Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
965 FXUS62 KILM 261749 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 149 PM EDT Wed Jul 26 2017 .SYNOPSIS... Drier weather will work into the area behind a cold front today. The front will dissipate to our south on Thursday. Mainly isolated showers and thunderstorms will become numerous Friday into Saturday ahead of an unseasonably strong cold front. Strong to severe thunderstorms will be possible later Friday and Friday night. Much drier air is expected in the wake of this system early next week. && .NEAR TERM /THROUGH THURSDAY/... As of 1000 AM Wednesday...Cold front dropping southward has crossed the entire CWA and is aligned off to the NE parallel to the coast. Surface high pressure centered across New England is ridging down the coast behind this front, bringing in much drier air aloft as noted on GOES-16 water vapor imagery. The question today involves how much convection will develop, and if enough sunshine can drive temps above guidance. RAP and NAM soundings are drastically different in their evolution of the drier air today, but based off latest visible imagery the RAP appears to be handling the situation better with more rapid development of drier air. The exception to this will likely be along the SC coast and down into the Pee Dee which are closer to the front and will have deeper moisture persist longer. It is this area, as well, that has the best chance for tstms through this aftn. However, coverage of tstms will likely be atypical today, peaking late morning and then beginning to erode during the aftn as drier air filters north to south across the CWA. Do not expect any convection north of the state line except in Brunswick County, and abundant sunshine will likely drive temps into the low 90s inland NC zones, around 90 coastal NC and inland SC, with mid to upr 80s in SE zones which will experience more cloud cover. Convection will erode during the late aftn and a pleasant and mostly sunny evening is expected, followed by a seasonable and dry night with lows around 70 north, 74 south. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 300 AM Wednesday...A cold front will be in the process of dissipating to our S on Thu. Modest ridging aloft going into Thu erodes rather quickly and is replaced with increasing troughiness. Then as this trough deepens across the Eastern third of the CONUS, it helps to drive a cold front southward. This front will be very near our northwest zones by daybreak Sat. The expectation is that Thu will be a day of transition as initially drier air will show some erosion as deeper mositure begins to poke back to the N. Thus, slight chance or chance POPs for showers and thunderstorms appear warranted for mainly our southern zones, highest across the South Santee River area. Convection may begin to blossom offshore Thu night, perhaps skirting portions of the immediate coast. The deep moisture will be feeding N and focusing along and ahead of impressive trough, especially given the time of year. Precipitable water values climb to more than 2 inches and peak at more than 2.25 inches Fri night. At the same time, robust shortwave energy pivots across the eastern Carolinas with a southwest low-level jet of 50 kt impinging on the area and diffluence aloft. This will support increasing shower and thunderstorm activity during Fri with the most widespread coverage late Fri and Fri night and perhaps into Sat. This setup could very well support an organized severe thunderstorm event. The Pattern should be progressive enough to limit excessive rainfall concerns with very high moisture content being mitigated by quick storm motions. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 215 PM Tuesday...An unseasonably amplified upper trough becomes the primary feature and key player for late week and weekend sensible weather. This will translate to elevated rain chances Saturday as this system ushers a fairly strong surface trough across the coast. ECMWF and GFS clear this boundary off the coast into early Sunday, the GFS much stronger. Both suggest therefore some drying and cooling, but of differing magnitude. A blend still brings surface dewpoints into the 60s early next week, helping to take off the bite of high absolute humidity values. A dry mid-level air intrusion will curtail deep convection Sunday through early next week. A few showers could linger and remain favored closer the coast in proximity to higher moisture and the oceanic front, but the overall coverage should trend down Sunday onward. Temperatures will be slightly below normal as cool air advection pushes into the balmy sea air. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 18Z...Cold front has sunk south of the terminals this aftn with dry air advecting in from the north. Before this dry air can move into the terminals, scattered showers and tstms have developed, mainly along the coast and into SC. However, latest visible imagery shows clouds beginning to erode from the NW, and have tempered tstm mention in TAFs. Still expect VCSH at all terminals except LBT through this aftn, with tempo TS mentioned at the Myrtles. Brief IFR is possible although MVFR is most likely. Winds will be primarily E/NE through tonight at speeds around 10 kts. Any tstms will erode quickly this evening leaving a mostly clear night with light NE winds. While moisture will be eroding in the column, forecast profiles suggest enough low-level moisture on the onshore winds to create some IFR stratus tonight. The hydrolapse rates appear favorable only in the very lowest levels so confidence is low, but have added few/sct at all terminals overnight before returning to VFR again after sunrise on Thursday. Extended Outlook...MVFR or lower flight restrictions are likely in association with numerous thunderstorms later Fri and Fri night. Some of the thunderstorms may be strong to severe. Flight restrictions may persist into portions of Sat as well. VFR Sunday and Monday.
-- End Changed Discussion --
&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Wednesday...No changes with this update other than to increase POP from NE to SW through early aftn. Previous discussion from 600 AM below: As of 600 AM Wednesday...In the wake of a cold front, the wind direction has shifted to the NE or ENE and we expect this direction to hold across the waters with speeds of 10 to 15 kt. The on shore winds will push seas up from less than 3 ft this morning to 3 to 4 ft later today into tonight. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 300 AM Wednesday...A cold front will be in the process of dissipating to our S on Thu. A stronger cold front will be approaching from the N Fri night. A light easterly flow early on Thu will veer to SE and S Thu afternoon. Wind speeds will increase Thu night as the direction veers to SW. SW winds will then persist through the end of the period as they increase to near 20 kt later Fri and Fri night. Seas will build in response to the increasing wind, building from 2 ft Thu and Thu eve to 3 to 4 ft Fri afternoon and 4 to 5 ft Fri night. Small Craft Should Exercise Caution conditions appear likely late in the period. Thunderstorms will be few if any Thu but we do expect them to become numerous during Fri and especially Fri night. LONG TERM /SATURDAY THROUGH SUNDAY/... As of 215 PM Tuesday...Wind direction will become changeable this period, but the good news is that wind-speeds will decrease as a front lays up along the coast then offshore. TSTMS will be numerous along the front into Saturday, so a radar update should be on the checklist for the first part of the weekend. TSTMS will decrease in coverage Sunday, although the Gulf Stream and outer waters may remain unsettled due to the offshore front. Gusts to 20 KT from the SW may persist into Sat morning ahead of the front. Then once the front moves through later Sat and Sat night, the wind direction will shift to the NW and N and then NE on Sun. Wind speeds Sat afternoon through Sun will be on the order of 10 kt. Seas of 4 to 5 ft early Sat will subside to 3 to 4 ft, but a modest NE push may bring some 5 ft seas back across portions of the outermost waters on Sun. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...JDW SHORT TERM...RJD LONG TERM...MJC AVIATION...JDW MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.