2-17. Warning Formats and Content. Originators issue tropical cyclone and tropical depression warning messages in
PLAIN LANGUAGE format specified in Appendices B and C, respectively. Warning messages include the following,
when applicable:
a. Type of tropical cyclone.
b. Number of tropical cyclones presently active in AOR.
c. Time and forecast position of the center.
d. Movement of the center during previous six hours.
e. Accuracy (estimated) of warning position.
f. Method of fix.
g. Speed and location of maximum surface winds and peak gusts.
h. Radius of area with 100 KT surface winds.
i. Radius of area with 50 KT surface winds.
j. Radius of area with 35 KT surface winds.
k. Repeat (forecast) position.
l. Vector indicating mean direction and speed between forecast positions.
m. Twelve-hour forecast position and intensity (including gusts) and radius of area with 100 KT surface winds, radius of
area with 50 KT surface winds, and radius of area with 35 KT surface winds.
n. Twenty-four hour forecast position and intensity (including gusts), radius of area with 100 KT surface winds, radius of
area with 50 KT surface winds, and radius of area with 35 KT surface winds.
o. Thirty-six hour forecast position and intensity (including gusts), radius of area with 100 KT surface winds, radius of area
with 50 KT surface winds, and radius of area with 35 KT surface winds. For tropical depression warnings, include only forecast position and intensity (including gusts).
p. Forty-eight hour outlook position and intensity (including gusts), radius of area with 100 KT surface winds, radius of area with 50 KT surface winds, and radius of area with 35 KT surface winds.
q. Seventy-two hour outlook position and intensity (including gusts), radius of area with 100 KT surface winds, radius of area with 50 KT surface winds, and radius of area with 35 KT surface winds. Seventy-two hour outlooks are not used in Southern Hemisphere warnings.
r. Remarks, include:
(1) Standard issue times for the next four (two) daily warnings in Northern (Southern) Hemisphere areas.
(2) First warning on a tropical cyclone refers to the last formation alert message, if applicable. Note significant departures from previously forecasted movement or development with a brief non-technical explanation. When available fix data do not show reasonable agreement, include appropriate comments in the warning and in the Prognostic Reasoning Message. Discuss any changes or amendments.
NOTE: Forecast radii of surface winds greater than 100, 50, and 35 knots, when provided, are intended for open water areas. Issuing authorities do not predict local winds conditions over land masses affected by topography and other small scale influences. They do adjust forecast wind speeds and radii due to the influence of major large scale features (e.g., Korean Peninsula, the island of Luzon). Local meteorologists, who use official warnings as guidance, can best forecast specific winds conditions. Wind radii will not be included for any forecast position where the cyclone is expected to be extratropical. See Appendix B, Note 3, for additional guidance.
STANDARD FORM FOR TROPICAL CYCLONE WARNINGS
1. Standard Form for PLAIN LANGUAGE Tropical Cyclone Warnings
This PLAIN LANGUAGE warning format is used for dissemination of tropical cyclone warning information. Compose warnings by deleting inapplicable items in parentheses and filling in items in brackets. The text is unclassified and the precedence is
usually IMMEDIATE (refer to Chapter 4, paragraph 4-5).
* (TYPHOON) (HURRICANE) (TROPICAL) (STORM) (DEPRESSION)
[NAME/NUMBER] WARNING [NUMBER] (AMENDED) (CORRECTED)
(RELOCATED) (UPGRADED) (DOWNGRADED) (FROM) (TYPHOON)
(HURRICANE) (TROPICAL) (STORM) (DEPRESSION) [NAME/NUMBER]
* [NUMBER] ACTIVE TROPICAL CYCLONES IN (WESTPAC) (EASTPAC)
(SOPAC)(SIO) (NIO)
* MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
* - - -
* WARNING POSITION
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MOVEMENT PAST (SIX) (TWELVE) HOURS (DEGREES) (AT) (SPEED)
(QUASI) (STATIONARY) (ERRATIC) (OTHER MOVEMENT INFORMATION)
* POSITION ACCURATE WITHIN [ ] NM
* POSITION BASED ON (EYE/CENTER) (FIXED/LOCATED) BY (COMBINATION
OF)(AIRCRAFT) (RADAR) (SATELLITE) (SYNOPTIC DATA)
(EXTRAPOLATION)
* PRESENT WIND DISTRIBUTION:
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM)
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* % REPEAT POSITION: [ . ] (N) (S) [ . ] (E) (W)
* FORECASTS:
* 12 HRS VALID AT:
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM)
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* VECTOR TO 24 HR POSIT: [ ] DEG/ [ ] KTS See Note 2.
* - - -
* 24 HRS, VALID AT:
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM)
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* VECTOR TO 36 HR POSIT: [ ] DEG/ [ ] KTS See Note 2.
* - - -
* 36 HRS, VALID AT:
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM)
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* VECTOR TO 48 HR POSIT: [ ] DEG/ [ ] KTS See Note 2.
* - - -
* EXTENDED OUTLOOK:
* 48 HRS, VALID AT:
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* $ VECTOR TO 72 HR POSIT: [ ] DEG/ [ ] KTS See Note 2.
* - - -
* $ 72 HRS, VALID AT:
* % [ ] Z - - - [ . ] (N) (S) [ . ] (E) (W)
* MAX SUSTAINED WINDS - [ ] KT, GUSTS [ ] KT
* (RADIUS OF 100 KT WINDS - [ ] NM
* (RADIUS OF 50 KT WINDS - [ ] NM)
* (RADIUS OF 35 KT WINDS - [ ] NM)
* - - -
* @ REMARKS:
* # % NEXT WARNINGS AT [ ] Z (DTG [ ] Z), [ ] Z (DTG [ ] Z), [ ] Z (DTG [ ] Z), [ ] Z
(DTG [ ] Z)
(Brief non-technical discussion regarding cyclone development, intermediate position for three hours after initial warning time, significant departure from previous movement, maximum sea height associated with Tropical Cyclone wind maximum and/or other information of use to the recipient.)
* (This is the final (JTWC) (NAVPACMETOCCEN) warning on (identity of tropical cyclone) (Next warning will be issued by [ ] at [ ] Z).)
NOTES
1. Symbols
# - (For Northern Hemisphere) Tropical Cyclone Warnings will
be issued at 0300Z, 0900Z, 1500Z, and 2100Z.
# - (For Southern Hemisphere) Tropical Cyclone Warnings will be issued at 0300Z and 1500Z, or 0900Z and 2100Z.
* - Start of new line.
% - Enter check sums after each date time group and latitude
and longitude given.
$ - Not used for Southern Hemisphere warnings.
@ - When issuing warning number one, include reference by
date/time group to latest formation alert message, in
remarks.
2. This vector may not realistically describe expected path and speed of the tropical cyclone and thus should be used with caution. The vector is the mean direction and speed computed for a straight line movement between each forecast position. The main purpose of the vector is to aid in immediate decision making for storm evasion, etc. There is no substitute for actually plotting tropical cyclone warnings for a realistic
appraisal of the cyclone's expected movement and intensity.
3. For tropical cyclones in the western Pacific that are expected to undergo extratropical transition while maintaining maximum sustained surface winds of 35 knots or greater, the forecast period will be tailored to match the NAVPACMETOCCEN WEST Guam High Wind and Seas Warning (WWPN PGFW) that is currently in effect. JTWC warnings issued at 00/12Z and 06/18Z will have a forecast period of 36 and 30 hours respectively, with forecasts positions and maximum sustained wind speeds that agree with the NAVPACMETOCCEN WEST Guam WWPN currently in effect. JTWC forecast positions labeled as EXTRATROPICAL will not include wind radii. Instead, the warning remarks will refer the reader to the current WWPN warning for the expected surface wind distribution at the end of the forecast period.
4. Use following format for describing sea height in remarks: Maximum significant wave height at (Warning position time) Z is ( ) feet.
5. For tropical cyclones becoming extratropical or dissipating, the following applies:
a. Use "BECOMING EXTRATROPICAL" or "EXTRATROPICAL" in a warning to signify a system is losing its tropical characteristics.
b. Use "DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER (WATER) (LAND)" in the final forecast period for cyclones that are forecast to dissipate.