Area Forecast Discussion
Issued by NWS Newport/Morehead, NC
Issued by NWS Newport/Morehead, NC
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727 FXUS62 KMHX 010558 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 158 AM EDT Wed May 1 2024 .SYNOPSIS... A weak surface trough will move through the area tomorrow. High pressure then builds in for a couple of days before yet another cold front impacts the area over the weekend. && .NEAR TERM /OVERNIGHT/... As of 2140 Tuesday...ISO showers that popped up near the HWY17 corridor as the seabreeze passed has stopped. No more shower initiation is expected through the first half of the night and any precip will be from upstream convection that pushes into the FA. Aside from subtle Td (and therefore RH and AppT grids) changes, the forecast remains largely unchanged. Previous Disco as of 350 PM Tue...Upper ridge is beginning to move offshore this afternoon as a well-defined shortwave over eastern TN continues to dig towards the Carolinas. At the surface, high pressure remains anchored south of Bermuda extending inland, although a weak surface trough associated with the aforementioned mid-level wave will gradually encroach into the area through tomorrow. Hi-res guidance this morning has depicted a slightly more southern track of the shortwave overnight, with the strongest attendant lift now across SC and far southeastern NC. Consequently, CAMs now show the bulk of the heavier precipitation overnight passing to our south as well and trimmed back areal coverage of PoPs accordingly. A few more isolated showers are still possible farther inland. Maintained a mention of thunder primarily along the coast where instability will remain highest (up to 500 J/kg). Given a lack of shear (0-6 km under 15 kt), no severe threat is anticipated. Very mild lows tonight owing increasing cloud cover and light and steady southwesterly winds, favoring temperatures in the mid 60s. && .SHORT TERM /WEDNESDAY/... As of 405 PM Tue...Shortwave/low will be overhead and moving offshore tomorrow morning while surface trough to our west continues to migrate towards the area. CAMs depict a busy weather day as convergence with the approaching trough and diurnal sea breeze aid in convective development early tomorrow afternoon. Airmass will be sufficiently unstable to support scattered thunderstorm development (HREF average surface CAPES reach up to 1000 J/kg, with most aggressive members at 1500 J/kg). The severe threat is low but non-zero, as shear will initially be weak in the afternoon but begin to increase late as northwesterly mid-level winds increase on the backside of the upper trough. If a strong storm were to develop, strong wind gusts would be the primary threat. Given a northeasterly mean storm motion, convection is likely to remain pinned closer to the coast and migrate little inland, although resultant outflow boundaries will likely spark additional cells. Some locally heavy rainfall is likely, but given how dry the past month has been flooding concerns are minimal. Concentrated the highest PoPs along the Highway 17 corridor. Activity will quickly begin to die off with loss of heating. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... As of 330 PM Tuesday... KEY MESSAGES - Inland highs in the low to mid 80s for the rest of the week - Best rain chances Wednesday and then an unsettled weekend and start to the new week FORECAST DETAILS We return to warm, dry weather on Thursday and Friday with a ridge building over the southeast US. Highs will be in the mid 80s across the coastal plain and low 70s at the beaches. Unsettled weather returns this weekend with multiple chances for showers and thunderstorms. Surface high pressure will be gradually washed out as a surface low forms due to a shortwave trough moving across the southeast. At the same time, a cold front associated with a deep low over south-central Canada will move into our area and stall. PoPs increase west to east on Saturday with shower and thunderstorm activity possible through Monday (15-30% chance). && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /through 06z Thursday/... As of 130 AM Wednesday... KEY MESSAGES - TSRA risk on Wednesday - BR/FG likely late Wednesday evening (60-80% chance) FORECAST DETAILS A weak upper level wave, and an associated surface trough, will move slowly east across the coastal Carolinas over the next 24 hrs. These features will combine with a moistening and destabilizing environment, leading to an increased risk of SHRA and TSRA. Overnight, the TSRA risk looks to be highest offshore and perhaps as far inland as KMRH and KNJM. That is also the area that stands the best chance of low VFR CIGs (3-5k ft) over the next several hours. With continued low-level moistening, there will be a window of opportunity for a period of MVFR CIGs along and east of a line from OAJ to EWN. Guidance isn`t sold on the lower CIGs, so for now I`ve opted to go with a SCT020 layer to reflect the potential. On Wednesday, afternoon heating plus the seabreeze and the above- mentioned front and upper wave will likely lead to scattered SHRA/TSRA, with a focus in the 17z-23z timeframe. Where TSRA occur, sub-VFR conditions are likely (VIS and CIGs). The strongest TSRA will be capable of gusty/erratic winds to 40kt+. At this time, though, the risk of 50kt+ winds looks low (<5% chance at any one terminal). In the wake of the TSRA, light winds, clearing skies, and recent rainfall should support an increased risk of sub-VFR VIS due to BR/FG. The greatest BR/FG impacts are expected to hold off until after the current TAF cycle. LONG TERM /Wednesday night through Sunday/... As of 330 PM Tuesday...Pred VFR expected through the period but a few instances of unsettled weather are expected. An approaching disturbance will bring chances for showers and thunderstorms on Wednesday (30-60%). By Saturday, a cold front will be moving into the area and bring another chance for showers and thunderstorms (15-30%). Lowered CIGs and VIS are expected during these times. && .MARINE... SHORT TERM /through Wednesday/... As of 410 PM Tues...Pleasant boating conditions continue today as high pressure remains in control, although surface trough west of the Appalachians will gradually make its way eastward through tomorrow. Regional observations show seas of 3-4 feet with periods continuing to increase to 12-13 seconds. Southwesterly winds hover around 10-15 kt. Much of the same pattern is expected tonight as the past two, with winds gradually increasing into the early evening hours associated with the tightening thermal gradient. A few spotty gusts to 25 kt are possible primarily across the northern waters tonight into the overnight hours, but not enough to warrant headlines. Trough will move into area waters tomorrow with ambient winds gradually easing through the day, but threat of showers and a few thunderstorms will increase in the early to mid-afternoon, especially for the inland rivers and sounds. Seas remain under 5 feet through the period. LONG TERM /Wednesday night through Sunday/... As of 330 PM Tuesday... KEY MESSAGES - Sub-SCA conditions with multiple chances for showers and thunderstorms FORECAST DETAILS Although marine conditions are forecast to remain below SCA criteria, opportunities for showers and thunderstorms are possible Wednesday and this weekend. Winds will be variable through the period due to several systems moving through but will remain around 5-10 kt with 2-4 ft seas. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...MS/CEB SHORT TERM...MS LONG TERM...OJC AVIATION...RM/OJC MARINE...MS/OJC