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LEGALISTICS
1. The webmaster is not trained in matters meteorological, but takes an
active interest in tropical cyclones. No responsibility can therefore be
taken for the consequences of any actions resulting from information
relayed on this site.
2. The tropical cyclones logo is linked from Wikimedia, and is in the public domain.
3. The video is copyright NOAA, and consent for its use on this site has been obtained from that organisation.
INFORMATION
The information on tropical weather systems, whether disturbances or actual cyclones, is given with abbreviations.
Directions are quoted as angles (in degrees) and their corresponding compass points:
N = North
E = East
S = South
W = West
Times are given in Greenwich Mean Time (GMT), which is the same as Universal Time Coordinated (UTC).
Distances are given as miles, meaning nautical miles.
1 nm = 1.852 km
1 knot = 1 nm / hour
The strength of tropical cyclones is given as follows:
Tropical depression = maximum sustained windspeeds 30 knots or lower
Tropical storm = maximum sustained windspeeds 35 to 60 knots
Hurricane / typhoon / tropical cyclone = maximum sustained windspeeds 65 knots or higher
Please note that southern hemisphere systems are named as Tropical cyclones, irrespective of strength.
TROPICAL DISTURBANCES
NHC often highlights areas of disturbed weather in its area of responsibility before the system in question is formally recognised as an Invest. These are listed in the bulletins, with the system designation marked in italics as: No Invest Assigned. The corresponding label is NIA followed by a letter according to the basin where it occurs:
A = Atlantic
E = Eastern Pacific
C = Central Pacific
Updated May 2022