Hurricane and tropical storm positions are given in terms of
latitude and longitude to the nearest one-tenth of a degree.
Latitude lines run across hurricane tracking charts (maps) from
left to right. longitude lines run from bottom to top. Latitude
gives the north-south position on the earth's surface, longitude
the east-west position. Therefore, by knowing the latitude and
longitude of a storm, we can locate it on a map. As an example,
try to locate 32.3 degrees north latitude and 64.8 degrees longitude.
You should be very close to the island of Bermuda.
A hurricane tracking chart appears in the January issue Field
Forum, and is suitable for reproduction. Larger (and more sophisticated)
charts are available from commercial sources.
For example, Kornor Enterprises sells heavy-duty plastic laminated
charts in various sizes. Erasable marker and instructions are
included. The company has agreed to sell the charts to ARRL members
at a special, reduced price: 17x22"-$12.50; 11x15" --
$10.50; and 8.5x11" -- $8.50. (Includes shipping/handling).
Identify yourself as an ARRL member when ordering. Order from
Kornor Enterprises, PO Box 461, Cleveland, OH 44094, American
Express, VISA, and MasterCard credit cards accepted. The KORNOR
map is used by the staff at the National Hurricane Center in Coral
On the KORNOR map, solid black lines are drawn for every five
(5) degrees of latitude and longitude. White lines are drawn for
every (1) degree. By definition, one degree of latitude is equal
to 60 nautical miles. This gives us a convenient way of estimating
distances on a chart. Measure the distance between any two points,
then lay this distance out on one of the north-south longitude
lines. Count the number of degrees of latitude and
multiply by 60 to find the distance in nautical miles. To convert
to statute miles, multiply that answer by 1.15. One nautical mile
equals 1.15 statute miles. One knot (nautical mile per hour) equals
1.15 statute miles per hour.
Hurricane tracking software is also available.
During major activity, storm coordinates are provided in 3- and
6-hour updates on NOAA weather radio services around the country
in the 160 MHz region. Modern 2-meter FM rigs with extended receive
capability cover NOAA broadcast frequencies.
Tropical Storm and Hurricane Terminology
TROPICAL DISTURBANCE: An area of showers and thunderstorms that
may have a slight cyclonic (counter-clockwise) surface circulation
and maintains its identity for at least 24 hours. These are very
common occurrences in the tropics.
TROPICAL DEPRESSION: A storm system displaying a noticeable rotary
circulation with maximum sustained wind speeds of 38 miles per
hour (33 knots).
TROPICAL STORM: Displays a substantial rotary circulation with
sustained winds of 39 to 73 miles per hour (34-63 knots). When
reaching tropical storm strength, a storm is given a name to aid
HURRICANE: Strong rotary circulation with sustained surface winds
of 74 miles per hour (64 knots) or more. In the western North
Pacific and most of the South Pacific, such storms are called
Typhoons. In the Indian Ocean they are called Cyclones.
Advisories, Watches and Warnings
SMALL CRAFT ADVISORY: Alerts boaters to wind or sea conditions
that might be hazardous to small boats. Usually wind speeds must
be at least 20 miles per hour (18 knots). Issued when a tropical
storm or hurricane moves within several hundred miles of the coast.
Boaters are advised to take precautions and not venture into the
GALE WARNING: Coastal wind speeds between 39 and 54 miles per
hour (34-47 knots).
STORM WARNING: May be issued when winds of 55-73 miles per hour
(48-63 knots) are expected on area waters.
HURRICANE WATCH: Issued when there is a threat of hurricane conditions
developing within 24 to 36 hours.
HURRICANE WARNING: Hurricane conditions with winds of 74 miles
per hour or more (64 knots) and/or dangerously high tides and
waves are expected within 24 hours. People within the warning
area should begin to take action to protect life and property.
TORNADO/SEVERE THUNDERSTORM WATCH: Tornadoes and severe thunderstorms
often develop when hurricanes and tropical storms make landfall.
A watch means these storms are possible.
TORNADO/SEVERE THUNDERSTORM WARNING: Tornadoes or severe thunderstorms
are occurring within the warning area.
CATEGORY/ PRESSURE/ WINDS /SURGE - DAMAGE
Category 1/ 28.94"/ 74-95 MPH /4-5 ft - MINIMAL
Primarily to trees, foliage, and unanchored mobile homes. No real
damage to other structures. Some small craft my be torn from moorings.
Category 2/28.50"/96-110 MPH/6-8 ft - MODERATE
Some trees blown down. Some window, door and roofing damage. Small
craft torn from moorings in unprotected anchorages. Some evacuation
of shoreline residences and low-lying islands.
Category 3 /27.91"/ 111-130 MPH/ 9-12 ft - EXTENSIVE
Large trees blown down. Some structural damage to small buildings.
Mobile homes destroyed. Serious coastal flooding. Many small structures
near coast destroyed by wind and waves. Almost all small boats
torn from moorings.
Category 4/ 27.17"/ 131-155 MPH/ 13-18 ft - EXTREME
Extensive damage to roofs on many small residences. Terrain 10
feet or less above sea level flooded. Escape routes cut by rising
water 3 to 5 hours before center arrives. Massive coastal evacuation
Category 5/ 27.16"/ 156+ MPH/ More than 18ft - CATASTROPHIC
Complete failure of roofs on residences and many commercial structures.
Small buildings overturned or blown away. Massive evacuation from low ground
within 5-10 miles of the coast.
Transmit only when directed by a disaster net control station,
or station in the disaster area. Major nets include:
International Assistance and Traffic Net (IATN): 14.303 MHz
Hurricane Watch Net (HWN): 14.325 MHz
Friendly Caribus Connection: 14.283 MHz
Don't clog primary disaster frequencies by trying to force H&W
traffic into the disaster area. US amateurs' efforts must be directed
to receiving messages from the affected area, each one having
the potential of heading off numerous US-originated messages.
US amateurs must listen carefully for instructions on handling