FXUS62 KILM 111725
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1225 PM EST FRI DEC 11 2009
.SYNOPSIS...
A COLD AND DRY AIR MASS WILL BUILD IN FROM THE NORTH THROUGH
SATURDAY. LOW PRESSURE DEVELOPING OFF THE COAST WILL BRING RAIN
LATE SATURDAY INTO SUNDAY. A BRIEF WARM UP MONDAY AND EARLY TUESDAY
WILL BE FOLLOWED BY A STRONG COLD FRONT LATE TUESDAY. COLD HIGH
PRESSURE BUILDS IN WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 9 AM FRIDAY...COLD AND DRY HIGH PRESSURE WILL BUILD IN FROM
THE WEST...WITH CENTER OF HIGH PASSING JUST TO THE NORTH
OVERNIGHT. WE WILL ALSO GET THE BEGINNINGS OF COASTAL TROUGH
DEVELOPMENT BY THE END OF THE NEAR TERM. TEMPERATURES DID NOT GET
QUITE AS LOW AS EXPECTED THIS MORNING AS WINDS STAYED UP
OVERNIGHT...KEEPING THE ATMOSPHERE WELL MIXED. STILL COLD
THOUGH...MID 30S MOST PLACES. CONTINUED COLD AIR ADVECTION TODAY
WILL KEEP TEMPS WELL BELOW NORMAL...MID TO UPPER 40S. AIDING BELOW
NORMAL TEMPERATURES TODAY WILL BE CLOUD COVER. SATELLITE LOOPS AND
MODEL SOUNDINGS SHOW A STEADY STREAM OF HIGH CLOUDS OF VARYING
EXTENT AND THICKNESS WILL MOVE OVERHEAD TODAY. VERY DRY AND STABLE
AT THE LOW AND MID LEVELS SO NO CHANCE FOR RAIN IN THE NEAR TERM.
MIN TEMPS IN THE 20S TONIGHT STILL LOOKS REASONABLE AS HIGH
CENTER WILL BE NEARLY OVERHEAD...ALLOWING WINDS TO DECOUPLE EARLY
AND IMPROVING OUR PROSPECTS FOR STRONG RADIATIONAL COOLING. WILD
CARDS WILL BE AMOUNT AND DURATION OF HIGH CLOUD COVER AND THE
POSSIBILITY OF WINDS PICKING UP JUST A BIT JUST BEFORE SUNRISE AS
COASTAL TROUGH DEVELOPS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...
DRY AND CHILLY WEDGE OF HIGH PRESSURE IN PLACE ON SATURDAY. A
COASTAL TROUGH WILL DEVELOP BY MIDDAY AND BROAD LOW LEVEL WARM
ADVECTION BY LATE AFTERNOON. CLOUDS MAY INCREASE RATHER QUICKLY AND
SOME LIGHT RAIN SHOULD IMPINGE UPON SOUTHERN ZONES BY EVENING OR
NIGHTTIME. HEAVILY FAVORING THE MUCH SLOWER TIMING OF THE WRF AS THE
ANTECEDENT AIR MASS WILL BE EXTREMELY DRY. IN FACT...RADAR WILL
PROBABLY SHOW A FEW HOURS WORTH OF LIGHT RETURNS LATE SATURDAY
BEFORE ANY PRECIPITATION BEGINS TO REACH THE GROUND. WAA FURTHER
STRENGTHENS BY 06Z SUNDAY. AT THIS TIME RAIN CHANCES WILL RAMP UP
CONSIDERABLY...BOOSTED BY LOW LEVEL CONVERGENCE AS A WEAK CLOSED
WAVE DEVELOPS WITHIN THE OFFSHORE TROUGH. TEMPERATURES MAY ALSO
BEGIN TO RISE. QPF PROSPECTS ARE INTERESTING...EVEN THE DRYER GFS
IMPLYING TOTALS IN THE HALF INCH TO ONE INCH RANGE LESS THAN HALF OF
THE WRF FORECAST. WITH THE AFOREMENTIONED DRY AIR TO OVERCOME AND
THE LACK OF MID AND UPPER LEVEL SUPPORT FOR OMEGA WILL FAVOR THE
LOWER AMOUNTS AT THIS TIME. WAA/ISENTROPIC UPGLIDE SHUTS DOWN BY
MIDDAY SUNDAY AS THE SURFACE AND LOW LEVEL WAVE MOVE OFF TO THE
NORTHEAST. NOT MUCH TO SCOUR OUT THE LOW LEVEL MOISTURE SO LIGHT
RAIN OR DRIZZLE MAY LAST INTO SUNDAY AFTERNOON AND CLOUDS MAY
PERSIST INTO SUNDAY NIGHT. SUNDAYS TEMPERATURE FORECAST WILL HINGE
GREATLY UPON THE TRACK OF THE LOW. 00Z RUN HINTING AT A COASTAL PATH
SUCH THAT THERE COULD BE A SIGNIFICANTLY WARMER AFTERNOON ALONG THE
COAST THAN INLAND ZONES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 3 AM FRIDAY...
A WEAK SURFACE HIGH WILL BE FOUND OFF THE COAST ON MONDAY WHILE A
FLAT RIDGE BUILDS IN THE MID LEVELS. AFTERNOON TEMPERATURES SHOULD
END UP IN THE MID 60S DESPITE WHAT COULD BE A FAIR AMOUNT OF
CLOUDINESS ASSOCIATED WITH BROAD ISENTROPIC UPGLIDE. THIS SOURCE OF
LIFT COULD ALSO LEAD TO SOME LIGHT RAIN BY MONDAY NIGHT. THE BEST
RAIN CHANCES WILL COME TUESDAY THOUGH AS AN ARCTIC COLD FRONT AND
UPPER DYNAMICS APPROACH FROM THE NORTHWEST. AHEAD OF THE BOUNDARY
COULD BE ANOTHER POTENTIALLY WARM AFTERNOON WITH HIGHS IN THE MID OR
UPPER 60S. STRONG CAA TUESDAY NIGHT INTO WEDNESDAY AS 1035MB HIGH
BUILDS IN. GUIDANCE NOT IN GOOD AGREEMENT WITH HOW DEEP THE TROUGH
GETS AND THEREFORE HOW DEEP INTO THE ARCTIC AIR THE CAROLINAS GET.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 18Z...TERMINALS ARE VFR AND EXPECTED TO REMAIN VFR THROUGHOUT
THIS TAF PERIOD.
EXPECT MID-LEVEL CEILINGS THIS AFTERNOON INCREASING TO HIGH-LEVEL
CIRRUS CEILINGS THIS EVENING. WINDS WILL BE NORTHWEST TO NORTH THIS
AFTERNOON AT 10-15 KNOTS. WINDS DECREASE LATE THIS AFTERNOON AND
EARLY THIS EVENING TO 5 KNOTS OR LESS AS A LOW LEVEL INVERSION SETS
UP. WINDS GRADUALLY VEER TO THE NORTHEAST DURING THE OVERNIGHT HOURS.
TEMPO MID/HIGH LEVEL CEILINGS EXPECTED SATURDAY MORNING. WINDS WILL BE
NORTHEAST TO EAST AROUND 10 KNOTS. COULD BEGIN TO SEE SOME SCATTERED
LOW CLOUDS 3-4K BY MID TO LATE MORNING.
EXTENDED OUTLOOK...CHANCE IFR SATURDAY NIGHT INTO SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 9 AM FRIDAY...COLD HIGH PRESSURE BUILDING IN FROM THE WEST
TODAY...WITH CENTER OF HIGH PASSING TO THE NORTH OF THE WATERS
OVERNIGHT. A COASTAL TROUGH WILL BEGIN TO DEVELOP BY THE END OF
THE NEAR TERM. WINDS ARE N TO NW IN THE 15 TO 20 KT RANGE THIS
MORNING WITH SEAS RANGING FROM 1 FT NEAR SHORE TO 5 FT AT 41013.
SEAS WITHIN 20 NM OF THE COAST MOSTLY IN THE 2 TO 4 FT RANGE. THIS
WILL BE THE GENERAL RULE UNTIL TONIGHT...WHEN COASTAL TROUGH
DEVELOPMENT WILL PINCH THE GRADIENT AND ALLOW WINDS TO PICK UP A
BIT FROM THE NE...LIKELY A SOLID 20 KTS BY MORNING. SEAS WILL
BUILD ABOUT A FOOT AS A RESULT. WILL LOOK AT THE POSSIBILITY OF
RAISING ANY FLAGS WITH THE AFTERNOON PACKAGE.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...SATURDAY BEGINS WITH STRONG HIGH PRESSURE
OVER VIRGINIA. A COASTAL TROUGH WILL BEGIN TO DEVELOP DURING THE
MORNING AND THEN STRENGTHEN THROUGH THE AFTERNOON. NORTHEASTERLY
WINDS WILL VEER AND INCREASE AS THIS HAPPENS AND SMALL CRAFT
ADVISORY-WORTH WINDS AND SEAS BOTH EXPECTED TO DEVELOP IN THE
PINCHED GRADIENT. ONSHORE WINDS MAX OUT SATURDAY NIGHT AS WEAKLY
CLOSED OFF LOW DEVELOPS AND MOVES UP THE COAST BY SUNDAY MORNING.
BEHIND THIS FEATURE WINDS WILL QUICKLY TURN TO OFFSHORE. NEAR SHORE
SEAS WILL TAPER QUICKLY WHILE AWAY FROM SHORE THE DECREASE WILL BE
MORE TEMPERED.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 3 AM FRIDAY...MONDAY IS A TRANSITIONAL DAY WITH WEAKENING
HIGH PRESSURE BUILDING IN FROM THE WEST AND ENDING UP CENTERED
OFFSHORE. WINDS WILL GROW QUITE LIGHT AND GO VARIABLE IN
DIRECTION. EXPECT SEAS TO DIMINISH TO 2 FT OR SO. THE EASTWARD
PROGRESSION OF THE HIGH TUESDAY WILL ALLOW FOR A SOUTHERLY WIND TO
BECOME ESTABLISHED. THE APPROACH OF A SHARP COLD FRONT LATER
TUESDAY WILL VEER THESE WINDS TO SOUTHWESTERLY AND INCREASE SPEEDS
BY PERHAPS A FEW CATEGORIES...MAYBE BRIEFLY INTO SMALL CRAFT
ADVISORY CRITERIA. A STRONG COLD SURGE TO FOLLOW TUESDAY NIGHT
WITH OFFSHORE WINDS AND A CONTINUED STRONG GRADIENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...REK
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
MARINE...ALL
