Key MESSAGE 1, Cold front has moved well offshore late this afternoon and has ushered in strong CAA and ensuing gusty nrly winds. There continues to be high confidence that a strong coastal low turning nor'easter will form well off the Carolina coast through the latter half of the weekend into early to mid next week. Strong winds, high waves, and coastal flooding as well as extremely dangerous marine conditions will be the result.
There is still model uncertainty beyond early week on where the low pressure area will be, but the trend in 17/12Z global guidance including ensemble packet has shifted a bit further offshore. Nevertheless, this does Not diminish any of the advertised high coastal impacts, as long duration and long fetch nnerly winds will bring large waves and pile up water along the coast, leading to coastal flooding well into the week.
High winds on the coast still expected. Have fine-tuned the wind adv, taking W Carteret out but keeping the OBX and nern zones closer to the stronger gradient winds in tact. High wind warning criteria being met appear to be lessening, though can't rule out a few gusts reaching 60 mph early this evening with the initial CAA surge. With the further offshore track during the week, this should also keep winds lower.
2-4 foot above ground level coastal flooding will be possible with minor to moderate impacts throughout the Outer Banks, Core Banks and Downeast Carteret County. Impacts are expected to both sound and oceanside locales with potentially significant impacts to vulnerable areas on the ocean side. A mix of coastal flood headlines is in effect to cover these hazards. Additionally, a high surf advisory is in effect for the Outer Banks with breaking waves of generally 8-14 feet expected in the surf zone. A moderate to high risk of rip currents is also expected through much of the week.
KEY MESSAGE 2, After record breaking heat the last several days, temperatures are expected to cool significantly. Maximum temperatures through the period are expected to remain in the 60-70 degree range with cooler values inland and warmer temperatures near the coast. Overnight lows will range from the 40s inland just after the frontal passage to the 50s by the end of the week with coastal locations in the 50s early in the forecast period to near 60 by the end of next week. Winds will remain breezy, particularly in the afternoons depending upon the eventual track of the offshore nor'easter.
Regarding rain, main batch should end by this evening as area of fgen/lift shifts offshore. As the low meanders offshore, some wrap around rain may ocnl sneak back onshore, with best chances on the OBX over the next several days.
18z Saturday through Thursday CIGs quickly lowering this afternoon, bottoming out at IFR for a time into this afternoon. Eventually some drier air working in should help to raise CIGs to MVFR, or even low VFR, especially at KISO and KPGV. The low CIGs will be accompanied by areas of light to moderate RA with MVFR VIS at times before the rain ends by early eveniong.
Regarding post-frontal winds, it will be breezy with 20-30kt gusts expected at times, especially this afternoon/evening onwards, highest winds at KMRH.
Outlook (Sun Night through Thu): Good flying conditions expected next week as the offshore low remains well east of the coast, though ocnl gusty winds, esp during the daytime hours with better mixing.
Latest obs show winds beginning to pick up offshore with sustained values of around ~30 kt gusting to ~40 kt most locales. Have converted remaining storm warnings to gale warnings, as surge of winds not expected to be widespread ~50 kt. Still can't rule out sporadic gusts to around 50 kt for the ctrl coastal waters, though will quickly wane later this evening with strongest gradient winds shifting well offshore as CAA surge wanes.
Very dangerous marine conditions will continue as low pressure will form well off the NC coast but cont to supply a steady fetch of strong nerly winds into ENC. Gale warnings are in effect through early Wed, and may have to be extended with oncoming fcst shifts esp if coastal storm stalls off the coast the middle of next week. There is large model spread beyond early week on how long the low will meander, as a blocking pattern remains to the north and east.
Outlook (Sun night through Thu): Wave periods will peak around 13-15s Sunday into mid week as waves build to 7-15 ft in the 0-20nm zones and 15-25 ft in the 20-60 nm zones. These hazardous conditions are expected to continue into next week, although the eventual end time is still uncertain.
Nc, wind advisory until 8 pm EDT Monday for ncz047-081-203>205. Coastal flood advisory from 8 pm this evening to 5 pm EDT Monday for ncz094-194. Coastal flood advisory from 6 am Sunday to 11 am EDT Monday for ncz195. Beach hazards statement until 8 pm EDT this evening for ncz196- 203>205. Coastal flood advisory until 8 pm EDT Monday for ncz196. Wind advisory until noon EDT Monday for ncz196. High surf advisory from midnight tonight to 8 pm EDT Monday for ncz196-204. High surf advisory until 5 pm EDT Tuesday for ncz203-205. Coastal flood advisory until 5 pm EDT Tuesday for ncz203. Coastal flood warning until 5 pm EDT Tuesday for ncz204-205. Marine, gale warning until midnight EDT Monday night for amz131-156- 158-188-230. Gale warning until 5 am EDT Wednesday for amz135-150-152-154- 180-182-184-186-231. Small craft advisory until midnight EDT Monday night for amz136. Gale warning until 10 pm EDT Sunday for amz137.
