textproduct: NWS Wilmington

SYNOPSIS

Shower and thunderstorm chances increase today with even better storm chances Thursday and possibly Friday. Rain chances decrease slightly for the weekend, but afternoon showers and thunderstorms remain a fixture into the middle of next week.

NEAR TERM /THROUGH TONIGHT/

Typical summertime weather continues with Bermuda high pressure offshore. Could see a few showers move onshore in deep southerly flow early this morning before dissipating. An upper shortwave currently seen on water vapor imagery moving into the Great Lakes region will approach the Mid-Atlantic this evening. Majority of the PVA associated with the shortwave will remain to our north. Mid- level ridging from the east will lead to a bit of subsidence in our area, strongest near the coast, which will limit afternoon convective coverage to scattered versus widespread. PWATs remain high with adequate instability (for any storms that can break the subsidence cap). A cluster of storms to the west may approach our area this evening into early tonight, but expect them weaken as they reach I-95. Seasonable temperatures today, with highs in the low 90s. Dewpoints in the mid 70s will create another humid day with heat indices in the triple digits, but below heat advisory threshold. Low temps tonight in the low to mid 70s.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Decent coverage of showers and thunderstorms seems like a given on Thu. Deep moisture remains in place, precipitable water is 120-130% of normal, and 500mb heights will be falling as 5h trough slowly moves in from the west. The Piedmont trough and weak sea breeze will add in some low level convergence while heating pushes CAPE to 2k-3k J/kg. Some of the guidance does show a bit of mid-level dry air in forecast soundings in the afternoon which could curtail coverage a bit. If this drier air does manifest coverage would be knocked back a peg or two, high chance to likely instead of likely to widespread.

Confidence is lower concerning rain chances Fri. Mid-level humidity on Thu is 70-80% in the afternoon, but by Fri afternoon this same layer has humidity 30-40%. The drier air is a result of some weak subsidence as the slow moving 5h trough axis shifts just east of the forecast area Fri afternoon. Still think storms will develop, there is plenty of low level moisture, CAPE values are similar to Thu, perhaps slightly lower, and the Piedmont trough and sea breeze will still be present. Just expect coverage to be a category or two lower compared to Thu. Highs will be near to slightly below normal each day with lows a little above normal.

LONG TERM /SATURDAY THROUGH TUESDAY/

Although the setup is not quite typical, the result will be typical July in the Southeast. In other words, hot and humid with daily showers and thunderstorms. Bermuda High remains in place, which is common, but the Piedmont trough will work its way to the coast and maybe just off it sometime early next week. Weaker high pressure then builds in from the northwest with potential for a weak wave or 2 developing along the trough during the middle of next week. Later in the period the highest rain chances may shift closer to the coast, where the trough is, but there will be plenty of surface based instability with highs in the low to mid 90s inland for daily bouts of diurnal convection across the forecast area.

AVIATION /05Z WEDNESDAY THROUGH SUNDAY/

Moist low levels and elevated boundary layer winds are expected to produce IFR/low MVFR stratus inland early this morning, dissipating within a few hours of sunset. Ceilings of 700-1200 ft are forecasted, and have highlighted this in LBT and FLO TAFs. Diurnal cumulus and a few high clouds will dominate this afternoon, with scattered thunderstorms inland into this evening. Winds remain out of the south, with gusts of 15-20 kts this afternoon across coastal areas with sea breeze.

Extended Outlook...Intermittent flight restrictions are possible each day due to afternoon/evening convection and the potential for early morning fog/stratus.

MARINE

Through Tonight... Benign conditions continue across the local coastal waters as Bermuda high persists. South-southwest winds 10-15 kts through tonight, with gusts to 20 kts possible this afternoon. Seas around 3 ft, predominantly due to southerly wind wave, with 1 ft long period ESE swell still present.

Thursday through Sunday... Bermuda High will maintain southwest flow over the waters into the start of next week. Speeds increase to around 15 kt in the afternoon as the Piedmont trough strengthens with daytime heating. Speeds do decrease a bit for the weekend, especially Sun, as the Piedmont trough moves closer to the coast and the gradient weakens slightly. Seas will run 3-4 ft into the weekend with a gradual reduction in later Sat and Sun in response to the slightly decreased wind speeds. Seas will continue to be a mix of a southeast swell and a longer period southerly wind wave.

ILM WATCHES/WARNINGS/ADVISORIES

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