Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 301155 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 755 AM EDT TUE AUG 30 2016 .SYNOPSIS... Tropical Depression Eight is expected to make its closest approach to land tonight near the Outer Banks and may become a weak tropical storm. A cold front will move across the area late Thursday night and Friday. At the same time, another tropical cyclone is forecast to move across northern Florida and then accelerate to the northeast ahead of the front. At this time it is unclear as to how close to the coast the tropical cyclone will track. A more offshore trajectory will keep the impacts minimal across the coastal Carolinas. The unsettled weather should end with the arrival of much cooler and drier Canadian high pressure for the holiday weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 700 AM Tuesday...Significant swell from Gaston will peak today and a High Risk of Rip Currents remains in effect for all beaches into this eve. Showers and some thunderstorms were occurring offshore this morning. Tropical Depression Eight still looks weak and disorganized from a satellite perspective this morning. The depression was creeping to the NW but is expected to gradually turn to the N today as it follows a weakness in the subtropical ridge, making its closest approach to land near the Outer Banks tonight. Thereafter, it will get picked up by the developing east coast trough and accelerate to the NE on Wed. A mid-level area of low pressure was still evident in the vicinity of SAV. This feature is not expected to move much during the period. Still looks like even deeper moisture lurking offshore will get drawn inland around this feature and ahead of TD Eight with a general troughiness aligned along the coast. It is a little perplexing that the high resolution HRRR is not showing much of any shower activity across the FA today. Given the deep onshore flow and high moisture content of the air, do not see why POP gradient and magnitude should be that much different from Mon. Through tonight, will carry mainly good chance along the coast, trailing back to slight chance west of Interstate 95. We under-forecast the high temps on Mon and so tried to correct for that this go around with highs near 90 or in the lower 90s with upper 80s at the beaches. Lows tonight will be in the lower to mid 70s. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 300 AM Tuesday...It does not appear any significant subsidence will occur in the wake of Tropical Depression Eight. A general troughiness will remain with perhaps some shortwave energy pivoting around the weakening upper low along the GA/SC coast. A cold front will approach from the NW Thu night and should move into if not through the area before stalling late Thu night and Fri morning. At the same time, a tropical cyclone is expecting to be on a NE heading as it moves off the east coast of FL. Still too early to know how strong this tropical system will be and how close it will pass as it accelerates to the NE ahead of the front. At this time, its main impacts should be across the waters, but we will continue to closely monitor. At any rate, the risk for at least scattered showers and thunderstorms will remain on Wed throughout and then again Thu and Thu night ahead of the approaching front. Temps will be slightly above normal. Despite the showers and associated cloud cover, highs will be within a deg or two of 90 both days and lows will be in the lower to mid 70s. The beaches will be mainly in the mid and upper 80s. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 300 AM Tuesday...A cold front will continue to drop south while a tropical system moves northeast parallel to the Carolina coast Friday. NHC is currently forecasting TD #9 to lift out of the Gulf and ride by within a couple of hundred miles off the southeast coast as a tropical storm. The forecast winds will be determined by the exact strength and track of this system but at this time expect strongest winds should brush our outer coastal waters on Friday. Should see increased shwr/tstm activity as front moves through, but looks like drier and cooler air will be making its way south into area behind front and associated with subsidence on the back end of the tropical storm. GFS continues to show pcp water values up near 2 inches Fri morning, but dropping off to 1.25 inches by Fri eve and down below an inch most places by Sat morning. Deep mid to upper trough will move slowly southeast through the weekend and although there should be subsidence and dry air on the back end of tropical system, dynamics aloft may keep some clouds and possible pcp mainly over coastal waters over the weekend. Otherwise should see high pressure build in at the surface with cooler and drier northerly flow bringing temps down below normal into early next week. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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AS OF 12Z...VFR at all terminals with N-NE winds and showers and thunderstorms offshore. Through the morning hours a TEMPO MVFR cig could occur, best confidence at the coastal terminals, otherwise terminals will remain VFR the remainder of the TAF valid period. Convection will remain offshore, but by mid-late morning will begin to develop over land areas, especially along the immediate coast. This should be mostly in the form of showers, although cannot rule out an isolated thunderstorm. Convection will possibly linger into the late evening and early overnight hours at the coastal terminals. EXTENDED OUTLOOK...Chance of TEMPO MVFR/showers Wed and Fri. VFR Thus and Sat.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 700 AM Tuesday...Tropical Depression Eight was still hanging on and on a NW to N course will make its closest approach to land near the Outer Banks tonight, perhaps as a weak tropical storm. For this reason, Tropical Storm Warnings have been posted for portions of the Outer Banks. We have issued a Small Craft Should Exercise Caution headline through today for the waters from Cape Fear to Surf City for 4 to 5 ft seas. Otherwise seas will be 3 to 4 ft. These higher seas are due to swell energy moving across our waters from distant hurricane Gaston. The easterly swell will have periods of 12 to 14 seconds. NE winds will range from 10 to 15 kt, but up to 15 to 20 kt for the northernmost waters today. NE to ENE winds near 10 kt are expected tonight. Seas tonight will be mainly 3 to 4 ft. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 300 AM Tuesday...The swell from Gaston will be weakening across the area. However, we will be closely monitoring a tropical cyclone which will be accelerating to the NE from FL ahead of a cold front. The cold front will reach our waters Fri morning. It is still too early to forecast the impacts across the Carolina waters from this tropical system. Mariners should prepare for building seas and increasing NE winds, from S to N, as early as the early morning hours of Fri. LONG TERM /FRIDAY THROUGH SATURDAY/... As of 300 AM Tuesday...Tropical Depression 9 should lift north and track up within a couple of hundred miles of the Carolina coast on Friday as a cold front drops south. This tropical system may reach tropical storm force in outer waters on Friday especially out toward Frying Pan Shoals. Will need to keep a close watch on track and intensity of this tropical system. Overall expect northerly winds to increase on back end of system through Friday with tropical storm conditions possible through Friday possibly into early Saturday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...High Rip Current Risk through this evening for SCZ054-056. NC...High Rip Current Risk through this evening for NCZ106-108-110. MARINE...None. && $$ NEAR TERM...RJD SHORT TERM...RJD LONG TERM...RGZ AVIATION...MRR is the U.S. government's official web portal to all federal, state and local government web resources and services.