Area Forecast Discussion
Issued by NWS Wilmington, NC

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818 FXUS62 KILM 271330 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 930 AM EDT Thu Apr 27 2017 .SYNOPSIS... High pressure offshore will bring a warming and drying trend late this week through the weekend. A weakening cold front will bring a few or a thunderstorm tonight inland and early Friday at the coast. A stronger frontal system will bring a chance of rain late Monday and early Tuesday. Another storm system may impact the region with a soaking rain next Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 930 AM Thursday...Robust southwest flow and the approach of a weakening cold front into the I-95 corridor this evening is on tap. Present timing brings a few showers or an isolated TSTM 9-10 PM this evening into our deep interior. Continued diurnal cooling however and waning low-level convergence due to veering winds to SW overnight will likely kill the convective intensity after midnight, possibly full dissipation. Current POPs look representative for tonight and no significant changes planned. The previous forecaster discussion below. As of 330 AM Thursday...Moderately strong warm advection will push afternoon high temperatures a solid category above climatology. Most areas away from the immediate marine influence will heat up into the mid 80s. Moisture too will be on the rise in the warm advection zone though most of it may remain just to our west. There are considerable differences regarding not only the eastern progress of the moisture but also the sense of timing. The 00Z EC supports the far less agressive WRF but did raise POPS a bit in deference to the much wetter GFS as well as to match with neighboring WFOs. Any storms that do make some progress into western zones this evening will then fizzle out as they both encounter the ridging offshore and also lose daytime heating. Again the GFS maintains action through the night mainly along the coast with a tongue of warm advection and a bit of a low level jet. Will carry 20 POPS to cover for this possibility. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 330 AM Wednesday...Models now consistent with stalling the approaching cold front just west and north of the FA early Friday. Weak dynamics and avbl instability, models indicating 2k to 3+k CAPE, will all combine to carry widely scattered showers or thunderstorms across portions of the FA. Convection will also occur along the pinned sea breeze boundary by Fri midday thru the aftn. Fri highs will see widespread 80s with a few 90 degree readings possible inland from the coast. For Fri night thru Sunday morning, ridging both aloft and at the sfc will be the primary drivers for sensible wx conditions across the FA. The building heights 590+ dam and subsidence overhead will help keep convection to a minimal, if any at all. The sea breeze will be active in terms of cu development along it, however any vertical growth of the cu will be suppressed. Sat highs will see widespread 80s again. With southerly flow in the lower levels during Sat thru Sat night, the marine influence will push further inland, also aided by the sea breeze, and keep 90+ degree readings well inland, ie. along or west of the I-95 corridor. Summertime readings for min temps can be expected with mid to upper 60s to around 70 at the coast where latest SSTs are in the 70s now. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 300 PM Wednesday...Surface and mid level high pressure just off the east coast will maintain deep southerly flow on Sunday. However, subsidence on the periphery of the ridge aloft should keep diurnal convection to a minimum. Cannot rule out an isolated sea breeze shower but any activity would be short lived and very isolated. Temperatures will be above to well above normal. Surface and mid level ridge start to weaken and drift east Mon, allowing a cold front into the region. Front moves across the area Mon night, likely accompanied by some convection. Although the parent low will be over the Great Lakes (along with the bulk of the dynamics) there are still at least a few signals pointing to some potential for strong/severe storms ahead of the front. Strong low level jet will be in place along with modest divergence aloft and potential for PVA as shortwaves rotate around the base of the trough. Confidence is low at this point as timing and instability remain in question but is something to keep an eye on. Front moves off the coast early Tue with high pressure building in from the west during the day then shifting overhead Tue night before moving offshore Wed. Flow aloft will remain west to southwest Tue and Wed as dry air and subsidence help dry the region out with temperatures running near climo. && .AVIATION /13Z THURSDAY THROUGH MONDAY/... As of 12Z...Mainly VFR conditions through this afternoon. A weak cold front will make it`s closest approach from the west tonight and early Fri before washing out altogether during Friday. MVFR conditions possible this evening thru the overnight period. For now will just indicate VCTS or VCSH during that time span. Ceilings may lower to MVFR or even IFR if you choose the NAM model. For now, will be more optimistic and indicate MVFR. Winds will start out SSW 5 to 10 kt and increase to S 10 to 15 kt with g20 kt this afternoon and evening. The higher gusts will occur across the coastal terminals due to an active sea breeze. Extended outlook...Isolated MVFR showers early FRI. Thereafter, VFR through Sunday. Periods of IFR/MVFR in convection late Monday into early Tuesday. && .MARINE... NEAR TERM /THROUGH THURSDAY/... As of 930 AM Thursday...SE waves 2-3 feet every 8-9 seconds and SSW waves 1-2 feet every 4-5 seconds will comprise the wave spectrum. No showers or TSTMS expected, until pre-dawn Thursday when a few marine showers are possible. No significant changes to the forecast, do expect gusts to 20 KT, possibly a bit higher this afternoon inshore as a vigorous sea breeze forms. As of 330 AM Thursday...Light SW winds will be increasing in speed today as a healthy cold front and upper wave approach from the west. The upper system will be shunted to our north however and the surface boundary will stall well west of the area. This likely spares the region from needing an advisory though late in the period there could be a few 25kt gusts as low level jetting remains along the coast to promote mixing. SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 330 AM Thursday...Sfc high pressure, ie. Bermuda high, centered well offshore and ESE of the Carolinas, will be the primary driver for winds and seas across the area waters. The sfc ridge axis extending west from the high`s center will extend westward and onshore in the vicinity of Cape Romain thruout this period. This will result in Southerly winds across the local waters, except SSW-SW from Cape Fear northward due to the ridging placement. Windspeeds will run 10 to 15 kt with gusts to 20 to 25 kt possible especially the nearshore waters during the evolution and any inland progression of the sea breeze. Significant seas will run 2 to 4 ft thruout, except up to 5 ft early Fri. Dominant direction will be from the SE early Friday and more southerly late Fri thru Saturday night. Dominant periods Fri will run 6 to 8 seconds then drop to 4 to 7 seconds Fri night thru Sat night due to wind driven waves becoming the main force. LONG TERM /SUNDAY THROUGH MONDAY/... As of 300 PM Wednesday...Bermuda High will maintain southwest flow through much of the period. Speeds 10 to 15 kt Sun will increase late Sun as gradient becomes more defined. Cold front approaches from the west as the surface high shifts east. Speeds increase to 15 to 20 kt Sun night and peak at 20 to 25 kt Mon with low level jet approaching 40 kt. Seas around 3 ft Sat into Sun will start building Sun night, approaching 8 ft on Mon. Headlines may be required as early as Sun evening. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...COLBY NEAR TERM...COLBY SHORT TERM...DCH LONG TERM...III AVIATION...RALF/43 is the U.S. government's official web portal to all federal, state and local government web resources and services.