Tropical Cyclone Observed Surface Wind Swath

Map Information

This nowCOAST time-enabled map service provides maps depicting the latest official NWS tropical cyclone forecast tracks and watches and warnings for all active systems in the Atlantic, Caribbean Sea, Gulf of Mexico, Eastern Pacific Ocean, and Central Pacific Ocean.
The map layer displays the cyclone's present location, past locations (best track), maximum estimated sustained surface wind (MPH), wind gusts, mean sea level pressure (millibars), forecasts of the cyclone's surface positions, maximum sustained winds and gusts at 12, 24, 36, 48, 72, 96 and 120 hours, and uncertainty of the forecast track depicted as a cone. Best track information is available for all storms in the Atlantic, Caribbean Sea, Gulf of Mexico and Eastern Pacific Ocean but not for storms in the Central Pacific Ocean. The track forecasts are based on information from the NWS/National Hurricane Center (NHC) and NWS/Central Pacific Hurricane Center (CPHC) Tropical Cyclone Public Advisories. This map service is updated twice per hour in order to obtain and display the latest information from the regularly scheduled NHC tropical cyclone public advisories as well as any intermediate or special public advisories. For more detailed information about the update schedule, see:https://new.nowcoast.noaa.gov/help/#section=updateschedule

Background Information

The map service is updated twice per hour in order to obtain and display the latest information from the regularly scheduled NHC tropical cyclone public advisories as well as any intermediate or special public advisories. The regularly scheduled advisories are issued every six hours at 0300, 0900, 1500 and 2100 UTC, and intermediate public advisories are issued as needed. Public advisories for Atlantic tropical cyclones are normally issued every six hours at 5:00 AM EDT, 11:00 AM EDT, 5:00 PM EDT, and 11:00 PM EDT (or 4:00 AM EST, 10:00 AM EST, 4:00 PM EST, and 10:00 PM EST). Public advisories for Eastern Pacific tropical cyclones are normally issued every six hours at 2:00 AM PDT, 8:00 AM PDT, 2:00 PM PDT, and 8:00 PM PDT (or 1:00 AM PST, 7:00 AM PST, 1:00 PM PST, and 7:00 PM PST). Public advisories for Central Pacific tropical cyclones are issued every six hours at 5:00 AM HST, 11:00 AM HST, 5:00 PM HST, and 11:00 PM HST. Intermediate public advisories may be issued every three hours when coastal watches or warnings are in effect, or every two hours when coastal watches and warnings are in effect and land-based radars have identified a reliable storm center. Additionally, special public advisories may be issued at any time due to significant changes in warnings or with the tropical cyclone (e.g. intensity, direction of motion).

The track and intensity forecasts represents the official forecast of center surface positions at 0-hour (initial location), 12, 24, 36, 48, 72, 96, and 120 hours as well as the connecting track. The international tropical cyclone symbols for Tropical Depression, Tropical Storm, or Hurricane are used to indicate the tropical cyclone category based on the NHC's forecast intensity at the different forecast projection hours. The labels of the predicted maximum sustained surface wind speed and gusts in knots, as well as Saffir-Simpson Category, for each of the 12 through 120 hour forecast center positions. In addition, the estimated observed maximum sustained surface wind speed, wind gusts, and lowest mean sea level pressure (MSLP, shown in millibars) of the initial (0-hour) position are also plotted on the map. NHC states that wind forecasts have an uncertainty near 20 knots each day. (The maximum sustained surface wind is defined as the highest 1-minute sustained surface wind speed occurring within the circulation of the tropical cyclone at the standard meteorological measurement height of 10 m (33 ft) in an unobstructed exposure. The predicted gust is the wind peak during a 3-5 second time period. The value of the maximum 3-second gust over a 1-minute period is on the order of 1.3 times (or 30% higher) than the 1-minute sustained wind speed.)

The map service also provides maps of the "working best track" or "best track" for presently active tropical cyclones in the Atlantic, Caribbean Sea, Gulf of Mexico, and Eastern Pacific Oceans. This information is not presently available for cyclones in the Central Pacific Ocean from the CPHC. The best track information represents the forecasters' best estimates of the location, intensity, and size of a tropical cyclone while the cyclone is still an active weather system. According to the NHC, the "best track wind swath shows how the size of the storm has changed and the areas potentially affected so far by sustained winds of tropical storm force (34 knots), 50 knot, and hurricane force (64 knot) from a tropical cyclone. These data are based on the wind radii contained in the Automated Tropical Cyclone Forecasting (ATCF) system's working best track. Users are reminded that the best track wind radii represent the maximum possible extent of a given wind speed within particular quadrants around the tropical cyclone. As a result, not all locations falling within the swaths will have experienced the indicated sustained wind speeds. These data are intended for geographic display and analysis at the national level and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:2,000,000-scale data."

The solid blue line represents the NHC forecast track from 0 to 72 hours and the dashed blue line indicates the forecast track from 72 to 120 hours. The track lines are provided as an aid in the visualization of official NHC track forecasts. Since there are an infinite number of ways to connect a set of forecast points and the motion of cyclones in between forecast projections, the lines should not be interpreted as representing a specific forecast for the cyclone location in between official forecast points. The second is that a tropical cyclone is not a point. The effects of a tropical cyclone can span many hundreds of miles from the system's center. The area experiencing tropical storm or hurricane winds can extend well beyond the greenish areas depicting the most likely track area of the center. In addition, the strength of winds can vary greatly in different quadrants of any tropical cyclone.

The forecast uncertainty is conveyed by the track forecast "cone," frequently referred to as the Cone of Uncertainty. The cone represents the probable track of the center of a tropical cyclone. The greenish area depicts the track forecast uncertainty for days 1-3 of the forecast, while the clear area enclosed by a white outline depicts the uncertainty on days 4-5. NHC historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. The cone is created by placing a set of imaginary circles along the forecast track at the 12, 24, 36, 48, 72, 96 and 120 hour forecast center positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors (NHC states that track errors have averaged near 225 nautical miles on Day 4 and 300 nautical miles on Day 5). The cone is then formed by smoothly connecting the area swept out by the set of circles.

The tropical cyclone watches and warnings depict the geographic extent of tropical storm and hurricane watches and warnings along the immediate coastline using the following color scheme: hurricane warning (red), hurricane watch (pink), tropical storm warning (orange) or tropical storm watch (yellow). The criteria for the different types of watches and warnings are the following: Tropical Storm Watch - An announcement for specific coastal areas that tropical storm conditions (sustained surface winds within the range of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) are possible within 36 hours. Tropical Storm Warning - A warning that sustained surface winds within the range of 34 to 63 knots (39 to 73 mph or 63 to 118 km/hr) associated with a tropical cyclone are expected in a specified coastal area within 24 hours or less. Hurricane Watch - An announcement for specific coastal areas that hurricane conditions (sustained surface winds of 64 knots [74 mph or 119 km/hr] or higher) are possible within 36 hours.
Hurricane Warning - A warning that sustained winds of 64 knots (74 mph or 119 km/hr) or higher associated with a hurricane are expected in a specified coastal area in 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force. The coastal areas placed under these watches or warnings are identified through the use of "breakpoints." A tropical cyclone breakpoint is defined as an agreed upon coastal location that can be chosen as one of two specific end points or designated places between which a tropical storm/hurricane watch/warning is in effect. NWS designates these locations along the U.S. East, Gulf, and California coasts, Puerto Rico, and Hawaii.

Time Information

This map is time-enabled, meaning that each individual layer contains time-varying data and can be utilized by clients capable of making map requests that include a time component.

This particular service can be queried with or without the use of a time component. If the time parameter is specified in a request, the data or imagery most relevant to the provided time value, if any, will be returned. If the time parameter is not specified in a request, the latest data or imagery valid for the present system time will be returned to the client. If the time parameter is not specified and no data or imagery is available for the present time, no data will be returned.

In addition to ArcGIS Server REST access, time-enabled OGC WMS 1.3.0 access is also provided by this service.

Due to software limitations, the time extent of the service and map layers displayed below does not provide the most up-to-date start and end times of available data. Instead, users have three options for determining the latest time information about the service:

Issue a returnUpdates=true request for an individual layer or for
the service itself, which will return the current start and end times of
available data, in epoch time format (milliseconds since 00:00 January 1,
1970). To see an example, click on the "Return Updates" link at the bottom of
this page under "Supported Operations". Refer to the ArcGIS REST API Map Service Documentation for more information.


    Issue an Identify (ArcGIS REST) or GetFeatureInfo (WMS) request against
    the proper layer corresponding with the target dataset. For raster
    data, this would be the "Image Footprints with Time Attributes" layer
    in the same group as the target "Image" layer being displayed. For
    vector (point, line, or polygon) data, the target layer can be queried
    directly. In either case, the attributes returned for the matching
    raster(s) or vector feature(s) will include the following:


            validtime: Valid timestamp.


            starttime: Display start time.


            endtime: Display end time.


            reftime: Reference time (sometimes reffered to as
            issuance time, cycle time, or initialization time).


            projmins: Number of minutes from reference time to valid
            time.


            desigreftime: Designated reference time; used as a
            common reference time for all items when individual reference
            times do not match.


            desigprojmins: Number of minutes from designated
            reference time to valid time.




    Query the nowCOAST LayerInfo web service, which has been created to
    provide additional information about each data layer in a service,
    including a list of all available "time stops" (i.e. "valid times"),
    individual timestamps, or the valid time of a layer's latest available
    data (i.e. "Product Time"). For more information about the LayerInfo
    web service, including examples of various types of requests, refer to
    the nowCOAST help documentation at:https://new.nowcoast.noaa.gov/help/#section=layerinfo

References

CPHC, 2015: Tropical Cyclone Product Help, NWS/CPHC, Honolulu, HI. (Available at https://www.prh.noaa.gov/cphc/pages/abouttcprod.php).

NHC, 2015: NHC Data in GIS Formats, NWS/NCEP National Hurricane Center, Miami, FL (Availalbe athttps://www.nhc.noaa.gov/gis).))

NWS, 2013: NWS Instructions 10-601, Tropical Cyclone Products, NWS, Silver Spring, MD (Available athttps://www.nws.noaa.gov/directives/).

Data and Resources

Additional Info

Field Value
Source http://www.caribbeangeoportal.com/datasets/10dc113cdf7f46f5878ebae4a7c5d708_10
Last Updated September 11, 2020, 09:40 (CDT)
Created August 6, 2020, 12:03 (CDT)
GUID http://www.caribbeangeoportal.com/datasets/10dc113cdf7f46f5878ebae4a7c5d708_10
Language
dcat_issued 2015-10-01T15:33:11.000Z
dcat_modified 2020-09-02T20:51:44.000Z
dcat_publisher_name NOAA GeoPlatform