Key MESSAGE 1, Meandering frontal boundary has finally made its way offshore early this morning, currently draped from roughly Wilmington to Onslow Bay where convection is blossoming. Behind this boundary, seeing a modest uptick in shower activity as mid-level shortwave digs across the mid-Atlantic. There have been a few elevated thunderstorms riding along an elevated frontal boundary with modest instability present, and this risk will likely persist for a few more hours as the front moves little.
The front is likely to wobble but move little through today as multiple mid-level waves traverse over the boundary in a persistent troughing pattern. The relative lull currently observed on radar is likely to fill in later this morning as SW LLJ increases once again, with heaviest coverage favored south of Highway 70 where low-level convergence is maximized along the frontal boundary. Like we saw yesterday, it is not going to be a constant downpour but rather sct to widespread shower and iso thunderstorm coverage. Very moist airmass remains in place with PWATs nearing 2.5" at times. Persistent cloud cover will keep temps down and limit available instability, so overall rainfall rates will not be as intense as yesterday. Still, given the likely coverage of activity some respectable rainfall accumulations are likely where training occurs.
00Z guidance suite continues to hint at the front lifting slightly back north tonight and into tomorrow as yet another wave traverses the frontal zone. It will be a rinse and repeat to this morning, with a likely lull in coverage before midnight and then another uptick on coverage as the LLJ restrengthens. Instability will remain poor to marginal which should reduce max potential rainfall rates somewhat, but rates up to an inch an hour are still very much possible. Notably, the aforementioned wave will help to deepen the mid-level trough, and a successive wave Sat night will help develop a weak wave of low pressure that should finally pull the frontal boundary and deeper moisture offshore.
Overall rainfall amounts have changed little with continued potential for 3-5" in corridors where training occurs. Highest probability of this is south of Highway 264 to the southern coast, as well as the Outer Banks from Oregon Inlet south. In any robust convection, higher amounts are probable. The REFS continues to show probabilities of 40-50% for amounts over 5" mainly along the southern coast south of Highway 70 for today and Saturday. We remain in a Slight (Level 2/4) risk of excessive rainfall through Saturday, per WPC.
The Flood Watch for the northern half of the FA will be allowed to expire this morning. Given the persistent heavy rainfall signal into the weekend, the segment for the southern half has been extended to Saturday morning and may need further extensions.
KEY MESSAGE 2, With Sunday and Monday trending drier with the lingering front finally getting carried offshore, focus then turns to another front approaching the eastern CONUS next mid- week. This boundary appears weaker and more progressive than our current boundary but will still provide a focus for showers and thunderstorms. Ahead of the boundary, strengthening southwesterly flow and building low-level thicknesses will bring a return of oppressive heat with at least a couple days of heat indices approaching or exceeding 105F possible.
06z Friday through Tuesday Scattered to numerous showers and an occasional thunderstorm will continue to impact area terminals through the next 24 hours. Conditions are currently predominantly IFR and will likely remain this way for the majority of the period. This is all due to a stalled front in the area. Cigs will continue to lower as well, with LIFR/IFR conditions north of the front and MVFR conditions to the south. Given uncertainties in the placement of the front, there are uncertainties regarding when/where LIFR/IFR conditions will occur. Best chc for thunder will be across the southern terminals EWN and OAJ.
Outlook (Friday night through Tuesday): Sub-VFR conditions in SHRA and low CIGs will continue to plague ENC through tomorrow as a frontal boundary remains stalled over the area. The front is forecast to finally shift south of ENC from north to south on Sat with gradually improving aviation conditions by Sunday.
Cold front is currently stalled over Onslow Bay this morning with regional observations showing winds at around 10 kt or less. Gradient will remain relaxed around the front as it moves little through today, perhaps lifting northward slightly later tonight. Winds and seas will remain safely below SCA through the period but multiple rounds of widespread rain and the occasional thunderstorm will continue to plague area waters into Saturday morning.
Outlook: A stalled front will finally shift offshore by Saturday night, with moderate northerly winds developing for all waters by Sunday. The risk of thunderstorms is expected to decrease on Sunday as well. A more typical summertime wind and sea pattern then returns next week.
Nc, flood watch until 8 am EDT this morning for ncz029-044>047- 079>081-203. Flood watch through Saturday morning for ncz090>092-094- 193>196-198-199-204-205. Marine, none.
