textproduct: Newport/Morehead City

WHAT HAS CHANGED

A Wind Advisory has been issued for portions of the OBX.

A High Surf Advisory has been issued for Hatteras Island.

Coastal flood headlines have been issued or upgraded.

Winds have slightly increased.

KEY MESSAGES

1) Large and slow moving coastal low to impact ENC with periods of rain, strong winds, and coastal flooding mid to late week.

MARINE: Gale force winds and very dangerous high seas mid to late week.

DISCUSSION

KEY MESSAGE 1...A consolidation of surface lows is expected to occur along an elongated baroclinic zone off the U.S. East Coast over the next 24 hours or so. Rapid deepening of a consolidated area of low pressure is then forecast later Wednesday into Thursday as a notable coastal low takes shape. This low is then forecast to move north towards Southern New England, then eventually weaken as it potentially wobbles around the New England coast over the weekend. Regarding the track and the strength of the low, most ensemble and deterministic guidance have shown a slight trend west, and have also generally trended deeper. Additionally, some guidance, particularly machine learning guidance, have trended a bit slower with the northward progression as well. For ENC, these trends could spell a longer duration of marine and coastal impacts, and potentially a slight uptick in the magnitude of impacts as well. Not all guidance have shown the westward shift, though, and this is something we'll continue to closely monitor moving forward.

Regarding sensible weather, showers and isolated thunderstorms are expected to persist through around sunset this evening across the ENC coastal plain, with periods of light rain closer to the coast. This showery type of pattern looks to continue through Thursday. While an area of focused lift and higher rainfall totals may still develop, the latest guidance have backed off on this potential, and it appears the risk of flooding due to rain is lower than previously thought.

By far, the greatest impacts with this coastal low are expected for the Outer Banks. There, a period of moderate to strong northeast to north winds are expected to develop as early as Wednesday, and then potentially last well into the day Friday, especially if the latest westward and slower trend holds. Probabilistic guidance shows a strong signal for reaching Wind Advisory criteria with both sustained winds and gusts, and and advisory has been issued for Dare County, Ocracoke, and Downeast Carteret County. For the OBX from Cape Hatteras north, peak gusts could top out around 50 mph, and this may lead to some minor tree and power line damage, along with a risk of isolated power outages.

The strong, and longer duration, of the winds is also expected to support an increased risk of coastal impacts. Building seas and increasing swell periods will lead to dangerous surf conditions in addition to a risk of beach erosion, wave runup, ocean overwash, and minor to moderate coastal flooding. Wave heights in the surf zone may reach 10-15ft at 10-13s from Duck to Cape Hatteras, peaking on Thursday. 6-8ft+ wave heights in the surf zone may last into this weekend. A High Surf Advisory is now in effect from this evening through Saturday evening. The strength, and duration, of the swell is expected to lead to an increased risk of ocean overwash and moderate coastal flooding for the vulnerable stretches of the coastline along Hatteras Island. Where dune structures are less vulnerable, minor coastal flooding will be possible.

For soundside areas adjacent to the southern Pamlico Sound, and the nearby Neuse River, persistent northeasterly winds may lead to minor coastal flooding later Wednesday through Friday. Eventually the winds are expected to turn more northerly, which may then allow the soundside coastal flooding risk to shift to portions of Ocracoke and Hatteras Villages.

Please continue to stay tuned for future updates as this is a complex and longer-duration coastal low event, with subtle changes in strength and path of the low leading to increased, or decreased, coastal impacts.

AVIATION /20Z TUESDAY THROUGH SUNDAY/

Forecast confidence is moderate over the next 24 hours.

SHRA and a few TSRA will continue to impact KPGV and KISO for the next few hours, with a lower risk for KOAJ, KEWN, and KMRH. CIGs have mostly raised to VFR for now, but the expectation is for CIGs to drop back down to IFR/MVFR conditions this evening, and then continue into Wednesday. Guidance is mixed on whether or not IFR CIGs last well into the day Wednesday or if, like today, they raise above IFR. For now I have the TAFs showing a rise to MVFR. Periods of SHRA will continue to impact the area, but the risk of TSRA should decrease after this afternoon.

Lastly, as a coastal low becomes better organized east of ENC, the strengthening gradient should lead to increasing NE winds on Wednesday, with a gradual increase in the risk of 20-25kt gusts.

Outlook: A coastal low will continue to support periods of gusty winds, low CIGs, and SHRA through the end of the week. CIGs may eventually rise to VFR levels by the weekend as drier air begins to wraparound the western periphery of the low.

MARINE

A couple of areas of low pressure off the North Carolina coast will begin to consolidate over the next 24 hours, with a notably strong coastal low forming, with a pressure as low as around 990mb likely. This will support a long-duration period of hazardous winds and seas for all marine areas. For the coastal waters, seas of 10-20ft will be possible, especially for the waters from Cape Lookout north through Duck. The nearshore coastal waters sheltered in N and NE flow south of Lookout may only have seas peak at 5-10ft. Swell periods will gradually build to 10-13s during this time as well. Marine headlines in effect nicely cover the expected hazards, and the only changes were to adjust the ending times for a few areas.

Outlook: Based on the latest guidance, hazardous marine conditions may last well into the weekend, especially for the coastal waters as seas remain elevated. However, winds should gradually lay down over the weekend as the low pulls away and weakens.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Wind Advisory from 2 PM Wednesday to 8 PM EDT Thursday for NCZ047-196-203>205. Coastal Flood Advisory from 2 PM Wednesday to 11 AM EDT Friday for NCZ094-194-196. Beach Hazards Statement from Wednesday morning through Wednesday evening for NCZ195-196-199-203>205. Beach Hazards Statement until 8 PM EDT this evening for NCZ203- 205. High Surf Advisory from 8 PM this evening to 8 PM EDT Saturday for NCZ203. Coastal Flood Advisory from 2 PM Wednesday to 11 PM EDT Friday for NCZ203. Coastal Flood Warning from 2 PM Wednesday to 11 PM EDT Friday for NCZ204-205. High Surf Advisory from 4 AM Wednesday to 8 PM EDT Saturday for NCZ205. MARINE...Gale Warning from 7 AM Wednesday to 8 AM EDT Friday for AMZ131- 230-231. Gale Warning from 7 AM Wednesday to 2 PM EDT Friday for AMZ135. Small Craft Advisory from 4 AM Wednesday to 2 PM EDT Friday for AMZ136-137. Gale Warning from 7 AM Wednesday to 6 PM EDT Friday for AMZ150- 152-180-182. Gale Warning from 2 PM Wednesday to 6 PM EDT Friday for AMZ154- 184-186. Gale Warning from 2 PM Wednesday to midnight EDT Thursday night for AMZ156-158-188.