FXUS62 KILM 302042
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
304 PM EST MON NOV 30 2009
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA THIS EVENING ACCOMPANIED BY A FEW
SHOWERS...BUT OVERALL RAIN AMOUNTS WILL BE LIGHT. HIGH PRESSURE WILL
BUILD QUICKLY INTO THE AREA LATE TONIGHT...PASSING ACROSS THE REGION
TUESDAY. LOW PRESSURE EMERGING FROM THE GULF OF MEXICO MAY BRING
MORE SIGNIFICANT RAINFALL TO THE EASTERN CAROLINAS WEDNESDAY THROUGH
EARLY THURSDAY. BUILDING HIGH PRESSURE IS EXPECTED TO OFFER UP
COOLER AND DRIER WEATHER ACROSS THE REGION LATE IN THE WEEK HEADING
INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...IMAGERY THIS AFTERNOON SHOWS A SWIFT NORTHERN
STREAM SHORT-WAVE DROPPING SE INTO THE CENTRAL APPALACHIAN MOUNTAINS.
THIS FEATURE WILL HELP ACCELERATE A FRONTAL BOUNDARY THROUGH THE
EASTERN CAROLINAS THIS EVENING. MUCH OF THE RAIN WITH THIS FRONT HAS
ALREADY FALLEN WEST OF AND ALONG THE APPALACHIANS. RELATIVELY DRY
AIR IN PLACE LOCALLY AND A SPEEDY FRONTAL PASSAGE WILL RESULT IN
LIGHT RAIN AMOUNTS THIS EVENING...WITH MOST LOCATIONS RECEIVING LESS
THAN A TENTH OF AN INCH WITH THIS PROGRESSIVE FEATURE IN QUICK
MOVING SHOWERS AT A PACE OF NEARLY 50 MPH! IT IS ALSO LIKELY THAT
QUITE A FEW LOCATIONS MAY NOT SEE ANY MEASURABLE RAIN THIS EVENING.
IT LOOKS LIKE THE NC ZONES WILL BE SLIGHTLY MORE FAVORED LOOKING AT
THE LATEST QPF FIELDS...BUT EVERYONE ACROSS THE FORECAST AREA HAVING
A CHANCE TO STEP OUTSIDE WILL FEEL THE AIR MASS CHANGE EARLY TUESDAY.
LATEST DATA SUGGEST FRONTAL PASSAGE WILL OCCUR BETWEEN 7P-8P ACROSS
FAR INTERIOR LOCATIONS THIS EVENING AND AROUND MIDNIGHT TO CLEAR THE
0-20NM COASTAL WATERS. DRY NORTHERLY FLOW WILL PUNCH INTO THE AREA
THROUGH THE WEE HOURS OF TUESDAY WITH BLUSTERY NORTH WIND GUSTS TO
GREET DAYBREAK TUESDAY.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...HIGH PRESSURE WILL BE BUILDING IN BEHIND COLD
FRONT ON TUES. NORTHERLY WINDS WILL USHER IN COOLER AND DRIER AIR
THROUGH THE MORNING. PCP WATER DROPS DOWN BELOW A QUARTER OF AN
INCH. THEREFORE EXPECT A SUNNY AND DRY DAY WITH TEMPS CLOSE TO
60...ABOUT 5 TO 10 DEGREES COOLER THAN MONDAY.
DRY HIGH PRESSURE WILL BE BRIEF AS CENTER SHIFTS FARTHER EAST AS LOW
PRESSURE SYSTEM TRACKS UP FROM THE GULF COAST. WINDS BEGIN TO VEER
AROUND WITH ON SHORE FETCH IN THE LOWER LEVELS PICKING UP TUES NIGHT
THROUGH WED AS WINDS SHIFT FROM N-NE TO SE. THEREFORE MOISTURE WILL
START TO INCREASE ACROSS THE AREA. DEWPOINTS TEMPS WILL INCREASE
ABOUT 20 TO 25 DEGREES BETWEEN TUES AFTN AND WED AFTN AS LOCAL AREA
TAPS INTO PLENTY OF ATLANTIC MOISTURE.
MODELS HAVE NOT COME TOGETHER WITH THE EXACT TRACK OF THE LOW ON
WED. GFS REMAINS FARTHEST EAST BUT STILL TRACKS JUST WEST OF THE
APPALACHIANS WHILE THE NAM REMAINS THE WESTERN MOST TRACK. AS
MENTIONED PREVIOUSLY THIS COULD MAKE THE DIFFERENCE IN TERMS OF MORE
STABLE TYPE PCP TRANSITIONING TO CONVECTION FOR OUR AREA. EITHER WAY
CLOUDS AND RAIN WILL OVERSPREAD THE AREA ON WED. RAIN CHANCES WILL
BE GREATER OVER INLAND SOUTH CAROLINA ZONES BUT WILL SPREAD
NORTHEAST REACHING WHOLE CWA BY AFTERNOON WITH PERIODS OF MODERATE
TO HEAVY RAIN. WITH FORECAST UNCERTAINTY IN EXACT TRACK OF LOW WILL
REMAIN A LITTLE LESS BULLISH WITH POPS...BUT BEST CHANCES OF PCP
WILL BE FROM LATE WED INTO EARLY THURS AS MOISTURE POOLS AHEAD OF
COLD FRONT WITH SYSTEM TAPPING INTO BOTH GULF AND ATLANTIC MOISTURE.
TEMPS WILL ACTUALLY INCREASE IN WAA AHEAD OF COLD FRONT THROUGH THE
EVENING HOURS. SHOULD SEE LOW TEMP AT THE START OF THE PERIOD WITH
TEMPS INCREASING THROUGH THE NIGHT UNTIL COLD FRONT MAKES IT
THROUGH. PCP BECOMES MORE CONVECTIVE IN NATURE IN WARM SECTOR AHEAD
OF COLD FRONT WED NIGHT INTO EARLY THURS AND THIS WILL ALSO INCREASE
POTENTIAL FOR FLOODING ACROSS THE AREA. AS FOR SEVERE
POTENTIAL...WOULD BE MORE OF A HIGH SHEAR LOW CAPE TYPE SCENARIO
WITH LLJ FORECAST UP TO 65 KTS AND H3 JET OVER 100 KTS BY MIDNIGHT
WED NIGHT INTO EARLY THURS. WILL HAVE TO SEE HOW SYSTEM PLAYS OUT TO
BE ABLE TO FINE TUNE SEVERE POTENTIAL.
WITH PLENTY OF RAIN INCREASING RIVER LEVELS WILL RISE AND STRONG ON
SHORE FETCH OF WINDS COMBINED WITH ASTRONOMICAL TIDES COULD PRODUCE
COASTAL FLOOD ISSUES BY THURS MORNING HIGH TIDES. OVERALL COULD SEE
VARIOUS ISSUES ARISE IN THE THE SHORT TERM PERIOD FROM FLOODING OF
LOCAL AREAS TO RIVER FLOODING TO COASTAL FLOODING.
&&
.LONG TERM/THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...TIMING DIFFERENCES EXIST WITH RESPECT TO
STRONG AND DYNAMIC FROPA THAT COULD OCCUR EARLY THURSDAY. FOR THE
MOST PART THIS WILL HAVE AN EFFECT ON THE LONG TERM FORECAST FOR
WIND DIRECTION AND THE SKY CLEARING AS MOST OF THE DEEP MOISTURE
AND RAIN CHANCES WILL COME JUST BEFORE THE LONG TERM. ONCE THE CAA
DOES SET UP THURSDAY AFTERNOON IT MAY BE STRONG ENOUGH FOR NON-
DIURNAL TEMPERATURES DROPS. POSSIBILITY FOR COASTAL FLOODING
AND/OR BEACH EROSION DUE TO HIGH WAVES AND EXTRATROPICAL STORM
SURGE ACCORDING TO GUIDANCE. THIS HAS BEEN HIGHLIGHTED IN THE
HAZARDOUS WEATHER OUTLOOK. TEMPS WILL DROP INTO THE UPPER 30S
THURSDAY NIGHT AS LAGGING UPPER TROUGINESS IN THE WEST PROMOTES
SOUTHWESTERLY FLOW. HIGHS FRIDAY A SOLID CATEGORY BELOW CLIMO. GFS
WANTS TO RETURN CLOUD COVER AND LOW PRECIP CHANCES FRIDAY NIGHT
INTO SATURDAY AS A FLAT WAVE MOVES UP THE BOUNDARY WELL OFFSHORE.
MOST TIMES THAT GUIDANCE HAS SHOWN THIS LATELY IT HAS BEEN
ERRONEOUSLY OVERDONE. THIS HAS REALLY CAST SOME CONSIDERABLE
UNCERTAINTY INTO FRIDAY NIGHTS TEMPERATURE FORECAST. CONTINUITY
HAS SOME OF THE COLDEST AIR OF THE SEASON WITH UPPER 20S
WIDESPREAD. NEW GUIDANCE IS 10+ DEGREES WARMER. SINCE THE CLOUD
IDEA IS A FAIRLY NEW ONE WILL NOT QUITE BUY INTO IT AT THIS TIME.
THE LAST VORT MAX OF THE LINGERING EASTERN U.S. TROUGH SWINGS
THROUGH ON SATURDAY BRINGING A FRESH BURST OF CAA. HIGHS MAY
STRUGGLE TO TOP 50 AND NIGHTTIME LOWS SHOULD BE IN THE LOW 30S IF
NOT A LITTLE COLDER. H850 TEMPERATURES CLAW THEIR WAY BACK TO
FREEZING OR THEREABOUTS ON SUNDAY SO ANOTHER AFTERNOON OF LOW/MID
50S AT BEST. MODERATION ON MONDAY WILL BE SLIGHT AS THE HIGH
REMAINS TO OUR NORTH.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z TERMINALS ARE VFR WITH SCATTERED MID AND HIGH LEVEL CLOUDS
AT THE COASTAL TERMINALS AND MID-LEVEL CEILINGS DEVELOPING AT
FLO/LBT. A DISSIPATING AREA OF RAIN CONTINUES TO MOVE EAST
TOWARDS THE TERMINALS AHEAD OF AN ADVANCING COLD FRONT. EXPECT THE
RAIN TO HOLD TOGETHER ENOUGH TO AFFECT THE FLO/LBT TERMINALS
AROUND 22Z AND CONTINUE TO AFFECT THE TERMINALS FOR SEVERAL HOURS
WITH TEMPO SHOWERS/MVFR VISIBILITIES. THE AREA OF RAIN WILL
CONTINUE ADVANCING EAST...AFFECTING THE COASTAL TERMINALS BY
01-02Z.
THE COLD FRONT WILL MOVE THROUGH THE FLO/LBT TERMINALS 01Z-03Z AND
THE COASTAL TERMINALS 03Z-05Z WITH WINDS SHIFTING TO THE NORTHWEST
AROUND 10 KNOTS...WITH A FEW GUSTS TO 20 KNOTS POSSIBLE FOR SEVERAL
HOURS AFTER FROPA. COULD BE A BRIEF PERIOD OF POST FRONTAL MVFR
CEILINGS BUT CHANCES ARE LOW ATTM THUS WILL NOT INCLUDE IN TAFS.
SKIES WILL BECOME CLEAR AFTER MIDNIGHT WITH WINDS VEERING TO THE
NORTH AND DECREASING TO LESS THAN 10 KNOTS IN THE PRE-DAWN HOURS.
COULD BE SOME LIGHT FOG DEVELOP IN THE PRE-DAWN HOURS WITH MOIST
SOILS...CLEAR SKIES AND COOL AIR ADVECTION...BUT THINK WIND SPEEDS
WILL CONTINUE TO PROVIDE SUFFICIENT MIXING TO INHIBIT FOG FORMATION.
VFR/CLEAR SKIES EXPECTED TUESDAY MORNING WITH NORTHEAST WINDS AROUND
8 KNOTS.
EXTENDED OUTLOOK...IFR CONDITIONS/ISOLATED THUNDERSTORMS POSSIBLE
WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...SMALL CRAFT ADVISORY REMAINS POSTED FOR THE
WATERS THROUGH THE OVERNIGHT PERIOD...WITH GUSTY 25 KT WINDS AHEAD
OF AND BEHIND FRONTAL PASSAGE. IT APPEARS MORE LIKELY THAT 25
KNOT WINDS WILL VERIFY BETTER THAN 6 FOOT SEAS...BUT A PRETTY GOOD
BET THAT 5-6 FOOT SEAS WILL BE FOUND BETWEEN 15-20NM OUT OVERNIGHT.
2 TO 4 FOOT SEAS MUCH OF TODAY WITH FRYING PAN AND OUTER SEAS
APPROACHING 5 FEET LATE AFTERNOON TO EARLY EVENING. DOMINANT WAVE
PERIODS WILL RUN BETWEEN 4-6 SECONDS AS SW CHOP AND SHORT WAVELENGTH
ENERGY PREVAILS THROUGH TONIGHT. WEAK SE SWELL WAS EVENT IN
SPECTRAL PLOTS THIS AFTERNOON...BUT THIS ENERGY ONLY AROUND A FOOT
OR TWO IN HEIGHT AT BEST THROUGH THE NEAR TERM PERIOD. LATEST WIND
DATA POINTS TO A FRONTAL PASSAGE ACROSS THE 0-20NM WATERS BETWEEN 10
PM NEAR SHORE TO WELL OFFSHORE BY MIDNIGHT. ADVISORY FLAGS CURRENTLY
SET TO EXPIRE AROUND DAYBREAK TUESDAY AS GUSTINESS OF NORTHERLY FLOW
BEGINS TO GRADUALLY EASE JUST AFTER THE PRESSURE GRADIENT PEAK.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...WINDS AND SEAS WILL DECREASE THROUGH THE DAY
TUES AS HIGH PRESSURE BUILDS IN BRIEFLY. WINDS WILL VEER AROUND FROM
N-NE TUES MORNING TO E-SE BY WED MORNING AS HIGH PRESSURE SHIFTS OFF
SHORE. THIS ON SHORE FLOW WILL PERSIST THROUGH WED AS GRADIENT
TIGHTENS BETWEEN HIGH PRESSURE OFF SHORE AND LOW PRESSURE MOVING
NORTH OUT OF THE GULF COAST. WINDS AND SEAS WILL INCREASE RAPIDLY
WED AFTN AND WILL INCREASE WELL ABOVE SCA CRITERIA BY LATE WED. WNA
MODEL HAS BEEN CONSISTENTLY FORECASTING 10 TO 12 FT SEAS IN OUTER
WATERS WITH A PEAK EARLY THURS MORNING SHORTLY AFTER MIDNIGHT. SCA
CONDITIONS WILL PERSIST FROM WED AFTN THROUGH THE NIGHT AS LOW
PRESSURE SYSTEM TRACKS OFF TO THE NORTH AND COLD FRONT APPROACHES
FROM THE WEST. WINDS WILL VEER AROUND TO S-SW AT 20 TO 25 KTS BY THE
END OF THE PERIOD WITH SEAS STARTING TO DECREASE.
LONG TERM/THURSDAY THROUGH SATURDAY/...
AS OF 3 PM TUESDAY...STRONG FRONTAL PASSAGE SOME TIME AROUND THE
BEGINNING OF THE LONG TERM BUT TIMING ISSUES REMAIN. THIS WILL
HAVE BEARING ON THE FLAGS THURSDAY AND HOW LONG THEY LAST.
CURRENTLY IT APPEARS THAT SMALL CRAFT ADVISORY LIKELY NEEDED ON
ACCOUNT OF 6 FT SEAS THROUGH ROUGHLY MIDDAY THURSDAY OR EARLIER
AFTERNOON...DEPENDING ON TIMING OF FRONT. THEREAFTER THE SWING TO
OFFSHORE WIND DIRECTION PAIRED WITH DECREASING GRADIENT WINDS
SHOULD BRING IMPROVING CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND
THE BOUNDARY FOR THE REMAINDER OF THE LONG TERM BUT FAIRLY SLOWLY.
THIS WILL KEEP A NORTHERLY COMPONENT IN THE WIND DIRECTION FOR THE
DURATION AS SPEEDS NO WORSE THAN THE 10 TO 15KT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...MJC
SHORT TERM...RGZ
LONG TERM...MBB
AVIATION...MRR
