Area Forecast Discussion
Issued by NWS Wilmington, NC

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

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