Tide and Storm Surge Forecast (TSSF)#

The Tidal and Storm Surge (TSSF) model is a mathematical and computational tool used to predict the total water level of the combined astronomical tide and storm surge (i.e. does not include waves) at specific coastal locations. Forecasts include:

  • Tide Level Forecast: Astronomical tidal forecasts are predictions of the daily variation in sea levels due to the gravitational interactions between the Earth, the moon, and the sun.

  • Surge Forecast: Surge is the positive or negative change in sea level as a result of wind and atmospheric pressure changes.

  • Total Water Level: The combination of storm surge and astronomical tide.

Wave effects are not included in the Tidal and Storm Surge Forecast, which over short periods of time, can cause localised water levels to be elevated above those forecast (due to wave set-up). Users should therefore make their own allowances for any such wave effects based on other relevant sources of information, local experience, and observations.

Available variables#

The following variables are available on the platform:

  • Surge residual, in m.

  • Total water level, in m.

  • Tidal level, in m.

Temporal resolution#

The TSSF is produced every morning and evening for the short-range forecasts of astronomical tide, surge residual and total water level. Forecasts are generated daily between 09.30 and 11.30 hours and between 20.30 and 22.30 hours, respectively for all forecast points and for at least 60 hours ahead, with a time step of 15 minutes.

Update frequency#

The TSSF provides three daily forecasts; morning and evening short-range forecast and a medium-range forecast.

The Surge Forecast is produced once daily to provide an extended outlook, or medium-range forecast, of surge residual. Forecasts are generated between 10.00 and 15.00 hours for all the forecast points.

Note: The forecast service expresses time in Coordinated Universal Time (UTC). During British Summer Time (BST) the published times will need to be adjusted accordingly, by adding 1 hour to the forecast times.

Data sources#

Data provided directly by Met Éireann.