Key MESSAGE 1, Notable upper level ridging will build over the Southeastern U.S. Through mid-week. Beneath the ridge, south to southwesterly low-level flow will continue to support very warm low- level thicknesses. In fact, thicknesses may approach 2-3 standard deviations above the mean for this time of year. Synoptically, this favors well above normal to record level temperatures. Adding support to this potential is forecast aids like the ECMWF EFI guidance, which show a very strong signal for record, or near- record, temperatures. This will be most apparent inland away from the influence of local water bodies. However, even along the coast, water temperatures have now warmed into the 60s, and it will still be warm there, especially prior to the diurnal seabreeze. For perspective, normal highs this time of year are in the low 60s. The equates to highs Tuesday and Wednesday running a solid 10-20 degrees above normal. Please see the CLIMATE section below for additional information on records at some select locations.
KEY MESSAGE 2, A neutral to slightly negative upper level shortwave is forecast to move through the Carolinas on Thursday. At the surface, a cold front will move SE across ENC during the day, reaching the coast by the afternoon hours. Strong moisture transport ahead of the front, plus strong frontal forcing and enhanced upper level dynamics should support an area of scattered to numerous showers along the front Thursday. Additionally, low to mid 60s dewpoints beneath modest lapse rates may allow a narrow ribbon of modest instability to develop. While deep layer shear is forecast to be more than sufficient for thunderstorm organization, a diurnally unfavorable timing of the frontal passage and limited instability should keep the severe thunderstorm risk muted. Some machine learning guidance show a weak signal for severe weather, though, so the risk isn't zero. Something to watch, but for now the key message is that the risk is low. This front will briefly usher in a notably cooler and drier airmass across ENC Thursday night into Friday.
18z Monday through Saturday VFR conditions for most this afternoon, although a lingering 3 kft ceiling is present in some inland terminals. These should rise above 3kft in the next 1-2 hours with the warming this afternoon. Areas of fog may re- develop again overnight into Tue morning as light to calm winds spread over the region. We do have some drier air with a very shallow inversion, so expecting the nature of fog to be more patchy and shallow, with potential for stratus instead of winds struggle to go calm. Regardless, the forecast for tonight is of lower confidence with the range of possibilities going from LIFR to VFR. Tomorrow, fog and low stratus should lift by 13-15Z, leading to another day of light SW winds and VFR ceilings.
Outlook, Sub-VFR may return Thursday with scattered to numerous showers and gusty winds.
Sea Fog: Sea fog has moved in to coastal waters between Cape Lookout and Surf City, with visibilities dropping below 1 SM. A marine dense fog advisory has been issued until 22Z for this, with low confidence on how long it will linger this afternoon. Tonight as the surface layer saturates sea fog chances increase across the CWA outside of the Gulf Stream. There is a scenario where the sea fog currently observed between Cape Lookout and Surf City continues through tomorrow morning.
Outside of sea fog impacts, fairly benign boating conditions are expected to continue through Tuesday night. During this time, southwest winds of 5-10kt are expected, along with seas of 2-3 ft.
Outlook: On Wednesday, the pattern will begin to change as the gradient tightens ahead of an approaching cold front. This will lead to building winds and seas on Wednesday, continuing into Thursday. Prefrontal, southwesterly winds of 10-20kt are expected Wednesday- Thursday morning, followed by northerly winds of 15-25kt behind the font. This is expected to support an increased risk of hazardous conditions for small craft. Additionally, the warmest waters may see wind gusts approach gale force behind the front on Thursday. Barring significant changes, marine headlines will eventually be needed for most, if not all, waters. High pressure builds in behind the front, allowing winds and seas to lay down some by Friday.
Nc, none. Marine, dense fog advisory until 6 pm EDT this evening for amz158.
