Definitions
By
international agreement, tropical cyclone is the general term for
all cyclonic, counterclockwise circulations originating over
tropical waters, classified by form and intensity as follows:
Tropical
disturbance - A rotary circulation with little to no
development on the ocean surface but better development in the
upper atmosphere and no strong winds, a common phenomenon in the
tropics.
Tropical
depression - A low-pressure area with some rotary circulation
on the ocean surface and a sustained wind speed of less than 39
mph.
Tropical storm
- A low-pressure area with a distinct rotary circulation and
sustained wind speeds of 39 to 73 mph.
Hurricane - A
low-pressure area with a strong and pronounced rotary circulation
and a sustained wind speed of at least 74 mph.
Categorical
strength
The Saffir-Simpson
scale is used to rate the strength of hurricanes:
- Category 1 - Winds of
74 to 95 mph. Damage: minimal
- Category 2 - Winds 96
to 110 mph. Damage: moderate
- Category 3 - Winds 111
to 130 mph. Damage: major
- Category 4 - Winds 131
to 155 mph. Damage: severe
- Category 5 - Winds
above 155 mph. Damage: catastrophic
Advisories
- Advisory - A way of
disseminating hurricane and storm information to the public
every six hours.
- Special Advisory - A
warning given any time there is a significant change in
weather conditions or change in warning.
- Intermediate Advisory -
A way of updating regular advisory information every two to
three hours if necessary.
- Gale Warning - Wind
speeds of 39 to 54 mph expected.
- Storm Warning - Wind
speeds of 55 to 74 mph expected.
- Hurricane Watch - A
hurricane may threaten the area within 36 hours.
- Hurricane Warning - A
hurricane is expected to strike the area within 24 hours or
less.
- Evacuation Order - The
most important instruction you will receive. Once issued, an
evacuation order is mandatory under state law.
2002 storm names
Arthur, Bertha,
Cristobal, Dolly, Edouard, Fay, Gustav, Hanna, Isidore, Josephine,
Kyle, Lili, Marco, Nana, Omar, Paloma, Rene, Sally, Teddy, Vicky,
Wilfred
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