textproduct: Newport/Morehead City

SYNOPSIS

A warm front will lift north through the area tonight with a strong cold front crossing the area early 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 /THROUGH TONIGHT/

As of 7 PM Thu...

Key Messages

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

Latest analysis shows low pressure continuing to move across the Great Lakes with the attendant cold front pushing across the Ohio and Tennessee River Valleys. KMHX radar show an area of prefrontal showers moving into the FA from the SW and will continue to overspread this area through the evening. Little change in forecast reasoning from the previous discussion and expect heavier precip with isolated to scattered thunderstorms possible from late this evening into the early morning hours of Friday.

Previous discussion...A potent upper level trough is expected to move eastward 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 isolated to 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" are possible. 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 brief damaging wind and/or 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. Along the OBX, a period of strong southerly winds is expected to develop along the northward- advancing warm front and SFC low. Wind Advisory continues 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.

SHORT TERM /FRIDAY/

As of 2 PM Thu...The cold front will push offshore late morning and early afternoon, with cooler and dry air pushing in. The bulk of the showers will push off the coast Fri morning, with a few lingering showers possible along the front through late morning. Gusty SW winds will become W behind the front, with gusts 25-35 mph, a bit stronger along the coast where Wind Adv continues. Above normal temps will continue, likely seeing highs (mid- upper 60s) during the first half of the day then falling during the afternoon.

LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/

As of 2 PM Thu...

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 /00Z FRIDAY THROUGH TUESDAY/

As of 7 PM Thursday...

Key Messages

- Sub-VFR conditions expected overnight with showers and isolated to scattered thunderstorms ahead of a cold front

- South-southwesterly Low Level Wind Shear expected from late this evening through daybreak Friday.

- The front will push through around mid-day Friday with clearing skies but expect wind gusts around 25-30 kt in westerly post frontal flow.

Currently seeing pred VFR conditions across the region but an area of prefrontal showers are spreading NE into the area and have seen vsbys drop to MVFR at DPL in moderate showers. Conditions will continue to deteriorate through the evening with a cold front continuing to approach the area. Widespread MVFR is expected from late this evening through much of Friday morning with periods if IFR/LIFR in heavier showers or even an isolated thunderstorm overnight from roughly 04-09Z. The cold front is progged to push across ENC around mid-day Friday with skies clearing pretty quickly through the afternoon.

A strengthening low level jet to around 50-60 kt will bring LLWS concerns from late evening through daybreak Friday but expected improving conditions after 12z.

Winds will become gusty overnight as gradients tighten ahead of the front and expect gusts around 20-25 kt inland to 30-40 kt along the coast, but heavy rain or thunderstorms may briefly transport even stronger gusts to the sfc. Winds become westerly behind the front and could see gusts around 25-30 kt Friday afternoon as deeper mixing ensues. This may bring crosswind concerns at EWN runway 4R/32L.

Outlook: Predominantly VFR through the weekend into early next week as high pressure returns across the region.

MARINE

As of 2 PM Thu...

Key Messages

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

A period of impactful winds and seas is expected this evening through Friday across the waters. Latest obs show NE-S winds 5-15 kt with seas 2-3 ft. Southerly winds will begin to increase late this afternoon 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 Gale Warnings remain in effect. Upgraded to Gale for the northern waters and Pamlico sound. Elsewhere, across the inland rivers and northern sounds, SCAs continue. 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 8-15 ft range from Oregon Inlet south through Surf City. North of Oregon Inlet, seas of 5-10 ft 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 2 PM Thu...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. High Surf Advisory continues from late tonight through early Friday afternoon. Have also issued a CF Advisory with the overwash potential.

MHX WATCHES/WARNINGS/ADVISORIES

NC...High Surf Advisory from 1 AM to 1 PM EST Friday for NCZ196-204- 205. Coastal Flood Advisory from 1 AM to 1 PM EST Friday for NCZ204- 205. Wind Advisory from 1 AM to 10 AM EST Friday for NCZ204-205. MARINE...Small Craft Advisory from midnight tonight to 7 PM EST Friday for AMZ131-136-137-230-231. Gale Warning from midnight tonight to 11 AM EST Friday for AMZ135. Gale Warning from midnight tonight to 2 PM EST Friday for AMZ150. Gale Warning until 2 PM EST Friday for AMZ152-154-156-158.