Key MESSAGE 1, Multiple rounds of showers and thunderstorms expected across ENC through early tonight. The first area of storms has already fired up along the sea breeze, with a scattered line of storms from near Jacksonville to Downeast Carteret and the Pamlico Sound. Here, SPC mesoanalysis shows plenty of instability with MPCAPES of 2500 j/kg. This coincides with effective shear of 20 to 25 kts, peaking around the western Pamlico Sound. Shear and instability profiles support isolated downburst potential, with some hail not out of the question. All parameters are lower than yesterday so the current marginal risk (level 1 out of 5) seems reasonable from SPC. In addition to the severe threat, PWATS above 2 inches support locally heavy rain. This would be of special concern in any urbanized areas or the Outer Banks, due to our ongoing drought.
Meanwhile a disturbance in the jet stream winds aloft moving into northwest North Carolina now, will sweep through by 03Z tonight. In response a broken line of storms has already formed near Raleigh. Expect this line to fill in, as it merges with and catches up to the sea breeze activity and enters an area of higher instability (our area). All in all, much of Eastern NC will see some period of rain and thunder this evening. Later tonight a back door cold front will move through, ending our rain chances after midnight.
KEY MESSAGE 2, Dangerous heat builds out of the central part of the United States and into our area by weeks end. No significant changes to the extended forecast as an omega block sets up across the Eastern CONUS with anomalous ridging persisting across the the midwest and eastern US next week. This will bring the potential for an extended period of dangerous heat to ENC starting Thursday and continuing into the July 4th weekend. Nws probabilistic Heat Risk values of reaching major heat risk levels or higher are currently sitting at about, 60-80% on Thurs, and 80-90% on Fri/Sat which is fairly notable given the higher end values this far out. This would be reflective of high temperatures above 100 inland, with heat indices potentially reaching or exceeding 110 degrees. Those sensitive to heat and anyone planning on spending ample amounts of time outside later next week should continue to monitor the forecast trends as this potential heat wave would have impacts on the holiday weekend.
18z Sunday through Friday Multiple rounds of convection possible all TAF sites through early evening. Beyond the next few hours, hard to pinpoint exact impacts. For now we used a tempo group to show the most confidence the next few hours as a sea breeze moves near or past the terminals, and a new line of storms moves in from the west.
Medium confidence later tonight behind a backdoor cold front, MVFR cigs build in from the north. Some IFR cigs can't be ruled out, especially at KPGV, but confidence is too low at the moment. Improvement to VFR may be slow Monday, and not until mid morning.
Outlook (Mon afternoon through Thu): Patchy fog and low stratus will be possible each morning.
Showers and thunderstorms likely on the waters through early tonight. Any storm that develops would bring a threat for locally enhanced winds and seas, as well as frequent and dangerous lightning. The best potential for stronger storms through the next few hours appears to be near and over the Pamlico Sound and Neuse Rivers.
Outlook (Monday through Friday): Winds will eventually shift from the SW to the NE into Monday from N to S behind a backdoor cold front. We will have a brief window of near SCA conditions Monday afternoon and evening, especially off Cape Hatteras and closer to the Gulf Stream where winds briefly may touch 25 kts with seas nearing 6 feet for a time. By Tuesday, winds wil begin to relax with east to southeast light winds through the end of the week.
Nc, none. Marine, none.
