Key MESSAGE 1, Strong high pressure building into the Mid-Atlantic and low pressure well off the FL coast will result in a period of continued long period swell across the OBX. The high waves combined with King Tides this week will lead to additional minor coastal flooding impacts.
For Hatteras Island, seas offshore are in the 4-6 foot range this evening, but the long period swells will continue to cause issues for vulnerable areas. For ocean-side: high tide is around 0900 PM EDT today. Soundside high tides lag by up to 3 hours behind the oceanside tides. The National Parks Service and NCDOT have reported substantial beach erosion from south Nags Head to Buxton, along with significant overwash occurring on side streets in Rodanthe. Due to hazardous road conditions and flooding, NC-12 remains closed from the Marc Basnight Bridge to Rodanthe.
Minor coastal flooding of vulnerable locations will be likely well into this week despite the diminishing of winds, with "sunny day" flooding across much of the tidal regions of ENC around times of high tide, then slowly improve as the King Tides ease later in the week and into the weekend. Coastal flood advisories continue through the high tide cycle on Thursday.
KEY MESSAGE 2, Dry high pres with near climo temps expected today and tonight, then warming to above normal mid week through the weekend. A coastal trough offshore could bring isolated showers to coastal communities tomorrow into tomorrow night. Pops have been increased to ~20% to account for this. Thunder chances remain below 5% along the coast tomorrow. Late week into the weekend, hts/thicknesses build further, and temps climbing back to 5-10 degrees above climo with highs around 80F inland to low 70s OBX. Low temps will warm above climo as well with readings in the mid 50s for most locales away from the immediate coast. Next chance of rain is Sunday.
00z Wednesday through Sunday Forecast confidence is moderate over the next 24 hours.
A moistening northeast to east low-level flow atop a cool boundary layer is expected through tonight which is a favorable setup for low stratus and FG development. Guidance is mixed on whether stratus or FG will be the dominant source of sub-VFR conditions. The previous TAFs leaned towards stratus, and since there isn't a strong model consensus one way or another, I opted to keep the 00z TAFs unchanged on that point. It's worth noting that guidance appears to be too aggressive with stratus development compared to what is on satellite right now. If this trend holds, FG may end up the dominant cause of sub-VFR conditions. The potential exists for a period of LIFR/IFR conditions (via FG or low stratus). Vis and CIGs are expected to improve to VFR by 13-16z on Wednesday, but 3-4k ft stratus may linger for much of the day. Additionally, the increased moisture and a sharpening coastal trough may lead to some SHRA development right along the coast, potentially impacting KEWN and KMRH during the day Wednesday.
Outlook (Wed through Sat): Outside of Wednesday, expect VFR conditions to continue through at least Sat with quasi- stationary high pres over the region. Coastal sections could see ocnl MVFR STCU at times with flow cont off the Atlantic.
High pres ridging into the waters bringing N/NE winds 10-15 kts, and elevated seas are only slowly subsiding due to the long period nature of the swells. With a ~18 hours period of seas below 6 ft, elected to drop the previous SCA, and issue a new SCA starting at 12Z Wednesday, continuing through Thursday.
Outlook (Wed through Sat):Early Wed morning renewed nerly pres gradient redevelops with SCA seas and/or winds. The winds and seas finally diminish by early Thu north of Ocracoke, and by Thu evening for remaining southern coastal waters. High building in late week brings pleasant boating conditions to the region.
Nc, coastal flood advisory until 2 pm EDT Thursday for ncz195-196- 199-203>205. Beach hazards statement until 8 pm EDT this evening for ncz196- 203>205. Marine, small craft advisory from 8 am Wednesday to 8 pm EDT Thursday for amz152-154-156-158.
