Key MESSAGE 1, Latest surface analysis shows surface high slowly migrating off the mid-Atlantic coast this afternoon as broad mid-level ridging continues to dominate over the southern plains and southeastern CONUS. After the seemingly unrelenting heat and humidity of the past few weeks, today's weather stands in stark contrast with highs in the low 80s and Tds dipping into the mid to upper 50s.
As the high moves offshore, southerly to southwesterly flow will resume across the Carolinas bringing a gradual return of temps into the 90s as well as a jump in humidity with Tds gradually working back into the 70s. Mid-level subsidence aloft will keep precipitation chances very subdued at least into tomorrow despite the uptick in instability, although cannot completely rule out an isolated shower or two along typical sound and sea breeze convergence zones. Shortwave approaches from the central plains on Thursday, weakening the ridge and aiding in a slightly more favorable environment for isolated to widely scattered showers and thunderstorms.
KEY MESSAGE 2, Friday the high continues to shift offshore and a front sweeps south through the Mid-Atlantic region. Ahead of this front, continuous warm, moist advection in southerly flow will help build PWATs to near 2". This will bring scattered to numerous sea breeze showers/tstorms back in the forecast. Meanwhile, despite the high shifting offshore, some residual ridging should slow down the progression of the front as it moves south. Where the front ends up stalling remains a point of uncertainty in the forecast with a handful of guidance now showing the front getting hung up right across the middle of eastern NC. Wherever the boundary sets up, along it training showers/thunderstorms are possible, and a narrow swath of deep layer shear right along the front would bring both a low end hydro and severe threat. The extent of the hydro and severe threat are dependent on the frontal location and will continue to be monitored. As of this afternoon, hydrologic concerns remain the primary hazard but a low-end severe risk remains in the cards.
The front lifts back north Saturday into Sunday as a shortwave moves through the region. This shortwave will bring slightly better chances for showers and thunderstorms this weekend. Shear doesn't look to be impressive, but ample moisture will promote a marginal hydro threat. There is some uncertainty with how much instability is in play Saturday, as it is dependent on cloud cover and associated surface heating. In a low-end CAPE outcome, (500-1000J/kg) we would have long skinny CAPEs that suggest just a hydro threat and less frequent lightning. Meanwhile a high- end CAPE outcome (2000-4000 J/kg) would bring more pulse- like thunderstorms capable of producing some gusty winds, frequent lightning, and heavy rainfall rates. Regardless of how Saturday plays out, there is higher confidence on a low- CAPE outcome Sunday. While heavy showers and some thunderstorms are possible Sunday with the shortwave, the severe threat appears to be more muted.
18z Tuesday through Sunday Widespread VFR conditions remain in place across all of eastern NC as high pressure remains in control and shifts off the coast of the mid-Atlantic. Main concern for aviation interests tonight will be a patchy fog risk as skies are expected to be clear and winds calm, despite very dry air aloft. Slightly higher probabilities for at least MVFR vis restrictions are forecast west of EWN, but remain low (no higher than 20-30%).
Tomorrow, remain but with winds veering south to southwest as high moves further offshore. Cannot completely rule out an isolated shower or storm along area sea and sound breezes.
NOTE: AMD NOT SKED has been appended to the EWN TAFs as the site is not transmitting through normal channels. The site is still reporting via telephone so it will be monitored, but not as frequently as when it is completely operational. The next closest ASOS is at Cherry Point (KNKT).
Outlook (Thursday through Sunday): Primarily VFR conditions are expected to continue into Thursday but with an uptick in shower and thunderstorm coverage. A front is expected to approach the region Friday and Saturday bringing a chance of showers and thunderstorms with periods of sub-VFR conditions possible.
Improving marine conditions observed across area waters as east to northeast winds ease to 10 to 15 knots and seas down to 3-5 feet with periods of 8-11 seconds. Improving conditions expected through tonight and into tomorrow as high pressure moves offshore and winds subside, eventually veering south to southwesterly Wednesday into Thursday.
Outlook (Wed through Sat): SW winds expected to be around 10-20 kt Thu with seas building 2-4 ft as a front approaches the area. Winds have trended up slightly ahead of the front Thursday afternoon into evening, and there is a slight chance (20%) of SCA conditions across northern waters and sounds.
A coastal trough may also set up Thursday night into Friday, bringing increased tstorm chances along the Gulf Stream. The front is forecast to stall to our north, but with the proximity of the front and additional shortwaves moving through this weekend, we are expecting a more unsettled pattern Friday- Sunday.
Nc, beach hazards statement until 8 pm EDT this evening for ncz196- 203>205. Marine, none.
