Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 060806 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 406 AM EDT WED MAY 6 2015 .SYNOPSIS... A LOW PRESSURE SYSTEM ORGANIZING NEAR THE BAHAMAS WILL LIFT NORTH TODAY AND THEN MEANDER AND STRENGTHEN OFF THE SOUTHEAST COAST INTO THE WEEKEND. THIS SYSTEM MAY TRACK VERY CLOSE TO THE COAST...CREATING PERIODS OF GUSTY WINDS AND HEAVY RAINFALL THURSDAY THROUGH SATURDAY. THIS LOW PRESSURE WILL WEAKEN BUT MAY CONTINUE TO CREATE UNSETTLED WEATHER THROUGH MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST WITH THIS LATE EVENING UPDATE. THE COAST IS IN BETWEEN CIRRUS BANDS WITH MAINLY CLEAR SKIES CURRENTLY...BUT THICKER CIRRUS SHOULD BUILD BACK IN OVER THE NEXT FEW HOURS. DISCUSSION FROM 730 PM FOLLOWS... HIGH PRESSURE OFF THE CAROLINA COAST EXTENDS A RIDGE AXIS WESTWARD BETWEEN 34-35 DEGREES LATITUDE. LOW PRESSURE DEVELOPING IN THE BAHAMAS IS PUSHING A STREAM OF CIRRUS CLOUDINESS NORTH ALONG THE COAST. GFS/CANADIAN 200 MB MOISTURE PROGS SHOW THIS CIRRUS WILL PROBABLY BE WITH US THROUGH THE NIGHT EAST OF I-95...AND I HAVE INDICATED PARTLY CLOUDY SKIES IN THE FORECAST AS A RESULT. THE MOISTURE IS THIN ENOUGH VERTICALLY THAT IT SHOULD HAVE LITTLE IMPACT ON TEMPERATURES. MOS GUIDANCE (IN PARTICULAR THE GFS MOS GUIDANCE) HAS BEEN TOO WARM RECENTLY. OVER THE PAST TWO NIGHTS THE GFS MOS HAS SCORED ERRORS OF +4 TO +6 DEGREES AT ILM...LBT AND CRE. DESPITE THE CIRRUS CLOUDINESS...THIS FACT PLUS THE PRESENCE OF THE RIDGE AXIS AND A LONG PERIOD OF LIGHT TO CALM WINDS HAS LED ME TO REDUCE FORECAST LOWS BY SEVERAL DEGREES FOR LOCATIONS NORTH AND WEST OF MYR/CRE. NO OTHER SIGNIFICANT CHANGES ARE NEEDED. DISCUSSION FROM 300 PM FOLLOWS... ONSHORE FLOW WILL WEAKEN DURING THE EVENING AND ANY CUMULUS WILL DISSIPATE WITH THE LOSS OF HEATING. SKIES OVERNIGHT WILL BE MOSTLY CLEAR WITH SOME THIN HIGH CLOUDS POSSIBLE FROM THE AREA OF DISTURBED WEATHER FAR TO THE SOUTH. OTHERWISE... TIME HEIGHT CROSS SECTIONS INDICATE A DRY COLUMN IN THE H85-5 LAYER. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS THINK A BLEND TOWARD THE COOLER MET NUMBERS WILL WORK TONIGHT...WHICH IS A NOTCH BELOW CLIMO. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...A TROUGH OF LOW PRESSURE CURRENTLY BLOSSOMING OFF THE SOUTH FLORIDA COAST IS EXPECTED TO INTENSIFY OFF THE SOUTHEAST COAST THROUGH LATE WEEK...AND POSSIBLY DEVELOP SOME TROPICAL OR SUBTROPICAL CHARACTERISTICS AS IT MEANDERS IN THE VICINITY. UNFORTUNATELY...EVEN AT THIS TIME RANGE THERE IS MUCH LOWERED CONFIDENCE THAN USUAL...BUT HOPEFULLY SOME OF THIS WILL BE IMPROVED TODAY AS NHC IS PLANNING ITS FIRST RECON FLIGHT INTO THE SYSTEM. THAT BEING SAID...I STILL NEED TO WRITE A DISCUSSION AND CREATE A FORECAST EVEN WITH LIMITED CONFIDENCE. THERE ARE A FEW THINGS WE CAN GLEAN FROM THE SETUP AND FROM THE GUIDANCE...EVEN THOUGH WHOLESALE CHANGES CANNOT BE MADE. THERE IS HIGH CONFIDENCE THAT A LOW PRESSURE WILL DEVELOP...AND THAT IT WILL MEANDER SLOWLY NEAR THE COAST AS IT GETS BLOCKED BY MID-LEVEL RIDGING TO THE NORTH. THERE IS HIGH CONFIDENCE THAT IT WILL RETROGRADE WEST OR EVEN SW THU/FRI...AND THERE IS HIGH CONFIDENCE THAT PERIODS OF RAINFALL...POSSIBLY HEAVY AT TIMES...WILL IMPACT AT LEAST THE COASTAL SECTIONS OF THE CWA. BEYOND THAT HOWEVER...TIMING...TRACK...INTENSITY...AND OTHER IMPACTS (WIND...CONVECTION...DURATION) ARE STILL VERY MUCH IN QUESTION. THE NAM IS LIKELY TOO STRONG AND TOO FAR NORTH...WHILE THE GFS LIES ON THE WEAK/SOUTH END OF THE ENVELOPE. AN INTERMEDIATE SOLUTION OF THE ECMWF/CMC MAY BE MOST PRUDENT AT THIS POINT THEN. WILL CONTINUE WITH THE INHERITED FORECAST AND SHOW HIGHEST POP ON FRIDAY...BUT OTHERWISE ATTM EXPECT DETERIORATING CONDITIONS THURSDAY INTO FRIDAY WITH AT LEAST INCREASING WINDS AND PERIODS OF SHOWERS...SOME OF WHICH AGAIN...MAY BE HEAVY AT TIMES. HIGH TEMPS WILL LIKELY REMAIN JUST BELOW CLIMO IN THE TROPICAL AIR MASS DUE TO RAIN AND CLOUDS...WITH HIGHS STAYING IN THE MID TO UPR 70S. MINS WILL STAY ABOVE CLIMO AS GUSTY WARM WINDS AND CLOUDS KEEP LOWS WELL INTO THE 60S. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...HOW THE LONG TERM DEVELOPS WILL HINGE STRONGLY ON WHAT OCCURS DURING THE SHORT TERM. A LOW PRESSURE SYSTEM...POSSIBLE SUBTROPICAL STORM...WILL STILL BE SOMEWHERE IN THE VICINITY...POSSIBLY INLAND...POSSIBLY STILL OFFSHORE...DEPENDING ON WHICH MODEL IS PREFERRED. FAVOR THE SLOWER GUIDANCE AT THIS POINT...BUT WITH SO MUCH UNCERTAINTY STILL IN THE FORECAST AS THE SYSTEM MEANDERS BENEATH AN UPPER RIDGE...WILL AGAIN MAKE ONLY MINIMAL CHANGES TO THE EXTENDED. UNSETTLED WEATHER ASSOCIATED WITH THIS LOW PRESSURE MAY PERSIST INTO MONDAY WITH PERIODS OF RAIN AND WIND...BEFORE AN UPPER TROUGH FINALLY KICKS THE SYSTEM OFF TO THE NORTHEAST AHEAD OF A COLD FRONT WHICH WILL APPROACH AT THE END OF THE PERIOD. TEMPS SAT-MON WILL HOVER AROUND CLIMO...DEPENDING ON HOW THE LOW EVOLVES...BUT SHOULD WARM QUITE A BIT AHEAD OF THE COLD FRONT EARLY NEXT WEEK. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...HIGH PRESSURE CENTERED WELL OFFSHORE FROM CAPE HATTERAS WILL CONTINUE TO RIDGE BACK TO THE WEST ACROSS NC TODAY. GOOD DECK OF MAINLY OPAQUE CI/CS ACROSS ALL LOCATIONS WILL AFFECT THE FA THRUOUT THIS 06Z ISSUANCE PERIOD...AND LIKELY LIMIT MORNING MVFR CONDITIONS FROM BR. THE BEST THREAT FOR BR WILL BE ACROSS LBT/FLO TERMINALS. LATEST MSAS SHOWS A CLOSED SFC LOW JUST OFF MIAMI. LATEST MODELS INDICATE THIS SFC LOW TO FURTHER DEVELOP AND LIFT NORTHWARD LATER TODAY THROUGH TONIGHT. MODEL CONFIDENCE REMAINS LOW WITH ITS INTENSITY BUT SLIGHTLY BETTER IN ITS NORTHWARD MOVEMENT/POSITIONING. NEVERTHELESS...WILL INDICATE MID- HIGH LEVEL BKN/OVC CEILINGS BY LATE THIS AFTN THRU 06Z THU. AS FOR PCPN CHANCES...WILL GO WITH THE VCSH FOR THE MYR AND CRE COASTAL TERMINALS ONLY FOR SEVERAL HRS LEADING UP TO 06Z THU. EXTENDED OUTLOOK...LOW CONFIDENCE REMAINDER OF EXTENDED DUE TO UNCERTAINTY IN TRACK OF HYBRID LOW OFF THE SOUTHEAST U.S. COAST THU THRU THE UPCOMING WEEKEND. VFR TO MVFR BY THU...WITH MVFR/IFR FROM RAIN/CEILINGS AND INCREASING ONSHORE WINDS BY LATE THU...FRI INTO THE UPCOMING WEEKEND. BASICALLY LOOKING AT WORSE CONDITIONS ALONG THE IMMEDIATE COAST DURING THE EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST AT THIS TIME. ANY SE WINDS RESULTING FROM THIS AFTERNOON`S SEABREEZE CIRCULATION SHOULD BACK AROUND TO THE EAST WITHIN A FEW HOURS. CURRENT BUOY OBS OF 2-3 FEET SUPPORT THE CURRENT FORECAST. DISCUSSION FROM 300 PM FOLLOWS... NORTHEAST TO EAST FETCH WILL PERSIST THROUGH TONIGHT WITH HIGH PRESSURE CENTERED OFFSHORE AND LOWERING PRESSURE IN THE VICINITY OF THE BAHAMAS. SEAS WILL GRADUALLY BUILD AS A RESULT OF THE PRESSURE GRADIENT...WITH CHOPPY 3-4 FT CONDITIONS POSSIBLE BY EARLY WEDNESDAY. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...SMALL CRAFT ADVISORY HAS BEEN HOISTED BEGINNING TONIGHT...AND WILL PERSIST THROUGH AT LEAST 8PM FRIDAY NIGHT AS A LOW PRESSURE DEVELOPS AND STRENGTHENS OFFSHORE. THERE IS STILL CONSIDERABLE UNCERTAINTY EVEN IN THE SHORT TERM...BUT IT APPEARS A LOW PRESSURE SYSTEM DEVELOPING OFF THE FLORIDA COAST WILL MOVE NORTH AND THEN STALL NEAR THE LOCAL WATERS THU/FRI. AS IT MEANDERS IN THE VICINITY IT WILL CAUSE INCREASING WINDS FROM THE E/NE...POSSIBLY BECOMING NORTH LATE ACROSS THE SOUTHERN WATERS...ALL AT SPEEDS OF 15-20 KTS. THESE COULD BECOME HIGHER (OR LOWER) DEPENDING ON HOW THE LOW PRESSURE EVOLVES. REGARDLESS...MARINE CONDITIONS WILL BECOME POOR AS THESE INCREASED WINDS AND AN AMPLIFYING SWELL PUSH SEAS UP TO 4-8 FT THROUGH MOST OF THE PERIOD. SOME IMPROVEMENT IS CURRENTLY FORECAST LATE...BUT THIS MAY CHANGE ONCE THE TRACK OF THE LOW BECOMES MORE CLEAR...AND MARINERS SHOULD KEEP APPRISED OF THIS EVOLVING SITUATION. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...LOW PRESSURE WILL LIKELY STILL BE IMPACTING THE AREA THROUGH THE WKND...BUT HOPEFULLY IN A WEAKENED STATE. UNCERTAINTY REMAINS THROUGH THE EXTENDED...AND WHILE CONDITIONS ARE NOT CURRENTLY FORECAST TO BE HEADLINE CRITERIA...THEY WILL REMAIN HAZARDOUS WITH A VARIETY OF WIND DIRECTIONS AND SPEEDS POSSIBLE AS THE LOW CENTER MOVES...POSSIBLY DIRECTLY ACROSS THE COASTAL WATERS. ATTM EXPECT THE NC WATERS TO EXPERIENCE WORSE CONDITIONS THAN OFF THE SC COAST...BUT AGAIN...MUCH STILL MAY CHANGE. WINDS OF 15-20 KTS FROM THE EAST ARE LIKELY NORTH OF THE LOW...WITH WEAKER N/NW WINDS ON THE BACK SIDE OF THE SYSTEM. WAVE HEIGHTS WILL REMAIN IN THE 3-5 FT RANGE AS A HIGH AMPLITUDE SWELL PERSISTS EVEN AS WINDS BEGIN TO EASE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 8 PM EDT FRIDAY FOR AMZ250-252-254-256. && $$ SYNOPSIS...JDW NEAR TERM...DCH/TRA SHORT TERM...JDW LONG TERM...JDW AVIATION...DCH MARINE...DCH/TRA/JDW

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.