🌊 US Weather Warriors MarineCast — Saturday, July 18, 2026
Small Craft Advisories blanket the Atlantic coastal waters and nearly every Chesapeake Bay zone — it's a rough-water day across Delmarva.
Today on the Water: SCAs are in effect from Cape May down through the Virginia capes and across most of the Chesapeake, most expiring between 9:45 AM and late tonight. Southerly winds strengthen through the afternoon, and scattered thunderstorms along a warm front are already producing gusty winds and heavy rain. A Heat Advisory is also up through 8:00 PM for lower Delmarva and Tidewater — hydrate hard if you're on deck.
Atlantic Coastal Waters (Lewes → southern VA coast): SCA conditions with building southerly flow and choppy seas through the day. Thunderstorm chances persist. Visibility briefly reduced in smoke this morning, improving by afternoon per LWX discussion.
Delaware Bay: Under the Cape May–Fenwick SCA until midnight tonight. Southerly winds strengthen this afternoon with a chance of showers and storms. Expect a short, steep chop building through the day.
Chesapeake Bay & Delmarva-facing Waters: SCAs stacked from the head of the Bay down to Cape Henry, most running into tonight or Sunday morning. SW winds 15–20 kt gusting 25 kt with a chance of showers and storms. Radar shows a cluster of strong cells (52–57 dBZ) 17–38 nm SW of Dover tracking W/WNW — moving away from the coast but a lightning threat for upper Bay and Potomac waters right now. Marine Weather Statement in effect for the upper Bay until 6:15 AM.
Wind & Seas Outlook: Peak wind and seas hit Tuesday night: SW 25–30 kt with Atlantic seas 6–7 ft, occasionally to 10 ft. Wednesday brings SW gusts to 30 kt on the Chesapeake.
Marine Alerts:
- Heat Advisory — until 8:00 PM today (lower Delmarva/Tidewater)
- Small Craft Advisory — Cape May to Fenwick, until 12:00 AM Sunday
- Small Craft Advisory — Fenwick to Parramore Island, until 9:45 AM today
- Small Craft Advisory — Parramore to NC border, until 8:00 AM Sunday
- Small Craft Advisory — Upper Chesapeake, until 11:00 PM today
- Small Craft Advisory — Mid/Lower Chesapeake & Tidal Potomac, until 6:00–10:00 AM Sunday
- Marine Weather Statement — Upper Chesapeake, until 6:15 AM
Best Window to be Out: Sunday during the day once the overnight SCAs lift — winds ease and seas drop before the next system builds Tuesday.
Worst Window: Tuesday night — SW 25–30 kt, seas to 10 ft offshore, storms in the mix.
Bottom Line: Stay tied up today unless you're in a capable boat with a short, protected run — this is an SCA day across the board.
— US Weather Warriors #DelmarvaWeather #MarineWeather #BoatingWeather