textproduct: Newport/Morehead City

WHAT HAS CHANGED

No significant changes from the previous forecast.

KEY MESSAGES

1) Potential for areas of locally dense fog through this morning.

2) Marginal risk of severe thunderstorms possible late tonight into Monday morning primarily north of US 264

3) Notable weather system to move through the Carolinas Tuesday night with a return of oppressive heat ahead of it and a risk of strong to severe thunderstorms along it

DISCUSSION

KEY MESSAGE 1...With freshly saturated soils thanks to the past several days of rain, boundary layer remains very saturated. Light to calm winds this morning and building high pressure are promoting a subsidence inversion and providing ideal conditions for low stratus and some fog. Expect clouds to gradually lower through the morning. Guidance has backed off a bit on the idea of dense fog owing to the persistent cloud cover, but if it does develop best chances remain for the inner coastal plain close to the I-95 corridor.

KEY MESSAGE 2...Cold front has now pushed farther offshore this morning and flow aloft has become increasingly northwesterly as strong heat dome over the western and central CONUS amplifies the flow pattern. This is promoting an elevated thermal gradient orientated NW to SE across much of the mid-Atlantic and Carolinas. Shortwave energy passing along this boundary, in juxtaposition of moderate instability and ample moisture will support a risk of showers and thunderstorms developing in the afternoon and pushing southeast. Axis of most supportive kinematics is expected to be displaced to our west and north, and CAMs keep most activity here during the day, rendering most of eastern NC dry today.

Of note, almost all guidance points to a semi-organized cluster of storms developing upstream in WV/VA in the late afternoon and quickly pushing SEward towards eastern NC overnight. An organized cluster in the forecast pre-storm environment would favor a marginal damaging wind threat. If this were to materialize, it would most likely approach areas along Highway 64 just before midnight. Activity would likely decay as it pushes farther southeast with poor shear and waning instability.

KEY MESSAGE 3...Anomalous upper troughing is forecast to remain in place across the Mid-Atlantic and Carolinas through at least the middle of the week. Within this regime, a convectively active NW flow pattern appears likely, and this is supported by deterministic, analog, and machine learning guidance. The signal remains strongest on Tuesday, particularly later in the day, and this is the day that the Storm Prediction Center has outlooked a portion of our area in an elevated (15% probability) of severe thunderstorms. Synoptically, the overlap of building instability and unusually deep layer shear for this time of year certainly appears favorable for severe thunderstorm development. EFI CAPE-shear values are in the 80-90th percentile for this event, especially for inland portions of the state.

In addition to the potential convective hazards, there will also be a risk of dangerous heat. This risk also looks to be focused on Tuesday when dewpoints and air temperatures are forecast to be the highest, with heat indices of 100-105 degrees.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Largely MVFR conditions in place this morning with persistent deck of stratus sitting over area terminals. There are some lower spots from OAJ southwestward in IFR to LIFR. Boundary layer will continue to lower through the morning and expect more widespread IFR conditions to develop with lowering stratus. Fog probabilities have dropped quite a bit over the past couple of hours, but cannot completely rule out locally dense occurrences where breaks in stratus occurs.

Conditions gradually improve after sunrise with VFR conditions likely to return by mid-morning. A few iso showers and thunderstorms are possible this afternoon mainly across the inner coastal plain, although there is a risk of a few overnight storms moving over terminals from northwest to southeast after 00z. A stronger storm or two is possible capable of producing gusty winds.

Outlook (Monday through Thursday): Typical summertime pattern expected through most of the week. Strong front is expected to cross terminals Tuesday into Wednesday, bringing ahead of it gusty SW winds up to 20-25 kt and a risk of strong to severe thunderstorms. Drier conditions are expected behind the frontal boundary outside of iso to widely sct afternoon convection.

MARINE

Cold front has pushed farther offshore early this morning placing area waters firmly in north to northwesterly flow of 10-15 kt and seas 3-5 feet. We are currently in the period of strongest winds, and flow is likely to subside later today and into tonight as frontal boundary weakens. Seas will respond in kind, dropping to 2-4 feet by this evening. Lingering convection roughly 60 nm offshore will continue to push offshore early this morning, and the rest of today looks to be convection free for area waters.

Outlook: Southerly flow then continues through the middle of this week. Winds are expected to build Tuesday and Wednesday, offering the next chance of 25kt winds and hazardous conditions for small craft. Occasional gale-force gusts will be possible for the outer coastal waters during this time. Seas will build to 3-7ft by the middle of the week as the winds build. Occasional rounds of thunderstorms will be possible through the middle of the week as well.

MHX WATCHES/WARNINGS/ADVISORIES

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