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Shipping forecast terms are strictly defined so that forecasts are as concise as possible consistent with clarity; information in an overlong forecast is, all too easily lost. The UK Shipping Forecast has to conform with the requirements of the BBC to keep the broadcast text to a maximum of about 330 words; brevity is also necessary to minimise length of NAVTEX transmissions. Although never specifically stated, the same terms will be used in all UK marine forecasts.

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These terms are defined on the Met Office pages describing the Shipping forecast. They are also to be found in Almanacs such as that published by the Cruising Association and in RYA Booklet G5. The sea areas used in the UK Shipping forecasts can be found on another page.

Gale warning terminology

The description of gales is in accordance with internationally agreed definitions . However, the UK Met Office also issues gales using gust criteria even when the mean speed is below gale force as below:-


Winds of at least Beaufort force 8 (34-40 knots) or gusts reaching 43-51 knots

Severe gale

Winds of force 9 (41-47 knots) or gusts reaching 52-60 knots


Winds of force 10 (48-55 knots) or gusts reaching 61-68 knots

Violent storm

Winds of force 11 (56-63 knots) or gusts of 69 knots or more

Hurricane force*

Winds of force 12 (64 knots or more)

* Note: The term used is "hurricane force", However the term "hurricane" on its own means an intense tropical cyclone of the kind that affects the Caribbean and Eastern Pacific. In the China Sea, it would be called a typhoon. Such tropical cyclones are not experienced in British waters. In that sense, Mike Fish was correct in 1987, although winds did reach Hurricane force! This is not a case of semantics It was a very deep low that deepened rapidly. Nevertheless. to a meteorologist it was not a hurricane.

Gale warning timing

The UK uses the following terms to indicate the expected times of onset of a gale.


Expected within six hours of time of issue


Expected within six to 12 hours of time of issue


Expected more than 12 hours from time of issue

Perhaps* Later

Used when a gale is considered possible in the "later" period, but the forecaster is not sufficiently sure to issue a warning.

* Note: If there is doubt about gales in the immediate or soon category, then the forecast may say "perhaps locally" or some such phrase, BUT a warning MUST be issued,


These are internationally agreed definitions of visibility. NOTE - these relate to the usage. Over land, for driving a vehicle, a fog would be below 200 m.


Visibility less than 1,000 metres


Visibility between 1,000 metres and 2 nautical miles


Visibility between 2 and 5 nautical miles


Visibility more than 5 nautical miles

Movement of pressure systems

These terms are used in the synopsis to describe speed of movement of weather patterns


Moving at less than 15 knots


Moving at 15 to 25 knots

Rather quickly

Moving at 25 to 35 knots


Moving at 35 to 45 knots

Very rapidly

Moving at more than 45 knots

Pressure tendency in station reports

Reports from coastal stations and Light vessels or buoys will give the pressure and a description of how the pressure has been changing.

Rising (or falling) slowly

Pressure change of 0.1 to 1.5 hPa in the preceding three hours

Rising (or falling)

Pressure change of 1.6 to 3.5 hPa in the preceding three hours

Rising (or falling) quickly

Pressure change of 3.6 to 6.0 hPa in the preceding three hours

Rising (or falling) v. rapidly

Pressure change of more than 6.0 hPa in the preceding three hours

Now rising (or falling)

Pressure has been falling (rising) or steady in the preceding three hours, but at the time of observation was definitely rising (falling)

Note: For those more familiar with the millibar, 1 hPa = 1 mb


Note that wind and current use different conventions. A wind blows FROM the stated direction. Currents are described as the direction that they are going TO. We talk about and East going tide

Wind direction

Indicates the direction from which the wind is blowing

Becoming cyclonic

Indicates that there will be considerable change in wind direction across the path of a depression within the forecast area


The changing of the wind direction clockwise, e.g. SW to W


The changing of the wind in the opposite direction to veering (anticlockwise), e.g. SE to E

Sea State


Wave height less than 0.5 m


Wave height of 0.5 to 1.25 m


Wave height of 1.25 to 2.5 m


Wave height of 2.5 to 4.0 m

Very rough

Wave height of 4.0 to 6.0 m


Wave height of 6.0 to 9.0 m

Very high

Wave height of 9.0 to 14.0 m


Wave height more than 14.0 m

Internationally recommended abbreviations that might be found in NAVTEX texts are on another page of this site.

This page is provided with acknowledgement to the UK Met Office and is copied from their website.

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