Key MESSAGE 1, Overall pattern over the next few days will be slightly less conducive for shower and thunderstorm development with high pressure expected to build in behind a passing front today and remaining in control. The front has pushed through most of the area this afternoon, with drier air filtering in. A few showers and storms from Cape Hatteras to Cape Lookout will continue to push eastward and offshore over the next few hours. There is also a slight chance on Tuesday as a weak wave of low pressure migrates along the stalled frontal boundary, although guidance has trended slightly drier with this feature, best chances still look to be for areas along and east of Hwy 17. The next best chance for stronger storms remains Thursday night into Friday ahead of a stronger front where deeper shear will likely be present along with strong instability as temperatures soar back into the 90s to near 100 and humidity remains oppressive. Like previous days, better kinematics and thus higher risk of organized convection will likely be to our north in the Mid-Atlantic, but medium-range AI NWP guidance still highlights much of the Carolinas in an elevated severe risk especially on Thursday, and potentially lingering into the day on Friday. The primary threat risk is damaging winds, but other hazards remain on the table.
KEY MESSAGE 2, Behind today's cold front, relatively cooler temperatures will prevail with highs dipping into the upper 80s to low 90s. As alluded earlier, increasing southwesterly flow ahead of the late-week front will boost low-level thicknesses and kick temperatures into the mid to upper 90s by Thursday. Paired with Tds in the low to mid 70s, widespread heat indices of 105-110 are likely. The passing front may cool things down briefly, but long range guidance suggests excessive heat will remain a concern into next week.
00z Tuesday through Saturday VFR conditions continue at the terminals this evening with high based cumulus gradually dissipating with loss of daytime heating. The cold front remains offshore and a weak area of low pressure is forecast to develop along it late tonight into Tuesday as an embedded mid level shortwave move through the broader upper trough over the eastern CONUS. Fog potential is low tonight as a drier airmass as built into the area behind the front. However, some guidance does suggest patchy low stratus may develop after midnight with highest probs across southeastern rtes where REFS is showing 20-40% chance of sub-VFR cigs, highest along the Crystal Coast. Will also see an increase of mid and high clouds late tonight as the aforementioned shortwave and sfc low approaches the area. Current ensemble probs show about a 20-30% chance of showers across the eastern half of the forecast area Tuesday as the low passes offshore, though some guidance is showing greater coverage leading to a low confidence forecast. Some of the more robust solutions would bring periods of sub-VFR conditions.
Outlook: Iso shower and thunderstorm risk will extend into Wednesday. More widespread convective threat returns Thursday and especially Friday with stronger front. Overnight fog and stratus threat possible each morning.
Latest obs show variable winds, generally N-NE 10-15 kt with seas 3-5 ft. Cold front is currently pushing through the southern waters and will remain stalled there, while a weak low develops along the front Tue. Winds will continue to diminish to less than 10 kt overnight with seas subsiding to 2-4 ft. Light NE-E winds start off Tue, becoming SE-S 5-15 kt in the afternoon. Shower and storm threat south of Hatteras will diminish late this afternoon.
Outlook (Tue night through Sat): Periodic nocturnal and early morning risk of showers and thunderstorms is possible each weeknight, although most likely odds will be Thursday night into Friday ahead of stronger front approaching area waters. This front will also be the next focus of widespread SCA conditions with a low risk but increasing risk of Gales across the outer waters.
Nc, none. Marine, none.
