Chesapeake Bay Waves

Normal Slightly Elevated Good Waves Large Waves | Flood (incoming) Ebb (outgoing) | Min 12 kn wind for foiling

Date & TimeTime	Tide	Current	WindWind kn	Score	Condition	River	Swell	Period
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Wind modelWind

Wave modelWave

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Current stationsTide stns

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<8 kn 8–15 kn 15–20 kn 20–25 kn 25–30 kn 30–35 kn 35+ kn | Wind speed at 10 m (kn): NOAA HRRR 3 km model, downscaled to the ~750 m grid · arrows point downwind, the way the wind is blowing, here and in the forecast tables · the compass label beside those table arrows is the usual weather convention and reads the opposite way: a “NE wind” blows toward the SW · ECMWF option: data © ECMWF, CC BY 4.0

<8 kn 8–15 kn 15–20 kn 20–25 kn 25–30 kn 30–35 kn 35+ kn | Peak wind gust (kn): a separate model diagnostic from the sustained wind on the Wind tab, which is the resolved mean flow and does not contain gusts · same colour scale as Wind, so flipping between the two shows the gust factor · arrows show wind direction

0 0.5 1 1.5 2 2.5 3 3.5 4 5 6 8+ | Significant wave height (ft): total sea, swell plus wind chop · NWPS (1.8 km) then GFS-Wave offshore, depth-adjusted fetch model in the Bay and sounds · arrows show the direction waves travel · ECMWF option: data © ECMWF, CC BY 4.0

0 2 4 6 8 9 | 10 12 14 16+ | Peak wave period, seconds: time between crests of the dominant waves · same sources as Waves · blue through yellow is wind chop and short wind sea; orange and hotter (10 s+) is real groundswell · arrows show the direction waves travel

<0.25 kn 0.25–0.5 kn 0.5–1 kn 1–1.5 kn 1.5–2 kn 2+ kn |

None Light chop Moderate Rough Very rough Extreme | “Wind against tide” index: when wind blows against a moving current the waves bunch up short and steep instead of rolling out, which is what turns a breezy day genuinely rough · score = the part of the wind opposing the flow × how hard the current runs, so both have to be strong: 15 kn straight into a 1 kn current scores ~15 · needs wind over 12 kn to register, and only shows where there is current data · arrows show wind (pointing downwind)

0 0.5 1 1.5 2 2.5 3 3.5 4 5 6 8+ | Swell height (ft): the dominant ocean swell only, propagated in from the Bay mouth · excludes local wind chop, so it reads lower than Waves · same height scale · unshaded = swell doesn't reach that water · arrows show the direction waves travel

40 44 48 52 56 60 64 68 72 76 80 84+ | Sea surface temperature, °F: a model forecast (NOAA's CBOFS and DBOFS in the bays, RTOFS offshore), typically within a degree or two of the buoys · the NC sounds are STOFS-3D, a coarser model there, so allow a few degrees · runs about two days ahead · unshaded water, such as marshes and small creeks, has no forecast · the station pills show measured water temperature

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Data sources: NOAA CO-OPS (tidal current & tide-level predictions) · Open-Meteo (hourly wind, forecast & archive) · NDBC buoy 44099 / Open-Meteo Marine (swell observations & forecast)

Forecasts here are computer model output and can be wrong, stale or missing. Some values (Bay and sound wave heights, sound currents, and the run scores) are estimated by this site, not by any official model. Not a substitute for the NWS marine forecast. Use at your own risk: see Terms & Privacy.

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