Area Forecast Discussion
Issued by NWS Newport/Morehead, NC
Issued by NWS Newport/Morehead, NC
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843 FXUS62 KMHX 080701 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 301 AM EDT Wed May 8 2024 .SYNOPSIS... High pressure will continue to strengthen offshore while weak troughing continues for the next few days, as warm moist southerly flow leads to unsettled conditions. A strong frontal system will move through Friday. Drier and more seasonable temperatures expected this weekend. && .NEAR TERM /THROUGH TODAY/... As of 3 AM Wed...Latest analysis shows high pressure anchored offshore, weak sfc troughing inland and mid level ridge building over the SE US. Mid-upper level ridging will grad shift offshore today, allowing more of a zonal flow aloft to develop over the Carolinas. Within the flow, an impulse, or two, lifting out of the Lower MS Valley will move through the SE later today and tonight, interacting with a moist and unstable airmass to support an increased risk of clusters of thunderstorms. Locally, there will also be some potential for convection along the seabreeze, which may be pinned closer to the coast courtesy of the westerly low-level flow. Challenging forecast regarding convective development today and tonight, and it remains low confidence. This type of setup is a classic one for MCS development, though with this type of pattern models can oftentimes struggle with the evolution of convection as it moves downstream. Diurnal heating of a warm, moist airmass will support moderate to locally strong destabilization this afternoon, with MLCAPEs increasing to 2-3,000 J/kg and deep layer shear 25-35 kt. This will support the potential for organized tstms, with potential for damaging winds (60+ mph), large hail (>1") and an isolated tornado. The caveat is that the evolution of upstream convection will have a significant impact on the airmass, as any early convection would tend to keep instability lower, and vice-versa. Eastern NC remains in a Slight risk of svr wx (west of Hwy 17) and a Marginal risk (east of Hwy 17). Timing wise, it looks like the greatest svr wx threat will be late this afternoon into early evening...though depending on the evolution, the threat could linger later into the evening. 00z CAMs show little convective development before 20z. Hot and humid today, with highs climbing to around 90/low 90s inland, and low to mid 80s for the beaches. Temps combined with dewpoints in the upper 60s will lead to heat index values peaking in the mid 90s for much of the area. && .SHORT TERM /TONIGHT/... As of 3 AM Wed...Convective threat will likely linger through this evening and possibly through the overnight hours. Initial seabreeze driven convection will likely weaken will loss of diurnal heating this evening, with potential for a secondary round of convection overnight as weakening MCS moves across the Carolinas. The potential for svr wx will continue, with main threats still damaging winds, large hail and an iso tornado. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As 330 AM Tue...There have been a few changes in the forecast since the previous update but the overall trend remains the same as ENC will remain unsettled into this weekend with a daily chance for showers and thunderstorms into Friday before potentially drying out on Sat. Highest risk for severe weather still looks to be on Thursday. High pressure ridging finally overspreads ENC early next week. Thursday...Have made some tweaks to the forecast for Thurs with the latest data and trends in mind. Upper level zonal flow begins to overspread ENC on Wed out ahead of a positively tilted upper trough which will be located in the Upper Midwest to start the period. Within this zonal flow, guidance has come into better agreement that a weak mid level disturbance will trek across the Carolinas and then offshore Wed evening into Thurs morning. As Wednesday`s shortwave pushes off the coast, any leftover shower and thunderstorm activity will quickly weaken Wed night into Thurs and push offshore. As we get into Thurs, upper level trough migrates over to the Great Lakes region while a jet streak begins to expand over the Mid-Atlantic increasing lift. At the mid levels a second and stronger mid level shortwave rounds the base of the trough and tracks over the Mid-Atlantic Thurs afternoon/evening while at the surface deepening low pressure system in the Great Lakes tracks NE`wards into the Northeast with its associated cold front nearing western NC and a prefrontal trough setting up over the Coastal Plain Thurs evening. With ample MLCAPE 1000-2000 J/kg over ENC in the afternoon, stronger wind shear 30-40 kts, and slightly stronger forcing, ENC will once again have another threat for scattered showers and isolated to widely scattered strong to severe tstms. Once again the main hazard within the strongest storms will be damaging winds and hail. Given the higher risk for severe wx on Thurs ENC is in a slight risk (level 2 out of 5) for severe weather Thurs afternoon and evening. Highs each day get into the low 90s inland and 80s across the OBX while lows only get down into the 60s. Friday through early next week... Upper level troughing finally pivots out of the Great Lakes and overspread the Mid-Atlantic on Fri into Sat with the last and likely strongest mid level shortwave rounding this troughs base on Fri. This is where the biggest change in the forecast has been as at the surface, low pressure in the Northeast will continue to trek NE`wards while its associated cold front finally tracks across the region slowing as it pushes offshore. A wave of low pressure develops along this frontal boundary on Fri as well and tracks along or near the coast. The eventual track will have a major impact on whether the area sees thunder on Fri as a low track just offshore keeps us on the cool and more stable side while a low track just inland gives us a threat for additional thunderstorms on Fri. For now kept thunder in the grids for Fri afternoon and evening until we get more clarity on the eventual evolution of the forecast. Either way Friday looks to have the best shot at widespread precip. Through the weekend and into next week general troughing remains over the Eastern Seaboard before gradually ejecting out into the Canadian Maritimes. Will have one more chance at a frontal passage Sun evening into Mon before surface ridging begins to overspread ENC from the west. Temps do cool over the weekend closer to normal. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /through tonight/... As of 3 AM Wed...Pred VFR conditions expected through most of the TAF period. HREF probs for stratus early this morning, at less than 10%. Scattered showers and thunderstorms expected to develop late in the afternoon, mainly after 20z which may bring occasional sub-VFR conditions along with the potential to bring strong wind gusts and hail. LONG TERM /Thursday through Sunday/... As of 330 AM Tue... Expecting primarily VFR conditions outside of any shower and tstm activity Thurs with the best shot at seeing widespread sub-VFR conditions on Fri. VFR conditions then return on Sat across the CWA. && .MARINE... SHORT TERM /through tonight/... As of 3 AM Wed...Latest obs show SW winds 5-10 kt north of Hatteras and stronger at 10-20 kt south of Hatteras, with seas 2-4 ft. SW winds will be increasing through the day as the thermal gradient strengthens. Could see a brief period of SCA conditions across the waters and Pamlico Sound late this afternoon and evening, with gusts to 25 kt, and seas building to 3-5 ft. There will be a risk of showers and thunderstorms, especially late afternoon through the overnight hours. LONG TERM /Thursday through Sunday/... As of 340 AM Tue...Not much change in the forecast overall as unsettled weather will remain in place into the end of the week promoting a daily chance at showers and thunderstorms across our waters each day. Locally enhanced winds and seas will be possible within any thunderstorm that makes its way into the area. Otherwise the background winds remain SW`rly at 10-20 kts on Wed with a few gusts up near 25 kts at times Wed aftn and evening as the thermal gradient sets up. As we get into Thursday, gradient tightens out ahead of an approaching cold front allowing winds to increase closer to 15-25 kts with gusts in excess of 20-30 kts across our waters. Strongest winds will be located across our coastal waters and larger sounds likely necessitating a SCA for Thurs across portions of ENC. As the front nears and begins to push offshore on Fri winds decrease closer to 10-15 kts and become more W`rly on Fri before becoming NW`rly and increasing slightly to 15-20 kts Fri night behind the frontal passage. NW`rly winds continue through Sat before winds return to a S`rly direction towards the end of the weekend. 3-5 ft seas along our coastal waters on Wed increase to 4-7 ft on Thurs as the winds increase with some 8 ft seas possible along the Gulf Stream waters. Seas gradually ease over the weekend as winds ease down to 2-4 ft. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...CQD SHORT TERM...CQD LONG TERM...RCF AVIATION...CQD/RCF MARINE...CQD/RCF