Key MESSAGE 1, ENC remains firmly entrenched in the warm sector, with front stalled to the north/west and deep moist SSW flow continuing. The front will remain quasi-stationary through the middle of the week and should be the primary focus for convection through Thursday. Away from the front, convection should mostly be seabreeze-driven, best chances along the coast early then shifting inland in the afternoon. The mean storm motion parallel to the front, plus moderate instability and 2" PWATs will continue to support a risk of intense rainfall rates and possible localized flooding. Some increase in mid-upper level westerly flow this afternoon will yield bulk deep layer shear approaching 25 kt, and thus some increase in the potential for storm organization during peak heating as moderate instability develops on the order of 2.5k J/KG.
Tonight, the cold front is expected to finally advance southward through srn VA this evening, and into nrn portions of ENC later tonight, Convection along the front may be ongoing in the early part of the evnening acrs srn VA, and if they become cold pool driven as some CAMs indicate, these storms may make it into the Albemarle region by around midnight. Thus a localized inc in pops here to 40-60% later this evening appears reasonable.
Thursday, tricky forecast in place, as aforementioned front placement will dicate coverage and intensity of potetial thunderstorms. If tonight's storms hold together longer, they would act to drive the front into ENC earlier, and thus limit convection threat to far srn portions of ENC, but if front gets held up and is on the slower side, storms would tend to intitiate further north. Have gone with a compromised soln, and have a broad area of chc pops for the nrn 2/3 of ENC, while likely to cat pops are in place for the srn portions, where the front interacting with developing sea breeze yields best chances for more widesprad showers/storms. With mid level flow inc even further, deep layer shear inc to 30+ kt, and coupled with moderately strong instability, may yield a strong to severe thunderstorm risk Thur afternoon through early eve.
KEY MESSAGE 2, The cold front sweeps through Thur night, bringing drier and cooler conditions Fri as N-E flow develops. The front will then quickly lift back N as a warm front on Sat. Some guidance still indicates potential low pres sweeping eastward along the front on Sat, though large model-to-model spread, as well as ensemble model spread, continues with the 27/00Z med range model suite, so a general chc showers remains for the FA. Best chances would be far srn areas of ENC where better moisture resides, but details in synoptic and mesoscale have yet to be resolved, so less than average confidence on the Saturday forecast remains.
KEY MESSAGE 3, Good confidence on another cold front sweeping through Sat night, bringing another round of more seasonable temps and humidity Sunday into early next week, with highs expected in the upper 70s, and lows in the 55-60 range inland, to 60-65 beaches.
12z Wednesday through Sunday MVFR (KPGV and KISO) to IFR (KEWN and KOAJ) cigs will lift back to VFR by 13-14Z. Sct showers and storms expected again this afternoon and eve with brief periods of sub VFR conditions wherever showers and tstms develop. Chance of storms will be handled with a prob30 at EWN and OAJ where local seabreeze has the best chance of tstorm formation after 17Z today. Chances for thunderstorms too low at ISO and PGV for a prob30 or VCTS mention attm.
Outlook (Thursday through Sunday): A cold front will push through the terminals late Thu and Thu night. Scattered to numerous showers and storms may bring periods of sub-VFR esp for srn terminals Thu afternoon. Drier and cooler conditions expected behind the front Friday. Periods of sub-VFR may return Sat with another chance for rain and some storms. Vfr returns Sunday behind frontal passage.
Latest obs show SW winds 10-20 kt with seas 2-4 ft. Seas remain elevated in combo of windswell and longer period NE swell from the northern Atlantic. Gradient will tighten this afternoon through tonight as thermal trough strengthens inland in tandem with approaching cold front from the north. Sw winds will increase to 20-25 kt for the coastal waters south of Oregon Inlet and Pamlico Sound. May see ocnl gusts to 25 kt for the Croatan/Roanoke due to the localized funneling from the SSW here but opt out of SCA issuance attm. The gradient relaxes late tonight with winds diminishing below 25 kt, though seas remain 6 ft through Thu morning for the coastal waters. No change to end times for the SCA's
Outlook (Thursday through Sunday): Unsettled weather will continue through Thursday with shower and thunderstorms chances persisting. The front will push south of the waters Thu into Thu night, with winds becoming N to NE behind the fropa from north to south across ENC and remaining through late Fri. Winds will remain below SCA levels behind the front, with seas generally 2-4 ft. Winds turn back around to the S on Sat as the front moves back north as a warm front. Then another front moves through Sat night, with winds becoming N to NE again by early Sunday. Sca conditions possible with this round of nerly flow on Sunday.
Nc, beach hazards statement through this evening for ncz195-196- 199-204-205. Marine, small craft advisory from 2 pm this afternoon to 6 am EDT Thursday for amz135. Small craft advisory from 2 pm this afternoon to 10 am EDT Thursday for amz152-154-156-158.
