Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 182218 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 618 PM EDT Wed Apr 18 2018 .SYNOPSIS... High pressure moves offshore tonight. A strong cold front arrives late tomorrow. High pressure will pass by well north of the area over the weekend. A slow moving area of low pressure will approach from the west and move overhead through the early and middle part of next week. && .NEAR TERM /THROUGH THURSDAY/...
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As of 618 PM Wednesday...No changes to ongoing forecast aside from loading the latest observations into the gridded forecast database for good initialization heading into the evening hours. Temperatures will drop into the 60s after dusk, then level off not long after midnight, in the low 60s inland and middle 60s near the coast, where breezes will be stronger and low-lvls more mixed. Inshore SSTs and surf temperatures have slowly risen to around 65 degrees. Dewpoints will rise into early Thursday and a higher humidity feel may be observed just ahead of a front. The recent GOES-E imagery shows a high probability of clear skies overnight, at most, bits and pieces of ice crystal clouds caught in rapid zonal wind flow, not impactful on forecast hourly temperature curves. As of 3 PM Wednesday...Surface high will linger off the coast into Thu before a strong cold front moves across the area during the day. Ahead of the front gusty winds and very dry conditions will once again lead to an increased fire danger risk. West- southwest winds of 15 to 20 mph are expected with gusts around 30 mph possible. Cold advection spreads over the area from west to east during the afternoon and will complicate high temp forecast somewhat. Highs will range from lower 80s closer to the coast with mid to upper 70s inland. Front passes dry, although it is likely to be accompanied by some flatter cumulus. Forecast soundings show an increase in moisture between 4k and 5k ft but the cap above 6k ft or so will prevent any deep upward motion. Band of increased moisture is narrow and by late afternoon any cloud should be off the coast with cold advection underway everywhere. Advection continues overnight with northwest winds gradually becoming north late in the period. Despite winds over 10 mph temperatures will drop into the upper 30s to lower 40s as the period ends.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday...Dry cold front will be off the coast as the period begins with surface high building in from the northwest. Strong cold advection sets up Thu night with temperatures dropping into the upper 30s to lower 40s for Fri morning. Mid-level trough is slow to move away from the east coast Fri. This keeps deep northwest flow and post trough subsidence over the forecast area through Fri night. Forecast soundings do show increasing moisture above 25k ft late in the period and some cirrus may spread over the region Fri night. Other than the late period high cloud skies should remain clear with no chance of rain. Precipitable water will stay under half an inch, sometimes dropping below a quarter inch, through the period. Temperatures below climo continue Fri and Fri night. Highs Fri may struggle to hit mid 60s despite an abundance of sunshine. Northerly winds ease up Fri night which could lead to strong radiational cooling. So despite airmass modification, lows Fri night will be similar to Thu night lows, and possibly cooler. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 300 PM Wednesday...Temperatures will remain below climatology through the period while the weather becomes increasingly unsettled. The Saturday through Sunday should be rain-free as high pressure is passing by to our north. As this happens a cutoff upper low will move across the Gulf states leading to cyclogenesis. Clouds and perhaps rain will then overspread the region Sunday night. With the high holding on to our north there will be a good overrunning surface with warm advection over the top. This will favor an appreciable QPF event, especially paired with the overall slow motion of the system; so much so that rain may last into Wednesday. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... As of 18Z...High pressure centered to our south will give us westerly winds today. A weak trough will slide into the area this afternoon. Little weather will be associated with it other than a slight wind shift and some cirrus. Tonight diminishing winds with little or no fog expected. Wednesday, the radiational inversion will break between 13-14Z, with moderate southwest flow expected and a strong warmup into the 80s. Extended outlook...VFR. && .MARINE...
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NEAR TERM /THROUGH THURSDAY/... As of 618 PM Wednesday...An Marine Weather Statement was needed to address the low water levels with the overnight low tide, dipping to 1-2 ft below the `normal` low tide. No other changes, SCA flags are flapping in stiff SW marine breezes, and pitchy, unwelcoming seas offshore. As of 3 PM Wednesday...Strong southwest flow this afternoon will continue overnight and Thu, prior to the passage of a strong cold front in the afternoon. Ahead of the front speeds will be 20 to 25 kt with potential for gusts around 30 kt. Once the front passes winds shift to offshore and decrease in speed somewhat. Currently the SCA headline expires at 21Z and have no plans to change the end time. Cannot rule out changes down the road and would not be shocked to see the headline extended out in time, just do not have high enough confidence at this time. Seas will build to 4 to 7 ft this evening and stay there into Thu afternoon before offshore flow knocks seas to 3 to 5 ft late in the day. SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday...High pressure to the northwest will build over the waters as Thu cold front moves farther away from the coast. Gradient remains pinched as the high builds in Thu night with 15 to 20 kt northwest winds gradually becoming north-northeast early Fri. Current SCA headline expires before the start of the short term period, but there is a chance the headline will need to be extended into Thu night to account for the northeast surge. Gradient relaxes Fri into Fri night as the high slowly drifts southeast. Northerly flow continues through the period but with speeds 10 kt or less from Fri afternoon on. Seas running 3 to 5 ft Thu night will slowly subside later Fri and Fri night, ending up around 2 ft. LONG TERM /SATURDAY THROUGH MONDAY/... As of 300 PM Monday...Large area of high pressure passing by to our north over the weekend. Initially this will bring fairly light NE winds but as the high moves farther east and an area of low pressure approaches the flow will turn easterly and wind will accelerate. Conditions should deteriorate to Advisory levels Sunday night. Additionally some fairly heavy rain will lead to considerable visibility restrictions adding to the hazard level of the marine environment.
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&& .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 6 PM EDT Thursday for AMZ250-252- 254-256. && $$ SYNOPSIS...MBB NEAR TERM...III/MJC SHORT TERM...III LONG TERM...MBB AVIATION...43/RAN is the U.S. government's official web portal to all federal, state and local government web resources and services.