-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 251104
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
604 AM EST WED FEB 25 2015

.SYNOPSIS...
A STRENGTHENING LOW PRESSURE SYSTEM WILL MOVE OUT OF THE GULF OF
MEXICO TODAY...AND OFF THE SOUTH CAROLINA COAST TONIGHT. THIS WILL
BRING PERIODS OF RAIN TO THE AREA TONIGHT...WITH SOME SNOW
POSSIBLE WELL INLAND. THIS LOW PRESSURE WILL PULL AWAY ON
THURSDAY...LEAVING SOME LIGHT DRIZZLE OR FREEZING DRIZZLE THURSDAY
MORNING BEFORE CONDITIONS DRY OUT. A WEDGE OF HIGH PRESSURE WILL
BUILD DOWN THE COAST FRIDAY AND INTO THE WEEKEND BRINGING DRY BUT
COLD CONDITIONS. A WARMING TREND WILL DEVELOP NEXT WEEK ALONG WITH
INCREASING RAIN CHANCES.

&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 430 AM WEDNESDAY...WINTER WX ADVISORY HAS BEEN ISSUED FOR
ALONG THE NORTHERN TIER OF THE ILM CWA...THAT WILL BE IN EFFECT
MID-EVENING TONIGHT THROUGH LATE MORNING THURSDAY. MAINLY FOR A
MIXTURE OF RAIN AND SNOW LATER THIS EVENING AND TONIGHT...WITH
LIGHT FREEZING RAIN OR DRIZZLE FOR THE ADVISORY AREA AFTER THE
CENTER OF THE LOW PASSES BY EARLY THU MORNING.

FAST MOVING SOUTHERN STREAM MID-LEVEL S/W TROF MOVING ALONG THE
GULF COAST STATES THIS MORNING...WILL PICK UP SOME GULF OF MEXICO
MOISTURE AND AID IN THE SFC LOW DEVELOPMENT ALONG THE GULF COAST
STATES TODAY. THE SFC LOW WILL QUICKLY MOVE ENE TO OFF THE SE U.S.
COAST BY LATE TONIGHT...THEN FURTHER INTENSIFIES AS IT ACCELERATES
TO THE NE TO OFF CAPE HATTERAS TOWARD DAYBREAK THU.

ALTHOUGH THE PATH OF THIS STORM THAT IS PROGGED TO TAKE IS A
PREFERRED MOVEMENT FOR WINTRY WX TO OCCUR ACROSS THE ILM CWA. ITS
EITHER JUST TOO CLOSE TO THE CAROLINA COASTS AS THE SFC LOW TRACKS
TO THE NE...ALLOWING SOME MILDER AIR IN THE LOW LEVELS...IE. SFC-
850MB...FROM OFF THE ATLANTIC OCEAN TO WORK ITS WAY ACROSS THE ILM
CWA. THEREFORE...PREVENTING A FULL FLEDGED FROZEN OR FREEZING
PCPN EVENT FOR THE ILM CWA. ANOTHER POSSIBLE REASON IS THAT THERE
IS A LACK OF COLD AIR AVAILABILITY ACROSS THE ILM CWA. MEANING...
THE COLD AIR NECESSARY FOR A WINTER SNOW EVENT FOR THE ILM CWA
DOES NOT REALLY TAP INTO ANY COLD AIR SOURCE REGION TO OUR
NORTH...IE. SFC HIGH RIDGING DOWN THE EAST SIDE OF THE
APPALACHIANS...WITH THE HIGHS CENTER LOCATED EITHER OVER
THE GREAT LAKES OR ACROSS THE NE STATES.

HAVING SAID ALL THIS...WILL STILL CARRY A MIXTURE OF POSSIBLE
FROZEN/FREEZING PCPN ACROSS BASICALLY THE NORTHERN PERIPHERY OF
THE ILM CWA. THERE MAY BE JUST ENOUGH COLD AIR AVAILABILITY FOR
WINTER WX PCPN. IT WILL ONLY TAKE A SLIGHTLY DEEPER ATM COLUMN OF
SUB-32 DEGREE TEMPS COMBINED WITH DECENT SET OF UVVS...AND
PORTIONS OF THE FA MAY SEE A QUICK BURST OF SNOW AS OUTLINED BY
MY COMRADE IN-ARMS TONIGHT.

FOR SUCH A FAST-MOVING AREA OF LOW PRESSURE...BASICALLY THE FA
WILL BE SUBJECT TO A 9 TO 15 HRS OF PCPN BEFORE ALL IS SAID AND
DONE. THE UPPER DYNAMICS ASSOCIATED WITH THIS LOW WILL BE VERY
EFFICIENT IN PRODUCING A DECENT SWATH OF 1 TO POSSIBLY UP TO 1.25
INCHES OF QPF MAINLY TONIGHT.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...BIGGEST CONCERN IN THE SHORT TERM INVOLVES
DEPARTING LOW PRESSURE THURSDAY...AND THE CHANCE FOR WINTRY PRECIP
ACROSS THE AREA.

CENTER OF STRENGTHENING LOW PRESSURE WILL BE OFF THE OUTER BANKS OF
NC TO START THURSDAY MORNING...AND WILL RAPIDLY PULL OFF TO THE
NORTHEAST THROUGH THURSDAY AFTN. ALTHOUGH THE MAJORITY OF THE
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL FALL ON
WEDNESDAY...LOW-LEVEL RESIDUAL MOISTURE BELOW 700MB WILL REMAIN INTO
THURSDAY EVENING. THIS OF COURSE WILL NOT PRODUCE HEAVY PRECIP...BUT
VERY LIGHT RAIN AND DRIZZLE...ALONG WITH WIDESPREAD LOW
CLOUDINESS...WILL PERSIST INTO THURSDAY NIGHT. THE QUESTION IS HOW
QUICKLY CAN SURFACE TEMPS FALL BELOW FREEZING DURING
THURSDAY...WHICH WOULD CREATE A FREEZING DRIZZLE SCENARIO. GUIDANCE
IS IN VERY GOOD AGREEMENT WITH TEMPS REMAINING JUST ABOVE FREEZING
NEAR THE COAST...BUT DROPPING TO BELOW INLAND. FORTUNATELY...THE
BETTER CHANCE FOR RESIDUAL PRECIP IS NEAR THE COAST...AND EVEN IN
THOSE PLACES THAT DO ENCOUNTER SOME -ZL WILL DO SO ONTO GROUND THAT
HAS EXPERIENCED RAIN ON WEDNESDAY. LOCAL TOP DOWN METHODOLOGY
PRODUCED A SHORT PERIOD OF -ZR/-ZL ACROSS THE COUNTIES ALREADY
WITHIN THE WSW - SO EXTENDED THE WSW UNTIL NOON THURSDAY FOR SOME
VERY LIGHT FREEZING DRIZZLE WHICH MAY ACCRETE UP TO 0.01 OR 0.02
INCHES...MOSTLY ACROSS ROBESON/BLADEN COUNTIES.

AS THE LOW PULLS AWAY THURSDAY NIGHT DRY ADVECTION COMMENCES AND SKY
CONDITIONS WILL IMPROVE DRAMATICALLY FRIDAY...ALTHOUGH LOW CLOUD
COVER WILL REMAIN AS A WEDGE OF HIGH PRESSURE BUILDS DOWN THE COAST.
STILL...FRIDAY WILL BE DRY...A NICE BREAK FROM THE ACTIVE WEATHER
RECENTLY.

TEMPS THROUGH THE PERIOD WILL REMAIN WELL BELOW NORMAL AS THE
CALENDAR APPROACHES MARCH. HIGHS BOTH THURSDAY AND FRIDAY WILL BE
ONLY IN THE LOW 40S...A FULL 20 DEGREES BELOW NORMAL...ALTHOUGH
FRIDAY WILL BE THE SLIGHTLY WARMER OF THE TWO. LOWS AT NIGHT WILL
ALSO BE VERY COLD...DROPPING WELL INTO THE 20S BOTH NIGHTS...BUT IN
THE DRIER COLUMN FRIDAY NIGHT MINS WILL LIKELY BE 2-3 DEGREES COOLER
THAN THOSE EXPERIENCED ON THURSDAY NIGHT.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 AM WEDNESDAY...COLD AND DRY FOR THE WEEKEND...WITH A
WARMUP EXPECTED NEXT WEEK BUT ACCOMPANIED BY UNSETTLED WEATHER.

WEDGE OF HIGH PRESSURE WILL EXTEND DOWN THE EAST COAST DURING THE
WEEKEND AS CONFLUENCE BETWEEN THE EASTERN CONUS TROUGH AND
DEVELOPING SE RIDGE DRIVES RISING SURFACE PRESSURE. SATURDAY AND
SUNDAY WILL BOTH LIKELY BE DRY DAYS...BUT NE FLOW WITHIN THE WEDGE
WILL LEAD TO LOW CLOUDINESS THROUGH THE WEEKEND...BUT LIKELY IN A
VARYING STATE. THIS SUGGESTS THE SUN WILL BE PRESENT AT TIMES.
HOWEVER...TEMPS WILL...SHOCKINGLY...REMAIN WELL BELOW CLIMO THROUGH
THE WEEKEND.

WEDGE BREAKS DOWN ON MONDAY AND SURFACE HIGH PRESSURE SLIPS OFFSHORE
LEADING TO A DRAMATIC WARMING TREND FOR EARLY NEXT WEEK.
HOWEVER...THIS WARMTH WILL BE SOMEWHAT UNREALIZED AS UNSETTLED
WEATHER WILL DEVELOP MONDAY AND PERSIST THROUGH THE REMAINDER OF THE
PERIOD. LARGE TROUGH DEVELOPING WEST OF THE AREA WILL DRIVE
VORTICITY IMPULSES JUST NORTH OF THE AREA...OVERTOP A STALLED COLD
FRONT WHICH WILL HOVER ACROSS THE CAROLINAS. OVERALL...THERE APPEARS
TO BE LIMITED FORCING LOCALLY FOR PRECIP...BUT INCREASING CLOUDS
WITH AT LEAST PERIODS OF SHOWERS SEEM LIKELY MONDAY/TUESDAY.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
AS OF 05Z...IFR CONDITIONS WILL CONTINUE THROUGH THE PRE-DAWN HRS
OF WED WITH THE LOW CEILINGS THE PRIMARY REASON. WILL SEE VSBYS
DROP TO 2 TO 5 MILES IN FOG AT TIMES BUT THE LOW STRATUS WILL BE
THE PRIMARY AVIATION ISSUE THROUGH SEVERAL HRS AFTER SUNRISE WED.
NEXT SOUTHERN STREAM S/W TROF TO AFFECT THE FORECAST AREA WITH
ANOTHER ROUND OF WINTRY PCPN. DIFFERENCE WITH THIS NEXT SYSTEM IS
THAT COLD AIR WILL BE A LIMITING FACTOR THUS LEAVING ONLY THE
INLAND TERMINALS...FLO AND LBT...THAT COULD FACE POSSIBLE
FROZEN/FREEZING PCPN LATER TONIGHT INTO DAYTIME THU. AT THIS
TIME...THE CONSENSUS IS THAT THE COASTAL TERMINALS WILL BE JUST
PLAIN RAIN. THUS...LOW CEILINGS AND REDUCED HORIZONTAL VSBY TO
RETURN LATE IN THE TAF ISSUANCE PERIOD FOR ALL TERMINALS.

EXTENDED OUTLOOK...MVFR/IFR CONDITIONS EXPECTED AS LOW PRESSURE
WILL MOVE ACROSS THE TERMINALS TONITE INTO EARLY THU...THEN
ACCELERATE NE OFF THE CAROLINA COASTS AND OFFSHORE DURING THE DAY
ON THURSDAY. FINALLY...A RETURN TO VFR CONDITIONS FRI THROUGH
SAT. MVFR/IFR POSSIBLE SUNDAY.

&&

.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST THIS EVENING AS WINDS AND SEAS ARE BEHAVING NICELY.
DISCUSSION FROM 645 PM FOLLOWS...

LOW PRESSURE WELL EAST OF THE SOUTH CAROLINA COAST WILL CONTINUE
TO PUSH NORTHEAST AND AWAY FROM THE AREA OVERNIGHT. THIS WILL
ALLOW WEAK HIGH PRESSURE INLAND TO SPREAD DOWN TO THE COAST
OVERNIGHT...WITH VEERING WINDS AND WEAKENING WIND SPEEDS. THE
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT FOR THE NC WATERS WHERE
THE FRYING PAN SHOALS BUOY IS STILL REPORTING 7.5 FOOT SEAS. WEST
OF FRYING PAN SHOALS CONDITIONS APPEAR TO BE IMPROVING A LITTLE
FASTER.

NOTE THAT SOME WIND SENSORS NEAR THE COAST APPEAR TO HAVE FROZEN
ANEMOMETER CUPS AND ARE NOT TO BE TRUSTED.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 AM WEDNESDAY...DEEPENING LOW PRESSURE WILL BE MOVING AWAY
FROM THE COAST DURING THURSDAY...BUT THE GRADIENT WILL REMAIN
PINCHED THE FIRST PART OF THE SHORT TERM. GUSTY NORTH WINDS WILL
REACH OVER 20 KTS FIRST THING THURSDAY...BUT WILL EASE QUICKLY
THROUGH THE AFTN TO BECOME 10-15 KTS THURSDAY NIGHT WHILE REMAINING
FROM THE NORTH. HIGH PRESSURE WILL BEGIN TO WEDGE DOWN THE COAST ON
FRIDAY...CAUSING RENEWED TIGHTENING OF THE GRADIENT...AND WINDS WILL
INCREASE SLOWLY...BECOMING 20-25 KTS ONCE AGAIN BUT FROM MORE OF A
NE DIRECTION FRIDAY NIGHT. SEAS THURSDAY MORNING WILL BE 5-8
FT...BUT WILL FALL QUICKLY THROUGH THE DAY AND THE ONGOING SCA
SHOULD BE ALLOWED TO EXPIRE LATE THURSDAY. SEAS WILL REMAIN BELOW 6
FT THURSDAY NIGHT AND FRIDAY...BUT WILL RISE ONCE AGAIN TO 4-6 FT
FRIDAY NIGHT WHEN A RENEWED SCA MAY BE NEEDED.

LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 400 AM WEDNESDAY...WEDGE OF HIGH PRESSURE WILL STRENGTHEN
SATURDAY...AND AN EXTENDED PERIOD OF GUSTY 20-25 KT NE WINDS WILL
OCCUR THROUGH SATURDAY. THIS DRIVES WAVE HEIGHTS TO 4-6 FT...AND AN
SCA WILL LIKELY BE NEEDED THROUGH SATURDAY. SATURDAY
NIGHT...GRADIENT SLOWLY BEGINS TO WEAKEN AS THE WEDGE BREAKS DOWN.
THIS CAUSES WINDS TO EASE TO 10-15 KTS BY SUNDAY MORNING WHILE
REMAINING FROM THE NE. WINDS WILL EASE FURTHER AND THEN VEER TO THE
SOUTH AS THE WEDGE DISSIPATES LATE SUNDAY. WAVE HEIGHTS FALL ON THE
DECREASING WINDS...FROM 4-6 FT LATE SATURDAY...TO 2-4 FT SUNDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
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SC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
     THURSDAY FOR SCZ017-023-024.

NC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
     THURSDAY FOR NCZ087-096-105.

MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EST
     THURSDAY FOR AMZ250-252-254-256.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JDW
NEAR TERM...DCH
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DCH