Area Forecast Discussion
Issued by NWS Wilmington, NC

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648 FXUS62 KILM 290553 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 153 AM EDT MON AUG 29 2016 .SYNOPSIS... A tropical airmass will affect the Carolinas for much of this week. In addition, the tropics have heated up with Tropical Depressions 8 and 9, and also Hurricane Gaston. While we don`t have to worry about a direct influence from Gaston, the swell it generates will affect the area coastline late tonight thru mid- week, elevating the rip current threat. For depressions 8 and 9, it will be a waiting game of whether these 2 depressions survive the next 24 to 48 hrs. By the end of this week, a strong cold front is expected to push across the Carolinas to well offshore. Strong high pressure will follow, finally drying things out. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 1030 PM Sunday...No changes to the earlier forecast update. As of 800 PM Sunday...The near term models, HiRes WRF and the RAP and to a lesser degree the HRRR, all illustrate the demise of convection over inland areas, ie. 1 county in from the coast and continuing further inland, during this evening. Thus POPs will be lowered to isolated chance for the night inland. However, pcpn activity is progged by the near term models to further develop over the adjacent Atlantic waters during this evening and pre-dawn Mon hours. Occasionally will see this pcpn take a trajectory that moves it onshore and inland. POPs to 40 to 50 percent will be painted along the coastal counties and local Atl waters. Temps and dewpoints were tweaked generally upwards by 1 to 3 degrees...especially across the coastal counties where onshore winds having moved across low to mid 80s SSTS. PWs have increased to 2+ inches across the entire ILM CWA, this due to onshore winds thruout the atm column bringing in that moistened tropical Atlantic airmass. Will need to monitor pcpn intensity and amounts that could possibly result in changing the Z/R relationship to tropical mode with regards to the KLTX 88D output. Moderate risk of rip currents across all beaches Monday. May need to upgrade that to High depending on how much Gaston Swell energy makes it to the local surf. TD #8 progged to remain far enough NE of the ILM CWA with no direct influence during its progged movements. With long period Gaston Swell affecting the area beaches late tonight and subsequent periods. Any waves from TD #8 will mesh within Gaston Swell along with the locally produced NE to ene wind waves. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...Tropical Depression Eight is projected to move WNW towards the Outer Banks of NC on Monday while strengthening to tropical storm status, making its closest approach to land on Tuesday morning before recurving back to the NE on Tuesday afternoon. Based on the projected track and development of this system, impacts over land for our forecast area are expected to be minimal with no watches, warnings or advisories expected. However, there may be a heightened rip current risk along the coast. A moist airmass and diurnal heating will encourage scattered convection on both days, with highest chances along the coast. Dry air inland will keep POPs and QPF in check for our northwestern-most counties. Temperatures will be within a few degrees of seasonal norms through the period. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 300 PM Sunday...A weak mid level pattern initially will give way to mid level troughing by the weekend. This trough will allow a cold front to move across late Thursday and take up residence to our south. The latest guidance has shifted the front a little more southward as well as the very dry mid level air. Not enough of a change to warrant any changes to the forecast for the weekend which include good chance pops across the south decreasing as you move north. Wildcard remains what happens to AL99. There is at least some hint of consensus (all of a couple of medium range cycles) that the system forms in the Gulf of Mexico and moves along the southeast coast possibly affecting our area Sunday and Monday. Seems the best option is to maintain slight chance pops which are basically climatology and wait it out. Warm temperatures Wednesday and Thursday cooling slightly behind the front but lows in the 60s may be difficult citing the lingering moisture. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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As of 06Z...Shwrs/tstms will continue to develop offshore and move towards the coast tonight in a warm and moist tropical air mass. Have included vcsh as shwrs expected to break up before reaching coastal TAF sites. Also continue with stratus all terminals and fog inland TAFS only. Similar pattern will continue with coastal shwrs/tstms overnight moving on shore over morning hours and other storms developing and moving inland through the day in NE to E winds around 10 kts. Some LIFR conditions this morning will be followed by mainly MVFR/VFR cigs and scattered showers and isolated thunderstorms this afternoon. EXTENDED OUTLOOK...Increasing chance of TEMPO sub VFR each day as tropical moisture/shower potential increases through Tuesday. VFR Wed/Thu. Shower potential increases again beginning Friday.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1030 PM Sunday...Status quo across the local waters. No changes needed to the previous update. Previous...................................................... As of 800 PM Sunday...Based on latest obs from buoys across the coastal and offshore waters, as well as local sites along the immediate coast (OMR), have decided to increase the NE winds overnight into subsequent periods. This a reflection of an increased sfc pg due to ridging across the Carolinas from the high over the NE States and the circulation associated with TD #8. Basically, looking at NE 10 to 15 kt or just a solid 15 kt. Significant seas will finally be influenced by the long period, 13 to 15 seconds, Gaston swell beginning late this evening or during the pre-dawn Mon hours. At this time, the leading edge of the dominant 13-15 second period Gaston swell extends from buoy 41025 to west of 41002. Local buoys, relatively speaking, 41108 and 41159 do indicate the 13-15 second period swell but its height is too small for it to be the dominate wave like whats now occurring at buoy 41025. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...Tropical Depression Eight is projected to move WNW towards the Outer Banks of NC on Monday while strengthening to tropical storm status, making its closest approach to land on Tuesday morning before recurving back to the NE on Tuesday afternoon. Based on the projected track and development of this system, impacts over the coastal waters are expected to be minimal with no advisories expected. Winds will generally remain in the 10 to 15 kt range through the period, backing from the NE on Monday to N on Tuesday. Seas north of Cape Fear in closest vicinity to the storm may peak at 3 to 5 ft Monday night and early Tuesday before subsiding back to around 3 ft on Tuesday night. Seas further south of Cape Fear will be lower. LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 300 PM Sunday...A very weak pressure pattern will prevail Wednesday into early Thursday leaving the sea breeze as the main driver of winds. With warmer overnight lows the land breeze shouldn`t be a factor. By Thursday afternoon a better defined southwest flow ahead of a decent front develops. Speeds here should be 10-15 knots. Northeast winds will develop Friday and pick up a little on the intensity. Overall seas will be 2-4 feet. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...DCH SHORT TERM...REK LONG TERM...SHK AVIATION...RGZ MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.