Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 190553 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 153 AM EDT Wed Oct 19 2016 .SYNOPSIS... Warm and dry weather over the next several days will give way to a strong cold frontal passage Friday. This will knock temperatures down into the 40s for lows this weekend, with highs in the 60s. A gradual warming trend early next week will bring temperatures to about normal for the season, accompanied by fair conditions. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 10 PM...Going forecast has a fine handle on things with high pressure in control. Previous discussion from 3 PM follows. Surface high pressure is centered offshore but extends a ridge axis westward across the Carolinas. In the upper levels high pressure sits across the Southeast states as well. This means except for a shallow layer of Atlantic moisture near the surface, the atmospheric column will remain very dry. Areas of fog may again develop late tonight as radiational cooling brings boundary layer temperatures down below the dewpoint. Forecast soundings suggest good moisture (60 degree dewpoints) will extend about 1000 feet vertically near the coast and 500 feet vertically inland. This is certainly sufficient for fog. The only potential problem with a foggy forecast is winds just off the surface should increase overnight to around 15 knots. While not enough to preclude fog, this may keep fog coverage more in the or "areas" category instead of "widespread." Forecast lows are near 60 with lower 60s near the beaches. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... As of 3 PM Tuesday...The surface ridge of high pressure will grow weaker on Thursday as a trough approaches from the northwest and as low pressure develops northeast of the Bahamas. The National Hurricane Center suggests there is an 80 percent chance a tropical or subtropical cyclone will form out of the storminess currently east of the Bahamas. Model ensembles show this potential development will not get close enough to the Carolina coast for any direct impacts. The trough approaching from the northwest does not extend across enough latitude to tap moisture from the Gulf of Mexico, and with such a late breakdown of the ridge off the Carolina coast there will be very little inflow from the Atlantic either. This means the system will remain very moisture-starved, and I am not introducing any showers into the forecast through Thursday night. Mainly clear skies and above-normal temperatures should continue. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 3 PM Tuesday...Chief headline this period remains a strong cold frontal passage Friday ushering the chillest air of the fall season this weekend, with lows in the 40s and maximums not likely to crest 70 degrees Saturday and Sunday. Along and just ahead of the front Friday it appears there is a brief window where moisture deepens up 700 MB, and low-level convergence associated with the front may trip off a few showers Friday afternoon. POP coverage for this feature to remain in the isolated category. The coolest portion of the extended period is daybreak Sunday deep into the 40s. The mildest air will be felt Friday just ahead of the front when we reach into the middle and upper 70s. The breeziest part of the forecast period remains Friday late afternoon through evening as robust cold air advection brings NW winds 15-25 mph. Higher gusts to 30 mph may occur from the ICW to the beach corridor then. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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As of 06Z...High pressure extending back across the area from center out over the Atlantic. Basically looking at a persitence forecast similar to previous couple of night with clear skies and near calm SW winds. Winds will be calm during the pre-dawn hrs allowing fog development. Daytime Wed will basically be a repeat of Tue daytime with the sea breeze developing during the midday and aggressively pushing inland. Will only indicate sct cu with no vertical development expected given the isothermal layer between 850mb and 700mb via latest progged soundings. Extended Outlook...Thu morning, possible MVFR/IFR from fog and low ceilings. Fri, possible brief MVFR in -SHRA and clouds, especially late in the day along the coast. Otherwise, remaining outlook is for vfr.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 10 PM Tuesday...High pressure over the western Atlantic extends a ridge axis westward and across the Carolinas. Light southerly seabreeze winds will turn offshore late tonight with a weak landbreeze. Spectral wave data from the Frying Pan Shoals shows a 14-15 second easterly swell dominates the sea state this afternoon. Sea heights should average 2 feet south of Cape Fear, 3 feet to the north. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 3 PM Tuesday...The ridge of high pressure over the Carolinas will begin to get squeezed from both the northwest and the southeast this week, getting narrower and narrower until finally dissipating late Thursday night. The culprit is a cold front and upper level trough advancing toward the area from the west, and developing low pressure east of the Bahamas which may become the next tropical or subtropical storm Wednesday or Thursday. While any potential tropical system will certainly remain too far offshore for any direct impacts, the weakening ridge should allow our winds to turn firmly northeasterly Thursday, but with wind speeds only around 10 knots. LONG TERM /FRIDAY THROUGH SUNDAY/... As of 3 PM Tuesday...A strong cold front Friday may bring Advisory conditions for small craft, mainly due to the expectation of gusts of 25-30 KT late Friday, given cool air advection over relatively mild waters. Additionally, seas will build to 5-6 feet along the very out ribbon of the 0-20 NM waters. Winds on Saturday will remain out of the NW but wind- speeds will diminish considerably. Sunday WNW- NW 12 KT or less. By Monday the high will dip south of the waters and WSW-W winds 12 KT or less is expected. Because of offshore flow this period, lowest seas will reside inshore, with appreciably higher sea heights across the outer waters due to fetch distance physics. && .TIDES/COASTAL FLOODING... As of 3 PM Tuesday...Exceptional amounts of water coming down the Black, Cape Fear, and Northeast Cape Fear Rivers is causing periodic coastal flooding in downtown Wilmington. Water levels as high as 7.37 feet MLLW occurred yesterday, with 7.22 feet MLLW at today`s high tide. Tidal anomalies should slowly decrease here over the next several days, but not before at least one more warning-level flood event with Wednesday afternoon`s high tide. The Coastal Flood Warning has been extended through 3 PM Wednesday. Note: Moderate coastal flooding (a warning-level event) is defined as 6.7 feet MLLW or higher at the Wilmington gauge. Tide forecast/anomaly analysis: Downtown Wilmington High Tides Tide + Anom = Total Water Level Wednesday 12:21 AM 4.84 + 1.7 = 6.54 feet MLLW Wednesday 12:53 PM 5.31 + 1.6 = 6.91 feet MLLW Thursday 1:21 AM 4.66 + 1.4 = 6.06 feet MLLW Thursday 1:55 pm 5.14 + 1.3 = 6.44 feet MLLW && .EQUIPMENT... As of 3 PM Tuesday...Power remains out at the Lumberton, NC airport. The emergency generator which had maintained power to the LBT ASOS since Hurricane Matthew gave out last night. Observations and climate data from Lumberton will remain missing until power can be restored, and LBT TAFs will remain in a `AMD NOT SKED UFN` mode until full metars flow. Also due to Hurricane Matthew, the Georgetown, SC NOAA Weather Radio broadcast remains off the air due to phone line issues. Our technicians are working on getting a temporary phone line up and running for this site as soon as possible. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...Coastal Flood Warning until 3 PM EDT Wednesday for NCZ107. MARINE...None. && $$ SYNOPSIS...MJC NEAR TERM...RAN SHORT TERM...TRA LONG TERM...MJC AVIATION...RGZ is the U.S. government's official web portal to all federal, state and local government web resources and services.