textproduct: Newport/Morehead City

WHAT HAS CHANGED

No significant forecast changes.

KEY MESSAGES

1) Dangerous heat builds through the week and into the weekend

2) Unsettled pattern expected to return by this weekend, including the next risk of strong to marginally severe thunderstorms

DISCUSSION

KEY MESSAGE 1...Mid-level ridging will overspread the Carolinas over the next couple of days with warming low-level thicknesses beneath it. Ridging plus much drier conditions aloft should put a cap on convection over the next couple of days, and will probably limit cloudcover as well. Strong heating plus all of the factors above should support highs rising into the mid to upper 90s inland, and around 90 along the coast.

With the dry airmass in place, dewpoints are expected to mix out into the 60s inland through at least Thursday, lowering the risk of 105+ heat indices. An additional mitigating factor is smoke from Canadian wildfires that is drifting south into the area. This has kept temperatures down a couple degrees from what was expected in the models and thus could mitigate the need for a heat advisory on Thursday but borderline heat advisory conditions will still exist during the afternoon.

From Friday on, dewpoints are expected to steadily increase with continued, and moistening, southerly flow. This should lead to dewpoints consistently staying in the 70s, even during peak heating/mixing. Heat indices of 105-110 degrees are expected Friday and Saturday. Sunday and Monday are more questionable due to afternoon convection.

KEY MESSAGE 2...Low- mid level troughing is forecast to setup across the Eastern U.S. over the weekend and into next week. Increasing moisture and instability, plus increasing low- level forcing, is expected to support a more active convective period. Initially, convection is expected to be primarily focused along the seabreeze Friday and Saturday, and will probably be more isolated in nature. An increasing coverage is then expected Sunday into Monday as tropical moisture increases. Deep layer shear is forecast to be weak (<25kt), but moderate to strong instability should support a daily risk of strong to marginally severe pulse-type convection. There is strong support for this in analog and machine learning guidance, especially Sunday- Tuesday.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Quiet aviation conditions expected tonight with smokey skies likely to linger through the period at higher elevations. Models showing only modest probabilities of shallow fog development tonight, and although most probabilistic guidance points to odds of fog development under 10% model soundings do point to just enough BL saturation to support some very patchy development right before dawn. If this does occur impacts to any terminals will be negligible.

Light SW winds expected through the period with the diurnal seabreeze moving through EWN and OAJ after 18z bringing a typical gusty period of S winds. No precipitation is expected.

Outlook (Thursday through Sunday): On Friday, isolated seabreeze TSRA will be possible. This is expected to be followed by an increasing risk of TSRA impacts over the weekend.

MARINE

Southerly winds developing this afternoon and building steadily through the evening hours. Despite this, seas are forecast to hold in the 2-3ft range through tonight at 7-9 second periods. No thunderstorms are expected through tonight.

Outlook (Thursday through Sunday): Southerly winds will continue to build through the weekend, peaking at 15-25kt by Saturday, then remaining around that range into next week. Seas will respond and build to 3-5ft by Saturday, then peak in the 4-7ft range by Sunday. The risk of thunderstorms is expected to increase over the weekend, particularly on Sunday.

MHX WATCHES/WARNINGS/ADVISORIES

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