Key MESSAGE 1, Notably warm low-level thicknesses beneath an anomalous mid-upper level ridging will continue to support above to well above normal temperatures across the Carolinas through Wednesday. Guidance shows similar low-level thicknesses each afternoon yielding highs generally in the lower 90s across the coastal plain but some warmer spots may reach mid 90s, remaining just shy of records. It will be closest across the coastal plain, however.
Additionally, despite increasing low-level moisture, ridging aloft should provide sufficient subsidence to suppress convective activity outside of perhaps a rogue shower or thunderstorm where convergence is maximized along the seabreeze. Still, probs of this occuring are low enough to keep out of the forecast with this update.
KEY MESSAGE 2, The mid-upper level ridge is forecast to break down some late-week and into the weekend. This should allow a front to drop south into the Thursday into Friday. There continues to be some uncertainty regarding whether or not the front fully makes it through ENC, whether it stalls, or whether it lifts quickly back north as a warm front. Given the strength of the ridge, it stands to reason that the front will struggle to get fully through ENC, and the forecast continues to reflect this scenario. Then, ridging may try to build back late in the weekend, which would favor the front lifting back north as a warm front by early next week.
Based on the above, increasing moisture and instability along the frontal zone should support an increased risk of showers and thunderstorms. Probabilistic guidance shows a solid chance of 0.25"- 0.75" each day from Thursday into the weekend. However, it should be noted that those amounts will be highly dependent on the evolution of the frontal zone. Initially when the front drops into the area, there may be just enough flow aloft to support some thunderstorm organization and perhaps a marginal risk of strong to severe thunderstorms. Machine learning and analog guidance support this potential as well. However, no one day stands out as having a higher risk of severe thunderstorms.
Notably high PWATs along the frontal zone should support higher rainfall rates in convection. However, notable hydro impacts are not expected due to the recent dry stretch and ongoing drought conditions.
18z Monday through Saturday Pred VFR through this evening with subsidence beneith an upper ridge limiting cloud development to few-sct diurnal cu. S-SW winds generally less than 10 kt ahead of the sea breeze, then could see gusts around 15-20kt behind it this afternoon into the early evening hours. Winds become light late tonight with clear skies bringing good radiational cooling conditions and could see fog and low stratus redevelop inland late tonight. Href probs for sub-VFR conditions currently around 40-60%.
Outlook: A dry seabreeze pattern looks to continue through Wednesday. Beyond then, a frontal boundary sagging south into ENC is expected to bring an increasing risk of SHRA, TSRA, and sub-VFR conditions.
A summer-like pattern continues through the middle of the week, with a daily building of winds to 10-20kt each afternoon and evening as the thermal gradient tightens. This will especially be the case for the inland rivers and sounds and the nearby coastal waters within 20nm of the coast. Seas will continue around 2-3ft, potentially up to 4 ft during the afternoon and evening.
Outlook: A frontal boundary is forecast to sag south into the area late-week, then meander around the area through the upcoming weekend. This leads to lower confidence regarding winds and seas, but especially wind direction. In general, the risk of 25kt+ winds appears low during this time ahead of the front, with slightly higher chances of seeing 25+kt gusts behind the front. There will be an increased risk of thunderstorms along the front as well.
Nc, none. Marine, none.
