🌊 US Weather Warriors MarineCast — Thursday, August 20, 2026
Small Craft Advisory conditions are in place on much of the Chesapeake through 8:00 PM, with increasing southerly winds, gusts near 20 knots, and thunderstorms adding localized hazards.
Today on the Water:
The Chesapeake is the main concern, especially on wider middle-Bay waters where persistent gusts near 20 knots are most likely outside storms.
Radar is quiet within 50 miles of Delmarva, but showers and thunderstorms remain in the forecast; patchy fog is also possible on the Bay tonight.
Coastal waters build this afternoon and tonight ahead of the front.
Atlantic Coastal Waters (Lewes → southern VA coast):
South winds increase from 5 to 10 knots to 10 to 15 knots this afternoon, with gusts up to 20 knots.
Tonight brings south winds 15 to 20 knots with gusts up to 25 knots, becoming west 5 to 10 knots after midnight. Seas run 2 to 3 feet, with showers and a chance of thunderstorms.
Delaware Bay:
East winds around 10 knots gust up to 20 knots tonight before turning north after midnight. Seas build to around 2 feet.
Showers and thunderstorms are mainly expected in the evening. Friday improves to north winds 5 to 10 knots, becoming northeast in the afternoon, with seas 1 foot or less.
Chesapeake Bay & Delmarva-facing Waters:
South winds increase to 10 to 15 knots this afternoon, with gusts up to 20 knots; waves include a southeast 2-foot component.
Numerous showers and thunderstorms are expected tonight, with north winds 5 to 10 knots and gusts up to 20 knots early in the evening. Patchy fog can reduce visibility.
Wind & Seas Outlook:
The peak wind and sea period is tonight, led by the Atlantic coastal waters with south winds up to 20 knots and 2-to-3-foot seas.
Friday is lighter on Delaware Bay; the lightest broader-water period listed is Monday night.
Marine Alerts:
- Small Craft Advisory for Chesapeake Bay waters from north of Pooles Island south to Smith Point, including Tangier Sound and nearby inland waters, until 8:00 PM Thursday.
- Flood Watch in effect until Friday, August 21 at 2:00 AM EDT for portions of the region.
Best Window to be Out: Friday on Delaware Bay, when north winds hold at 5 to 10 knots and seas stay 1 foot or less.
Worst Window: Tonight—particularly on the Chesapeake and Atlantic waters—with gusty winds, thunderstorms, rougher seas, and patchy Bay fog.
Bottom Line: Skip exposed Chesapeake and coastal runs today if you can; tonight is the period most likely to be uncomfortable and hazardous.
— US Weather Warriors #DelmarvaWeather #MarineWeather #BoatingWeather