FXUS62 KILM 040200
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
900 PM EST THU DEC 3 2009
.SYNOPSIS...
A DRY COLD FRONT WILL PUSH ACROSS THE REGION THEN WELL OFFSHORE
OVERNIGHT. HIGH PRESSURE WILL BUILD BRIEFLY INTO THE AREA FRIDAY.
RAIN IS EXPECTED FRIDAY NIGHT AND SATURDAY...AS A LOW PRESSURE
SYSTEMS TRACKS FROM THE NORTHEAST GULF OF MEXICO OFFSHORE TO THE
OUTER BANKS OF NORTH CAROLINA. HIGH PRESSURE WILL FOLLOW SUNDAY
INTO MONDAY WITH A COASTAL TROUGH MOVING INLAND MONDAY NIGHT INTO
TUESDAY...BRINGING A CHANCE OF SHOWERS. A STRONG COLD FRONT MAY
IMPACT THE EASTERN CAROLINAS DURING THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 900 PM THURSDAY...A DRY COLD FRONT ON OUR DOORSTEPS THIS
EVENING IS POISED TO PUSH SE ACROSS THE FORECAST LATE THIS EVENING
THEN OFFSHORE OVERNIGHT...CURRENTLY POSITIONED FROM AROUND VIRGINIA
BEACH TO NEAR COLUMBIA SC THIS MID-EVENING. NORTHERLY FLOW SHOULD
BUILD TO 3000-4000 FEET DEEP LATE TONIGHT...WEAKENING THEN VEERING
INTO DAYBREAK FRIDAY. 4500-5500 FOOT STRATO-CU CLOUD BASES EARLIER
IN VICINITY OF THE COLD FRONT OVER CENTRAL NC AND NORTHERN SC HAVE
DISSIPATED AND IT APPEARS WE ARE IN FOR A CLEAR MOONLIT NIGHT.
ONLY MINOR ADJUSTMENTS WERE MADE TO THE ONGOING FORECAST...MAINLY
TWEAKAGE OF TEMPERATURE AND DEWPOINT CURVES IN THE NEAR TERM.
DESPITE CLEAR SKIES....WINDS AND MIXING WILL HELP KEEP THE MERCURY
FROM PLUMMETING...BUT STILL COOL IN A 39-44 DEGREE RANGE BY FIRST
LIGHT FRIDAY. NORTH WINDS AND COOL AIR ADVECTION SHOULD PREVENT FOG
DEVELOPMENT...BUT WE COULD SEE SOME RADIATIONAL-COOLING INDUCED MIST
UNDER CLEAR SKIES JUST PRIOR TO FRONTAL PASSAGE WITH SOME LOCATIONS
DECOUPLED FROM THE PREFRONTAL BOUNDARY LAYER WSW WIND FLOW.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...IN WAKE OF REINFORCING COLD FRONT...WE WILL BE
UNDER THE INFLUENCE OF COLD AIR ADVECTION ON FRI. LONGWAVE TROUGH
WILL MOVE ACROSS THE MIDDLE OF THE COUNTRY FRI THROUGH SAT. VIGOROUS
SHORTWAVE TROUGH WILL ROUND THE BASE OF THE TROUGH AND LIFT OUT
ACROSS THE SOUTHEAST AND EAST COAST ON SAT. THIS WILL INVIGORATE AN
ELONGATED TROUGH OF LOW PRESSURE OFFSHORE OF THE SOUTHEAST COAST. A
SERIES OF WEAK AREAS OF LOW PRESSURE WILL MOVE UP ALONG THIS
BOUNDARY WITH THE LAST PULLING N OF OUR LATITUDE OVERNIGHT SAT.
ISENTROPIC UPGLIDE IS EXPECTED TO INCREASE ON THE COOL SIDE OF THIS
BOUNDARY SITUATED OFFSHORE. THIS WILL ALLOW...WITH TIME...A COOL
RAIN TO DEVELOP ACROSS THE AREA. THICKENING CLOUDS FRI AFTERNOON AND
EVE WILL YIELD PERIODS OF RAIN FRI NIGHT AND SAT. RAIN IS EXPECTED
TO END SAT NIGHT AS COLDER AIR BEGINS TO RUSH IN BEHIND THE
DEPARTING AREA OF LOW PRESSURE. AT THIS TIME...THE COLUMN DOES NOT
GET COLD ENOUGH TO SUPPORT SNOW UNTIL AFTER SIGNIFICANT DRYING IN
THE SNOW GROWTH AREA HAS ALREADY TAKEN PLACE...AND SO THE
PRECIPITATION SHOULD END AS ALL LIQUID. THERE IS THE POTENTIAL FOR
ANOTHER SIGNIFICANT RAINFALL EVENT THIS PERIOD AND THIS WILL BE
OCCURRING ATOP RIVERS WHICH WILL ALREADY BE RISING FORM THE HEAVY
RAIN OF WED.
AGAIN IT WILL BE A CHILLY PERIOD. DAYTIME HIGHS FRI WILL BE SLIGHTLY
BELOW NORMAL WITH MAXIMUMS ON SAT 10 TO 15 DEGREES BELOW NORMAL.
NIGHTTIME MINIMUMS WILL BE HELD TO THE 40S AS CLOUDS AND RAIN
INSULATE THE AREA. SAT NIGHT...AS SKIES CLEAR LATE AND COLD AIR
INTRUSION INTENSIFIES... MINIMUMS WILL DROP WELL DOWN INTO THE 30S
BY SUN MORNING AND JUST BELOW FREEZING WELL INLAND.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...THE LONG TERM BEGINS WITH A HIGH PRESSURE
WEDGE DOWN THE LEE SIDE OF THE APPALACHIANS. THIS WILL IN TURN HELP
THE THE DEVELOPMENT OF ANOTHER COASTAL TROUGH EARLY MONDAY MORNING
AND THIS FEATURE WILL REMAIN ALONG THE COAST THROUGH AT LEAST
TUESDAY EVENING. A LOW DEVELOPING OVER THE FOUR CORNERS CONTINUES TO
DEEPEN OVER TEXAS AND A SURGE OF WARM MOIST AIR WILL PUSH NORTHWARD
BY LATE TUESDAY FOLLOWED BY ANOTHER COLD FRONT THAT WILL SWEEP OFF
THE COAST WEDNESDAY EVENING. WE WILL HAVE TO WATCH OUT AS IT APPEARS
THIS WILL BRING ANOTHER LOW CAPE AND HIGH SHEAR EVENT TO THE REGION
WEDNESDAY.
TEMPERATURE FORECAST SHOWS A SLOW WARMING TREND WITH HIGHS BEGINNING
ON SUNDAY IN THE LOWER 50S AND REACHING THE MID TO UPPER 60S ON
WEDNESDAY BEFORE A COOL DOWN ON THURSDAY WITH THE COLD FRONTAL
PASSAGE. THE LOWS WILL START OUT SUNDAY NIGHT IN THE MID TO UPPER
30S AND WARMING INTO THE MID 40S WITH THE APPROACHING WARM AND COLD
FRONT COMBINATION TUESDAY NIGHT AND WEDNESDAY.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
A DRY COLD FRONT WILL MOVE THROUGH THE REGION IN THE NEXT FEW HOURS.
THE TAF SITES WILL EXPERIENCE A VEERING OF THE WINDS TO THE NORTH
AND SEE THE TEMPERATURES BEGIN TO DROP IN THE DRY...COOL AIR. A WAVE
WILL FORM ALONG THE OLD BOUNDARY FROM LAST NIGHT...WHICH IS
OFFSHORE...DURING THE DAY TOMORROW.
VFR WITH HIGH CIRRUS OVERNIGHT AND THROUGH THE MORNING. CLOUDS WILL
THICKEN AS THE WAVE DEVELOPS. A MID CLOUD CEILING BY 16Z AND AS THE
WAVE CONTINUES ITS DEVELOPMENT...LOW CLOUDS AT 4000 FEET WILL
ENCROACH ON THE TAF SITES LATE IN THE PERIOD. VISIBILITY REMAINS VFR
WITH THE DRY COLUMN. WIND NORTHEASTERLY 5 TO 10 KNOTS AFTER 16Z.
EXTENDED OUTLOOK...IFR SATURDAY IN RAIN. VFR SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 900 PM THURSDAY...HAVE EXTENDED ADVISORIES A FEW MORE HOURS
SINCE SEAS ARE SLUGGISH TO DIMINISH OFFSHORE...WHERE 6 FOOTER STILL
LINGER. 20 KNOT GUSTS CAN BE EXPECTED THROUGH THE OVERNIGHT PERIOD
AHEAD OF AND BEHIND THE FRONTAL PASSAGE...WHICH WILL KEEP SEAS FROM
FALLING VERY QUICKLY. BY DAYBREAK HOWEVER...ADVISORIES WILL LIKELY
BE DROPPED...POSSIBLY REPLACED WITH AN EXERCISE CAUTION STATEMENT
FOR LINGERING 5 FOOTERS OFFSHORE NORTH OF CAPE FEAR DAYBREAK FRIDAY.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...A MODEST NORTHERLY SURGE WILL BE UNDERWAY AT
START OF PERIOD...BUT THIS WILL QUICKLY WANE BY FRI AFTERNOON. WINDS
WILL BE FROM THE NE...BACKING TO N OR NNW BY SAT NIGHT. CONDITIONS
ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA THROUGH FRI NIGHT.
SMALL CRAFT ADVISORY CONDITIONS MAY DEVELOP ACROSS PORTIONS OF THE
AREA SAT AND SAT NIGHT AS PRESSURE GRADIENT TIGHTENS BETWEEN LOW
PRESSURE OFF THE COAST AND HIGH PRESSURE TO OUR W AND NW. THE
STRONGEST WINDS AND HIGHEST SEAS ARE EXPECTED LATE SAT AND SAT
NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...A COASTAL TROUGH WILL DEVELOP OVER THE MARINE
WATERS EARLY MONDAY AND WILL BE IN THE AREA UNTIL AT LEAST LATE
TUESDAY AS A LOW PRESSURE AREA OVER THE SOUTHWEST UNITED STATES
DEVELOPS AND SHIFTS EASTWARD. THIS LOW WILL BRING A WARM FRONT
NORTHWARD ACROSS THE WATERS LATE TUESDAY AND THE TRAILING COLD FRONT
WILL QUICKLY SHIFT ACROSS THE WATERS ON WEDNESDAY.
WINDS WILL BEGIN THIS PERIOD FROM THE NORTH TO NORTHEAST WITH A
VEERING TO THE EAST AND SOUTH LATE TUESDAY AHEAD OF THE COLD FRONT.
WITH A PERSISTENT NORTHEAST FLOW OF 15 TO 20 KNOTS SEAS MAY REACH 6
FEET AT 20 MILES OFF THE COAST SUNDAY INTO MONDAY MORNING AND A
SMALL CRAFT ADVISORY MAY BE REQUIRED AT THAT TIME.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 3 AM EST FRIDAY FOR AMZ250-252.
&&
$$
NEAR TERM....MJC
SHORT TERM...RJD
LONG TERM....DRH
AVIATION.....MDC
