This is a pre-passage source and decision desk, not a current forecast or clearance to depart. The map is centred approximately on the area, not on your route or a forecast-zone boundary.
Find each named coastal, offshore, bay or lake zone along the route. For inlets, bars and tidal narrows add current local notices and observations; an offshore wave forecast does not describe the entrance.
1. Primary sources
Open current bulletins and warnings for every sea area on the route. These links are starting points, not a promise that each covers the whole location; if unsure, identify the issuer through WMO–IMO.
2. Route and local effects
Use the bay forecast and consider fetch, thunderstorms and current separately.
Chesapeake Bay can build a short wind-driven sea over a long fetch while a nearby creek remains quiet.
Use NOAA bay zones and thunderstorm warnings; examine wind direction relative to fetch, tide and the exposed river mouth, not just a land-city forecast.
How to use this source set
Start with the warning, then the marine text for the exact named area. If the route crosses a zone boundary, obtain both bulletins. Note issue and valid times, wind units and the meaning of wave height. Where a link opens an agency portal, navigate to its current marine product; a homepage is not itself a forecast.
Compare with an exposed station or buoy if available. Check its position and observation time: a sheltered station does not overturn a warning for an open channel. If a bulletin is missing or stale, identify the issuing service via WMO–IMO and defer the decision until current information is available.
Before-passage check
- Mark departure, exposed legs, arrival and feasible diversions; find the responsible named marine areas for each.
- Check warnings, issue and valid times; assess conditions when you expect to reach each leg, not only at departure.
- Compare wind and gusts, waves and swell, visibility, thunderstorms and local effects; do not infer a strait from a sheltered harbour.
- Compare recent observations where available, noting their time and exposure; a mismatch calls for another check.
- Set the next bulletin check, a reassessment trigger, an alternative and a backup communication channel.
Model map — optional
Windy is a third-party model display, not the issuer of official warnings. Choose a layer and check its valid hour and model run. Nothing loads until you click.
Without JavaScript, open the map separately.
If connectivity fails
Before departure, save the current official text bulletin and warning with issue time. Arrange another way to receive updates, such as an appropriate coastal broadcast, NAVTEX or satellite channel. A saved map cannot replace new warnings.
How to choose weather tools · All sailing areas
Scope: Source list assembled 25 September 2026; check its freshness and coverage before use. This public area guide is not a current personalised forecast, navigational notice service or safety verdict. Personalised forecasts with AI and experts are in closed testing; public booking is not open. The skipper makes the decision.
Local passage-planning dossier
Assess the tributary, open Bay and destination separately; one town’s calm weather is not the Bay forecast.
Forecast sectors and coverage
NWS Baltimore/Washington covers upper/middle Bay and tidal Potomac products; lower-Bay products have their own issuing coverage. Trace the planned leg on the official zone map and use the linked lower-Bay forecast where needed.
Weather-sensitive legs
A long wind fetch over the Bay can differ from a sheltered river departure. Check wind direction against the Bay axis, exposed crossings and destination orientation; gusts and short wind waves can matter even on a modest-distance leg.
Observations, sea state and reassessment
Separate observed water level, predicted tide and available current measurements. Annapolis station 8575512 helps with local levels but does not measure every crossing or Severn River stream; inspect observation age and storm-related departures from prediction.
Worked planning scenario — not a live forecast
For an Annapolis day passage, compare the river exit, Bay crossing and return ETA. A later start that improves the river wind but moves the return into stronger Bay conditions may be worse for the actual trip; evaluate the full loop.
Official products by task
- NWS Baltimore/Washington marine — Upper/middle Chesapeake and tidal Potomac products, observations and links to lower-Bay forecasts.
- NOAA/NWS marine zones — Official coastal, offshore and high-seas product definitions and zone-map entry points.
- NOAA NDBC observations — Station map and timestamped buoy/coastal records; inspect sensor availability and exposure.
- NOAA Tides & Currents — Predictions and observations are separate products; choose station, timezone and datum.
Sector names help you locate the issuing product; they are not an automatic route-coverage match. Open the current issue and check boundaries, issue time and validity. This page does not display current warnings; an unavailable product does not mean no hazard.
Countries & territories
- United States
Choose a bay, coastal, offshore, Great Lakes or ocean product for the actual track.
Departure ports & bases
- Annapolis
Annapolis: a departure-source desk, not a generic city forecast.
Build your passage brief
Bring your route, leg timings, vessel and crew profile, checked sources and reassessment triggers into the brief. Personal AI analysis and expert review are available to invited closed-test participants; a port page does not extend the calculation service’s coverage.
A Sailing Weather editorial guide to local conditions, practical passage preparation and marine-weather sources. Source and structure review: 27 September 2026. For a specific passage, check current issues, validity and forecast coverage. The skipper retains the final decision and responsibility.
The Bay axis and the return leg deserve their own rows
For an Annapolis or tributary-based day sail, identify which leg crosses open Bay water and which follows a sheltered river. Compare the wind direction with the actual exposed fetch, then test the return when conditions may differ. NWS Baltimore/Washington's marine desk links upper/middle-Bay products and the lower-Bay issuer; use those products where the route extends beyond the initial coverage.
- NWS Chesapeake marine desk — Upper/middle Bay products and links to the lower-Bay issuer, observations and wave guidance.
Read measured level, predicted tide and current separately
A gauge near the starting harbour can show whether the observed level differs from prediction, but it does not describe the wave field across the Bay. Keep datum and timestamp attached to the level, and obtain the applicable current information if the route needs it. CBIBS and other observation links on the NWS desk can add context; check the selected platform's position, variables and last report.
- NOAA CO-OPS Tides and Currents — Separate measured water levels, tide predictions, current predictions and model forecasts.
- NWS Chesapeake marine desk
An afternoon warning can change the trip, not just the start
Rehearse a return delayed by a stop or reduced boat speed. Check whether the new ETA overlaps a short-term marine warning or a stronger open-Bay forecast. If so, reassess the full outing while a checked tributary or shorter itinerary still remains available. A quiet creek observation is not grounds to dismiss the warning over the exposed part, and a river-side alternative still needs its own access checks.
Editorial review of this material: 27 September 2026. This date concerns the page content; check current forecast issue times and validity at the original sources.