textproduct: Newport/Morehead City

WHAT HAS CHANGED

Winds trending slightly higher for end of week system. Aviation Disco updated.

KEY MESSAGES

1) Cool and dry conditions linger for the next couple of days with frost concerns tonight.

2) Approaching storm system near the end of the week will bring well below normal temperatures, breezy conditions, and a chance of rain.

DISCUSSION

KEY MESSAGE 1...Latest surface analysis depicts a weak surface trough transiting central and eastern NC this hour with sprawling high pressure centered over the southern plains extending in behind it. The trough will do little more than keep up winds just enough to hamper more robust radiational cooling tonight as well as keep any patchy fog risk at bay. Behind it during daytime hours today, steady NW winds at around 10 mph with higher gusts are likely.

As we've been mentioning for the past couple todays, tonight looks like the best candidate for fairly widespread frost, especially west of NC 17 as skies remain clear and winds inland will likely be calm with the high cresting overhead. As is typical in these environments deterministic guidance for lows are usually not aggressive enough, so blended in NBM 10th percentile to knock forecast lows into the mid 30s. Tuesday night is trending slightly warmer with an uptick in cloud cover, so probability of frost that night is shifting lower albeit not impossible.

KEY MESSAGE 2...Guidance is coming into better agreement for increasingly unsettled weather across the eastern CONUS as complex mid-level low deepens over the region and steers multiple shortwaves over the mid-Atlantic. Although specific details remain murky, it is increasingly likely that coastal low development will occur off the eastern coast as early as Thursday although its intensity and track remain uncertain. Probabilistic guidance favors a more northern track, which would keep heavier precipitation away from our area. NBM and deterministic ensembles show this well with overall probabilities of seeing more than a couple tenths of an inch under 20%.

Forecast winds have been trending upwards with this system, and probabilities for a period of W to NW winds as high as 25-30 kt with higher gusts have increased from the previous forecast. If this is realized, at least some coastal flooding concerns could arise along the Outer Banks. Given spread of guidance, it is too early to state the potential magnitude of impacts. Stay tuned for future updates.

Behind the system, unseasonably cool air will flood into the area knocking highs down into the 50s for the weekend and offer the first real opportunity for a freeze as 850mb temps fall below 0 C.

AVIATION /12Z MONDAY THROUGH FRIDAY/

As of 0630est... High pressure remains firmly in control over area terminals with SKC and light and VAR winds. Surface trough will transit the region bringing a shift and uptick in winds out of the northwest. Increased mixing brings stronger NW winds at around 10G15kt with gusts up to 20 kt at times, especially for near- shore sites. Tonight, SKC and winds likely decoupling opens the door for fog and frost potential if there's enough moisture left in the lower levels. Have VFR MIFG mention for OAJ and EWN with guidance that is showing fog keeps it closer to the coast.

Outlook: An extended period of VFR conditions is expected with much drier airmass and high pressure over the region through midweek. Approaching storm system at the end of the week brings an increase in rain chances, some gusty winds, and sub-VFR conditions.

MARINE

Latest observations this morning depict an increase in southwesterly winds as a surface trough approaches waters with winds up to 15-20 kt and an occasional gust to 25 kt. Seas are 4-5 feet for now, but expect seas to build further through the morning hours especially beyond 10 nm. SCA advisories remain in effect north of Ocracoke Inlet until 7 PM LT. This surge will quickly fall after sunset as high pressure crests overhead with winds across all waters falling to around 5 kt or less.

Outlook: Decent boating conditions expected through Wednesday with winds backing SW Tuesday ahead of another approaching trough, peaking at 10-15 kt. Attention then turns to a coastal low likely to develop off the mid-Atlantic coast as early as Thursday. Although magnitude of impacts remains uncertain, trend has been for stronger winds and the probability for Gales has increased from the previous forecast, especially so for the waters from Raleigh Bay north. Timing and low intensity remains a point of uncertainty, so mariners are encouraged to continue monitoring future forecasts.

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...Small Craft Advisory until 7 PM EST this evening for AMZ150- 152-154.