Area Forecast Discussion
Issued by NWS Wilmington, NC

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401 FXUS62 KILM 111518 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1018 AM EST Mon Dec 11 2017 .SYNOPSIS... The week looks dry although there is some risk for rainfall on Friday. Sunshine will bring a modest temperature rise and we will be close to normal by Tuesday. A strong cold front will move across the area late Tuesday with Arctic air returning Tuesday night through Wednesday night. Temperatures will moderate late week. A cold front may bring a brief cool down to start the weekend followed by a return to seasonable temperatures Sunday. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Monday...WV imagery this morning shows very dry air across the Southeast while a strong shortwave is digging into the western Great Lakes. At the surface, high pressure is settling across the Gulf Coast and extending into the Carolinas ahead of a low pressure system beneath the aforementioned shortwave. The high pressure extending into the Carolinas combined with the dry air aloft is producing a day of full sunshine with temps warming to near climo for the first time in 5 days. The weak gradient will keep winds light today as well, with direction gradually becoming SW as WAA develops. Highs today will reach to around 55 most places beneath full sunshine, and it will feel quite pleasant outside today. The strong shortwave will begin to approach tonight but should remain displaced far enough to the NW that there will be barely even be an increase in cloud cover until Tuesday. Continued WAA ahead of this front will keep mins much warmer tonight, dropping only to around 40 at the coast, mid 30s well inland. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 300 AM Monday...A digging upper trough will pivot across the Southeast states, moving across the eastern Carolinas late Tue and Tue eve. This will drive a strong cold front across the Forecast Area. Arctic air will plunge across the region in the wake of this front, bringing a brief return to the deep freeze. It still looks like the airmass will be too dry to support precipitation, but we should see a period of partly cloudy skies as the front moves through with clearing overnight Tue. It will be breezy on Tue with high temps likely just about the warmest of the week, reaching the upper 50s in most locations with a few 60 degree readings possible. 850 mb temps will drop to -9C to -13C by daybreak Wed. As dewpoints crash into the teens late Tue night, lows will drop to the mid and upper 20s by daybreak Wed and to date, we have not been colder than that this season. Strong cold and dry advection will keep winds elevated Tue night, bringing wind chill values as low as 15 to 20 degrees. The coldest day of the week will be on Wed when forecast highs are not expected to exceed the lower to mid 40s. Despite full sunshine, NW winds will make it feel as if it were at or below freezing for a good part of the day. The forecast for Wed night may need some refinement over the next day or so. At this time, it looks like a weak disturbance will race across the Mississippi and Tennessee Valleys in deep WNW flow and then move across the Carolinas late Wed night. Moisture profiles are showing a period of mid clouds associated with this feature. Should these clouds indeed arrive, they will help to disrupt radiational cooling processes, preventing temps from reaching their lowest potential. In the end, temps Wed night may end up near to just above the lows of the previous night with perhaps some upward pressure on readings toward Thu morning. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 300 PM Sunday...The extended will feature primarily a continuation of below normal temperatures as anomalous ridge across the western CONUS drives deep troughing over the eastern half of the country. This trough will be re-enforced Friday, and again late Sunday, as potent shortwaves dig through the longwave trough and cause a surge of cold air to envelop the Carolinas. Each of these shortwaves will be accompanied by a cold front, but for the most part these will be dry. However, the weekend front could be preceded by enough moist advection that showers will be possible. The ECM is much different from the GFS/CMC and does not produce a shortwave or cold front for Sunday. Despite the pattern being amplified, mid-level flow remains fast, so it seems likely another shortwave cold front would be in the vicinity by the end of the period and will lean the forecast in that direction, but much uncertainty exists by D7. Weak warm advection Thursday and Friday will bring a recovery in temperatures with a cool down on Saturday in the wake of a cold front. Temperatures by Sunday should be just about normal. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... As of 12Z...VFR through 12/12Z. W winds around 6 kt this morning will become S-SW this afternoon. Overnight under clear skies SW winds will increase to 6-10 kts as the pressure gradient increases ahead of the next front. Added LLWS by 08Z as soundings suggest WSW winds increasing to 35-40 kts @ 1500-2000 feet. Extended Outlook...VFR developing Sat evening and persisting through Wed. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Monday...High pressure extending towards the waters from the Gulf Coast will keep winds light through today while slowly backing from W/NW this morning to SW this aftn/eve. A cold front approaching from the NW will remain well displaced from the waters until Tuesday, but increasing winds within the pre-frontal warm sector will drive speeds up to 15-20 kts this evening, then 20-25 kts late, still from the SW direction. An SCA is in effect beginning 7am Tuesday for these winds, and for seas being pushed up to 4-6 ft on Tuesday, after climbing slowly from 2-3 ft this morning to 3-5 ft tonight. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 300 AM Monday...A Small Craft Advisory has been issued beginning Tue. The worst of the marine conditions should occur Tue night with a gradual improvement in conditions during Wed. A strong cold front will sweep across the waters Tue eve, driving cold and dry air into the area as WSW winds Tue shift to the NW Tue night. These NW winds will continue into Wed morning before backing to WNW Wed afternoon and then to W and WSW Wed night. Wind speeds will be 20 to 25 kt Tue and Tue night with the strongest winds expected Tue night when gusts may reach 30 kt. As the surge wanes, the strongest winds should be decreasing Wed morning and wind speeds are expected to decrease to 15 to 20 kt during Wed and to 10 to 15 kt Wed night. Seas will peak in the 4 to 6 ft range through the first half of the period and then subside to 2 to 4 ft during Wed and to 2 ft Wed night. The strong offshore wind component behind the front will quickly drive seas lower across the near shore waters. LONG TERM /THURSDAY THROUGH FRIDAY/... As of 300 PM Sunday...High pressure across the waters will allow winds to further ease on Thursday while a W/NW direction persists. Seas will fall to around 2 ft. Another cold front will approach during Friday, and ahead of this feature winds will become W/SW and increase to 15-20 kt, driving seas up to 4-6 ft, and another SCA may be required near the end of the week. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory from 7 AM Tuesday to 7 AM EST Wednesday for AMZ250-252-254-256. && $$ SYNOPSIS... NEAR TERM...JDW/MBB SHORT TERM...RJD LONG TERM...JDW AVIATION...MRR MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.