Key MESSAGE 1, Hot and humid conditions will continue through the weekend. Heat Adv in place for SUN for all but one zone of mainland ENC. Heat index values 105-110 deg through early evening. We will see a dip in heat MON with greater cloud coverage through the day and more rain helping bump down MaxTs into the upper 80s and low 90s, but SWern zones may still require heat headlines. Tue and WED MaxTs climb back into the low 90s for most and afternoon Tds approaching 80deg will bring heat headlines back into play.
KEY MESSAGE 2, There are several factors expected to support an increasingly active pattern into next week.
Upper level troughing will continue to strengthen over the Eastern U.S. With ridging shifting away from the area. Persistent S-SWerly flow E of the trough, potentially with a subtropical connection, should act to enhance low-mid level moisture across the area. Meanwhile, heating of a moistening boundary layer should lead to sufficient instability and reduced inhibition in support of periods of convection.
Lee- side troughing and, eventually, a frontal boundary that will reach the FA by MON should provide areas of enhanced low- level forcing today with gradually improving mid and upper level flow becoming more conducive to organized storm modes as trough aloft sharpens.
Today, the SFC front will approach the FA, though model to model timing differences still in place. General trend appears to be a slight slow down of the front entering the Nern FA, sometime this evening or the first half of tonight. Spc's outlook for today features a Slight Risk (lvl 2/5) for the bulk of the area. Moisture pooling and low level convergence will be maximized this afternoon into tonight as the cold front approaches. Pwats peak on the order of 2 and 3/4in in conjunction with increasing afternoon and evening instability. First round of convection is expected across the Inner and Outer Banks and inland waters, initiated with the seabreeze. Sbcapes on the order of 4kJ/kg are expected just ahead of the seabreeze which could lead to quickly developing tstorms. Main concerns will be the potential for damaging wind gusts, heavy rain and freq lightning late afternoon into tonight. Wpc continues its Slight Risk for excessive rainfall today.
Additionally, while guidance remains mixed, there is a modest signal for low pressure development across the northeastern Gulf. The National Hurricane Center has increased probability of development a bit to 60 60% over the next 2 days. Though no explicitly tropical impacts are expected from this system locally, this low should act to enhance rainfall along the SE coast by further increasing Gulf moisture transport from its Eern half through early next week while the stalled lingers across the region.
Tropics aside, deterministic and machine learning guidance continue to show a good signal for some strong to marginally severe thunderstorm potential during this period of active weather. Right now the strongest signal for severe potential through TUE is today. Given increased forcing from the approaching front and the potential tap of subtropical moisture, heavy rain and some hydro impacts may eventually be realized.
MON, the stalled boundary located somewhere between the Neuse River and the NC/VA border, inland troughing persisting, and plenty of moisture influx from the S and SW will keep cloudy and active forecast in place. Fortunately, the mid and upper level trough over NECONUS will be pushing offshore, ending the little mid and upper level dynamic support system for organized convection. Mon night, the boundary lifts back N, "warm- sectoring" the FA once again for TUE and WED.
A stronger front is forecast to approach and cross the area WED into THU, posing the next threat for severe weather later in the forecast period. Upper level pattern for this FROPA appears more supportive of stronger storms than the SUN/MON front with a sharper trough aloft digging further S than the weekend trough, with the base of this trough actually crossing directly overhead.
KEY MESSAGE 3, WED/THU stronger front is forecast to make it through the entirety of the land area of ENC, but still stall offshore. This will lead to mostly N-NEerly flow late week into the weekend, cutting down on the heat (mid to upper 80s/upper 60s splits into the weekend). Severe threat appears minimal behind the midweek front, but the multi day period of showers in the forecast could lead to hydro issues.
12z Sunday through Thursday VFR flight cats expected outside of storms into tonight with SW breeze. Better convective coverage expected today in two rounds, first along the seabreeze this afternoon into the evening and a second round of more organized convection ahead of and along a front pushing from N to S later this evening into tonight. Both rounds of storms could lead to periods of sub- VFR. A few stronger storms are also possible, with potential for damaging wind gusts, heavy rain, and frequent lightning.
Guidance is hinting at post-frontal stratocu and potentially dense fog along and immediately behind (north) of the front. Will include FEW to SCT cloud groups Outlook (Monday through Thursday): TSRA risk stays on the table for Monday with the stalled boundary lingering through the day and lifting back Nward MON night, though these storms are not expected to be as intense as today's. Another approaching front, this one looking stronger, renews stronger shower and thunderstorm chances WED into THU. Latest surface and buoy obs indicate S-SW winds 10-20 kt inside, 20-30kt (and some higher gusts) over PamSound and coastal waters with seas 4-8ft, highest near GStream. Scas continue for Pamlico Sound and nearshore coastal waters. Over the outer coastal waters, a few gale force gusts will remain possible. Diamond has been gusting to the low 30s for most of the overnight. Moderate to strong SW winds will continue Sunday, stronger south of Hatteras with seas 3-6 ft. Have extended the existing SCA for PamSound to encompass the pinched pressure gradient due to approaching front and stronger thermal gradient this afternoon and evening. Two rounds of showers and storms expected, first storms developing along and near the seabreeze this afternoon being advected over the inside waters into this evening. Second round will be later this evening into tonight when more organized convection works in a line from N to S across ENC. Both rounds have potential for strong to severe thunderstorms that could carry strong wind gusts, heavy rainfall, and frequent lightning. The front that approaches the area latter half of today will stall and meander between the Neuse and the NC/VA border until lifting back Nward MON night. Outlook (Monday through Thursday): For the outer waters, elevated winds and seas may last for much of the week. A stronger front is forecast to approach and cross regional waters mid to late week, bringing another round of strengthening SW winds and tstorm chances, mainly later Tue and Wed. Nc, heat advisory from 11 am this morning to 7 pm EDT this evening for ncz044>047-079>081-090>092-094-193>196-198-199. Beach hazards statement through this evening for ncz195-196- 199-204-205. Marine, small craft advisory until 2 am EDT Monday for amz135. Small craft advisory until 10 am EDT this morning for amz150. Small craft advisory until 6 am EDT Monday for amz152-154-156- 158. Marine
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