textproduct: Newport/Morehead City

WHAT HAS CHANGED

Severe Thunderstorm Watch in effect for much of eastern NC through this afternoon.

KEY MESSAGES

1) A strong cold front will cross the area this afternoon/evening with gusty winds, widespread rain, and a few thunderstorms expected. Thunderstorms may be capable of producing damaging wind gusts and an isolated tornado.

2) Low probability (< 10%) of a wintry mix behind the front generally north of Highway 264.

3) Strong cold front next week poses a potentially higher severe risk.

Marine...Conditions will deteriorate through the afternoon with Gales expected this afternoon through late tonight.

DISCUSSION

KEY MESSAGE 1...Strong cold front, in tandem with a potent mid-level shortwave digging towards the mid-Atlantic and taking on an increasingly neutral to slightly negative tilt, is crossing NC this hour driving a band of a few thunderstorms embedded in a line of showers. Strong gust front is racing ahead of this boundary with several recorded gusts of 40-45 kt immediately ahead of it, while stronger cells are posting winds near the 50 kt range. Buoyancy is weak ahead of this boundary - around 500 J/kg - but low-level shear is quite impressive, exceeding 60 kt out of the southwest per SPC mesoanalysis. Long straight hodographs favor organized storms to continue with a primary risk of damaging wind gusts, but a very brief tornado (lasting perhaps no more than a couple minutes at most) cannot be ruled out mainly in a QLCS setting. The front is expected clear the region by 5pm, ending the severe threat.

KEY MESSAGE 2...Temperatures will fall so rapidly behind this front (approx 10+ degrees/hour) that some models are showing a brief changeover to a wintry mix of rain, snow, and sleet early this afternoon. Highest risk of this is primarily confined to Virginia, but HREF does point to a marginal (< 10% chance) of some mixed precip intruding in areas north of Highway 264. Given the low odds, this will not be conveyed in the official forecast.

KEY MESSAGE 3...Next weather maker will be Sunday and Monday as a powerful Colorado low rapidly deepens over the central Plains and lifts towards the Great Lakes, quickly pulling a strong cold front across the southeastern CONUS and Carolinas. Finer details are yet to be determined, but it is likely the mid-level trough driving this cyclone will take on a neutral to negative tilt by the time the front reaches the Carolinas and quite a bit of shear will be present (likely at least 40 kt). Experimental mid-range AI guidance almost all are giving a signal for a severe risk, quite higher than today's with multiple hazards on the table. SPC currently has our area in a 15% risk, but this will need to be closely monitored in the coming days.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

VFR conditions persist across ENC this afternoon however this will change rather quickly as a cold front and its associated rain and thunderstorm activity approaches ENC. Current radar imagery has this activity just beginning to enter into the far western portions of the CWA and the rain and thunderstorm activity is forecast to quickly push east across ENC this afternoon. Within this thunderstorm activity there will be a significant wind shift as well as SW'rly winds at 15-20 kts with gusts up to 30 kts shift to a WNW to NW direction with gusts peaking as high as 30-40 kts immediately behind the front and within the initial thunderstorm activity. To account for this, have issued a tempo group for all terminals with ISO/OAJ/PGV starting at 18Z and going to 21Z and EWN starting at 19Z and persisting until 22Z. MVFR ceilings and potentially IFR vis is forecast within this activity as well this afternoon. Once rain and thunderstorm activity moves through ENC, skies will quickly clear getting to VFR conditions by about 22/23Z across most of NC outside of maybe the OBX where MVFR ceilings may hang around until about 00Z. Gusty NW-N'rly winds will remain in place until about the 22Z-00Z timeframe this evening before winds quickly ease from west to east. Afterwards VFR conditions and light winds will persist across all of ENC tonight into Friday morning.

Outlook...Pred VFR conditions expected Friday through Saturday. The next frontal system is expected to impact ENC Sunday through Monday bringing periods of sub-VFR conditions in showers and thunderstorms.

MARINE

Increasingly hazardous marine conditions are expected tonight due to a strong cold front that will cross the area this afternoon/evening.

Strong southwest winds of 20-30 kt with gusts to 35-40 kt are ongoing across area waters, with the exception of the far northern waters where the pre-frontal gust front is resulting in gusts exceeding 50 kt at times out of the north. Winds will continue to rapidly veer out of the north and surge to 30-40 kt with gusts to 35-50 kt through early this evening. Winds will quickly improve behind the front tonight into Friday with gusts forecast to drop below 25 kt by late tonight. Seas will peak this afternoon/evening at 5-8 ft.

Gale Warnings remain in effect for all coastal waters, the Pamlico Sound, and the northern rivers and sounds. Small Craft Advisories are in effect for the inland rivers but a few Gale force gusts are still possible, especially near the mouths of the rivers.

The cold front will be accompanied by a risk of thunderstorms, the strongest of which will produce enhanced wind gusts upwards of 50 kt and brief waterspouts.

Outlook: Winds and seas will lay down Friday and Saturday with more benign marine conditions expected. Winds and seas will rebuild Sunday into Monday associated with the next strong cold front.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Wind Advisory until 10 PM EDT this evening for NCZ196-203>205. MARINE...Gale Warning until 8 PM EDT this evening for AMZ131-230-231. Gale Warning until 11 PM EDT this evening for AMZ135-152-154- 156-158. Small Craft Advisory until 11 PM EDT this evening for AMZ136- 137. Gale Warning until 10 PM EDT this evening for AMZ150.