Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 211126 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 726 AM EDT Sun May 21 2017 .SYNOPSIS... Today will feature mostly cloudy skies with only a slight chance of showers. The upcoming work week looks rather unsettled with a series of storm systems moving across the southeast. The best chances of rain occur from late Monday through Wednesday. Conditions should dry out somewhat toward the end of the week. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Sunday...A back door cold front basically bisects the CWA this morning from east to west. This front will continue to push south basically making its way just past the Grand Strand and Florence. Low overcast ceilings have developed in its wake and will persist for much of the morning. As some breaks occur mixing will commence and the front will be well to the north by early Monday morning. There is little chance for showers or thunderstorms today although some guidance still hints at it. Therefore we have maintained the slight chance pops moreso for inland areas for a few hours this afternoon. Daytime highs will be somewhat cooler than Saturday with readings near 80 along the coast and middle 80s inland. I did opt for the cooler numbers citing the expected overcast skies. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 330 AM Sunday...An upcoming active weather week in store for the ILM CWA this period and beyond. Meaning, the FA will see alot more clouds and high probabilities for pcpn. The longwave upper ridging affecting the Carolinas will have pushed east and offshore by the start of this period. A rather well amplified longwave trof across the Central U.S. will expand eastward. With now SW flow aloft, tapping of Gulf of Mexico moisture is inevitable. Combined with low level Atlantic moisture tapped, PWs are progged to climb to between 1.5 to 2.0 inches. Frontal dynamics will provide the primary forcing at the start of this period. A cold front having approached from the west leading up to this period, will stall and orient itself from NE to SW across the East-Central Carolinas this period. Additional dynamics/forcing will come from mid-level s/w trofs or vorts rotating thru the longwave upper trof, and at times pushing across the FA and resulting in waves of sfc low pressure systems moving NE along the stalled front. This is quite evident during the late Monday night thru late Tuesday time frame. This same scenario repeats itself late Tuesday night into Wednesday of the long term period. The dynamics associated with the first sfc low passage will be more conducive to heavy rain producing convection, especially with PWS near 2 inches. This could result in shallow flooding. The dynamics associated with this second low will be more potent then the prior one. Various model progged soundings indicate Unidirectional winds develop by Wed daybreak with speeds just off the deck around 50 kt. This may lead to severe thunderstorm activity from late in the pre- dawn Wed hrs thru well into daylight Wednesday. Will identify the possible flooding and severe convection this week within the hazardous wx outlook. Overall, temps this period will run near normal for highs and above normal for lows. This results in a rather short diurnal temp range each day. Stayed close to a consensus of the models for temps and dewpoints. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 300 PM Saturday...Southwesterly vorticity-laden flow in place on Tuesday while a weak surface boundary drops into the region. Showers and thunderstorms should spread west to east across the area, becoming more numerous than previously anticipated. Low level wind fields are also stronger than previously progged but this may be related to some apparent convective feedback in guidance, especially the GFS. Assuming this is correct the severe weather threat appears minimal. The next batch of shortwave energy crosses on Wednesday, which should also shape up to be an active day of showers and thunderstorms. The previously anticipated minor severe threat is complicated by the GFS pushing the surface front south of the area. Should the area remain in the warm sector as anticipated then storms could approach severe criteria with damaging winds likely the main threat. The main trough axis swings through either Thursday or Thursday night and this should herald the trend towards dry weather with lower humidity and cooler temperatures especially at night. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/...
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As of 12Z Sunday...MVFR/IFR conditions likely for 1 to 2 hrs out from the starting block due to low ceilings and possibly reduced vsby from BR. For the remainder of the day...conditions to improve quickly to VFR by mid to late this morning. The backdoor front has now basically stalled across portions of the FA. It now extends inland in the vicinity of Little River Inlet. Not much convective activity expected along this front. The next cold front pushing eastward may become the next "problem child" front late tonight into Mon with an advertisement of convection across the inland terminals. For the coastal terminals may indicate VCTS for the time being. Overall light synoptic wind field , mainly the directions, will be determined by the placement of the front as it likely will wiggle north or south by 5 to 15 miles. Extended Outlook...Reduced flight categories will be possible in periodic showers and thunderstorms Monday afternoon through Wednesday. The strongest convective activity will occur during Wednesday.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 330 AM Sunday...Northeast winds have pushed into the waters off of Cape Fear on the strength of a back door cold front. A bit of a surge has JMPN7 up to 15 knots and this will continue for a few more hours. The southern most waters will probably not see a northerly component to the winds although the front is forecast to push a little further south than previously anticipated. The front will push back to the north late today and especially overnight with winds veering to east then finally southwest by early Monday. The highest speeds should occur this morning citing the previously mentioned surge, otherwise around ten knots should suffice. Significant seas will remain in check with mostly two feet although a few three footers could show up briefly in the spectrum near the higher winds. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 330 AM Sunday...Weak sfc ridging extending east across the local waters this period, will retreat back offshore early Monday. A frontal boundary moving east will stall across the east-central Carolinas by late Monday and remain stationary into Wednesday. Initially, winds and seas will remain rather docile during Mon. Low pressure systems are progged to develop along this stalled front, with one low affecting the FA late Mon night thru Tue afternoon. The next low, the more potent one, will affect the local waters late Tue night into Wed. Winds and seas will increase during the 1st low`s passage but remaining below any SCEC or SCA criteria. However, the 2nd low will deepen prior to reaching the local waters which consensus indicating SCEC and/or SCA thresholds will be met across portions or all of the ILM Waters. Will highlight this in the Hazardous Wx Outlook. LONG TERM /WEDNESDAY THROUGH THURSDAY/... As of 300 PM Saturday...Cold front slated to approach Tuesday while a large area of high pressure remains off the coast. Previously there was not to be an area of low pressure along the boundary to strengthen the wind fields and this is still likely though some guidance supports otherwise. The absence of the low should stave off advisory level winds/seas until Wednesday as previously anticipated but Tuesday deterioration not impossible at this point. Cold front approaches Thursday veering the flow and perhaps knocking about 5kt off the wind speeds. These two factors will allow for advisory to be dropped though SCEC may be needed. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...SHK SHORT TERM...DCH LONG TERM...MBB AVIATION...DCH MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.