Area Forecast Discussion
Issued by NWS Wilmington, NC

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629 FXUS62 KILM 190105 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 805 PM EST Wed Jan 18 2017 .SYNOPSIS... Weak high pressure will build over the region tonight and Thursday. Low pressure and its associated front will impact the area late Thursday night and on Friday. A brief period of weak high pressure on Saturday will be followed by a strong area of low pressure which will move across the deep south and bring gusty winds and possibly strong thunderstorms to the Carolinas late Sunday into early Monday. Dry conditions will return Tuesday and Wednesday as mild high pressure builds in from the west. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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As of 730 PM Wednesday...Currently a N to NE dissipating surge is pushing across the coastal Carolinas, this after the initial NW surge from earlier in the day associated with the CFP itself. Will see winds veer to the N to NE across the entire ILM CWA this evening, along with a general diminishing trend overnight. Places may go calm as the highs center moves closer to the FA from the NW. Sfc dewpoints have and/or will drop and remain in the 30s overnight via from initially drier air aloft mixing down and now associated with the change in airmass itself. Tonights lows only tweaked from quick look at 18Z various model Mos guidance. Looking at mainly thin Cirrus advecting overhead tonight...thus mostly clear for sky conditions. Previous..................................................... As of 3 PM Wednesday...Clouds dispersed a little quicker than forecast/modeled making for a sunny and warm afternoon albeit a breezy one at times. By evening low level wind barbs will line up with isotherms shutting off the cool advection behind the front leaving tonight`s low temperatures about 10 degrees above climatology despite a lightening wind and continued clear skies.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday... Upper ridging and weak surface pattern to bring a sunny start to Thursday. Late in the day a few clouds will move in from the SW ahead of the next system and the ridging aloft moves off the coast. Highs in the low 60s while cooler than today are still almost 10 degrees above normal. A more precipitous increase in moisture is slated for Thursday night. Models have been slowing with the arrival of rain chances Thursday night. It now appears that most of the rain is slated for Friday with a weak warm front and mid level shortwave. QPF prospects appear marginalized by the deepest mositure being shunted well to our north. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 3 PM Wednesday...Weak mid level ridge axis will move offshore Sat, tapping GOMEX moisture for the start of next week. Strong southwest flow, 300 mb jet exceeds 100kt at times, ahead of deepening southern stream system will spread deep moisture over the southeast. Precipitable water values will exceed 1.5 inches at times but there will also be some wrap around dry air to contend with. Strong low level jet, especially later Sun and Sun night does still pose a severe weather threat, but both the GFS and ECMWF have trended slightly faster with the system. Strong, veering winds ahead of the front, which is now progged to pass Mon morning, will lead to an abundance of shear but instability will be lacking. 850mb jet Sun night is likely to exceed 50 kt, which if mixed to the surface would likely result in at least a few severe storms. However, mixing will be the problem, especially given the nocturnal timing. So while severe weather cannot be ruled out it is more likely to be an isolated occurrence as opposed to a widespread event. Stacked low passes over the area Mon into Mon night. Diurnal convection is likely, mainly in the form of isolated showers and thunderstorms, as the cool core of the low moves into the area during peak heating. Trough may become negatively tilted as it exits the region Mon night but it is not likely to have an impact on the forecast area. Mid level ridging and weak high pressure will follow the exiting system and linger over the southeast through mid week. The surface high has origins in the southwest with little to no cold air present. Temperatures through the period will remain above to well above climo. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 00Z...High confidence for VFR conditions through the forecast period. High pressure will continue to build in from the northwest through Thursday afternoon. Light northerly flow overnight with northeasterly flow on Thursday. Time height shows dry air at all levels into Thursday morning, with perhaps some cirrus over the southern portion of the CWA. Extended Outlook...IFR ceilings are possible inland in low stratus Friday night as the next warm front and rainfall event develops. IFR ceilings could continue into Saturday morning. && .MARINE...
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NEAR TERM /THROUGH TONIGHT/... As of 730 PM Wednesday...The north to northeast surge dropping down the NC Coast has lost much of it`s zest as it pushed past Cape lookout to the Cape Fear region early this evening. Could see a few 20 kt wind gusts across the ILM NC waters but that too will dwindle in magnitude. The pre-dawn Thu hours will see a more stable N to NE wind at 10 to occasionally 15 kt. Significant seas initially in the 2 to 4 foot range, with the 4 footers across the ILM NC Waters early, will subside to 2 to 3 ft thruout overnight. Wind driven waves at 4 to 5 second periods will dominate the seas. The easterly ground swell affecting the local waters for more than a week has finally degraded to the point where it is no longer identifiable. Previous................................................. As of 3 PM Wednesday...Cold front will turn winds to N this evening and set up an abating trend as the gradient eases. Nearshore seas will settle most quickly due to the turn from coast-parallel flow to offshore with wave shadowing, even though their faces/periods may steepen/shorten. Most places will open up a bit in wave height, ending up generally with a 2-4ft forecast. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday...Pretty minimal wind and seas Thursday as a weak high builds in from the north. This will initially bring a light NE wind but as the high moves off the coast they will veer in direction. A light SE flow Thursday night could allow the daytime 2 ft waves to shrink even further. A warm front will turn the wind to SW by Friday with no significant increase in wind speed so waves won`t change much. LONG TERM /SATURDAY THROUGH MONDAY/... As of 3 PM Wednesday...Surface and mid level ridging will shift off the coast Sat, leaving light southerly flow over the waters. Speeds will remain 10 kt or less into Sun before starting to increase ahead of approaching storm system. Well developed storm will move across the southern states Sun and Mon, increasing low level southerly flow to a solid 20 kt Sun night and Mon. Front associated with the low will move across the waters late Mon with winds veering from south- southeast to southwest late Mon and Mon night. Cold air is lacking but gradient will keep winds 15 to 20 kt through the end of the period. Seas 2 to 3 ft Sat into Sun start to build in response to the increasing southerly flow. SCA headlines will likely be needed Sun night and could continue through the end of the period with seas approaching 10 ft at their highest.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...III NEAR TERM...DCH/MBB SHORT TERM...MBB LONG TERM...III AVIATION...DL is the U.S. government's official web portal to all federal, state and local government web resources and services.