Chesapeake Bay Operational Forecast System (CBOFS)

Water Levels and Currents for
Chesapeake BayT

he Chesapeake Bay Operational Forecast
System (CBOFS) updates the surface wind,
water level, current, temperature andsalinity nowcast and forecast guidance four times
per day (every six hours). The forecasts areprovided for 48 hours into the future. Animation
maps of Chesapeake Bay (shown on the right) as
well as time series at particular stations or points ofinterest (shown below) are available for 58 locations
for surface winds, water levels, currents,temperature, and salinity.

http://tidesandcurrents.noaa.gov/ofs/cbofs/cbofs.html

CBOFS animation maps and time seriesgraphics are available at http://tidesandcurrents.noaa.gov/ofs/cbofs/cbofs.html. The time series plot shownon the left displays observed andpredicted water levels as well as theCBOFS water level nowcast andforecast guidance for Chesapeake Bay
Bridge Tunnel, Virginia. On calm days
these lines will be close together.
However, during a storm event, theobserved water levels and the CBOFS
n o w c a s t a n d f o re c a s t
guidance will be different from the astronomic predictions. During storm events,
CBOFS provides valuable information on the changing water levels and currents
throughout the Chesapeake Bay.

Chesapeake Bay Operational Forecast System (CBOFS)

Output from CBOFS can be used for a wide variety of applications such as recreationalboating, fishing and sailing, shipment and vessel transect planning, storm effect tracking,hazardous material tracking and search and rescue, to name a few. Any activity where winds,
water levels, currents, water temperature and/or
salinity are a factor can benefit from the informationprovided by CBOFS.
To generate the wind, water level, current,temperature and salinity nowcast and forecast
guidance, CBOFS relies on real-time and forecast
data from the NOAA National Weather Service, realtime observations from CO-OPS and U.S. Geological
Survey gauges, and output from the U.S. Navy
Coastal Ocean Model.
Historic CBOFS output is available from CO-OPS
web services at http://opendap.co-ops.nos.noaa.gov/thredds/catalog.html. Additionally, the CBOFS map
animations and time series graphics archive ofsurface wind, water level, current, temperature andsalinity is located at ftp://tidepool.nos.noaa.gov/pub/outgoing/ofs/cbofs/graphics/.
For decades, mariners in the United States have depended on NOAA's Tide Tables for thebest estimate of expected water levels and tidal currents. These tables provide accurate
predictions of the astronomical tide and tidal currents (i.e., the change in water level andcurrent due to the gravitational effects of the moon and sun and the rotation of the Earth);
however, they cannot predict water level changes and variations in currents due to wind,atmospheric pressure, and river flow, which are often significant. As a result, NOAA’s
Center for Operational Oceanographic Products and Services (CO-OPS), Office of CoastSurvey, and National Centers for Environmental Prediction (NCEP) have developed aChesapeake Bay Operational Forecast System (CBOFS). CBOFS serves the Chesapeake Baycommunity, including U.S. port authorities and mariners, by providing water level, current,temperature and salinity nowcasts (predictions for locations where there are no observations)and forecast guidance based on nearby real-time observation data, meteorological forecasts
and astronomical predictions.
Access the Chesapeake Bay Operational Forecast System by clicking on the CBOFS icon on theCO-OPS Operational Forecast System web page: http://tidesandcurrents.noaa.gov/models.html
NOAA/National Ocean Service
Center for Operational Oceanographic Products and Services
1305 East-West Highway, Room 6635
Silver Spring, Maryland 20910
301-713-2981
Email: Tide.Predictions@noaa.gov
3/2011