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    Tropical Cyclone Climatology



    Climatology | Names | Wind Scale | Extremes | Models | Breakpoints
    Contents


    Overview

    A tropical cyclone is a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has a closed low-level circulation. Tropical cyclones rotate counterclockwise in the Northern Hemisphere. They are classified as follows:

    Tropical cyclones forming between 5 and 30 degrees North latitude typically move toward the west. Sometimes the winds in the middle and upper levels of the atmosphere change and steer the cyclone toward the north and northwest. When tropical cyclones reach latitudes near 30 degrees North, they often move northeast.


    Tropical Cyclone formation regions with mean tracks (courtesy of the NWS JetStream Online School)

     

    Atlantic & Eastern Pacific Climatology

    The Atlantic hurricane season runs from June 1st to November 30th, and the Eastern Pacific hurricane season runs from May 15th to November 30th. The Atlantic basin includes the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The Eastern Pacific basin extends to 140°W.

    The following figures and tables describe the progress of a typical hurricane season in terms of the total number of tropical systems and hurricanes produced throughout the year in the Atlantic and East Pacific basins.

    In the figures, curves represent the average cumulative production of all named tropical systems, all hurricanes, and those hurricanes which were Category 3 or stronger in those basins.

    For example, by the beginning of September in an average year we would expect to have had four named systems, two of which would be hurricanes and one of which would be of category 3 or greater in strength.

    The tables list benchmark dates when a given number of tropical systems, hurricanes, or category 3 storms should have been generated.

    [graph of average cumulative number of Atlantic basin systems per year]
    The average cumulative number of Atlantic systems per year, 1966-2009
    [graph of average cumulative number of Eastern Pacific basin systems per year]
    The average cumulative number of Eastern Pacific systems per year, 1971-2009


    Table 1. Progress of the average Atlantic season (1966-2009). Date upon which the following number of events would normally have occurred.
    Number Named systems Hurricanes Category 3 or greater
    1July 9Aug 10Sep 4
    2Aug 1 Aug 28Oct 3
    3Aug 13 Sep 9-
    4Aug 23 Sep 21-
    5Aug 31 Oct 7-
    6Sep 8 Nov 23-
    7Sep 16 --
    8Sep 24 --
    9Oct 4 --
    10Oct 19 --
    11Nov 23 --

    Table 2. Progress of the average eastern Pacific season (1971-2009). Date upon which the following number of events would normally have occurred.
    Number Named systems Hurricanes Category 3 or greater
    1 June 10 June 26July 19
    2 June 25July 14Aug 19
    3 July 5 July 29Sep 20
    4 July 14Aug 12 -
    5 July 22Aug 26 -
    6 July 30Sep 9 -
    7 Aug 7 Sep 24 -
    8 Aug 15 Oct 15 -
    9 Aug 24 --
    10Sep 1 --
    11Sep 10 --
    12Sep 19 --
    13Sep 28 --
    14Oct 11 --
    15Nov 5 --


    Number of Tropical Cyclones per 100 Years


    Peak Of Season

    The official hurricane season for the Atlantic Basin (the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico) is from 1 June to 30 November. As seen in the graph above, the peak of the season is from mid-August to late October. However, deadly hurricanes can occur anytime in the hurricane season.


    Points of Origin by 10-Day Period

    The figures below show the points of tropical cyclone genesis by 10-day periods during the hurricane season. These figures depict named storms only. The source years include 1851-2015 for the Atlantic and 1949-2015 for the Eastern Pacific from the HURDAT database.

     May 1-10 Tropical Cyclone Genesis Climatology

     May 11-20 Tropical Cyclone Genesis Climatology

     May 21-31 Tropical Cyclone Genesis Climatology

     June 1-10 Tropical Cyclone Genesis Climatology

     June 11-20 Tropical Cyclone Genesis Climatology

     June 21-30 Tropical Cyclone Genesis Climatology

     July 1-10 Tropical Cyclone Genesis Climatology

     July 11-20 Tropical Cyclone Genesis Climatology

     July 21-31 Tropical Cyclone Genesis Climatology

     August 1-10 Tropical Cyclone Genesis Climatology

     August 11-20 Tropical Cyclone Genesis Climatology

     August 21-31 Tropical Cyclone Genesis Climatology

     September 1-10 Tropical Cyclone Genesis Climatology

     September 11-20 Tropical Cyclone Genesis Climatology

     September 21-30 Tropical Cyclone Genesis Climatology

     October 1-10 Tropical Cyclone Genesis Climatology

     October 11-20 Tropical Cyclone Genesis Climatology

     October 21-31 Tropical Cyclone Genesis Climatology

     November 1-10 Tropical Cyclone Genesis Climatology

     November 11-20 Tropical Cyclone Genesis Climatology

     November 21-30 Tropical Cyclone Genesis Climatology


    Climatological Areas of Origin and Typical Hurricane Tracks by Month

    The figures below show the zones of origin and tracks for different months during the hurricane season. These figures only depict average conditions. Hurricanes can originate in different locations and travel much different paths from the average. Nonetheless, having a sense of the general pattern can give you a better picture of the average hurricane season for your area.


    June Hurricane Climatology

    July Hurricane Climatology

    August Hurricane Climatology

    September Hurricane Climatology

    October Hurricane Climatology

    November Hurricane Climatology



    High Resolution History Maps


    [Tropical Cyclone History Map for Atlantic and Eastern Pacific]
    All North Atlantic and Eastern North Pacific tropical cyclones


    Named Cyclones by Year


    [Graph of Tropical Cyclone Activity in the Atlantic Basin]
    Bars depict number of named systems (yellow), hurricanes (red), and category 3 or greater (purple), 1850-2014
    Download hires image
    Download table of data (PDF)


    Hurricane Return Periods

    Hurricane return periods are the frequency at which a certain intensity of hurricane can be expected within a given distance of a given location (for the below images 50 nm or 58 statute miles). In simpler terms, a return period of 20 years for a major hurricane means that on average during the previous 100 years, a Category 3 or greater hurricane passed within 50 nm (58 miles) of that location about five times. We would then expect, on average, an additional five Category 3 or greater hurricanes within that radius over the next 100 years.

    More information on return periods can be found from NOAA Technical Memorandum NWS NHC 38 (pdf) on the NHC Risk Analysis Program (HURISK).

    Note: The information on return period is generated with the 1987 HURISK program, but uses data through 2010.

     

    [Map of return period in years for hurricanes passing within 50 nautical miles]
    Estimated return period in years for hurricanes passing
    within 50 nautical miles of various locations on the U.S. Coast


    [Map of return period in years for major hurricanes passing within 50 nautical miles]
    Estimated return period in years for major hurricanes passing
    within 50 nautical miles of various locations on the U.S. Coast


    CONUS Hurricane Strikes


    [Map of 1950-2017 CONUS Hurricane Strikes]
    1950-2017 CONUS Hurricane Strikes (Courtesy of NCEI)


    CONUS Hurricane Strike Density (county maps)


    [Map of 1900-2010 Hurricane Strikes by U.S. counties/parishes]
    1900-2010 U.S. Hurricane Strikes


    [Map of 1900-2010 Hurricane Strikes by U.S. counties/parishes (West Gulf)]
    1900-2010 U.S. Hurricane Strikes - West Gulf


    [Map of 1900-2010 Hurricane Strikes by U.S. counties/parishes (East Gulf)]
    1900-2010 U.S. Hurricane Strikes - East Gulf


    [Map of 1900-2010 Hurricane Strikes by U.S. counties/parishes (Southeast)]
    1900-2010 U.S. Hurricane Strikes - Southeast


    [Map of 1900-2010 Hurricane Strikes by U.S. counties/parishes (Northeast)]
    1900-2010 U.S. Hurricane Strikes - Northeast


    [Map of 1900-2010 Major Hurricane Strikes by U.S. counties/parishes]
    1900-2010 U.S. Major Hurricane Strikes


    [Map of 1900-2010 Major Hurricane Strikes by U.S. counties/parishes (West Gulf)]
    1900-2010 U.S. Major Hurricane Strikes - West Gulf


    [Map of 1900-2010 Major Hurricane Strikes by U.S. counties/parishes (East Gulf)]
    1900-2010 U.S. Major Hurricane Strikes - East Gulf


    [Map of 1900-2010 Major Hurricane Strikes by U.S. counties/parishes (Southeast)]
    1900-2010 U.S. Major Hurricane Strikes - Southeast


    [Map of 1900-2010 Major Hurricane Strikes by U.S. counties/parishes (Northeast)]
    1900-2010 U.S. Major Hurricane Strikes - Northeast


    Central Pacific Climatology

    The following graphs and charts describe some of the climatology of tropical cyclone activity in the area served by the Central Pacific Hurricane Center, between 140 degrees West longitude and the International Date Line and north of the equator.

    Many factors affect the level of tropical cyclone activity from year to year. Among them are the state of the El Nino Southern Oscillation in the Pacific. Moderate to strong El Nino years are correlated with increased tropical cyclone activity in the Central Pacific and the occurrence of late season storms.

    Continuous satellite coverage has been available in the Central Pacific since 1971 so many climatologies start with that date.Earlier accounts of tropical cyclone activity are based on land, ship, and aircraft observations as well as some non-continuous satellite data.

    Hurricane Season Climatology Central Pacific (1971-2008)

      Hurricanes Tropical Storms Tropical Depressions Total
    Total Number 58 46 59 163
    Percent of All Systems 36% 28% 36%  

    Tropical Cyclones in the Central Pacific By Year

    Central Pacific Tropical Cyclones per year from 1971 to 2013

    Tropical Cyclones in the Central Pacific By Month

    Central Pacific Tropical Cyclones per month from 1971 to 2013

    The following charts show the storms that have come within 200 miles and 75 miles of Hawaii. Storms that do not make landfall in Hawaii can still cause considerable damage, mostly from winds and surf.

    Tropical Storms and Hurricanes Passing within 200 Miles of Hawaii since 1950

    Tropical Storms and Hurricanes Passing within 75 Miles of Hawaii since 1950


    Learn more about climate impacts from the NWS Climate Prediction Center.

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