Key MESSAGE 1, An anomalously strong ridge will remain in place across the Southeastern CONUS through Wednesday, with NAEFS standardized anomalies around 2-3 standard deviations above normal for the time of year across the area. As a result this will continue to bring well above avg temperatures to Eastern North Carolina today out ahead of an approaching cold front with near record to record high temperatures possible on Tue/Wed out ahead of an even stronger cold front (See CLIMATE Section below). Biggest threat for breaking records will be across inland locations as relatively cool water temps should moderate high temps near the immediate coast. Highs today will reach the upper 70s/low 80s along and west of US 17, and upper 60s/low 70s closer to the coast. A cold front then gradually pushes across ENC tonight into Monday bringing widespread showers and isolated thunderstorms as well as ample cloud cover which will help to bring down high temps a few degrees on Mon, but temps will remain well above normal regardless. After this front lifts back to the north, even warmer conditions are likely to develop Tue/Wed next week ahead of a stronger frontal system Thursday.
KEY MESSAGE 2, A positively tilted upper level trough will quickly traverse across the Mid-Atlantic and Northeast today with the tail end of this trough tracking across portions of the Southeast. At the mid levels a shortwave will be traversing along the southern periphery of this upper trough promoting lift across the Carolinas. At the surface, a cold front will track across the Carolinas and then linger around the area on Monday before lifting north as a weak warm front. Out ahead of the the cold front, a warm and moist airmass will be in place promoting some modest instability across the region with 500-1000 J/kg of MLCAPE forecast to overspread much of ENC this afternoon, while at the same time deep layer shear will increase to 25-30 kts. As we get into the afternoon, a seabreeze is likely to develop and push inland, eventually interacting with the incoming cold front. This will result in a chance for some scattered to widespread showers and thunderstorms across ENC. Showers and thunderstorms will start out isolated along the seabreeze but then quickly increase in coverage and intensity later this afternoon across the Coastal Plain as the seabreeze interacts with the incoming cold front, and this activity will then push towards the coast and offshore tonight. Some of these storms could become strong to severe in nature bringing a damaging wind and small hail threat within the strongest storms. Spc has put much of the area (outside of the OBX) under a marginal risk for severe thunderstorms today with greatest likelihood of seeing stronger storms occuring between about 2PM-11PM today along and west of Hwy 17. Have kept PoP's at likely to categorical for the most part given the good signal for storms. Overall model guidance suggests widespread rainfall amounts of 0.5-1.0 inches with locally higher amounts. While unlikely, (<20% chance of happening) HREF PMM QPF values for a 24 hour period (8AM Sun-8AM Mon) show amounts as high as 1-1.5 inches. Current thinking is this would be the max 24 hour amount possible and only occur if thunderstorms happened to train over each other. Either way given the ongoing drought any rain is welcome.
KEY MESSAGE 3, Guidance has been surprisingly consistent with the forecast for later this week showing a deep neutral to negatively tilted upper level trough approaching and tracking across the Eastern Seaboard on Thursday. At the surface a rapidly deepening low pressure system will be tracking NE'wards across the Great Lakes and Interior Northeast while its associated strong cold front sweeps E'wards across the Mid- Atlantic and Southeast. Ahead of this front, strong southwesterly winds will help bring up moisture, with PWATs modeled to be in the 1.25-1.5" range. While there will be ample forcing, there is still a fair amount of uncertainty on exact timing of the front which is typical given how far out the frontal passage is. This in turn impacts the amount of CAPE available. An earlier progression of the precip (Thursday Morning) would keep instability on the lower end, reducing a severe threat. However, an afternoon progression of the precip would maximize the available instability. This front will be worth monitoring for severe weather concerns as it gets closer. Given the impressive dynamics of this system, elected to not use NBM winds for Thursday as they appear to be much too low. Current forecast has wind gusts around 30 mph inland, 35mph along the coast. Behind the front cool, dry air moves in for Friday.
06z Sunday through Thursday Mix of VFR and MVFR currently across the terminals, mainly low stratus, with patchy sea fog lingering along the coast. Due to the SW breeze, fog not likely to be a concern inland (though sea fog along the coast likely to persist), though plenty of low level moisture will allow low stratus to develop. Widespread MVFR cigs likely to develop at the terminals, with potential for a few hours of IFR btwn 8-13z. Low stratus will mix out after 14-15Z this morning. Showers with sct thunderstorms develop on this afternoon and evening, as well as strengthening SW winds with gusts 20-25kt as a cold front approaches. Widespread sub- VFR likely (fog and low stratus) to develop late tonight into Monday morning.
Outlook, Monday through Thursday: Once this front pushes through the area it will likely stall near the region continuing to bring chances for sub-VFR conditions to ENC Mon and Tue (mainly periods of fog and stratus) before widespread VFR conditions officially return on Wed. Sub-VFR may return Thursday with scattered to numerous showers.
Latest obs show increasing SW'rly winds across our waters with widespread 10-15 kt winds noted across the inland waters and 10-20 kt winds noted along our coastal waters south of Oregon Inlet. Seas currently remain at 2-5 ft. Expect winds to increase slightly later this morning and into this afternoon as an approaching cold front tightens the pressure gradient. This will result in 10-20 kt SW'rly winds across our inland waters with 10-20 kt winds and 25-30 kt gusts along our coastal waters south of Oregon Inlet. In addition to this, seas will also build to 4-6 ft by this morning as well resulting in SCA conditions across our coastal waters south of Oregon Inlet. With this in mind, kept the ongoing SCA in place. Conditions change little through this afternoon, however, as we get into this evening a cold front will gradually push offshore bringing widespread showers and thunderstorms to our waters. Locally enhanced winds and seas will be possible within any of this activity with the thunderstorm threat likely lasting until after midnight tonight. As front pushes offshore the gradient will ease allowing for SW'rly winds to decrease down to 5-10 kts with gusts up around 15 kts. Seas will also fall closer to 3-5 ft tonight ending the ongoing SCA's by 2AM Mon.
Minor sea fog does continue to persist across portions of our coastal waters, though it is not as thick as previous nights given the elevated winds so do not expect a marine dense fog advisory to be needed this morning. Any leftover fog will likely dissipate by this afternoon with a minimal threat for sea fog forecast through tonight.
Outlook: Benign boating conditions forecast through Wed with widespread 5-10 kt winds and 2-4 ft seas forecast. However, a stronger front will likely cross the waters Thursday. Sw winds will strengthen ahead of the front Wed night with SCA conditions likely and gale force winds also possible. Both GFS and ECMWF ensemble probabilities show a greater than 50% chance for gales across our coastal waters on Thursday so we will need to monitor the forecast in the coming days.
Nc, none. Marine, small craft advisory until 2 am EST Monday for amz152-154. Small craft advisory from 8 am this morning to 11 pm EST this evening for amz156-158.
