Area Forecast Discussion
Issued by NWS Wilmington, NC

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189 FXUS62 KILM 251055 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 655 AM EDT Wed Sep 25 2024 .SYNOPSIS... High pressure to prevail through today with generally low rain chances. More unsettled weather is expected later Thursday through Friday as Tropical Cyclone Helene passes west of the forecast area. Nevertheless, look for possible impacts such as heavy rain, gusty winds, coastal flooding and isolated tornadoes. Cooler and drier high pressure should then return later in the weekend into early next week. && .UPDATE...
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Coastal Flood Advisory have been issued for this afternoon`s high tide. Minimal changes to the forecast. Routine Aviation discussion updated.
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&& .NEAR TERM /THROUGH TONIGHT/... Ridging to the east and an upper low to the west will maintain warm advective flow across the area today. Dry air aloft will maintain mostly clear skies and will also inhibit meaningful destabilization. Shallow showers will be possible, mainly inland, this afternoon. Have held PoPs around 20%. SE winds increase slightly overnight and temperatures remain mild. Lows in the lower 70s near the coast, around 70 inland. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Main story for this period will be the effects from Tropical Cyclone Helene as its circulation expands/grows prior to making landfall across the Florida Pan Handle Thu evening. Look for conditions to deteriorate during the day Thu from south to north as a swath of moisture, ie. rainband, moves up the coast and pivots inland. The worst of the conditions, wind, heavy rain, threat for tornadoes to occur late Thu afternoon thru Fri morning. As mentioned AFDs prior, PWs upwards of 2.25+ inches, and therefore when all said and done, widespread 1 to 2 inches of rainfall possible, locally higher amounts possible especially across the ILM SC CWA. Fri aftn thru Fri night, should see improving weather conditions && .LONG TERM /SATURDAY THROUGH TUESDAY/... Helene, or the remnants of, will get caught up in an upper cutoff low across the Mid Mississippi River Valley by Sat. Dry air rotating around the upper low, will push across the area Sat. Will be a warm day, with some clouds but only isolated convection possible with widespread mid to upper 80s and a few 90 degree readings possible. The sfc pg will relax quite a bit by Sat, with generally light SW winds expected. Models indicate the upper low to fill as it drops toward the ESE, reaching the FA by early next week. More clouds and scattered showers and possibly an isolated tstorm, expected both Mon and Tue, and mainly diurnally driven each day with the aid of the colder temps aloft. Should see temps drop at or just below normal the 2 days next week. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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Fog and stratus inland will continue for the next hour or so. Warm advective flow should allow this to dissipate quickly. Onshore flow near the coast may produce MVFR CIGs. VFR thereafter with an isolated shower possible. Kept chances low enough to prevent a FM or PROB group. Showers will be brief and unlikely to cause significant disruptions even if a shower hits the terminal. Extended Outlook... VFR conditions expected outside of predawn fog and stratus. Helene will likely pass west of the area Thursday night through Friday bringing a high chance for restrictions and gusty winds.
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&& .MARINE... Through Tonight...Southerly flow today will increase this evening as a surface low (what will become Hurricane Helene) deepens over the Gulf of Mexico. Winds around 10-15 knots this afternoon will increase to 15-20 knots tonight. Seas gradually build today from 2-3 feet to 3-4 feet. Widespread seas of 3-5 feet could develop before daybreak on Thursday. Thursday through Sunday Night...SCA thresholds to be met by noon or during the early afternoon. SE winds to increase thruout the day driven by Tropical Cyclone Helene`s increased circulation especially the wind radii on the eastern semi-circle. Thu will see the modest 11+ second period ENE Swell interact with the building SE wind driven short period waves. Will observe 6 footers commonplace by or during Thu afternoon. Gale Force gusts threat to primarily occur from Thursday evening thru midday Fri. Seas will peak in the double digit low teens during the mentioned period. Showers, storms with heavy rain and the threat for waterspouts can be expected from midday Thu through early Friday as the main swath(band) of moisture moves from south to north, up the Carolina coasts. Winds and seas should start to subside late Fri into Sat as winds go nearly offshore, with sub-SCA conditions returning for the latter 1/2 of the weekend. && .TIDES/COASTAL FLOODING... Minor coastal flooding remains a threat for the next several days, especially in NC. Minor flooding along the Lower Cape Fear River will impact both sides of the river during the afternoon high tides through Thursday. However, Helene is forecast to be a large storm and onshore winds could produce additional coastal flooding for each successive high tide starting on Thursday afternoon as it moves northward from the Gulf of Mexico through the southeastern US. Normal water levels should return this weekend. && .ILM WATCHES/WARNINGS/ADVISORIES...
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NC...Coastal Flood Advisory from 1 PM to 4 PM EDT this afternoon for NCZ106-108-110. Coastal Flood Advisory from 2 PM this afternoon to 8 PM EDT this evening for NCZ107. SC...None. MARINE...Small Craft Advisory from noon Thursday to noon EDT Saturday for AMZ250-252-254-256.
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&& $$ SYNOPSIS...ILM UPDATE...21 NEAR TERM...21 SHORT TERM...DCH LONG TERM...DCH AVIATION...21 MARINE...DCH/21 TIDES/COASTAL FLOODING...ILM