Patapsco River including Baltimore Harbor

ANZ538 · Coastal Waters Forecast, National Weather Service Baltimore MD/Washington DC · issued Sat, Sep 26, 4:57 PM EDT

Small Craft Advisory in force. Rest of this afternoon: N winds 15 kt with gusts to 25 kt. Waves 2 ft. Rain.

Patapsco River including Baltimore Harbor on the map

The zone and the zones around it, tinted where a marine warning or advisory is in force. Tap a neighboring zone to open its forecast.

Gale Warning
Small Craft Advisory

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Now

The nearest stations reporting each, as of Sat, Sep 26, 5:48 PM EDT.

Wind: NNW 18 kt, gusts 20 kt at FSKM2
Waves: 1.0 ft at 2 s at 44080
Water: 72°F at 44080

Alerts in force

Small Craft Advisory from Sat, Sep 26, 2:51 PM EDT until Sun, Sep 27, 6:00 PM EDT

Small Craft Advisory issued September 26 at 2:51PM EDT until September 27 at 6:00PM EDT by NWS Baltimore MD/Washington DC

The full text

* WHAT...Northwest winds 10 to 15 kt with gusts up to 25 kt.

* WHERE...Tidal Potomac River from Key Bridge to Cobb Island MD,
and Patapsco River including Baltimore Harbor.

* WHEN...Until 6 PM EDT Sunday.

* IMPACTS...Conditions will be hazardous to small craft.

Inexperienced mariners, especially those operating smaller
vessels, should avoid navigating in hazardous conditions.

The forecast

Coastal Waters Forecast from National Weather Service Baltimore MD/Washington DC, issued Sat, Sep 26, 4:57 PM EDT, valid until Sun, Sep 27, 4:00 AM EDT. Wind in knots, seas in feet.

SMALL CRAFT ADVISORY IN EFFECT THROUGH SUNDAY AFTERNOON

Rest of this afternoon: N winds 15 kt with gusts to 25 kt. Waves 2 ft. Rain.
Tonight: NW winds 15 kt with gusts to 25 kt. Waves 1 to 2 ft. A chance of rain.
Sunday: NW winds 15 to 20 kt with gusts to 30 kt. Waves 2 ft. Rain.
Sunday night: NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 to 2 ft. A chance of showers.
Monday: NW winds 10 kt with gusts to 20 kt. Waves 1 ft.
Monday night: NW winds 10 kt. Waves 1 ft.
Tuesday: W winds 5 to 10 kt...becoming light. Waves 1 ft or less.
Wednesday: S winds around 5 kt. Waves 1 ft or less.

Synopsis

Synopsis for the tidal potomac and md portion of the chesapeake bay

A strong Nor'easter will meander off the Mid Atlantic coast through Sunday before finally departing to the northeast Monday. High pressure will build into the area for the middle of next week. Small Craft Advisories and potentially gale conditions will continue through Sunday. Advisories may be needed through Monday.

Buoys and stations nearby

The latest report from each station within reach of the zone, nearest first. Distances in nautical miles from the middle of the zone.

Station	Distance	Wind	Waves	Water	Air	Pressure	Reported
FSKM2 8574728 - Francis Scott Key Bridge, MD	0 nm	NNW 18 kt, gusts 20			59°F	1010.1 hPa	Sat, Sep 26, 5:30 PM EDT
44080 Baltimore	0 nm	NNW 23 kt, gusts 29	1.0 ft at 2 s	72°F	57°F	1012.3 hPa	Sat, Sep 26, 5:48 PM EDT
BCFM2 Brewerton Channel Range Front Light (8574831)	1 nm	NNW 18 kt, gusts 21				1010.5 hPa	Sat, Sep 26, 5:30 PM EDT
BLTM2 8574680 - Baltimore, MD	4 nm	NNW 12 kt, gusts 17		79°F	60°F		Sat, Sep 26, 5:30 PM EDT
TCBM2 8573364 - Tolchester Beach, MD	13 nm	NNW 21 kt, gusts 25		68°F	60°F	1009.7 hPa	Sat, Sep 26, 5:30 PM EDT
APAM2 8575512 - Annapolis, MD	14 nm	WNW 15 kt, gusts 19		69°F		1010.3 hPa	Sat, Sep 26, 5:30 PM EDT

The past year

Warnings, watches and advisories the National Weather Service issued for this zone over the past 12 months, from the Iowa Environmental Mesonet’s archive.

Product	Issued	Most recent
Special Marine Warning	44	Thu, Sep 3, 2026, 10:53 PM EDT
Gale Warning	21	Thu, Jun 18, 2026, 9:00 AM EDT
Storm Warning	1	Sat, Feb 7, 2026, 6:00 AM EST
Severe Thunderstorm Watch	18	Thu, Sep 3, 2026, 8:38 PM EDT
Gale Watch	16	Thu, Jun 18, 2026, 9:00 AM EDT
Tornado Watch	5	Thu, Aug 20, 2026, 3:01 PM EDT
Small Craft Advisory	147	Mon, Sep 21, 2026, 6:00 PM EDT
Low Water Advisory	8	Sun, Feb 8, 2026, 3:00 PM EST
Dense Fog Advisory	7	Tue, Mar 10, 2026, 4:14 AM EDT
Freezing Spray Advisory	2	Mon, Jan 26, 2026, 6:00 PM EST

What this means

Marine forecasts give wind in knots (1 knot is 1.15 mph) and seas in feet, except the high seas forecasts, which give seas in meters. Seas are the significant wave height, the average of the highest third of the waves; individual waves may be more than twice that. On the Great Lakes the forecast gives waves, not seas. "Wave Detail" splits the seas into the wind waves and each swell, with its direction and period.

Each coastal office writes a Coastal Waters Forecast for the bays, sounds and ocean out to 20 to 60 nautical miles, or on the Great Lakes a Nearshore Marine Forecast within 5 nautical miles of shore; the Open Lakes Forecast covers the rest of each lake. The Ocean Prediction Center and the National Hurricane Center write the Offshore Waters Forecasts out to about 250 nautical miles, and the High Seas Forecasts beyond. Forecasts are issued at least twice a day and updated when they go wrong.

Small Craft Advisory: Winds or conditions hazardous to small boats. The thresholds are set by each NWS region: typically sustained winds or frequent gusts of 20 to 25 knots up to 33 knots, and seas of 5 to 7 feet or more.
Gale Warning: Sustained winds or frequent gusts of 34 to 47 knots, not from a tropical cyclone.
Storm Warning: Sustained winds or frequent gusts of 48 to 63 knots, not from a tropical cyclone.
Hurricane Force Wind Warning: Sustained winds or frequent gusts of 64 knots or more, not from a tropical cyclone.
Special Marine Warning: A thunderstorm or squall over the water with winds or gusts of 34 knots or more, hail of 3/4 inch or more, or a waterspout, for up to two hours.
Hazardous Seas Warning: Wave heights or steepness at or above the office’s warning threshold, when the wind alone does not warrant a warning.
Heavy Freezing Spray Warning: Spray freezing on a vessel at 2 cm (3/4 inch) an hour or more.
Tropical Storm and Hurricane Warnings: Tropical storm (34 to 63 knots) or hurricane (64 knots or more) conditions expected within 36 hours. Watches: possible within 48 hours.

Nearby

Open the live map with marine zones and buoys The hour-by-hour forecast for the middle of the zone Every Atlantic Coast zone

Sources

Coastal Waters Forecast CWFLWX from National Weather Service Baltimore MD/Washington DC, issued Sat, Sep 26, 4:57 PM EDT. Original at NWS. Buoy reports from the National Data Buoy Center. Past products from the Iowa Environmental Mesonet. Zone outlines from the NWS marine and offshore zone boundaries. Warnings and advisories from the NWS API, read 22:17 UTC. All public domain, from the National Weather Service.