Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 300244 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 944 PM EST Tue Nov 29 2016 .SYNOPSIS... Mild, southerly breezes will continue tonight and Wednesday as a cold front approaches the Carolinas from the west. This front will move offshore early Thursday morning. Canadian high pressure will bring cool, dry weather Thursday through Saturday. Several areas of low pressure developing along a front will bring clouds and increasing rain chances early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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As of 815 pm Tuesday...As the showers tracked east past the I-95 corridor, their areal coverage decreased along with their intensity. With this activity well away from the strong mid-level dynamics, expect this continued slow diffusion of the pcpn to continue overnight. Eventually, pops decrease to slight chance overnight and will hold onto that threat across the inland Carolinas. However, along the immediate coast, with wind just off the ground running 30 to 40 kt, showers may move onshore and/or parallel to the Carolina coastlines overnight due to frictional or speed coverage from those stronger winds moving onshore. Surface winds overnight will remain quite active keeping temps elevated, mainly in the mid to upper 60s. Even the immediate coast will remain in the 60s this due to ssts across the adjacent Atlantic inshore waters now into the mid to upper 60s with low 70s shown by local buoys just offshore...ie. 41037 and 41064. Local sfc dewpoints will also remain in the 60s with the atm having become quite moist with PWs in the 1.25 to 1.60 inch range. Previous................................................ As of 300 PM Tuesday...Temperatures are now well up in the 70s most everywhere except a bit lower at some beach locations. Isolated to widely scattered pre- frontal light showers continue area- wide with the forecast area firmly located in the warm sector of a slowly approaching frontal system. Guidance shows the slight to low chance of this activity continuing overnight with a focus on our inland counties. QPF will be minimal overall, with most places seeing well under a tenth of an inch. Strong WAA in advance of the front will continue to prop up temperatures through the overnight period, with lows remaining elevated in the mid 60s. Gusty winds will continue through the afternoon hours with peak gusts up around 30 mph not uncommon. VAD wind profiles show impressive winds not far off the deck, generally 40 kts within 2 kft. Winds will moderate after sunset.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... As of 3 PM Tuesday...The chance for convection, possibly strong to severe, continues through Wednesday in advance of a cold front. The best chances for precip and strong convection run from Wednesday afternoon through the evening hours, immediately preceding the front. Rain chances end from west to east as the front moves offshore Thursday morning. Thursday temperatures will be significantly cooler than Wednesday as a moderate CAA regime sets up post-FROPA. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 3 AM Tuesday...Models are in good agreement that Friday and Saturday will feature dry weather as Canadian high pressure builds eastward into the Carolinas. The airmass should be on the chilly side with daytime highs several degrees below normal both days. The subtropical jet will become quite active late this week, spreading a veil of cirrus overhead for Friday night and Saturday. I wish I could just stop the forecast with Saturday, because model consensus goes out the window for early next week. Major timing differences develop between the slower 00z ECMWF and the faster 12z GFS with a shortwave trough ejecting out of the desert Southwest and across the southern United States. While it appears a good portion of any early precipitation will remain light Sunday into Sunday night, varying positions of a warm front and subsequent low pressure development along the East Coast paint a confusing picture of what sensible weather might develop Monday through Tuesday. In the absence of an obvious initialization error to guide me to one model over another, I have generally followed WPC national guidance with respect to temperatures and precipitation Sunday through Tuesday. This keeps at least a chance of rain in the forecast each day, with temperatures on the cooler side of a GFS/ECMWF blend. Despite the ECMWF`s success record, WPC notes that the GFS 00z and 06z ensemble members are almost universally slower than the ECWMF with the movement of the upper system. This gives at least some confidence that the GFS solution has some validity in this case. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... As of 00Z..Isolated showers and the potential for MVFR/IFR due to areas of fog and low cigs tonight into early Wednesday morning. Otherwise expect VFR with increasing chances for showers and isolated thunderstorms on Wednesday. Latest radar imagery depicts light showers moving across portions of the forecast area. Anticipate this activity to remain VCSH tonight with southerly winds around 10 kts and intermittent higher gusts possible. Latest fcst soundings continue to suggest increasing chances for fog and low cigs overnight. As a result, anticipate conditions to deteriorate to MVFR/IFR. On Wednesday, expect VFR with increasing chances for showers and isolated thunderstorms. Southerly winds will increase to around 15 kts with higher gusts possible. Extended outlook...Potential for MVFR/IFR in showers/isolated thunderstorms late Wednesday thru Thursday morning. Otherwise expect VFR. && .MARINE...
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NEAR TERM /THROUGH TONIGHT/... As of 830 PM Tuesday...Strong SCA conditions late this aftn will drop to weak SCA conditions temporarily overnight due to a slight loosening of the sfc pg. In fact, wind speeds may temporarily drop to around 15g20+ kt which is below SCA thresholds. The significant seas will only show a slight subsiding trend, but remain within SCA thresholds. Expect the re-tightening to occur heading toward Wednesday sunrise and continuing in the time there-after. Basically looking at S to SSW winds re-increasing to 15 to 25 kt late this period. With the onshore wind direction, the warmer ssts just offshore have been getting pushed into the ILM coastal or local waters. As a result, the 30 to 40 kt winds progged just off the deck, will be able to occasionally mix down to the ocean sfc...resulting in potential gale force wind gusts mainly during Wed into Wed night. The increased SSTS will prevent any sea fog issues. Previous.................................................... As of 300 PM Tuesday...Small Craft Advisory will continue through the near term. There is the likelihood that conditions could improve overnight in places such that Small Craft Advisory criteria are no longer met. However, as conditions are likely to deteriorate again on Wednesday, have opted to keep the Advisory in place through the period. The latest obs show seas in the 5 to 8 ft range over the coastal waters, with southerly winds of 20 to 25 kts and occasional gusts to 35 kts. Latest guidance shows a temporary loosening of the gradient overnight, which will account for the period of slightly more favorable conditions. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...The Small craft Advisory is expected to continue through late Wednesday night, when the close proximity of a cold front will loosen the gradient enough to allow conditions to improve by daybreak on Thursday. The front will move across the waters early on Thursday, with gradual improvement through the remainder of the period. LONG TERM /FRIDAY THROUGH SATURDAY/... As of 300 pM Tuesday...Canadian high pressure will build into the Carolinas from the west Friday and Saturday, finally reaching the area late Saturday night. Although major model differences develop next week, through Friday and Saturday the models are in good agreement with gradually diminishing offshore winds and dry weather.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 6 AM EST Thursday for AMZ250-252- 254-256. && $$ SYNOPSIS...TRA NEAR TERM...DCH/REK SHORT TERM...REK LONG TERM...TRA/CRM AVIATION...SGL

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