Tropical cyclone warnings and watches

In Canada, terminology is fairly similar to that of the United States, but there are a few differences:[13]

• Watches are issued 36 hours prior to a tropical cyclone making landfall.
• Warnings are issued 24 hours prior to the tropical cyclone making landfall.
• If sustained winds 70 km/h and/or gusts 90 km/h or stronger are predicted, a conventional wind warning will be issued along with the tropical cyclone watches and warnings.
• A storm surge warning may be issued if abnormally high water levels are predicted.

A two-stage warning system was long-established in China for tropical cyclones of tropical storm intensity of above.[14] Nowadays, the use of this system is restricted to coastal waters only. Thus, warnings may be discontinued even if a cyclone is maintaining tropical storm intensity inland. Color-coded alerts (below) may be in effect independently of any two-stage warnings.

Later, China Meteorological Administration standardized the system for national use.[15] This set is part of a larger warning system that covers other forms of severe weather conditions, such as extreme temperature, torrential rainfall, drought, etc.

Level	Name	Sign	Meaning
IV	Blue typhoon alert 台风蓝色预警信号		Within 24 hours, it may or may have been affected by tropical cyclones. The average wind power on the coast or land is above 6, or the gust above 8 and may continue.
III	Yellow typhoon alert 台风黄色预警信号		Within 24 hours, it may or may have been affected by tropical cyclones. The average wind power on the coast or land is above 8, or the gust above 10 and may continue.
II	Orange typhoon alert 台风橙色预警信号		Within 12 hours, it may or may have been affected by tropical cyclones. The average wind power on the coast or land is above 10, or the gust above 12 and may continue.
I	Red typhoon alert 台风红色预警信号		Within 6 hours, it may or may have been affected by tropical cyclones. The average wind power on the coast or land is above 12, or the gust above 14 and may continue.

Guangdong continued to set up the White typhoon alert for typhoon, indicating that tropical cyclones may affect the area within 48 hours. In some inland areas that are less affected by tropical cyclones (such as Qinghai, etc.), there is no typhoon warning signal, but when it is hit by tropical cyclones, a strong wind warning signal will be issued. The winds represented by each color are consistent with the typhoon warning signal.

Typhoon warning signals used in Guangzhou from June 1, 1995 to November 1, 2000:[16]

Typhoon warning signals used from November 1, 2000 to May 2006[17]：

Name	Signal	Meaning
White typhoon alert		Tropical cyclones may affect the area within 48 hours.
Green typhoon alert		Tropical cyclones will be within 24 hours or are affecting the area, with an average wind level of strong winds (6-7) (41-62 km/h).
Yellow typhoon alert		Tropical cyclones will be within 12 hours or are affecting the area, with an average winds level of strong gale (8-9) (63-87 km/h).
Red typhoon alert		Tropical cyclones will be within 12 hours or are affecting the area, with an average winds level of strong storm (10-11) (88-117 km/h).
Black typhoon alert		Tropical cyclones will be within 12 hours or are affecting the area, with an average winds level of typhoon (>12).

Typhoon warning signals used from June 1, 2006 to December 31, 2014:[18]

Name	Signal	Meaning
White typhoon alert		Tropical cyclones may affect the area within 48 hours.
Blue typhoon alert		It may be affected by tropical cyclones within 24 hours, the average wind power can reach above level 6, or gusts above 7; or it has been affected by tropical cyclones with an average wind power of 6–7, or gusts of 7–8, and may continue.
Yellow typhoon alert		It may be affected by tropical cyclones within 24 hours, the average wind power can reach above level 8, or gusts above 9; or it has been affected by tropical cyclones with an average wind power of 8–9, or gusts of 9-10, and may continue.
Orange typhoon alert		It may be affected by tropical cyclones within 12 hours, the average wind power can reach above level 10, or gusts above 11; or it has been affected by tropical cyclones with an average wind power of 10–11, or gusts of 11–12, and may continue.
Red typhoon alert		It may be affected by tropical cyclones within 6 hours, the average wind power can reach above level 12; or it has been affected by tropical cyclones with an average wind power of 12, and may continue.

Typhoon warning signals used since January 1, 2015:[19]

Name	Signal	Meaning
White typhoon alert		Tropical cyclones may affect the area within 48 hours.
Blue typhoon alert		It may be affected by tropical cyclones within 24 hours, the average wind power can reach above level 6, or gusts above 7; or it has been affected by tropical cyclones with an average wind power of 6–7, or gusts of 7–8, and may continue.
Yellow typhoon alert		It may be affected by tropical cyclones within 24 hours, the average wind power can reach above level 8, or gusts above 9; or it has been affected by tropical cyclones with an average wind power of 8–9, or gusts of 9-10, and may continue.
Orange typhoon alert		It may be affected by tropical cyclones within 12 hours, the average wind power can reach above level 10, or gusts above 11; or it has been affected by tropical cyclones with an average wind power of 10–11, or gusts of 11–12, and may continue.
Red typhoon alert		It may be affected by tropical cyclones within 6 hours, the average wind power can reach above level 12; or it has been affected by tropical cyclones with an average wind power of 12, and may continue.

Shenzhen currently uses a different signal from Guangdong Province:[18][20]

Zhuhai adopts the signal style of Guangdong Province, but the meaning of the signal is different:[21]

Shenzhen and Zhuhai used digitally arranged typhoon signals from June 4, 1994 to November 1, 2000,[22] but they have now been replaced by typhoon warning signals.

The coastal ports of various cities in mainland China will still hang the squash signal when the typhoon hits.[23] The sign is roughly the same as the typhoon signal used in Shenzhen and Zhuhai.[24]

The Pearl River Delta uses a variety of warning systems to inform the public regarding the risks of tropical cyclones to the area.

The Hong Kong Observatory issues typhoon signals to indicate the existence and effects of a tropical cyclone on Hong Kong. The first numeric warning system was used in 1917.

The Macao Meteorological and Geophysical Bureau in Macau uses a similar system.[25]

In Hong Kong the typhoon signal system consists of 8 signals in 5 levels numbered non-consecutively for historical reasons.[26][27] Each signal has a day signal and a night signal for hoisting, which are still hoisted in Macau but no longer hoisted in Hong Kong. Day signals are also used as signal symbols in both places.

Signal	Symbol	Note	Wind speed	Gust
No.1		(Standby) A tropical cyclone is centred within 800 km of the territory.	NA	NA
No.3		A definite warning that a tropical cyclone is expected to come near enough to Hong Kong to cause strong winds in Hong Kong. It normally gives 12 hours warning of strong winds generally over Hong Kong at sea level, but in exposed areas, winds may become strong sooner. Implication for citizens: Do not need to go to kindergartens, some places and events.	Strong wind with a sustained speed of 41–62 km/h	≥ 110 km/h
No.8. NW / SW / NE / SE		Gale or storm force wind. 4 different symbols for different directions. Implication for citizens: usually no need to go to school or work for most people if hosted before a certain hours before official work hours; depends on official announcement & employment contracts.	sustained speed of 63–117 km/h from the northwest, southwest, northeast, southeast quadrants respectively	≥ 180 km/h.
No. 9		(Hong Kong) Gale or storm force wind is increasing or expected to increase significantly in strength. / (Macau) The centre of a tropical cyclone is approaching and Macau is expected to be severely affected.	It usually implies that wind speeds are expected to reach the range 88 to 117 kilometres per hour.
No. 10		Hurricane-force wind. Implication for citizens: no need to go to work or school. Most public transportation stop.	winds range upwards from 118 kilometres per hour.	≥ 220 km/h

The Japan Meteorological Agency (JMA) is the government agency responsible for gathering and providing results for the public in Japan, that are obtained from data based on daily scientific observation and research into natural phenomena in the fields of meteorology, hydrology, seismology and volcanology, among other related scientific fields. Its headquarters is located in Tokyo.

JMA is also designated one of the Regional Specialized Meteorological Centers (RSMC) of the World Meteorological Organization. It has the responsibility for weather forecasting, tropical cyclone naming and distribution of warnings for tropical cyclones in the Northwestern Pacific region.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) releases tropical cyclone warnings in the form of Tropical Cyclone Wind Signals (or just storm signals).[30] An area having a storm signal may be under:

• TCWS #1 - Tropical cyclone winds of 30–60 km/h are prevailing or expected within the next 36 hours.
• TCWS #2 - Tropical cyclone winds of 61–120 km/h are prevailing or expected within the next 24 hours.
• TCWS #3 - Tropical cyclone winds of 121–170 km/h are prevailing or expected within the next 18 hours.
• TCWS #4 - Tropical cyclone winds of 171–220 km/h are prevailing or expected within 12 hours.
• TCWS #5 - Tropical cyclone winds greater than 220 km/h are prevailing or expected within 12 hours.

The given lead time may be shortened based on the tropical cyclone's position. The lead time is also only valid for the first issuance. These storm signals are usually hoisted when an area (in the Philippines only) is about to be hit by a tropical cyclone. Thus, as a tropical cyclone gains strength and/or gets closer to an area having a storm signal, it may be raised to another higher signal in that particular area. Whereas, as a tropical cyclone weakens and/or gets farther away from an area, it may be downgraded to a lower signal or may be lifted (that is, an area will have no storm signal).

The IMD issues warnings in four stages for the Indian coast.

• Stage 1: Cyclone watch - Issued 72 hours in advance, it discusses the likelihood of development of a cyclonic disturbance in the north Indian Ocean and the coastal region likely to experience adverse weather.
• Stage 2: Cyclone alert - Issued 48 hours in advance of the commencement of adverse weather over the coastal areas.
• Stage 3: Cyclone warning - Issued 24 hours in advance of the commencement of adverse weather over the coastal areas. The location of landfall is discussed at this stage.
• Stage 4: Landfall outlook - Issued 12 hours in advance of the commencement of adverse weather over the coastal areas. The track of the cyclone after the landfall and the possible impact inland is discussed at this stage.

Cyclonic storm conditions mean what winds in excess of 63 km/h (39 mph) are possible.[33]

The United States Department of Defense uses a multi-stage system called the Hurricane Condition (HURCON) in the North Atlantic and the Northeast Pacific and the Tropical Cyclone Condition of Readiness (TCCOR) in the western Pacific to prepare bases and evacuate assets and personnel in advance of adverse weather associated with tropical cyclones.[34]

The alerts are recommended by weather facilities either on base or by central sites like the National Hurricane Center or the Joint Typhoon Warning Center and are generally related to the timing and potential for destructive sustained windspeeds of above 50 kn (58 mph; 93 km/h).[34] Recommendations are then considered by base or area commanders along with other subjective factors for setting the alert status like assets, holidays or the bases experience in emergency preparedness.[34] The bases prefer to set these alerts sequentially, from HURCON or TCCOR 5 with destructive winds expected within 96 hours, through levels 4, 3, 2 and if needed to a series of four different level 1 conditions, however depending on the cyclone's movement or location some of these signals can be skipped.[34][35] After a system passes and stops affecting the base, the authorities can decide to revert to the lowest level or stay in a heightened approach if another tropical cyclone is approaching.[34]