textproduct: Newport/Morehead City

SYNOPSIS

A coastal trough will move inland today, followed by a warm front lifting north through the area tonight. A strong cold front then crosses the area on Friday. From this weekend through the middle of next week, a series of fast moving cold front will cross the area, with brief periods of high pressure in between.

NEAR TERM /UNTIL 6 PM THIS EVENING/

As of 230 AM Thursday...

Key Messages

- Strong cold front to move through tonight/Friday morning with widespread rain, scattered thunderstorms, gusty winds, and minor coastal impacts

Light winds and a moist boundary layer may support areas of fog early this morning. However, the risk of widespread dense fog appears low for now.

Once we get past this morning, a coastal trough developing offshore is forecast to move inland, and may provide just enough forcing for a few showers. The chance of showers has been decreased some from the previous forecast, but there still appears to be enough of a signal to keep a mention in for most of the area. Developing southerly flow today should lead to highs topping out another step higher compared to yesterday. This should support above to well above normal temperatures by mid December standards.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/

As of 230 AM Thursday...

A potent upper level trough is forecast to translate east across the Great Lakes/Ohio Valley tonight, taking on a negative tilt as it moves through the ERN U.S. Deep southerly flow ahead of this wave will lead to a plume of anomalous moisture (1.50"+ PWATs) getting pulled north from the Gulf to the Carolinas later tonight through early Friday morning. Meanwhile, the flow aloft will become increasingly diffluent over the Carolinas as the upper wave begins to take on a negative tilt. At the SFC, a warm front is forecast to lift through the area tonight, with convergence possibly enhanced due to weak low pressure developing along it. The combination of increased large-scale forcing for ascent, strong low-level convergence, and anomalous moisture should lead to an area of moderate to heavy rain from this evening into the overnight hours. Additionally, an area of elevated instability nosing north into the area may support scattered thunderstorms embedded within the larger area of rain. The highest rainfall rates are expected where thunderstorms occur. For the area, at large, most should see rainfall totals of 0.50"-1.00". However, where thunderstorms occur, rainfall totals of 1-3" appear plausible. Where the highest rainfall rates occur, some minor flooding impacts will be possible.

Regarding the severe weather potential tonight, the risk appears low. The recent stretch of below normal temperatures has lead to a notable cooling trend across the nearby coastal waters, with SSTs now in the 50s. Southerly flow over these cooler waters should lead to a maritime inversion advecting inland, leading to a lowered risk of SFC-based convection. The one exception is along the Outer Banks from Cape Lookout north through Cape Hatteras, where nearby shelf waters aren't as cool (ie. 60s vs 50s). This may allow SBCAPE of 250- 500j/kg to overlap with strong deep layer shear and notable SRH. The most likely scenario is for the strongest thunderstorms to remain just offshore. However, a reasonable worst case scenario is for a few strong to severe thunderstorms to pass near, or over, the OBX between the Capes, with a damaging wind and brief tornado risk.

In the wake of the overnight/early morning precip, a notable dryslot is forecast to overspread the area in advance of a cold front. Should any clearing occur beneath this dryslot, there would be several hours where warm temps and deeper mixing overlap with a strong SW LLJ before it shifts away from the area. Forecast soundings and momentum transfer guidance suggest the potential for a period of 30-40 mph wind gusts during this time, especially east of HWY 17. In light of this, forecast wind gusts were increased over land for a few hours Friday morning. Along the OBX, a period of strong southerly winds is expected to develop along the northward- advancing warm front and SFC low. In light of this, a Wind Advisory has been issued for Ocracoke and Hatteras Islands, primarily for sustained winds of 30+ mph. However, occasional gusts of 40-50 mph also appear possible, with enhanced gusts most likely in/around convection.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

As of 230 AM Thursday...

Key Messages

- Active clipper pattern with multiple dry fronts and temperatures averaging out near normal through the middle of next week

A very amplified upper level pattern is forecast to develop by next week, with anomalous ridging over the Central U.S., and troughing to the east. For the Carolinas, then, it looks like we shift back into a progressive, but mostly dry, pattern. Despite troughing in place, it looks like an active clipper pattern will lead to a temperature roller coaster, with cold and warm air alternating with the passage of each clipper. It also looks like this will prevent any substantial surge of cold air moving in or lasting long, with temps averaging out around normal for late December.

AVIATION /12Z THURSDAY THROUGH MONDAY/

As of 630 AM Thursday...

Key Messages

- Patchy fog tapering off 1-2 hours after sunrise

- Increasing cloud cover & lowering CIGs through the day Thursday, becoming sub-VFR Thursday night

Patchy fog for areas north of hwy 17 this morning where there is little to no low/mid cloud cover. By 13Z visibilities should be improving with the exception of NOBX where some localized sea fog may linger into the afternoon. A VFR day for TAF terminals Thursday. Warm front moves through in the afternoon, but probability of sub- VFR CIGs along this front is low (<20%) so did not include it in the TAFs. OBX terminals and terminals west of the forecast area would have higher chances of seeing a brief period of MVFR CIGs this afternoon along the warm front. Tonight as the frontal system approaches, CIGs rapidly drop to MVFR then IFR/LIFR, and moderate to heavy rainfall moves into the region. In addition, LLWS spreads over the region tonight with a potent LLJ overhead.

Outlook: Showers will linger into Friday morning but expect clearing from W to E with VFR conditions and gusty winds returning late Friday and remain pred-VFR through the weekend as high pressure returns.

MARINE

As of 640 AM Thursday... Sea fog potential for waters near NOBX lingering into the afternoon with light southeasterly winds. For now no marine DFA issuance expected, but it will be something to keep an eye on.

Previous Discussion...As of 230 AM Thursday...

Key Messages

- A strong cold front will move through tonight/Friday morning with moderate to strong southerly winds, hazardous seas, and a risk of thunderstorms

A period of impactful winds and seas is expected this evening through Friday across much of the ENC waters. Southerly winds will begin to build later today as a coastal trough moves inland. Winds then quickly build this evening into tonight as a cold front approaches, and as a warm front and weak surface low move through. The tightened gradient during this time is expected to support a period of 20-35kt winds. Over the warmer coastal waters, gusts of 35- 45kt will be possible, and this is where a Gale Warning remains in effect. Elsewhere, gusts of 20-30kt will be more common, and Small Craft Advisories are in effect. The one headline change on this shift was to add the Pamlico, Pungo, and Neuse Rivers to the Small Craft Advisory, as guidance now shows a better signal for 25kt wind gusts there overnight tonight into Friday afternoon. There will be an increased risk of thunderstorms late tonight into early Friday morning, especially over the warmer coastal waters from Surf City north through Cape Hatteras. For those waters, thunderstorms will be capable of producing wind gusts of 50kt+ and waterspouts.

Winds will begin to lay down by Friday evening as high pressure starts to nose into the region. At the height of the winds, seas are expected to peak in the 8-14ft range from Oregon Inlet south through Surf City. North of Oregon Inlet, seas of 5-9ft are expected.

Outlook: An active clipper pattern looks to setup from this weekend into next week, with several fronts quickly crossing the area. Each front will likely be accompanied by a quick round of moderate to strong winds, with 25kt+ wind gusts possible at times.

TIDES/COASTAL FLOODING

As of 230 AM Thursday...

Strong southerly winds will develop ahead of a cold front this evening, lasting into the day Friday. This will lead to an increased risk of large, breaking waves for beaches from Cape Lookout to Cape Hatteras. In addition to the dangerous surf conditions, the strength of the wind-driven swell may be enough to cause some minor ocean overwash and beach erosion, especially along the more vulnerable stretches of the coast along Ocracoke and Hatteras Islands. In light of this, a High Surf Advisory has been issued from late tonight through early Friday afternoon.

MHX WATCHES/WARNINGS/ADVISORIES

NC...High Surf Advisory from 1 AM to 1 PM EST Friday for NCZ196-204- 205. Wind Advisory from 1 AM to 10 AM EST Friday for NCZ204-205. MARINE...Small Craft Advisory from 10 PM this evening to 2 PM EST Friday for AMZ131-136-137-230-231. Small Craft Advisory from 7 PM this evening to 2 PM EST Friday for AMZ135. Small Craft Advisory from 10 PM this evening to 4 AM EST Saturday for AMZ150. Gale Warning from 8 PM this evening to 2 PM EST Friday for AMZ152-154-156-158.