Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 012324 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 724 PM EDT TUE SEP 1 2015 .SYNOPSIS... LATE SUMMERTIME HEAT WILL RETURN WEDNESDAY THROUGH FRIDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHEAST THIS WEEKEND...BRINGING COOLER TEMPERATURES THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 730 PM TUESDAY...VERY FEW CHANGES ARE NEEDED TO THE FORECAST WITH THIS EARLY-EVENING UPDATE. THE SEABREEZE IS EASY TO PICK OUT ON RADAR IMAGERY ABOUT 40 MILES INLAND ACROSS SC...AND 20-40 MILES INLAND OVER NC. BIGGEST ISSUE TO WATCH TONIGHT IS HOW MUCH HIGH CLOUDINESS ADVECTS OVERHEAD FROM FLORIDA/SOUTH GEORGIA. DISCUSSION FROM 200 PM FOLLOWS... FAIRLY DECENT CU FIELD DEVELOPED OVER FORECAST AREA THIS AFTERNOON. THESE CLOUDS WILL DIMINISH AND CLUSTER MAINLY ALONG CONVERGENT BOUNDARY FROM SEA BREEZE THIS AFTERNOON. EXPECT A FAIRLY QUIET AFTERNOON WITH A GOOD DEAL OF SUNSHINE..AND TEMPS BACK UP RIGHT AROUND NORMAL...MID TO UPPER 80S. LACK OF MOISTURE IN THE LOW TO MID LEVELS AND DRIER DOWNSLOPE FLOW WILL KEEP MOST SHWR ACTIVITY AT BAY BUT CANNOT COMPLETELY RULE OUT ISOLATED SHWR IN LOCALIZED CONVERGENCE ALONG SEA BREEZE BOUNDARY OVER GEORGETOWN. A RIDGE EXTENDS UP THE SOUTHEAST COAST IN THE MID TO UPPER LEVELS WITH W-SW FLOW AS EVIDENT BY THE WATER VAPOR IMAGERY. THE DEEP PLUME OF TROPICAL MOISTURE EXTENDS FROM NORTHERN GA NORTHEAST INTO ATLANTIC AND WILL PUSH SLIGHTLY NORTH WHILE REMAINING SOUTH OF FORECAST AREA. AT THE SURFACE A WEAK TROUGH EXTENDS FROM AREA OF LOW PRESSURE WELL OFF THE HATTERAS COAST. THIS REMAINED THE FOCAL POINT FOR DEEPER CONVECTION THIS AFTERNOON TO THE SOUTH OF AREA AND THE CONVECTIVE DEBRIS CLOUDS WILL STREAM MAINLY EAST TO SLIGHTLY NORTHEAST REACHING INTO COASTAL SOUTH CAROLINA IN UPPER LEVEL S-SW WINDS. BASICALLY WEAK HIGH PRESSURE WILL HOLD OVER THE CAROLINAS THROUGH TONIGHT WITH MAINLY DRY FORECAST. DEWPOINTS HOLDING UP AROUND 70 WITH SHALLOW MOISTURE IN PLACE TONIGHT. OVERALL DO NOT EXPECT FOG BUT IF ANY SHWRS DEVELOP OR IN PLACES WITH SOME LINGERING MOISTURE...MAY SEE SOME SHALLOW FOG. EXPECT LOWS IN THE LOWER TO MID 70S...A BIT ABOVE NORMAL. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...HIGH PRESSURE ALOFT WILL REMAIN SOUTH OF THE AREA. A SERIES OF WEAK MID-LEVEL DISTURBANCES WILL TRACK NE OUT OF THE GULF OF MEXICO AND THEN ACROSS THE DEEP SOUTH... REMAINING TO OUR SOUTH. AS A NW FLOW ALOFT ESTABLISHES ITSELF ACROSS THE CAROLINAS...AN EMBEDDED MID-LEVEL SHORTWAVE WILL APPROACH THE EASTERN CAROLINAS LATE WED NIGHT AND THU. THE PIEDMONT TROUGH AND SEABREEZE BOUNDARY WILL BECOME IDENTIFIABLE WITH STRONG HEATING WED AFTERNOON AND THU AFTERNOON. MOISTURE IS NOT ALL THAT IMPRESSIVE WED...BUT THERE IS AN UPTICK IN PRECIPITABLE WATER VALUES AND IN DEPTH OF MOISTURE LATE WED NIGHT AND DURING THU. AT THIS TIME...FEEL THE HIGHEST RISK FOR SHOWERS AND THUNDERSTORMS WILL BE ON THU. WILL CARRY UP TO 30 POPS...ALTHOUGH LATER FORECASTS MAY SEE THE NEED TO RAISE THESE VALUES. LATE SUMMERTIME HEAT WILL BE WITH US DESPITE THE FACT THAT METEOROLOGICAL SUMMER ENDED WITH THE FIRST OF SEPTEMBER. HIGHS BOTH AFTERNOONS WILL BE IN THE LOWER TO MID 90S. SEABREEZE INFLUENCES SHOULD BE STRONG ENOUGH TO KEEP THE BEACHES AND NEARBY LOCATIONS IN THE UPPER 80S. THE DRIER AIR AND DEVELOPING LAND BREEZE WARRANT MAINLY LOWS IN THE LOWER 70S. HOWEVER...A FEW OF THE COOLEST INLAND SPOTS SHOULD DROP JUST BELOW 70 WHILE THE BEACHES BOTTOM OUT MAINLY IN THE MID 70S. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 300 PM TUESDAY...CHALLENGING FORECAST IN THE EXTENDED AS THE REMNANT VORTICITY FROM LAST WEEKS TROPICAL STORM ERIKA MEANDERS ACROSS THE SOUTHEAST. THIS VORTICITY IS MOST EASILY NOTED IN 850MB PLAN-VIEW FORECASTS...AND ALTHOUGH THE EXTENDED MODELS DIFFER WITH THEIR EVOLUTION...IT IS EXPECTED THAT THIS VORTICITY LOBE WILL MEANDER AND SLOWLY WEAKEN THROUGH EARLY NEXT WEEK. AS ERIKA`S REMNANTS MOVE SLOWLY TOWARDS THE GEORGIA COAST...THEY WILL COMBINE WITH WEAK 500MB SHORTWAVES TO CREATE TROUGHING ALONG THE SOUTHEAST COAST. IT IS EXPECTED THAT THE WAVE OF LOW PRESSURE ASSOCIATED WITH THIS ENERGY WILL TRAVERSE ALONG THIS BOUNDARY OFFSHORE. HOWEVER...AS IT TRIES TO LIFT NORTHEAST IT WILL BE IMPEDED BY SURFACE RIDGING BEHIND A BACK DOOR TYPE COLD FRONT PROGGED TO DROP SOUTH ON SATURDAY. LIFT ATOP THIS RIDGE WILL CREATE A GOOD CHANCE FOR SHOWERS WITH ISOLATED TSTMS...ESPECIALLY SATURDAY...WITH LESSER CHANCES FRIDAY AND SUNDAY. THE GFS KEEPS US VERY WET SAT-MON...BUT HAS BEEN OVERDONE RECENTLY...AND WILL SIDE WITH THE DRIER ECMWF WHILE MAINTAINING LOW CHC/SCHC POP FOR CONSISTENCY. A BETTER CHANCE FOR SHOWERS AND TSTMS MAY REDEVELOP MONDAY AS THE RIDGE TRIES TO BREAKDOWN ALLOWING FOR RESIDUAL MOISTURE FROM ERIKA TO LIFT FURTHER NORTHEAST...BEFORE DRYING DEVELOPS ON TUESDAY. TEMPS FRIDAY WILL BE NEAR CLIMO BEFORE DROPPING TO BELOW NORMAL SAT- SUN-MON BEHIND THE BACK DOOR FRONT...ALTHOUGH MINS WILL BE AROUND NORMAL. A RETURN TO SEASONABLE TEMPS IS EXPECTED TUESDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 00Z...POTENTIAL FOR AREAS OF FOG TO CREATE MVFR LATE OVERNIGHT INTO THE EARLY MORNING HOURS. OTHERWISE EXPECT VFR AS HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA. VFR PREVAILS THIS EVENING AS RADAR REMAINS QUIET AND SOUTHEAST WINDS CONTINUE AROUND 8 KTS OR LESS AND LINGERING FEW/SCT MID TO HIGH CLOUDS. GIVEN NEARLY CLEAR SKIES...LIGHT WINDS...AND A BIT OF MOISTURE RETURN PER LATEST GUIDANCE...WOULD NOT ENTIRELY RULE OUT AREAS OF FOG LATE OVERNIGHT INTO THE EARLY MORNING HOURS. SOME GUIDANCE IS INTRODUCING IFR...BUT GIVEN LOWER CONFIDENCE ATTM...HAVE KEPT WITH TEMPO MVFR. ON WEDNESDAY...EXPECT VFR WITH LIGHT WINDS IN THE MORNING BECOMING SOUTHERLY IN THE AFTERNOON AOB 10 KTS. WOULD NOT ENTIRELY RULE OUT AN ISOLATED AFTERNOON SHRA. EXTENDED OUTLOOK...PREDOMINATELY VFR WITH BRIEF MORNING FOG AND ISOLATED/SCATTERED AFTERNOON CONVECTION. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 730 PM TUESDAY...SEABREEZE WINDS ARE FIRMLY FROM THE SOUTH. THESE DIRECTIONS SHOULD VEER AROUND TO THE WEST BY MIDNIGHT WITH SPEEDS REMAINING 10 KNOTS OR LESS. NO SIGNIFICANT CHANGES ARE NEEDED TO THE FORECAST. DISCUSSION FROM 200 PM FOLLOWS... WEAK PRESSURE PATTERN OVER THE WATERS WITH TROUGH LINGERING IN THE OFF SHORE WATERS TO THE EAST. OVERALL EXPECT A WEAK MAINLY OFF SHORE FLOW WITH ON SHORE SEA BREEZE THIS AFTERNOON FADING OUT BY THIS EVENING. WINDS WILL BE RIGHT AROUND 10 KT OR LESS THROUGH TONIGHT SEAS WILL BE ON A DOWNWARD TREND BUT GENERALLY LESS THAN 3 FT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM TUESDAY...THE PRESSURE GRADIENT WILL REMAIN VERY RELAXED. THE SEABREEZE AND PIEDMONT TROUGH WILL COMBINE TO PRODUCE THE HIGHEST WINDS DURING THE LATER AFTERNOON AND EARLY EVE HOURS...UP TO AROUND 10 KT. THE WIND DIRECTION WILL BE S AND SSW WHILE THE WINDS ARE STRONGEST. A LATE NIGHT LAND BREEZE WILL SHIFT WINDS TO A MORE OFFSHORE DIRECTION DURING THE MORNING. SEAS WILL BE AROUND 2 FT WITH A WEAK SOUTHEAST GROUND SWELL PRESENT. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 300 PM TUESDAY...A TROUGH OF LOW PRESSURE WILL DEVELOP OFFSHORE ALONG THE COAST WHILE A RIDGE OF HIGH PRESSURE PUSHES DOWN FROM THE NE. THIS WILL CREATE E-TO-NE WINDS THROUGH THE PERIOD...INCREASING ON SATURDAY AS A NE SURGE FOLLOWS THE STRENGTHENING OF THE HIGH PRESSURE RIDGE. WIND SPEEDS FRIDAY WILL BE LESS THAN 10 KT...RISING TO 15 KT MUCH OF SATURDAY BEFORE EASING SLIGHTLY ON SUNDAY. ALTHOUGH A WEAK SE GROUND SWELL WILL REMAIN IN THE SPECTRUM...SEAS WILL BECOME INCREASINGLY WIND- WAVE DOMINATED WITH A NE 5 SEC CHOP GROWING IN AMPLITUDE SATURDAY AND SUNDAY. SIGNIFICANT SEAS WILL BE 1-2 FT FRIDAY...BUILDING TO 3-4 FT SATURDAY INTO SUNDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...RJD LONG TERM...JDW AVIATION...SGL

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