FXUS62 KILM 231724
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1224 PM EST WED DEC 23 2009
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL RIDGE DOWN THROUGH THE SOUTHEAST
FROM CANADA UNTIL THURSDAY. PRECIPITATION CHANCES WILL INCREASE
INTO CHRISTMAS DAY...ALONG WITH A WARMING TREND...AS A FRONT
APPROACHES FROM THE SOUTHWEST. A DRIER AND COOLER AIR MASS WILL
BUILD IN BEHIND THIS FRONT THROUGH THE SECOND HALF OF THE WEEKEND
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 9:30 AM WEDNESDAY...HAVE MADE SOME MINOR ADJUSTMENTS TO
TEMPERATURE TRENDS AND CLOUD COVER GRIDS...OTHERWISE NO CHANGES TO
ONGOING FORECAST. CURRENT TREND IS FOR MOSTLY SUNNY SKIES BECOMING
PARTLY SUNNY...THIS MAY HAVE TO BE UPGRADED TO MOSTLY SUNNY AT NOON
DEPENDING ON THE EVOLUTION OF THE HIGH LEVEL MOISTURE JUST TO THE
WEST IN EASTERN GA. MUCH OF THIS HAS BEEN DISSIPATING. LATEST LAV
GUIDANCE SHOWS HIGHS LOOK GOOD IN THE MIDDLE 50S ACROSS THE BOARD.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE WILL RIDGE DOWN THROUGH THE
SOUTHEAST CONUS FROM CANADA THROUGH THURS AS FRONTAL SYSTEM
APPROACHES FROM THE SOUTHWEST. NORTHERLY WINDS WILL INCREASE AS
THEY BEGIN TO VEER AROUND TO THE E-NE BY THURS EVNG AND THEN E-SE
THROUGH FRI MORNING WITH AN INCREASING ON SHORE PUSH. IN A TYPICAL
WEDGE-LIKE SCENARIO...EXPECT SW-S WINDS TO BEGIN TO OVERRUN SHALLOW
COOL AIR MASS IN PLACE. BY FRI MORNING H85 TO H7 SOUTHERLY FLOW WILL
INCREASE TO 45 TO 60 KTS AS SFC WINDS SLOWLY VEER AROUND FROM THE NE
TO E. LOOKS LIKE BEST ISENTROPIC LIFT WILL COME SHORTLY AFTER
MIDNIGHT ON THURS LASTING THROUGH CHRISTMAS EARLY AFTN. MOISTURE
PROFILES SHOW LOWER CLOUDS AND PCP POSSIBLE FRI EVENING ALONG THE
COAST AS WINDS BECOME ON SHORE AND MAY SEE SOME MOISTURE CONVERGENCE
ALONG THE COAST...BUT MOST OF THE RAIN WILL NOT COME UNTIL AFTER
MIDNIGHT OR SO. DEEPER LAYER MOISTURE WILL BE PRESENT THROUGH AT
LEAST EARLY FRI AFTN. LOOKS LIKE WAVE OF LOW PRESSURE DEVELOPS BY
FRI MORNING AND FRONT MAY BE SLOW TO MAKE IT OFF THE COAST AS MID TO
UPPER LEVEL FLOW REMAINS SW OR PARALLEL TO FRONT WITH MAIN H5 BROAD
TROUGH STILL BACK OVER THE PLAINS. PCP WATER INCREASES UP OVER 1.5
INCHES FRI...BUT DROPS DOWN BELOW A HALF INCH BY END OF PERIOD
INLAND. SHOULD BE A DECENT QPF EVENT THURS NIGHT THROUGH FRI AFTN.
OVERALL SHOULD SEE INCREASE IN CLOUDS THROUGH THURS AND PCP
SPREADING ACROSS AREA FROM THE SW LATER IN THE DAY AND THEN RAINY
AND MILD ON CHRISTMAS DAY.
AS FOR TEMPS...SHOULD REMAIN COOLER INITIALLY ON THURS WITH WEDGE
IN PLACE AND TEMPS HOLDING IN THE MID 50S MOST PLACES. BY THURS
NIGHT INTO FRI AS WINDS BECOME ON SHORE THE DEWPOINTS AND TEMPS
WILL INCREASE REACHING INTO THE UPPER 50S INLAND TO 60S ALONG THE
COAST IN INCREASING WARM AND MOIST FLOW.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...BROAD H5 TROUGH STILL HANGING WAY BACK OVER
CENTRAL CONUS WITH SW FLOW BECOMING MORE WESTERLY AS BASE OF
TROUGH FLATTENS THROUGH THE WEEKEND. THEREFORE EXPECT A GRADUAL
DECREASE IN TEMPS THROUGH THE WEEKEND BUT MORE IN THE WAY OF
DRYING. WILL GET PUSH OF COLDER AIR LATE MON AS TROUGH AXIS
FINALLY CLEARS THE COAST AND DEEPER NW FLOW OF COLD AIR COMES
FUNNELING INTO THE CAROLINAS. THIS BLAST OF COLD AIR MAY BE BRIEF
AS H5 RIDGE PUSHES MID LEVEL HEIGHTS BACK UP BY MID WEEK. OVERALL
FRONT SHOULD PUSH OFF THE COAST WITH A CLEARING TREND THROUGH
EARLY SAT. THEN DRYING AND COOLING TREND THROUGH THE REMAINDER OF
THE WEEKEND INTO EARLY NEXT WEEK. TEMPS SHOULD START OUT ON THE
WARM SIDE BUT WILL COOL DOWN BACK AROUND NORMAL THROUGH THE
WEEKEND AND THEN BELOW NORMAL LATE MON INTO TUES. LOW LEVEL
THICKNESSES AND 850 TEMPS PEAK FRI EVENING AND THEN SEE A DECLINE
THROUGH THE REMAINDER OF THE WEEKEND IN A DRIER AND COOLER
WESTERLY FLOW.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AS OF 18Z...SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM
THE NORTH KEEPING VFR AT ALL THE TERMINALS THROUGH THE TAF PERIOD
WITH DEVELOPING CIRRUS CIGS. WINDS WILL INITIALLY BE LIGHT BUT
INCREASE LATE TONIGHT AS GRADIENT TIGHTENS. SOME LOW STRATUS COULD
DEVELOP AT THE COASTAL TERMINALS TONIGHT...BUT EXTENT OF COVERAGE IS
STILL UNCERTAIN.
HIGH CONFIDENCE THROUGH THE REST OF THE AFTN WITH VFR AT ALL
TERMINALS UNDER HIGH PRESSURE. 25K FOOT CIRRUS BEGINNING TO FILL IN
ACROSS THE SOUTHERN TERMINALS AS EVIDENCED ON 11U-3.9U
SATELLITE...AND EXPECT COVERAGE TO CONTINUE TO INCREASE THROUGH THE
EVENING. ALSO NOTICING DEVELOPMENT OF STRATOCUMULUS JUST OFFSHORE
WHICH WILL PLAY A ROLE AT THE COAST TONIGHT AS WINDS VEER TO THE
E/NE AND INCREASE TO 10 KT OR MORE. THIS DECREASES FORECAST
CONFIDENCE FOR OVERNIGHT AS THIS WIND MAY ADVECT SOME OF THESE LOWER
CIGS INTO ILM/CRE/MYR. EXPECT SCT TO BKN 5K FOOT CIGS AT THE
COAST...WITH COVERAGE STILL DIFFICULT TO DETERMINE...AND WILL LET
FUTURE TAFS MORE SPECIFICALLY EVALUATE POTENTIAL SINCE CIGS WILL NOT
OCCUR UNTIL 06Z OR LATER. INLAND TERMINALS WILL NOT SEE ANY OF THIS
LOW LEVEL STRATUS. TOMORROW...CLOUDS BEGIN TO APPROACH FROM THE WEST
IN ADVANCE OF THE NEXT SYSTEM...AND FLO SHOULD SEE SOME 3500 FT CIGS
DEVELOP BY THE END OF THIS PERIOD. COASTAL TERMINALS WILL CONTINUE
TO SEE LOW LEVEL STRATUS AS NE FLOW PERSISTS AROUND THE EAST SIDE OF
THE WEDGE.
EXTENDED OUTLOOK...MODERATE CONFIDENCE IN PERIODS OF IFR OVERNIGHT
THURSDAY THROUGH SATURDAY MORNING WITH RAIN AND LOW CEILINGS. VFR
SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 9:30 AM WEDNESDAY...HAVE TRIMMED BACK WINDS A KNOT OR TWO
BASED ON THE PAST COUPLE HOURS OF BUOY OBSERVATIONS. THE TRENDS
REMAIN INTACT HOWEVER WITH AROUND 10 KNOTS THIS MORNING INCREASING
TO A RANGE OF 10-15 KNOTS THIS AFTERNOON.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...GRADIENT WILL BECOME PINCHED ON THURS AS
WEDGE HOLDS ON INLAND AND COASTAL TROUGH BECOMES MORE PRONOUNCED
THEN A CONTINUED INCREASE IN WINDS WILL COME AS FRONTAL SYSTEM
ADVANCES FROM THE SOUTHWEST THROUGH FRI. WINDS WILL VEER AROUND
THROUGH THURS NIGHT BECOMING INCREASINGLY ON SHORE. WINDS AND SEAS
SHOULD REACH SCA CRITERIA THURS NIGHT INTO FRI MORNING WITH
INCREASING ON SHORE FETCH. ONCE COASTAL TROUGH/WARM FRONT BLOWS
INLAND BY FRI AFTN SHOULD SEE A STRONG SOUTHEAST WIND WHICH MAY
PUSH SEAS UP NEAR 4 TO 5 FT NEAR SHORE AND UP TO 10 FT IN THE
OUTER WATERS BY FRI NIGHT. WNA SHOWS PEAK IN WINDS AND SEAS FRI
EVENING AHEAD OF FRONT WHICH SHOULD MOVE ACROSS THE WATERS BY
EARLY SAT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...FRONT WILL MOVE FARTHER OFF SHORE THROUGH
SAT WITH OFF SHORE WEST TO NORTHWEST FLOW HELPING TO KNOCK SEAS
DOWN NEAR SHORE. SHOULD START OUT JUST ABOVE SCA WITH SEAS NEAR 6
FT IN OUTER WATERS BUT OFF SHORE FLOW SHOULD HAVE NEAR SHORE SEAS
DOWN TO 2 TO 4 FT BY SAT MORNING. NOT MUCH OF A COLD SURGE
EXPECTED BEHIND FRONT...BUT ENOUGH COOL AND DRY AIR TO KEEP SEAS
FROM DECREASING AND LEVELING OFF SEAS JUST BELOW SCA THROUGH THE
REMAINDER OF THE PERIOD. WINDS SHOULD BE IN THE 15 TO 20 KT RANGE
OUT OF THE WEST THROUGH MOST OF THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...SHK
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...JDW
