Marine forecasts glossary
Marine forecasts contain a number of terms which are
used to convey specific meanings.
Gale
warnings
Gale
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
Storm 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'; the term 'hurricane'
on its own means a true tropical cyclone, not experienced
in British waters.
Imminent Expected within six hours
of time of issue
Soon Expected within six to 12 hours
of time of issue
Later Expected more than 12 hours
from time of issue
Visibility
Fog Visibility less
than 1,000 metres
Poor Visibility between 1,000 metres
and 2 nautical miles
Moderate Visibility between 2 and
5 nautical miles
Good Visibility more than 5 nautical
miles
Movement of
pressure systems
Slowly Moving at
less than 15 knots
Steadily Moving at 15 to 25 knots
Rather quickly Moving at 25 to 35
knots
Rapidly Moving at 35 to 45 knots
Very rapidly Moving at more than
45 knots
Pressure tendency
in station reports
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
Wind
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
Veering The changing of the wind
direction clockwise, e.g. SW to W
Backing The changing of the wind
in the opposite direction to veering (anticlockwise),
e.g. SE to NE
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