Key MESSAGE 1, Forecast through tomorrow will be heavily dependent on various mesoscale features, which in turn will dictate where stronger storms and flooding will be focused. Fluctuation's in risk areas are likely as ongoing convective evolution is analyzed.
Environment today has indeed been favorable for strong storms and torrential rainfall. Convection got an early start, developing as early as 11 AM and blossoming along the stalled frontal boundary, then compounding with convergent outflows and diurnal sound and sea breezes. Severe and flooding risk has decreased substantially for the rest of this evening, as outflows have worked over the environment bringing widespread convective inhibition to the region. Still. Pwats are impressive and moderate rainfall is occuring and expected to continue.
The combination of lesser surface based instability and an anomalously moist airmass should continue to support the potential of 1-2"/hr rainfall rates. Continued rainfall chances tonight keep the Flood Watch in effect, but current radar trends suggest flooding threat is decreasing.
Convective threat remains tomorrow as front remains stalled over the region. Like today, convection could get an early start as soon as 15z and spread inland through the afternoon. Shear will be quite a bit weaker and the severe threat will be less than 5%, but high forecast PWATS point to another day of efficient rainmakers and potential flooding concerns.
00z Saturday through Wednesday Widespread light to moderate rain occuring, with some thunder observed along the coast. Rain chances continue through the night, with inland locales likely remaining thunder free as SBCIN has spread over the region from outflows earlier today. However, some high-res guidance is showing showers/tstorms inland as a shortwave moves through. This outcome seems to be more unlikely than not, so have kept thunder mentions out of TAF sites at this time. Sub-VFR conditions (both vis and cig) are expected to set in tonight with rich low level moisture and light to calm winds.
An increased TSRA risk is expected to return Saturday afternoon/evening with heavy rain, frequent lightning, and strong to severe storms possible. Sub-VFR CIGs could linger through much of the day Saturday, it all depends on how much daytime heating eats away at any stratus deck overhead.
Outlook: The TSRA risk should take a step down on Sunday, but the risk isn't low either. It may not be until Monday before the risk substantially lowers.
Local and regional observations show a frontal boundary has pushed south and stalled over area waters, orientated roughly from Ocracoke to the mouth of the Neuse River. Winds on either side of the boundary are around 10 kt with seas a subdued 2-3 feet. Main threat for marine interests through tonight and into tomorrow will be convection, especially overnight as a complex originating over SC progresses and begins to impact waters close to midnight. These storms will pose a risk of strong winds potentially exceeding 40 kt as well as waterspouts, especially for cells close to the frontal boundary.
Outlook: An active thunderstorm pattern is expected to last into at least tomorrow, with a somewhat lower risk by Sunday and Monday. A more dominant southerly flow is expected to become established on Saturday and last into Sunday. A cold front then moves through late Sunday with a west to northwest wind shift. Seas build to 3-5ft on Saturday, then lay down to 2-3ft by late Sunday as winds also lay down. Light winds and reduced seas are then expected into the middle of next week.
Nc, flood watch until 8 am EDT Saturday for ncz044-079-080-090>092- 094-193-194-198. Marine, none.
