Extratidal Water Level: recent observations

Tangier Island Port Isobel (TIPI)

Note - This data and webpage is a work in progress.

Other Intervals: Last 30 days | Last 3 daysLast 30 days cf Last 3 days | 36-hour Forecast
Other Stations: BRDH | BISH | CBBT | JMTN | KIPT | MNPT | SWPT | WACH | WMPT | YRCG || All

We are currently developing the quality control and tidal constituents to incorporate this station into our Tidewatch system.

If you have questions or suggestions on this project, please contact me, David Forrest

VIMS TDS server for interoperable TIPI data access: --

See also:

Note that the red line (m30) is a weighted running mean of the last 30 days of observations, indicating a recent baseline to compare against.  The other tidal datums described below and the tidal model have not been established for this station, due to the short history of observations.

Legend Definitions & Datum
Sensor Observation (dashed = forecast)

The solid red line shows the observed water level (unverified data from the U.S. National Oceanic and Atmospheric Administration). The dashed red line shows our water-level forecast for the next 36 hours.

Predicted Astronomic (m30) Tide

The blue line shows our prediction of the astronomic tide. This incorporates two factors:

  1. The expected daily change in water level produced by gravitational interactions of the Earth, moon, and sun. These are the familiar tide charts, and can be predicted years in advance.
  2. A plus or minus "m30" value, which is a 30-day running mean of the actual water level observed at a tidal station. m30 represents a time-local departure from mean sea level due to seasonal variations in winds and currents, decadal fluctuations in sea level, and the long-term sea-level trend relative to land.
Residual (dashed = forecast)

The green line is the residual difference between the predicted astronomic tide and the observed water level. Values are positive when observed values exceed predicted values, and negative when observed values fall below predicted values. The solid green line shows the observed residual; the dashed green line shows our forecast for the residual over the next 36 hours.


Observed and predicted water-level values are displayed in feet and referenced to the elevation benchmark North American Vertical Datum of 1988 (NAVD88). This is the datum in which house and road elevations are typically given.

For a more detailed discussion, visit the Tidewatch Background page.


The Virginia Institute of Marine Science (VIMS) makes no warranty concerning any of the data displayed on this website ( Read our Disclaimer and Methods Disclosure statement.