The Marine Unit
SEA AREA FORECAST (View current Sea Area Forecast)
The Sea Area Forecast issued by Met Éireann covers
Irish Coastal Waters out to 30 nautical miles, and also includes the
Irish Sea area
as shown in the map
The Sea Area Forecast issued by Met Éireann contains the following
- Meteorological or General Situation: A description of the meteorological
situation over Ireland at the stated time and of adjacent weather
systems, e.g. depressions,
anticyclones or frontal troughs, which are expected to have an influence
on the forecast areas during the following 24 hours. Explanation
of some terms used
- Imminent: within 6 hours,
- Soon: between 6 and 12 hours
- Later: between 12 and 24 hours.
- The speed of movement of pressure and frontal systems is described
- Slowly: up to 15 knots
- Steadily: 15 to 25 knots
- Rather quickly: 25 to 35 knots
- Rapidly: 35 to 45 knots
- Very Rapidly: greater than 45knots.
The general forecast follows giving wind, weather and visibility for
waters and the Irish Sea.
Marine Weather Services Brochure (
- Wind: The wind strength is given in Beaufort Force and wind direction
the 16-point compass. VIEW BEAUFORT SCALE
- Weather: The following are some terms used in the Forecast and
- Fine: Dry, mainly sunny day. Clear after dark.
- Fair: Dry, good sunny or clear spells(cloud no more than 3
- 5 okta of medium or low cloud or 6 - 8 okta of high cloud).
- Cloudy: 6 - 8 okta of
low or medium cloud.
- Mist: Visibility restricted by water droplets.
- Haze: Visibility restricted by dust or smoke.
- Other terms such as rain or hail shower are self explanatory.
- Visibility: descriptions of visibility mean the following:-
- Good: more than 5 nautical miles (9km)
- Moderate: 2 - 5 nm (4 - 9 km)
- Poor: 0.5 to 2 nm (4km)
- Fog: less than 0.5 nm (1,000m)
- Swell Warnings: when significant swell height of greater than 4
metres is expected.
- Outlook: A brief outlook is given for the 24 hours following the
by the forecast.
* Coastal Reports (from a selection of the following stations):
- Malin Head
- Dublin Airport
- Roches Point Automatic
- M2 buoy
- M3 buoy
- M4 buoy
- M5 buoy
- M6 buoy
The coastal reports include:
(a) wind direction on the 16 point compass
(c) visibility in nautical miles and tenths of,
(d) pressure in hectopascals (millibars)
(e) pressure tendency, which describes the change
in pressure over the past 3 hours, according to this scale:
0.0 - 0.4hPa
0.5 - 1.9hPa = rising/falling slowly
2.0 - 3.4 hPa = rising/ falling
3.5 - 5.9 hPa = rising or falling rapidly
6.0hPa or greater = rising or falling very rapidly
Wave Heights / State of Sea
The wave height is the vertical distance between the crest and the preceding or following trough. The table below gives a description of the wave system associated with a range of Significant Wave heights. The Significant wave height is defined as the average height of the highest one-third of the waves. (It is very close to the value of wave height given when making visual observations of wave height.)
|Sea State (Descriptive)
||Significant Wave height (in meters)
||0 - 0.1
||0.1 - 0.5
||0.5 - 1.25
||1.25 - 2.5
||2.5 - 4
||4 - 6
||6 - 9
||9 - 14
Individual waves in the wave train will have heights in excess of the significant height. The highest wave of all will have a height about twice the significant height.
- Gale warnings are issued by Met Éireann for Irish coastal
waters, which are regarded as extending 30 miles out from the
the Irish Sea
or part thereof.
- Gale Warnings are issued if winds of Beaufort Force 8 are expected.
- Strong Gale Warnings are issued if winds of Beaufort Force 9 or
of at least 52 knots are expected.
- Storm Force Warnings are issued if Beaufort Force 10 or frequent
gusts of at
least 61 knots are expected.
- Violent Storm Force Warnings are issued if Beaufort Force 11 or
of at least 69 knots are expected.
- Hurricane Force Warnings are issued if winds of greater than 64
knots are expected.
Small Craft Warnings
Small Craft Warnings are issued if winds of
Beaufort Force 6 (min. mean of 22 knots) are expected up to 10 Nautical
Media and Commercial Availability of Sea Area Forecasts
Sea Area Forecasts are issued and broadcast live from Met Éireann's
Forecasting Division on RTÉ Radio 1. Any gale warnings are also included on hourly
news bulletin on RTÉ Radio.
The Irish Coast Guard (ICG) Coast Radio Stations.
ICG Coast Radio Stations make a prior announcement of weather forecasts
VHF Radio Ch16 and then broadcast the forecast on the named relevant VHF Radio
working channel. Sea Area Forecasts are broadcast every 3 hours beginning
at 0103 local time.
i.e. broadcast times are:- 0103, 0403, 0703, 1003, 1303, 1606, 1903, 2203 local
Gale Warning broadcasts are also preceded by an announcement on Marine
VHF Ch16. They are broadcast on receipt and are repeated at the next
one of the
times:- 0033, 0633, 1233 and 1833 local time.
Telephone recorded sea area forecast, small craft warnings and warnings
of gales and heavy swell are available by clicking the weatherdial logo
A forecast of conditions on Dublin Bay is included with the general
Dublin Forecast. The number is: 1550 123 854.
Forecasts and charts by fax are available on Weatherdial Fax by dialling
(use tone dial handset on fax) 1570 131 838
The latest Sea Area Forecast, Small Craft Warning and
Warnings (if any) are available on this site.