textproduct: Newport/Morehead City

WHAT HAS CHANGED

Severe potential increasing for interior eastern NC this afternoon and early evening.

PoPs tweaked based on radar trends

KEY MESSAGES

1) Widespread showers and isolated to scattered severe thunderstorms ahead of a cold front this afternoon and evening.

2) Cooler, drier, and more seasonable behind the frontal passage this weekend.

DISCUSSION

KEY MESSAGE 1...Prefrontal trough right ahead of a strong cold front is currently over the inner coastal plain and is slowly progressing eastward. This is bringing robust forcing into a region with around 1kJ/kg of CAPE, deep shear of 30-35 knots, and increasing moisture. Dewpoints are now in the low 70s for portions of eastern NC, especially east of hwy 17. This has increased the available moisture/instability, and as a result the threat of severe weather has INCREASED for this afternoon and evening inland. SPC has upgraded portions of the CWA to a "Slight" (2/5) risk of severe weather. Main concerns are damaging wind gusts up to 60 mph. Some small hail with the cooler air aloft and mid-level lapse rates 6-7 C/km can't be ruled out. In addition, there is a low-end risk for a brief, weak, isolated tornado or two. Areas that have more backed winds out of the SSE or SE as the front approaches would see a more pronounced chance of tornado formation as that would locally enhance low level SRH values.

We could see localized QPF values of >1.5", but at this point flooding potential is low as we have been very dry as of late.

The main threat window runs from early afternoon to around sunset inland, lingering slightly longer over the Outer Banks but with a diminishing severe risk as instability collapses. The main front sweeps offshore late tonight with any remaining showers exiting the OBX around or shortly after midnight. There will likely be a delay between the main front coming through and the dry air surge, so would not be surprised to see a period of low stratus Fri night into Sat morning.

KEY MESSAGE 2...A more seasonably dry airmass will be ushered in for the weekend behind the front. Expect a return to mostly sunny skies and highs in the upper 60s to low 70s Sat, then cooler yet for Sun with 60-65. Lows will be in the 40s, with some 30s for some of the normally colder spots. We will have to monitor the temp forecast for any frost concerns Sunday morning.

AVIATION /15Z FRIDAY THROUGH TUESDAY/

Forecast confidence is moderate over the next 24 hours.

A strengthening cold front will move east across central and eastern NC today, eventually moving offshore by tonight. Scattered SHRA and TSRA will accompany the front, some of which could produce wind gusts in excess of 40kt. There will also be a risk of significant reductions to VIS (LIFR/IFR). While not likely, a low-end tornado risk is present as well, mainly for inland TAF sites. Ahead of the front and TSRA, gradient/mixing winds are gusting up to 20-25kt out of the south.

The most uncertain part of the forecast is CIGs. CIG heights have varied between 1000ft and 4000ft early this afternoon, and this will probably continue to decrease until the front gets closer. In the wake of the cold front, guidance insists on a period of low CIGs due to residual low- level moisture. During this time, CIGs may fall as low as IFR/LIFR for several hours until late morning Saturday.

Outlook: An extended period of VFR conditions is expected after today's TSRA as a much drier airmass builds in across the region.

MARINE

Increasing southerly winds through all area waters as a cold front approaches from the west later today. Gusts should remain generally below 25 knots ahead of the front. Behind the front, winds switch to the north/northwest, gusting to near 20 knots. Gusts exceeding 25 kt will likely be concentrated beyond 20nm offshore, so no headlines are in effect. Seas will persist at 3-5 ft nearshore and near 4-6 ft offshore through today. The cold front moves through this evening into the overnight hours for our waters, and ahead of this boundary strong thunderstorms capable of gusty winds and a brief waterspout are possible. Behind the front, high builds in and winds gradually lighten through Saturday.

Outlook (Saturday night through Tuesday): High builds in this weekend into next week, keeping winds below 20 kts and skies rain-free. Despite the decrease in winds, elevated seas may linger through the weekend for 20-60nm zones at around 4-6 feet, and an isolated 6 foot wave is possible just within 20nm primarily for waters in Raleigh Bay.

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...None.