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Weather Forecast Glossary
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GALE WARNINGS
GALE:
Winds of at least 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 is Hurricane Force:
the term hurricane on its own is only used to imply a true tropical
cyclone.
IMMINENT:
Expected within 6 hours of time of issue.
SOON:
Expected within 6 to 12 hours of time of issue.
LATER:
Expected more than 12 hours from time of issue.
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VISIBILITY
FOG:
Visibility less than 1000m
POOR:
Visibility between 1000m. and 2 n.miles
MODERATE:
Visibility between 2 and 5 n.miles
GOOD:
Visibility more than 5 n.miles.
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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
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PRESSURE TENDENCY IN STATION REPORTS
STEADY:
Change less than 0.1hPa in the preceding 3 hours
RISING (OR FALLING) SLOWLY:
Pressure change of 0.1 to 1.5 hPa in the preceding 3 hours.
RISING (OR FALLING) SLOWLY:
Pressure change of 1.6 to 3.5 hPa in the preceding 3 hours.
RISING (OR FALLING) QUICKLY:
Pressure change of 3.6 to 6.0 hPa in the preceding 3 hours.
RISING (OR FALLING) VERY RAPIDLY:
Pressure change of more than 6.0 hPa in the preceding 3 hours.
NOW RISING (OR FALLING):
Pressure has been falling (rising) or steady in the preceding 3 hours,
but at the time of observation was definitely rising (or falling)
(1hPa = 1mb) |
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WIND
WIND DIRECTION:
Indicates the direction from which the wind is blowing.
WIND 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 in the direction of motion of the hands of
a clock, e.g. SW to W..
BACKING:
The opposite direction to veering, e.g. SE to NE.
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