000
FXUS62 KILM 071123
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
622 AM EST WED JAN 7 2009
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS THE REGION TODAY. BEHIND THE
FRONT...STRONG WINDS WILL CONTINUE THROUGH THURSDAY. HIGH
PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH EARLY
SATURDAY. ANOTHER COLD FRONT WILL MOVE SOUTHEAST ACROSS THE
CAROLINAS SATURDAY NIGHT...BUT IS NOT EXPECTED TO PRODUCE ANY
SIGNIFICANT PRECIPITATION. CHILLY HIGH PRESSURE WILL FOLLOW SUNDAY
AND PERSIST INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...A STRONG COLD FRONT WILL BLAST EAST ACROSS
THE COASTAL CAROLINAS EARLY THIS AFTERNOON. THE FRONT ITSELF SHOULD
BE ACCOMPANIED BY FAIRLY SOLID A LINE OF SHOWERS...HOWEVER THE BIG
FORECAST CONCERN THROUGH TONIGHT IS WIND. THE MODELS ARE IN
EXCELLENT AGREEMENT THAT A LOW LEVEL JET WITH WIND SPEEDS OF 55-65
KT AT 925 MB (2000 FT AGL) WILL DEVELOP AHEAD OF THE FRONT. EVIDENCE
OF THESE INCREASING WINDS ALREADY EXISTS WITH WIDESPREAD 20-30 KT
GUSTS IN THE MIDDLE OF THE NIGHT ACROSS CENTRAL/WESTERN SOUTH
CAROLINA.
THE FRONT WITH ITS NARROW LINE OF SHOWERS WILL RACE EAST TODAY...BUT
NOT BEFORE SOME FILTERED SUNSHINE IS ABLE TO DESTABILIZE THE
BOUNDARY LAYER AND MIX STRONGER WINDS DOWN TO THE SURFACE. ALONG
I-95 AND POINTS WEST THERE MAY ONLY BE ~2 HRS OF DAYLIGHT BEFORE THE
FRONT ARRIVES AND ENDS THE WARM ADVECTION...BUT ALONG THE COAST AND
PARTICULARLY IN THE CAPE FEAR AREA TEMPERATURES COULD GET QUITE
WARM...POTENTIALLY AS HIGH AS 73 DEGREES. THE POTENTIAL FOR GUSTS UP
TO 50 MPH EXISTS WITH THE DEEPER MIXING THESE WARM TEMPERATURES
WOULD IMPLY. THE NGM MOS SUGGESTS WE COULD SEE UPPER 70S IN THE
CAPE FEAR AREA TODAY. IF THIS WERE TO VERIFY IT WOULD IMPLY VERTICAL
MIXING ON THE ORDER OF 2800 FT...AND THE POTENTIAL TO MIX DOWN 60-70
MPH WINDS. THIS IS NOT EXPECTED...BUT COULD BE REGARDED AS A WORST
CASE SCENARIO.
A SECOND ROUND OF STRONG WINDS SHOULD DEVELOP DURING THE AFTERNOON
HOURS AND LASTING INTO THE EVENING IN THE COLD ADVECTION BEHIND THE
FRONT. STEEP LOW-LEVEL LAPSE RATES WILL DEVELOP AS COLDER AIR POURS
IN...AND WIDESPREAD 40-50 MPH WIND GUSTS ARE AGAIN EXPECTED. WINDS
WILL BEGIN TO DROP TO MORE MANAGEABLE LEVELS BY MIDNIGHT AS LOWS
SLIDE INTO THE UPPER 30S INLAND TO LOWER 40S AT THE COAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM WEDNESDAY...THURSDAY WILL BE DOMINATED BY A DEEP EAST
COAST UPPER TROF AND STRONG CAA BEHIND AN INTENSE SFC LOW LIFTING
THRU THE CANADIAN MARITIMES. HERE IN THE EASTERN CAROLINAS WE CAN
EXPECT A DRY BUT BREEZY DAY. WELL-MIXED BOUNDARY LAYER TO START
THE DAY SUGGESTS THAT DIURNAL TEMP RECOVERY WILL BE LIMITED...AND
LOW-LEVEL THICKNESS PROGS AND 850MB TEMPS ONLY SUPPORT HIGHS IN
THE MID 50S. THEREFORE HAVE GONE WELL UNDER GUIDANCE MAX TEMPS.
SUSTAINED WINDS WILL AVERAGE 15-20MPH...WITH SOME GUSTS TOUCHING
30MPH ESPECIALLY IN THE LATE MORNING/EARLY AFTERNOON.
UPPER TROF MOVES OFFSHORE THU EVENING...AND WITH HIGH PRESSURE
BUILDING FROM THE DEEP SOUTH WE SHOULD SEE CLEAR SKIES AND WINDS
GOING NEARLY CALM. FAVORABLE RADIATIONAL COOLING CONDITIONS WILL
ALLOW MOST LOCATIONS TO DROP TO FREEZING OR BELOW.
FRIDAY ACTUALLY LOOKS LIKE THE COOLEST DAY WITH THE SFC HIGH
SETTLING OVER THE CAROLINAS. THERMAL TROF AT 850MB EXITS TO THE
EAST BUT MIXING WILL BE TOO SHALLOW TO REALIZE THAT. HAVE GONE IN
LINE WITH MOS CONSENSUS OF LOWER/MID 50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...MAIN PLAYER OVER THE WEEKEND IS A MOISTURE-
STARVED COLD FRONT WITH A FEW QUESTIONS ABOUT TIMING. GFS IS
6-12 HRS FASTER THAN THE ECMWF...WHICH HPC FAVORS AND IS THE
PREFERRED SOLUTION HERE. BASED ON THAT TIMING THE BEST SHOT FOR
PRECIP IS SAT NIGHT...BUT EVEN THEN THE LACK OF MOISTURE LIMITS US
TO A SLIGHT CHANCE POP WHICH IS NOT MENTION-WORTHY THIS FAR OUT.
BROAD UPPER TROF AND COOL AND DRY HIGH PRESSURE WILL HOLD SWAY
SUNDAY THROUGH TUESDAY...BRINGING TEMPS AT LEAST SLIGHTLY BELOW
CLIMO BOTH DAY AND NIGHT. GFS AND ECMWF BOTH SUGGEST THAT WE COULD
TAP INTO SOME ARCTIC AIR HEADING INTO MID-WEEK...BUT THAT STILL
APPEARS TO BE BEYOND DAY 7.
&&
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
OVERVIEW...A COLD FRONT WILL MOVE THOUGHT THE TERMINALS TODAY. A
NARROW BAND OF LIGHT MODERATE SHOWERS CAN BE EXPECTED ALONG THE COLD
FRONT WITH A SHORT PERIOD OF POST FRONTAL LIGHT RAIN. VERY WINDY
CONDITIONS EXPECTED WITH GUSTS AS HIGH AS 40 KNOTS.
MVFR CEILINGS 2-3K WILL MOVE INTO THE FLO/LBT TERMINALS WITHIN THE
NEXT HOUR AND WILL SPREAD INTO THE COASTAL TERMINALS BY MID MORNING.
THESE CEILINGS WILL LIFT TO VFR AFTER FROPA. THE PREVIOUS SET OF
TAFS HAD PRETTY GOOD TIMING OF THE SHOWERS AND PROBABLY WILL NOT
TWEAK THE TIMING BUT MAYBE AN HOUR OR SO. CURRENT SATELLITE TRENDS
INDICATE POTENTIAL FOR HEAVY SHOWERS IS DECREASING SO THINK THE
CHANCE OF ANY IFR IS EVEN LESS THAN EARLIER THOUGHT.
KCAE VWP IS INDICATING 50 KNOTS AT 2K FEET. SURFACE WINDS ARE 15
KNOTS GUSTING TO 25 KNOTS AT FLO. WILL INITIALIZE WITH LLWS IN
FLO/LBT TAFS. THE LO-LVL JET WILL SHIFT TO THE COASTAL TERMINALS BY
MID MORNING BUT EXPECT SURFACE WINDS TO ALSO INCREASE THUS LLWS
CONDITIONS NOT EXPECTED.
EXTENDED...A STRONG PRESSURE GRADIENT WILL PRODUCE WINDY CONDITIONS
THROUGH EARLY FRIDAY BEFORE HIGH PRESSURE BUILDS IN FROM THE WEST.
VFR WEATHER EXPECTED THROUGH SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...A STRONG COLD FRONT WILL MOVE THROUGH THE
COASTAL WATERS THIS AFTERNOON BRINGING HIGH WINDS AND DANGEROUS
SEAS. A LOW LEVEL JET IS SHOWN ON VIRTUALLY ALL GUIDANCE TO REACH
55-65 KT BY LATE MORNING JUST AHEAD OF THE FRONT. VERY STABLE THERMAL
CONDITIONS BROUGHT ABOUT BY THE COOL WATER TEMPERATURES WILL
INSULATE THE OCEAN SURFACE FROM THE FULL FORCE OF THESE WINDS...BUT
ENOUGH MOMENTUM SHOULD MAKE IT DOWN TO NECESSITATE UPGRADING TO A
GALE WARNING NORTH OF LITTLE RIVER INLET THROUGH TONIGHT. AFTER
COLLABORATION WITH NWS CHS WE WILL CONTINUE THE SMALL CRAFT ADVISORY
FOR OUR SOUTH CAROLINA COASTAL WATERS...BUT MARINERS SHOULD BE
ADVISED THIS IS A `HIGH END` ADVISORY WITH WIND GUSTS APPROACHING
33-35 KT AT TIMES. SEAS WILL BUILD TO AS HIGH AS 7-9 FT OFF THE SC
COAST...AND 8-11 FT OFF NC.
COLD ADVECTION BEHIND THE FRONT TONIGHT WILL LEAD TO A SECOND PERIOD
OF STRONG GUSTY WINDS DURING THE EVENING HOURS. GALE-FORCE WINDS ARE
EXPECTED OVER THE NC COASTAL WATERS...BUT CONDITIONS SHOULD BEGIN TO
IMPROVE AFTER MIDNIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM WEDNESDAY...SOLID SCA WINDS ARE EXPECTED TO PERSIST
THROUGH THE DAY ON THURSDAY...AS LOW-LEVEL WINDS REMAIN QUITE
FRISKY THROUGH A DEEPLY MIXED BOUNDARY LAYER. WIND DIRECTION
ALMOST DUE WEST...WHICH IS NOT A PURE OFFSHORE TRAJECTORY AND EVEN
20 NM OFFSHORE...SEAS WILL VARY WIDELY DUE TO THE SHAPE OF THE
COASTLINE. LOOK FOR SEAS UP TO 6 OR 7 FT CONTINUING IN THE
VICINITY OF FRYING PAN SHOALS...WHILE THE MORE BLOCKED SC WATERS
WILL SEE NO MORE THAN 5 FT. HAVE MADE NO CHANGES TO GOING
HEADLINES...WHICH CARRY THE SCA THRU THE END OF THU AFTERNOON FOR
THE SC WATERS. AT THIS TIME WILL NOT TRY TO STEP DOWN FROM THE
GALE WARNING THAT IS FLYING FOR THE NC WATERS.
WINDS WILL SHIFT NW AND DIMINISH THU NIGHT ONCE THE UPPER TROF
AXIS MOVES OFFSHORE AND SFC HIGH PRESSURE BUILDS FROM THE DEEP
SOUTH. SEAS WILL SUBSIDE ACCORDINGLY. COULD SEE LIGHT AND
VARIABLE WINDS ON FRI WITH THE HIGH OVERHEAD.
LONG TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...RETURN FLOW DEVELOPS LATE FRI NIGHT INTO
SATURDAY AHEAD OF THE NEXT COLD FRONT. MODEST LOW-LEVEL JETTING
ADVERTISED BY THE GFS...BUT IN WAA IT WILL NOT BE ENOUGH TO BREACH
ADVISORY THRESHOLDS. SEAS BUILD TO AROUND 4 FT AHEAD OF THE
FRONT. STILL NOT VERY CONFIDENT IN THE FRONTAL TIMING AND HAVE
LEANED TOWARD THE SLOWER HPC/ECMWF SOLUTION WHICH CALLS FOR FROPA
SAT NIGHT...AND NOT MUCH OF A CAA SURGE BEHIND THE FRONT. EVEN IF
THE GFS IS RIGHT ANY POST-FRONTAL SURGE WILL BE SHORT-LIVED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT EST TONIGHT
FOR SCZ017-023-024-032>034-039-046.
NC...WIND ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT EST TONIGHT
FOR NCZ087-096-097-099>101.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THURSDAY FOR AMZ254-256.
GALE WARNING UNTIL 2 AM EST THURSDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RAS
LONG TERM...RAS
AVIATION...MRR
