Key MESSAGE 1, Several low amplitude and weakly sheared shortwaves sweep across the Mid Atlantic and Southeast this weekend. Gom is cutoff from moisture with sfc low pressure(s) expected to remain south of the region, and thus precip looks to be much more spotty in nature.
For Saturday, overrunning light rain (up to ~25-30% chance) with perhaps a few embedded storms (10-15% chance) are still in the forecast for inland areas. Best chances of seeing rain across the Sern coast and OBX where low level convergence is maximized in an area between a developing low and the Wern periphery of the offshore high. The coastal areas will have a better chance of seeing more convective showers and maybe some thunder (15-20%). It will not be an all- day washout, but periods of showers or light rain with an iso storm will be present as a warm front lifts through and weak lift transits the area.
Sunday, forecast has trended even drier, with subsidence in wake of aforementioned light overrunning event, and the FA in broad srly flow leading to MaxT in the low 80s. Can't rule out a shower or two across the Wern FA (Coastal Plain counties) in the late afternoon, but bulk of guidance on the dry side, including the AIFS, which as been quite consistent.
KEY MESSAGE 2, Decent agreement on next stronger shortwave and attendant cold front moving through the region MON. This system will have decently strong dynamics with fairly sharp troughing aloft pivoting over ECONUS to become more negatively tilted and potentially steeper lapse rates, but latest solutions have the most support aloft arriving slightly later than the SFC front which is expected to reach Nern extent of the FA around or shortly after sunrise MON. A severe thunderstorm threat is possible with this system, with the main threats appearing to be severe wind gusts and large hail, along with heavy downpours. Cape values on the order of 1-1.5K J Kg per latest 09 0Z model suite which is now within the window of some regional guidance. Still outside of HiRes guidance resolution window, but available models suggests another quick half to one inch of rain for a lot of the area with the Sern coast potentially seeing up to an inch and a half this FROPA. Spc has added a marginal threat (level 1/5) for the Crystal Coast, which is where the greatest instability would be with the front approaching ~HWY70 during peak heating. Stout CAA out of the N (strongest winds over coast, 20-25kt gusts) will bring in cool air and keep skies mostly clear into mid- week. Upper 40s/upper 60s split TUE.
KEY MESSAGE 3, A stacked low cutting across the Sern extent of the Great Lakes and high pressure migrating offshore brings warm and moist air across the Carolinas mid week ahead of the next front set to cross the area around the Thursday time frame. Will need to watch this system for severe potential as well.
06z Saturday through Wednesday A weak area of low pressure is forecast to develop overnight within a more broad surface trough in the vicinity of KMRH. It appears likely that SCT SHRA and TSRA will develop in the vicinity of this developing low, but should move quickly ENE within the fast westerly flow aloft. This should keep the greatest risk of low CIGs and TSRA east of the TAF sites, but this activity could skirt runways along the OBX. In the wake of the morning activity, a fast moving upper level wave is forecast to move through Saturday afternoon and could be accompanied by another risk of SCT SHRA and TSRA. Guidance shows less confidence in the placement and coverage of the afternoon activity, therefore I have opted to keep SHRA/TSRA out of the TAFs for now. In the wake of the afternoon wave, guidance shows the potential for sub-VFR conditions in either low stratus or BR/FG, and this potential will continue to be monitored.
Outlook: The next opportunity for sub-VFR conditions looks to be focused Sunday night into Monday as a cold front sags south towards, and eventually through, ENC with an increased risk of SHRA and TSRA. Reduced VIS and lowered CIGs are expected as well.
Seerly winds become more SWerly while strengthening to 15-20kt. Winds on the Gulf waters, especially S of Hatteras will occasionally gust to 25 kt, but will not issue any SCAs for the time being due to marginal nature of these stronger wind gusts and seas remaining below 6 ft. Showers and a few storms will sweep across the waters on Saturday as weak low pressure moves through the region. Best chance for thunder is over the Gulf waters where greater instability will reside.
Outlook (Sunday through Wednesday): Winds and seas diminish on Sunday, generally Werly easing to 10kt or less through the morning, becoming more Serly later in the day. Showers possible outside of ~40nm. Swerly winds strengthen some SUN night into MON ahead of next fropa with SCA conditions becoming more likely with post frontal northerly flow of 25+ kt MON evening and into Tuesday. Scas likely for all coastal waters with inside waters potentially seeing SCA gusts. Offshore waters showing gale potential overnight MON into early TUE morning. Winds diminish later Tuesday into Wednesday as high pres reestablishes itself.
Nc, none. Marine, none.
