Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 171657 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1157 AM EST Fri Feb 17 2017 .SYNOPSIS... High pressure to our south will move offshore tonight and Saturday. An upper level disturbance may bring some light showers Saturday night. Warmer temperatures during the weekend should last through next week. Dry weather during the early and middle portions of next week may turn wetter late in the period. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Friday...A mainly sunny day with the only clouds being some thin cirrus now and again. We will be under the influence of warm air advection as SW winds take hold this afternoon. Hourly temps out of the gate needed to be modified upward this morning, but otherwise we still expect highs to reach the mid and upper 60s with lower 60s across the more immediate coastal areas and coolest across coastal Brunswick County and southern New Hanover County. Short Wave ridging aloft will approach from the west today, with it`s north to south ridge axis overhead by daybreak Sat. High level clouds are expected late tonight as moisture overrides the upper ridge. Lows tonight will be in the 40s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 AM Friday...Longwave pattern aloft somewhat in a state of flux this period due to the progressive nature of both upper s/w trofs and ridges across the United States. A closed upper low and weak sfc low over eastern TX Sat morning, is progged by the models to dampen and open up to just a s/w by the time it pushes across the ILM CWA Sat night. The weak sfc low accompanying is also progged by the models to weaken into a sfc trof as it passes across the FA Sat night. Enough moisture accompanies it and/or what little moisture it`s able to tap off the Gulf of Mexico, will be enough to produce mostly cloudy skies by late Sat aftn thru early Sun. Could only illustrate a low chance POP, 20-30 at most, mainly from again late Sat thru early Sun as the entire system progresses from west to east across the FA. With dynamics sfc and aloft weak at best along with very limited if any instability, pcpn will be in the form of light rainshowers with no thunder being mentioned. Temps on Sat will warm to the lower 70s, cooler at the immediate coast. With Sat nite lows in the upper 40s to around 50. Not much CAA occurs after the system departs for Sun, in fact NW flow to occur at the sfc and thru atm column. This compressional heating from the downslope flow off the Appalachians will counter any CAA that does occur, resulting in widespread 70s for Sun highs. Sun night lows will still be above normal in the low to mid 40s. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 300 AM Friday...Impressive amplitude develops by Monday with ridge axis just to our west. Being on the east side of not only the mid level but also surface and low level highs there will still be a weak sense of cool advection in the boundary layer. This will offset the impressive height rises but most areas will still end up on the warm side of 70 especially inland. As the pattern progresses into Tuesday and Wednesday the low level flow will turn more onshore. Pair the increased marine influence with height falls and 70 will be a harder high to attain for some areas, though such a value is still some 10 degrees above climatology. For weather aspects other than temperatures we look to the deep troughiness that unphases but leaves a strong cutoff to meander across the Gulf through the midweek period. Timing cutoffs correctly has always been a challenge for model guidance and may be for some time to come. The best forecast this far out in time is to show a gradual increase in cloud cover and rain chances Wednesday and Thursday. Temperatures will not show much variation from those early in the period save for perhaps increasing nighttime lows as the clouds increase (though there are arguably some model solutions that keep the system too far to our south for that). && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 18Z...VFR this TAF cycle. Generally a S-SW wind flow at 11 KT or less through the period. High clouds will increase 12z-18z Saturday, mainly cirrus and scattered mid level clouds ahead of an approaching low pressure system moving east across the Gulf states. No TSTMS or restrictions visibility through 18z Saturday. EXTENDED OUTLOOK...Possible MVFR/IFR conditions in isolated showers Sat night thru early Sun due to the passage of a weak low pressure system and cold front. Otherwise expect VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Friday...High pressure to our S will bring a wind shift to the SW this afternoon with SW to WSW winds tonight. The gradient will be a little tighter tonight and so wind speeds under 10 kt today will increase to 10 to 15 kt this eve and overnight. Seas will be 2 ft or less today and 2 to 3 ft tonight. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 AM Friday...Saturday will feature ridging from offshore Florida and the lee side trof across the central Carolinas, combining to produce SW winds 10 to 15 kt with some gusts up to 20 kt, becoming more westerly Sat night. The upper s/w trof and accompanying sfc trof will sweep from west to east across the area waters Sat night thru early Sun. After it`s passage, Sunday thru Sunday night will see NW winds only around 10 kt due to the lack of any sfc pg after the system`s departure. Significant seas thru the period will only run 1 to 3 ft, possibly some 4 footers off Cape Fear during Sat into Sat night. Short period wind driven waves will remain the primary input to the sig. seas. LONG TERM /MONDAY THROUGH TUESDAY/... As of 300 AM Friday...A large upper ridge will be just inland on Monday. A similarly north-south elongated surface high will be found near a similar longitude, just slightly to the east. The center of this high will be north of New York State. This will create a long northeasterly fetch into the local area, though some turning to a more easterly direction will be possible over southern zones as the flow curves around the southern periphery of the high. Changes heading into Tuesday will be minor. The high progresses eastward along with its parent upper ridge. Wind will remain quite light and tend to veer a bit. This could channel a bit more swell energy into the Carolina coastal waters though overall dominant wave height likely will not change appreciably since according to WNA guidance said swell energy will be very weak. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...DCH/RJD SHORT TERM...DCH LONG TERM...MBB AVIATION...MJC is the U.S. government's official web portal to all federal, state and local government web resources and services.