIS IS MIXING DOWN CREATING 30 KT GUSTS. 
THIS WILL CONTINUE THROUGH THE EVENT UNTIL THE COLD FROPA. THE 
STRONGEST GUSTS WILL OCCUR IN HEAVIER SHOWERS WHERE PRECIPITATION 
CAN DRAG DOWN SOME OF THE HIGHER WINDS FROM ALOFT. 

AFTER THE COLD FROPA TONIGHT DEWPOINTS WILL RAPIDLY DROP SO HAVE REMOVED 
IFR STRATUS POTENTIAL. LOW CONFIDENCE IN POTENTIAL MVFR FOG AT 
FLO/LBT OVERNIGHT...BUT ATMOSPHERE HAS BEEN PRECONDITIONED AND SKY 
CONDITIONS WILL IMPROVE SO HAVE MENTIONED THIS IN TAFS. STILL 
BELIEVE SOME LLWS IS POSSIBLE AT ILM AS THE LLJ PULLS AWAY TONIGHT 
BUT IT WILL ONLY BE FOR A SHORT DURATION AROUND 02Z WHEN WINDS FIRST 
EASE AT THE SURFACE. TOMORROW WILL BE A MUCH NICER DAY WITH VFR 
AFTER SUNRISE.

EXTENDED OUTLOOK...VFR SUNDAY. SLIGHT POTENTIAL FOR MVFR CIGS WITH 
LOW PRESSURE TROUGH MONDAY. VFR TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM FRIDAY...STRONG SOUTHEASTERLY WINDS WILL CONTINUE IN 
ADVANCE OF COLD FRONT THIS AFTERNOON. WINDS WILL VEER SOUTH AND 
GRADUALLY DECREASE FROM SOUTH TO NORTH AS FRONT APPROACHES...WITH 
FRONT MOVING OFFSHORE OUR SC COUNTIES THIS EVENING AND OFFSHORE CAPE 
FEAR JUST AFTER MIDNIGHT. AFTER FROPA WINDS WILL TURN OFFSHORE AND 
DECREASE...ALLOWING SEAS TO GRADUALLY SUBSIDE A FEW FEET. 
HOWEVER...EXPECT SEAS WILL STILL RANGE UP TO 6 FT BY DAYBREAK 
SATURDAY MORNING...SO WILL CONTINUE SMALL CRAFT ADVISORY AS IS 
THROUGH THE NEAR TERM. 

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...MODEST W-NW WINDS WILL PREVAIL SATURDAY ON
INTO SUNDAY AFTERNOON...WITH SPEEDS GENERALLY 10-15 KT. SEAS WILL
START OUT AT OR NEAR ADVISORY THRESHOLDS...AS THE WAVES CRANKED UP
BY THE STRONG SOUTHERLY FLOW TODAY AND TONIGHT SLOWLY DECAY.
OFFSHORE TRAJECTORY SHOULD KNOCK SEAS DOWN TO 2-4 FT BY SAT
EVENING.  

GRADIENT WILL TIGHTEN UP SUNDAY NIGHT WITH THE FIRST PIECE OF THE
COLD FRONT THAT WILL REINFORCE THE HIGH PRESSURE. COULD SEE WEST
WINDS INCREASE TO 20 KT BY DAYBREAK MONDAY...ESPECIALLY ALONG
FRYING PAN SHOALS. FORECAST SEAS ARE CLOSE TO SWAN
GUIDANCE...BUILDING TO 4-5 FT AWAY FROM SHORE LATE SUN NIGHT. 

LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...MID TO UPPER TROUGH SWINGS THROUGH BY MON 
EVENING WITH DEEP NW FLOW DEVELOPING MON NIGHT. SHOULD SEE A DECENT 
COLD SHOT WITH INCREASED WINDS OUT OF THE NORTHWEST AS HIGH PRESSURE 
BUILDS IN THROUGH TUES. THIS SHOULD PRODUCE NW WINDS UP AROUND 20 
KTS MON NIGHT INTO TUES. SEAS MAY BUILD NEAR SCA THRESHOLDS IN OUTER 
WATERS WITH MUCH LOWER SEAS NEAR SHORE IN AN OFFSHORE WIND FLOW. BY 
LATE TUES CENTER OF HIGH MIGRATES EASTWARD ACROSS THE OHIO VALLEY 
AND EAST TOWARD THE MID ATLANTIC COAST BY WED EVENING AS COASTAL 
TROUGH DEVELOPS ACROSS THE SOUTHEAST. THEREFORE WINDS WILL START TO 
VEER AROUND TO THE NORTH BY TUES NIGHT AND WEAKEN AS GRADIENT FLOW 
RELAXES THROUGH WED. LIGHTER MORE VARIABLE FLOW BY WED UNDER 10 KTS 
WITH SEAS DOWN BELOW 3 FT LATE TUES THROUGH WED NIGHT INTO THURS.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EST SATURDAY FOR AMZ250-252-
     254-256.

&&

$$

NEAR TERM...REK
SHORT TERM...RAS
LONG TERM...RGZ
AVIATION...JDW