Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 211629 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1129 AM EST Wed Feb 21 2018 .SYNOPSIS... Temperatures will remain well above normal, even into the weekend, as strong high pressure holds offshore. A cold front will approach the coast this weekend, and stall over, or just south of the area early next week, bringing a chance of rain. High pressure will build from the north through the middle of next week, keeping temperatures closer to normal. && .NEAR TERM /THROUGH TONIGHT/... As of 1014 AM Wednesday...Able to axe the DFA a tad early, and now the stage is set for a sunny and warm day today, with near record warmth on tap. Diurnal cumulus will become abundant, but along the immediate coast is where the most sunshine minutes may rack up, barring prolonged bouts of landward marching sea fog. Have rebuilt sky cover grids to indicates less coastal clouds, as the strengthening sea breeze creates a zone of subsident air near shore, conversely, as a zone of convergence advance inland this afternoon. Since the synoptic wind and sea breeze motion trajectory are nearly aligned, the convergent zone should make progress well inland this afternoon. A few light showers with surface heating may spring up in this convergence inland later today, but sure to be low-topped, brief, non- extensive, and a challenge to get measurable rain. As of 4 AM Wednesday...Temps will once again, reach near or record breaking highs this afternoon as ridge aloft and plenty of WAA produce readings up near 80 most places away from the beaches. The 850 temps will remain right around 14 to 15C through the period. Expect another night of decent radiational fog with patchy dense fog once again. Temps will drop to within a couple of degrees of 60 most places, which is more representative of max temps this time of year. Records for today 2/21 include, ILM 78 in 2014, FLO 81 in 1997, and CRE 76 in 1953. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 400 AM Wednesday...The Forecast Area will remain under the influence of a strong, but slowly weakening Western Atlantic Ridge. The ridge will slowly shift S as we progress from Thu into Fri. A backdoor cold front is expected to stall N of the area Fri before moving back to the north. Subsidence should continue to largely suppress convection, but moisture does grow a little deeper which should allow for greater vertical depth to the cumulus field. Low level moisture remains high and guidance continues to support fog/low stratus development, especially during the late night and early morning hours. Will include patchy fog in the gridded forecast at this time, although at least some of this fog will likely become dense. The theme remains the same regarding sea fog as well. Dewpoints remain marginally favorable while the prevailing wind direction veers slightly to become a little more favorable as compared to recent days. Will portray patchy fog lingering at the beaches longest each morning and developing soonest during the late eve. Highs will be around 80 each afternoon with a sharp temp gradient near the coast due to marine influences. Highs at the beaches will be about 10 degrees cooler. Lows will be in the upper 50s and lower 60s. Record highs should continue to be challenged or broken... 02/22 City High Temperature Forecast/Daily Record High Wilmington 79/78 in 2003 Florence 82/80 in 1990 N Myrtle Beach 74/75 in 2007 Lumberton 81/78 in 2003 02/23 City High Temperature Forecast/Daily Record High Wilmington 78/80 in 1975 Florence 81/83 in 1975 N Myrtle Beach 75/74 in 2017 Lumberton 80/78 in 1971 && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 300 PM Tuesday...An exceptional upper level ridge will remain anchored off the East Coast through this weekend. Model consensus 500 mb heights peak on Wednesday at 593 dam along the coast, nearly 3 standard deviations above normal, and among the highest values ever measured this early in the year. Nestled beneath this upper ridge will be the Bermuda high at the surface. This summerlike feature will maintain a south- southwesterly wind across the Carolinas and with very warm conditions continuing. Record high temperatures could occur on Sunday ahead of a cold front, with highs all weekend ranging from the upper 70s to lower 80s away from the cooler beaches. A strong subsidence inversion Saturday should keep the area dry despite what should be plenty of cumulus around. By Sunday an upper trough shearing northward as it moves into the ridge may punch a large enough hole in the inversion to allow some deeper convection to develop. As the cold front moves through the area early Monday, the GFS and Canadian models suggest more showers could develop in a brief period of overrunning behind the front, however the ECMWF is dry. All models show the front should be far enough south by Tuesday for drier weather to develop with temperatures falling much closer to normal. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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As of 18Z...A summer like high pressure system resides offshore with southerly flow and subsidence. A few showers are possible mainly in our western CWA where there is less subsidence,otherwise just scattered cumulus. Tonight, another warm night with another round of possibly dense fog expected. Thursday, becoming VFR with continued southerly flow. Extended Outlook...Morning IFR/BR possible through Friday am. Showers possible Saturday night through Monday.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1014 AM Wednesday...Fog still plaguing the inshore waters and will hold onto marine `dense fog advisory` at least until noon. Extending the marine fog advisory is possible, Dominant wave periods will hold around 7 seconds, from the SE at 3 ft, up to 4 ft outer waters. No TSTMS in the near term, but a few light showers can be expected from time to time. The primary hazard remains low visibility in patchy dense sea fog. As of 600 AM Wednesday...Light southerly flow around Bermuda High will persist through tonight. Expect winds to remain 10 kts or less except a spike in winds in the afternoon due to sea breeze. Expect seas to hold around 2 to 3 ft most waters with a slight increase in SE swell through the period. This very warm and moist air over the cool shelf waters will produce sea fog which will be dense at times. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 300 AM Wednesday...The coastal waters will remain under the influence of a strong, but slowly weakening Western Atlantic Ridge. The ridge will slowly shift S as we progress from Thu into Fri. A backdoor cold front is expected to stall N of the area Fri before moving back to the north. The biggest hazard to mariners will be sea fog. We have included patchy fog in the gridded forecast through the period. Sea surface temps will be in the mid to perhaps upper 50s. Dewpoints, while unseasonably high for late Feb, will only be marginally conducive for sea fog development. However, the wind direction will veer slightly which will allow for slightly better residence times over the cool shelf waters. Benign wind and sea conditions will persist. The wind direction will be S to SW at 10 kt or less although wind speeds may briefly reach 10 to 15 kt across the near shore waters due to the afternoon seabreeze circulation. Seas will be 2 to 4 ft. LONG TERM /SATURDAY THROUGH SUNDAY/... As of 300 PM Tuesday...High pressure will remain anchored off the East Coast between Cape Fear and Bermuda through the weekend. This should maintain a south-southwesterly wind direction through the period. As a cold front crosses the southern Appalachians Sunday, our pressure gradient will tighten substantially. Relatively gentle winds Saturday should increase to around 20 knots on Sunday with seas building to a very choppy 5-6 feet. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Dense Fog Advisory until noon EST today for AMZ250-252-254-256. && $$ SYNOPSIS...8 NEAR TERM...RGZ/MJC SHORT TERM...RJD LONG TERM...TRA AVIATION...43 is the U.S. government's official web portal to all federal, state and local government web resources and services.