April 2023 Tropical Cyclones Report

Summary

Three named storms occurred across the globe in April, which was below the 1991-2020 average of 4.1. Two of these storms reached major tropical cyclone strength (≥111 mph)—both in the Australian region. The global accumulated cyclone energy (ACE: an integrated metric of the strength, frequency, and duration of tropical storms) was below its 1991-2020 average in April.

The first Northern Hemisphere named storm of 2023 was Tropical Storm Sanvu in the West Pacific. Sanvu was a named storm for less than two days. The activity in the West Pacific for both April and January-April were below average. The lack of activity in the other Northern Hemisphere basins has been normal.

The Australian region produced two major cyclones in April: Herman and Ilsa. Herman remained far from land in the southeastern Indian Ocean. However, Ilsa's landfall set a record for the strongest winds observed in western Australia. According to the Australian Bureau of Meteorology, ten-minute sustained winds of 118 kt were observed on Bedout Island—the same location as the previous record holder: 105 kt from Cyclone George in 2007. Fortunately, Ilsa made landfall in a sparsely populated portion of northwestern Australia, which limited its impacts.

No storms were active in either the South Indian Ocean or the Southwest Pacific in April. This lack of activity is below the 1991-2020 averages but is also not uncommon. Since 1981 (43 years), 10 Aprils had no storms in the South Indian Ocean and 19 Aprils had none in the Southwest Pacific.

North Atlantic

No North Atlantic Tropical Cyclones occurred during April 2023.

North Atlantic Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.1 (1 in 10 Aprils)	4th (tied with 39 other Aprils)	1 (1992, 2003, 2017)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	0
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.2 (2 in 10 Aprils)	4th (tied with 39 other Aprils)	3.2 (2003)

North Atlantic Tropical Cyclone Season Counts January-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.2 (2 in 10 seasons)	6th (tied with 37 other seasons)	1 (11 seasons)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 seasons)	2nd (tied with 41 other seasons)	1 (1908, 1938, 1955, 2016)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 seasons)	1st (tied with 42 other seasons)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.5 (5 in 10 seasons)	6th (tied with 37 other seasons)	6.5 (1955)

East Pacific

No East Pacific Tropical Cyclones occurred during April 2023.

East Pacific Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	1 (1980)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	0
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.0 (0 in 10 Aprils)	1st (tied with 42 other Aprils)	0.7 (1980)

East Pacific Tropical Cyclone Season Counts January-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.1 (1 in 10 seasons)	4th (tied with 39 other seasons)	2 (1992)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.1 (1 in 10 seasons)	3rd (tied with 40 other seasons)	1 (1992, 2016)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 seasons)	2nd (tied with 41 other seasons)	1 (1992)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.8 (8 in 10 seasons)	4th (tied with 39 other seasons)	13.9 (1992)

West Pacific

April 2023 West Pacific Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Sanvu	TS	April 20Apr 20-21	50 mph	999 mb

West Pacific Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	0.7 (7 in 10 Aprils)	7th (tied with 18 other Aprils)	3 (1956, 1971, 1999)
Typhoon Winds ≥ 74 mph (64 kts)	0	0.4 (4 in 10 Aprils)	16th (tied with 27 other Aprils)	2 (1951, 1956, 1971, 1999)
Major Typhoon Winds ≥ 111 mph (96 kts)	0	0.3 (3 in 10 Aprils)	12th (tied with 31 other Aprils)	1 (21 Aprils)
Accumulated Cyclone Energy ACE×10⁴ kt²	1.2	7.4	19th	46.9 (1997)

West Pacific Tropical Cyclone Season Counts January-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	1.7	23rd (tied with 12 other seasons)	6 (1965)
Typhoon Winds ≥ 74 mph (64 kts)	0	0.7 (7 in 10 seasons)	26th (tied with 17 other seasons)	3 (5 seasons)
Major Typhoon Winds ≥ 111 mph (96 kts)	0	0.4 (4 in 10 seasons)	19th (tied with 24 other seasons)	2 (1953, 1956, 1957, 2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	1.2	13.2	32nd	62.3 (1956)

North Indian

No North Indian Tropical Cyclones occurred during April 2023.

North Indian Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.2 (2 in 10 Aprils)	8th (tied with 35 other Aprils)	1 (7 Aprils)
Cyclone Winds ≥ 74 mph (64 kts)	0	0.2 (2 in 10 Aprils)	6th (tied with 37 other Aprils)	1 (5 Aprils)
Major Cyclone Winds ≥ 111 mph (96 kts)	0	0.1 (1 in 10 Aprils)	4th (tied with 39 other Aprils)	1 (1991, 2006, 2019)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	1.5	8th (tied with 35 other Aprils)	17.6 (1991)

North Indian Tropical Cyclone Season Counts January-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.5 (5 in 10 seasons)	14th (tied with 29 other seasons)	2 (1991, 1994, 2006, 2019)
Cyclone Winds ≥ 74 mph (64 kts)	0	0.2 (2 in 10 seasons)	6th (tied with 37 other seasons)	1 (5 seasons)
Major Cyclone Winds ≥ 111 mph (96 kts)	0	0.1 (1 in 10 seasons)	4th (tied with 39 other seasons)	1 (1991, 2006, 2019)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	1.7	14th (tied with 29 other seasons)	18.4 (1991)

South Indian

No South Indian Tropical Cyclones occurred during April 2023.

South Indian Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	1.1	33rd (tied with 10 other Aprils)	3 (1981, 2019)
Cyclone Winds ≥ 74 mph (64 kts)	0	0.8 (8 in 10 Aprils)	26th (tied with 17 other Aprils)	2 (1996, 2015, 2018, 2019)
Major Cyclone Winds ≥ 111 mph (96 kts)	0	0.4 (4 in 10 Aprils)	18th (tied with 25 other Aprils)	1 (17 Aprils)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	11.9	33rd (tied with 10 other Aprils)	52.5 (2016)

South Indian Tropical Cyclone Season Counts July 2022-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	8	10.1	31st (tied with 6 other seasons)	15 (1997)
Cyclone Winds ≥ 74 mph (64 kts)	6	5.9	15th (tied with 8 other seasons)	11 (2019)
Major Cyclone Winds ≥ 111 mph (96 kts)	3	3.5	18th (tied with 10 other seasons)	9 (2019)
Accumulated Cyclone Energy ACE×10⁴ kt²	119.9	93.2	8th	186.9 (1994)

Australia

April 2023 Australia Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Herman	4	March 29-April 2Mar 29-Apr 2	145 mph†	932 mb†
Ilsa	4	April 8Apr 8-13	145 mph	929 mb
†Value occurred in March

Australia Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	2	1.6	7th (tied with 18 other Aprils)	4 (2000)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	2	0.9 (9 in 10 Aprils)	1st (tied with 11 other Aprils)	2 (13 Aprils)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	2	0.5 (5 in 10 Aprils)	1st (tied with 5 other Aprils)	2 (6 Aprils)
Accumulated Cyclone Energy ACE×10⁴ kt²	16.9	10.5	9th	38.9 (2000)

Australia Tropical Cyclone Season Counts July 2022-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	9	10.3	27th (tied with 1 other season)	19 (1999)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	5	4.8	13th (tied with 7 other seasons)	9 (1992, 1996)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	4	2.4	5th (tied with 4 other seasons)	6 (2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	66.4	58.7	12th	111.3 (1999)

Southwest Pacific

No Southwest Pacific Tropical Cyclones occurred during April 2023.

Southwest Pacific Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.7 (7 in 10 Aprils)	24th (tied with 19 other Aprils)	3 (1983, 1998)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	0	0.3 (3 in 10 Aprils)	13th (tied with 30 other Aprils)	3 (1983)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	0	0.1 (1 in 10 Aprils)	5th (tied with 38 other Aprils)	1 (1983, 1989, 1998, 2020)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	2.9	24th (tied with 19 other Aprils)	30.9 (2020)

Southwest Pacific Tropical Cyclone Season Counts July 2022-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	6	6.7	17th (tied with 8 other seasons)	16 (1998)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	3	3.6	19th (tied with 7 other seasons)	10 (1998)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	1	1.9	19th (tied with 14 other seasons)	6 (2003)
Accumulated Cyclone Energy ACE×10⁴ kt²	25.3	48.7	27th	128.5 (1998)

Global

April 2023 Global Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Herman	4	March 29-April 2Mar 29-Apr 2	145 mph†	932 mb†
Ilsa	4	April 8Apr 8-13	145 mph	929 mb
Sanvu	TS	April 20Apr 20-21	50 mph	999 mb
†Value occurred in March

Global Tropical Cyclone April Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	3	4.1	26th (tied with 9 other Aprils)	7 (1989, 2000, 2017)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	2	2.3	18th (tied with 12 other Aprils)	5 (1989)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	2	1.3	6th (tied with 8 other Aprils)	5 (1989)
Accumulated Cyclone Energy ACE×10⁴ kt²	18.2	34.5	32nd	80.0 (1989)

Global Tropical Cyclone Season Counts January-April 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	13	21.4	42nd	30 (1986)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	9	11.6	35th (tied with 4 other seasons)	18 (1994)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	4	6.5	32nd (tied with 4 other seasons)	12 (2019)
Accumulated Cyclone Energy ACE×10⁴ kt²	166.4	179.0	21st	306.4 (1994)

Data Description

The data in this report are derived from NCEI's IBTrACS dataset (Knapp et al. 2010; Schreck et al. 2014). IBTrACS tropical cyclone track and intensity data from agencies and sources around the globe. In this report, data from NOAA's National Hurricane Center (NHC) are used for the North Atlantic and East Pacific. The other basins use data from the U.S. Military's Joint Typhoon Warning Center (JTWC).

Historical values use the "best track" data that have been analyzed by forecasters after the season using all available data. Operational procedures and observing systems have changed with time and between regions, which makes these data heterogeneous. Intensity data are generally the most reliable since the early 1970s in the Atlantic (Landsea and Franklin 2013) and since the mid-1980s in other regions (Chu et al. 2002). The number of short-lived storms (≤2 days) has also increased since around 2000 due to improvements in observations and analysis techniques (Landsea et al. 2010).

Values for the current year are provisional values from the operational forecast advisories. IBTrACS obtains these from NCEP's TC Vitals, the NCAR Tropical Cyclone Guidance Project, and NHC provisional data. These values are subject to change during the post-season best track analysis. They also only include 6-hourly storm fixes, which means they may miss special advisories at landfall, peak intensity, etc.

The tropical cyclone seasons in the Southern Hemisphere begin in July and end in June, while the Northern Hemisphere seasons are counted from January to December. Storms are counted in all basins, months, and years in which they occur, which means some storms may appear more than once. However, the global totals only include each storm one time.

References

• Chu, J.-H., C. R. Sampson, A. S. Levine, and E. Fukada, 2002: The joint typhoon warning center tropical cyclone best-tracks, 1945–2000. Naval Research Laboratory, Reference Number NRL/MR/7540-02-16, 22 pp., https://www.metoc.navy.mil/jtwc/products/best-tracks/tc-bt-report.html.
• Knapp, K. R., M. C. Kruk, D. H. Levinson, H. J. Diamond, and C. J. Neumann, 2010: The International Best Track Archive for Climate Stewardship (IBTrACS). Bull. Amer. Meteor. Soc., 91, 363–376, https://doi.org/10.1175/2009BAMS2755.1.
• Landsea, C. W., and J. L. Franklin, 2013: Atlantic Hurricane database uncertainty and presentation of a new database format. Mon. Wea. Rev., 141, 3576–3592, https://doi.org/10.1175/MWR-D-12-00254.1.
• ——, G. A. Vecchi, L. Bengtsson, and T. R. Knutson, 2010: Impact of duration thresholds on Atlantic tropical cyclone counts. J. Climate, 23, 2508–2519, https://doi.org/10.1175/2009JCLI3034.1.
• Schreck, C. J., K. R. Knapp, and J. P. Kossin, 2014: The Impact of Best Track Discrepancies on Global Tropical Cyclone Climatologies using IBTrACS. Mon. Wea. Rev., 142, 3881–3899, https://doi.org/10.1175/MWR-D-14-00021.1.