textproduct: Newport/Morehead City

WHAT HAS CHANGED

Updated Aviation Discussion

KEY MESSAGES

1) More seasonable September temps for the beginning of the week with a warming trend developing late week.

2) More unsettled pattern expected Friday through the weekend.

DISCUSSION

KEY MESSAGE 1...High pressure will continue to build across the Mid-Atlantic and Carolinas today with a cooler/drier NE-E flow over the area bringing seasonable and comfortable temps for early September, with highs in the low to mid 80s and dewpoints generally in the 60s. Temps will begin to warm mid to late week as the high shifts offshore allowing southerly flow to re- develop Wednesday onwards. High temps climb back into the upper 80s to lower 90s and dewpoint temps into the low to mid 70s late in the week. Mostly dry weather will prevail through mid week as upper ridging build in from the west and a drier airmass in place, although as dewpoints and PWATs creep up late week, slight chance of showers have been introduced for the sea/sound/river breeze convergence zones (in the vicinity of Mainland Dare/Hyde and East Carteret counties).

KEY MESSAGE 2...Friday the high continues to shift offshore and a front sweeps south through the Mid-Atlantic region. Ahead of this front, continuous warm, moist advection in southerly flow will help build PWATs to near 2" by Friday. This will bring scattered to numerous sea breeze showers/tstorms back in the forecast for Friday. Meanwhile, despite the high shifting offshore, some residual ridging should slow down the progression of the front as it moves south Friday. Long range models are in good agreement on this front stalling just to our north in VA, but model trends will need to be analyzed in the coming days in case the front shifts further south than what the 00Z guidance shows this morning. Along the front training showers/thunderstorms are possible, and a narrow swath of deep layer shear right along the front would bring both a low end hydro and severe threat. However, given the front is currently forecast to stall to our north, at this point both hydro and severe potential is limited Friday. IF the front shifts further south into eastern NC, collisions with the afternoon sea breeze could result in a more messy situation, but this is a worst case scenario that is not backed by most models at this time.

The front lifts back north Saturday into Sunday as a shortwave moves through the region. This shortwave will bring slightly better chances for showers and thunderstorms this weekend. Shear doesn't look to be impressive, but ample moisture will promote a marginal hydro threat. There is some uncertainty with how much instability is in play Saturday, as it is dependent on cloud cover and associated surface heating. In a low-end CAPE outcome, (500-1000J/kg) we would have long skinny CAPEs that suggest just a hydro threat and less frequent lightning. Meanwhile a high- end CAPE outcome (2000-4000 J/kg) would bring more pulse- like thunderstorms capable of producing some gusty winds, frequent lightning, and heavy rainfall rates. Regardless of how Saturday plays out, there is higher confidence on a low- CAPE outcome Sunday. While heavy showers and some thunderstorms are possible Sunday with the shortwave, Severe threat appears to be more muted.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR conditions are currently noted across all of ENC early this morning. Expect light winds, some high clouds, and dry conditions across all flight routes as high pressure ridge centered to the north extends across the Carolinas for the remainder of this morning. VFR conditions continue later today with few/sct cumulus at 5kft. Tonight winds go calm, and with skies expected to be generally clear there is a slightly better BR/FG signal. However, with the drier airmass still in place Tuesday, it will likely be shallow in nature.

NOTE: AMD NOT SKED has been appended to the EWN TAFs as the site is not transmitting through normal channels. The site is still reporting via telephone so it will be monitored, but not as frequently as when it is completely operational. The next closest ASOS is at Cherry Point (KNKT).

Outlook (Wednesday through Sat): High pressure will build in from the north through mid week, with pred VFR conditions expected. A front is expected to approach the region Friday and Saturday bringing a chance of showers and thunderstorms with periods of sub-VFR conditions possible.

MARINE

Small craft advisory has dropped for coastal waters from Cape Hatteras to Surf City, as winds and seas have dropped below 25 kt/6 ft. Winds gradually diminish through the day today. This afternoon winds will be NE 5-10 kt gusting to 10-15 kt. The high pressure system leads to much more pleasant boating conditions through mid- week.

Outlook (Wed through Sat): Winds and seas will continue to ease Wed as high pressure builds in. SW winds 5-15 kt return Wed night and 10-20 kt Thu with seas building 2-4 ft as a front approaches the area. A coastal trough may also set up Thursday night into Friday, bringing increased tstorm chances along the Gulf Stream. The front is forecast to stall to our north, but with the proximity of the front and additional shortwaves moving through this weekend, we are expecting a more unsettled pattern Friday- Sunday.

MHX WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement through this evening for NCZ196- 203>205. MARINE...None.