FZUS51 KLWX 211457 CWFLWX Coastal Waters Forecast National Weather Service Baltimore MD/Washington DC 1057 AM EDT Tue Apr 21 2026 Tidal Potomac River and Maryland portion of Chesapeake Bay. Forecasts of wave heights do not include effects of wind direction relative to tidal currents. Expect higher waves when winds are blowing against the tidal flow. Waves flat where waters are iced over. ANZ500-212000- 1057 AM EDT Tue Apr 21 2026 .SYNOPSIS FOR THE TIDAL POTOMAC AND MD PORTION OF THE CHESAPEAKE BAY... High pressure will build in today. A weak cold front looks to drop in from the north Wednesday, then cross the Mid-Atlantic by Thursday. Small Craft Advisories may be needed Wednesday in a south to southwest flow. Additional Small Craft Advisories are possible later this week and weekend as multiple fronts and waves of low pressure traverse the region. $$ ANZ535-212000- Tidal Potomac from Key Bridge to Indian Head- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...S winds 5 to 10 kt. Waves 1 ft. .TONIGHT...S winds 5 to 10 kt. Waves 1 ft. .WED...SW winds 5 to 10 kt. Waves 1 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft. .THU...NW winds around 5 kt. Waves 1 ft. .THU NIGHT...NW winds around 5 kt. Waves 1 ft or less. .FRI...E winds around 5 kt. Waves 1 ft. A chance of showers through the night. .SAT...E winds 5 to 10 kt. Waves 1 ft. A chance of showers in the morning. Showers likely. $$ ANZ536-212000- Tidal Potomac from Indian Head to Cobb Island- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...SE winds 5 kt...becoming S late. Waves 1 ft. .TONIGHT...S winds 10 to 15 kt. Waves 1 ft. .WED...SW winds 10 to 15 kt...becoming W 5 kt late. Waves 1 ft. Showers likely. .WED NIGHT...W winds around 5 kt. Waves 1 ft. .THU...NW winds around 5 kt. Waves 1 ft. .THU NIGHT...S winds around 5 kt. Waves 1 ft or less. .FRI...E winds around 5 kt. Waves 1 ft. A chance of showers through the night. .SAT...E winds 5 to 10 kt. Waves 1 ft. A chance of showers in the morning. Showers likely. $$ ANZ537-212000- Tidal Potomac from Cobb Island to Smith Point- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...E winds 5 kt...becoming SE 15 kt late. Waves 1 ft. .TONIGHT...S winds 10 to 15 kt...becoming 15 kt late. Gusts up to 20 kt. Waves 2 ft. .WED...SW winds 10 to 15 kt with gusts to 20 kt... becoming W 5 to 10 kt in the afternoon. Waves 1 to 2 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds 5 kt. Waves flat. .THU NIGHT...S winds around 5 kt. Waves flat. .FRI...NE winds around 5 kt...becoming SE. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt...becoming NE after midnight. Waves 1 to 2 ft...building to 3 ft after midnight. A chance of showers in the afternoon. Showers likely through the night. $$ ANZ530-212000- Chesapeake Bay north of Pooles Island- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...SW winds 5 to 10 kt. Waves 1 ft or less. .TONIGHT...S winds 5 to 10 kt. Waves 1 ft. .WED...SW winds 5 to 10 kt. Waves 1 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves flat. .THU...NW winds around 5 kt. Waves flat. .THU NIGHT...NW winds around 5 kt. Waves flat. .FRI...E winds around 5 kt. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt. Waves 1 ft. A chance of showers in the morning, then showers likely. $$ ANZ531-212000- Chesapeake Bay from Pooles Island to Sandy Point- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...SE winds 5 to 10 kt. Waves 1 ft. .TONIGHT...S winds 10 to 15 kt with gusts to 20 kt. Waves 2 ft. .WED...SW winds 10 to 15 kt...diminishing to 5 kt in the afternoon. Waves 1 to 2 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds 5 kt. Waves flat. .THU NIGHT...SE winds around 5 kt. Waves flat. .FRI...E winds 5 to 10 kt. Waves 1 ft or less. A chance of showers. .SAT...E winds 10 to 15 kt. Waves 1 to 2 ft. A chance of showers in the morning, then showers likely. $$ ANZ538-212000- Patapsco River including Baltimore Harbor- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...SE winds 5 to 10 kt. Waves 1 ft or less. .TONIGHT...S winds 5 to 10 kt. Waves 1 ft. .WED...SW winds 5 to 10 kt. Waves 1 ft or less. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves flat. .THU...NW winds 5 kt. Waves flat. .THU NIGHT...NW winds around 5 kt. Waves flat. .FRI...E winds around 5 kt. Waves 1 ft or less. A chance of showers. .SAT...E winds 5 to 10 kt. Waves 1 ft. A chance of showers in the morning. Showers likely. $$ ANZ539-212000- Chester River to Queenstown MD- 1057 AM EDT Tue Apr 21 2026 .REST OF TODAY...S winds 5 to 10 kt. Waves 1 ft or less. .TONIGHT...S winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft. .WED...SW winds 10 to 15 kt...diminishing to 5 kt in the afternoon. Waves 1 to 2 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves flat. .THU...NW winds around 5 kt. Waves flat. .THU NIGHT...SE winds around 5 kt. Waves flat. .FRI...E winds 5 to 10 kt. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt. Waves 1 ft. A chance of showers in the morning, then showers likely. $$ ANZ532-212000- Chesapeake Bay from Sandy Point to North Beach- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...SE winds 5 to 10 kt...increasing to 15 kt late. Waves 1 to 2 ft. .TONIGHT...S winds 15 to 20 kt. Waves 2 to 3 ft. .WED...SW winds 10 to 15 kt with gusts to 20 kt... becoming W 5 kt late. Waves 3 ft...subsiding to 1 ft in the afternoon. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds 5 kt. Waves flat. .THU NIGHT...W winds 5 kt. Waves flat. .FRI...E winds 5 to 10 kt. Waves 1 ft or less. A chance of showers. .SAT...E winds 10 to 15 kt...becoming NE 15 to 20 kt after midnight. Waves 1 to 2 ft. A chance of showers in the morning, then showers likely. $$ ANZ540-212000- Eastern Bay- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...W winds 5 kt...becoming S this afternoon. Waves 1 ft or less. .TONIGHT...S winds 10 to 15 kt with gusts to 20 kt. Waves 1 to 2 ft. .WED...SW winds 10 to 15 kt with gusts to 20 kt... becoming W 5 kt late. Waves 1 to 2 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds around 5 kt. Waves flat. .THU NIGHT...S winds around 5 kt. Waves flat. .FRI...E winds 5 to 10 kt. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt. Waves 1 ft. A chance of showers in the morning, then showers likely. $$ ANZ533-212000- Chesapeake Bay from North Beach to Drum Point- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...SE winds 5 to 10 kt...increasing to 15 kt late. Waves 1 ft. .TONIGHT...S winds 15 to 20 kt. Waves 2 to 3 ft. .WED...SW winds 15 to 20 kt...becoming W 5 to 10 kt in the afternoon. Waves 3 ft...subsiding to 1 ft in the afternoon. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds around 5 kt. Waves 1 ft or less. .THU NIGHT...SW winds around 5 kt. Waves flat. .FRI...NE winds 5 kt...becoming SE. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt...becoming NE 15 to 20 kt after midnight. Waves 1 to 2 ft. A chance of showers in the morning, then showers likely. $$ ANZ541-212000- Choptank River to Cambridge MD and the Little Choptank River- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...S winds 5 to 10 kt. Waves 1 ft or less. .TONIGHT...S winds 15 to 20 kt. Waves 1 to 2 ft. .WED...SW winds 10 to 15 kt with gusts to 20 kt... becoming W 5 kt late. Waves 1 to 2 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft or less. .THU...NW winds around 5 kt. Waves 1 ft or less. .THU NIGHT...S winds around 5 kt. Waves flat. .FRI...E winds 5 to 10 kt. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt...becoming NE 15 to 20 kt after midnight. Waves 1 to 2 ft. A chance of showers in the morning, then showers likely. $$ ANZ542-212000- Patuxent River to Broomes Island MD- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...NE winds 5 kt...becoming SE this afternoon. Waves 1 ft. .TONIGHT...S winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. .WED...SW winds 10 to 15 kt with gusts to 20 kt... becoming W 5 kt late. Waves 1 ft. Showers likely. .WED NIGHT...NW winds around 5 kt. Waves 1 ft. .THU...NW winds 5 kt. Waves less than 1 ft. .THU NIGHT...SW winds around 5 kt. Waves 1 ft. .FRI...E winds around 5 kt. Waves 1 ft. A chance of showers through the night. .SAT...E winds 5 to 10 kt. Waves 1 ft. A chance of showers in the morning, then showers likely. $$ ANZ534-212000- Chesapeake Bay from Drum Point to Smith Point- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...NE winds 5 kt...becoming SE 10 to 15 kt this afternoon. Waves 1 ft. .TONIGHT...S winds 15 to 20 kt. Gusts up to 25 kt. Waves 3 ft. .WED...SW winds 15 to 20 kt with gusts to 25 kt... becoming W 5 to 10 kt in the afternoon. Waves 2 to 3 ft. Showers likely. .WED NIGHT...NW winds 5 kt. Waves less than 1 ft. .THU...NW winds 5 kt. Waves less than 1 ft. .THU NIGHT...S winds around 5 kt. Waves 1 ft or less. .FRI...E winds 5 to 10 kt. Waves 1 ft. A chance of showers through the night. .SAT...E winds 10 to 15 kt...becoming NE 15 to 20 kt after midnight. Waves 2 to 3 ft. A chance of showers in the afternoon. Showers likely through the night. $$ ANZ543-212000- Tangier Sound and the inland waters surrounding Bloodsworth Island- 1057 AM EDT Tue Apr 21 2026 ...SMALL CRAFT ADVISORY IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH WEDNESDAY MORNING... .REST OF TODAY...NW winds 5 kt...becoming S late. Waves 1 ft or less. .TONIGHT...S winds 15 to 20 kt. Gusts up to 25 kt in the late evening and overnight. Waves 2 ft. .WED...SW winds 15 to 20 kt with gusts to 25 kt... becoming W 5 to 10 kt in the afternoon. Waves 1 to 2 ft. A chance of showers. .WED NIGHT...NW winds 5 kt. Waves less than 1 ft. .THU...NW winds 5 kt. Waves less than 1 ft. .THU NIGHT...SW winds 5 kt. Waves less than 1 ft. .FRI...SE winds 5 to 10 kt. Waves 1 ft or less. A chance of showers through the night. .SAT...E winds 10 to 15 kt...becoming NE 15 to 20 kt after midnight. Waves 1 to 2 ft. A chance of showers in the afternoon. Showers likely through the night. $$