Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 210847 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 447 AM EDT THU JUL 21 2016 .SYNOPSIS... Today will be seasonable and rain-free behind a weak cold front. Temperatures will surge back above normal for the weekend, with the possibility of showers and thunderstorms increasing early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Thursday...Dry air in the mid and upper levels under northerly flow will affect the area this period. Subsidence aloft, along with its inversion, will place a lid on convection across the ILM CWA this period. A weak mid-level s/w trof will remain west of the ilm cwa as it drops southward later today into this evening. Convection associated with it may affect the far western portions of the ILM CWA and as a result indicated low chance pops. In addition, enough forcing along the sea breeze may produce a few isolated thunderstorms along the sea breeze. The GFS keeps aftn/evening instability on the low side 1800 CAPE or less whereas the NAM paints 3000-4000 CAPE. Given what occurred Wed, will stay closer to the GFS soundings. Overall, plenty of sunshine with diurnally driven cu and a mostly clear night. For temps, stayed closer to the GFS Mos guidance. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 345 AM Thursday...NO POPS being fcst in this 2 day period. Increasing heat combined with the humidity, will result in heat indices shy of Advisory criteria on Friday but should break through thresholds and become widespread on Saturday. High pressure aloft will bake the Central U.S. this period. One of its ridge axis`s will extend just north of the area during this weekend. With dry and warming air in the mid levels, along with primarily subsidence aloft, the ILM CWA will see a decent convective lid across the region thruout this period. Clouds will be limited to diurnally driven cu/sc this period...enhanced by the sea breeze. In all, no POPs. Widespread 90s for both days, with sfc dewpoints slowly increasing and becoming widespread 70s by Saturday. Mixing from aloft may bring down some 60 degree dewpoints inland on Fri but likely not the case for Sat. Will indicate Heat Advisory conditions for Sat in the HWO. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 3 AM Thursday...500mb ridge right overhead Sunday and Monday and this should keep hot temperatures and little to no precipitation chances in the forecast. Guidance is showing some areas hotter Sunday vs Monday while other guidance reverses this trend. In the end unless the sea breeze dictates otherwise along the coast both days appear quite similar and both likely candidates for Heat Advisories. The ridge may be more stalwart than previously though especially according to the 00Z GFS which now shows little to no retrogression and thus a similar hot and humid forecast. We may now have to wait until Wednesday for just enough retrogression of the ridge from some vorticity centers to stream across the area in the resulting NW flow. This could temper the heat and also lead to better chances of thunderstorm, maybe strong to severe ones. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... As of 06Z...Sky has cleared and wind has gone light and variable as anticipated. This will allow inland sites to radiate to where some fog and perhaps stratus will develop. At any coastal location fog should remain MVFR at worst. Inland locales may dip down to IFR or even brief LIFR (mainly if a low CIG develops). By daybreak all terminals back to VFR. Winds will be N-NE veering to the E-S as the day progresses. A few showers possible near KFLO in the afternoon. EXTENDED OUTLOOK...Brief periods of MVFR/IFR from isolated afternoon convection through Saturday. Otherwise expect VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 330 AM Thursday...The stalled front across or just south of the area waters will provide a n thru e wind directions across the local waters today into tonight. Winds near shore will become southeast due to the sea breeze this aftn/evening. The stalled front will slowly dissipate tonight and Fri with winds tonight becoming ne thru se. The sfc pg will remain towards the relaxed side, yielding wind speeds at 10 kt or less. Significant seas will run 2 to 3 ft. Other than the local wind chop, seas will primarily be driven by an ese 1 to 2 foot ground swell at 8 to 9 second periods. Could see an isolated sea breeze induced tstorm this aftn or early evening. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 400 AM Thursday...High pressure will build across the waters from the High`s center offshore from the SE States during this period. Inland, the Piedmont trof will become a mainstay during this period. The 2 features will combine and affect the area waters with winds becoming SW thruout on Fri and continuing thru Saturday. The mesoscale sea breeze will result in S to SSW winds nearshore each aftn and evening and provide the increased wind chop. The sfc pg will be somewhat relaxed Fri with wind speeds generally around 10 kt. The sfc pg tightens Sat thru Sat night with wind speeds at 10 to 15 kt with gusts up to 20 kt possible Sat Aftn thru Sat Night. Significant seas will run 2 to occasionally 3 ft on Fri with the 1 to 2 foot ese-se ground swell dominating. For Sat, increasing SW winds will build the local wind chop and when added to the 1 to 2 foot ground swell, significant seas will run 2 to 4 ft. No convection being forecast this period. LONG TERM /SUNDAY THROUGH MONDAY/... As of 3 AM Thursday...A very unsettled set of changing conditions. This is not only fairly typical during the heart of summer but it becomes even moreso during a heatwave. Winds will be 10-15kt and southwesterly with a piedmont trough in place while the Bermuda high is displaced eastward of its normal position. Seas will average 2 to 3 and occasionally 4 ft. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MBB NEAR TERM...DCH SHORT TERM...DCH LONG TERM...MBB AVIATION...MBB

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