The Tropical Cyclone Public Advisory contains a list of all current watches and warnings on a tropical or subtropical cyclone. It also gives the cyclone position in terms of latitude and longitude coordinates and distance from a selected land point or island, as well as the current motion. The advisory includes the maximum sustained winds in miles per hour and the estimated or measured minimum central pressure in millibars and inches. The advisory may also include information on potential storm tides, rainfall or tornadoes associated with the cyclone, as well as any pertinent weather observations.
Public advisories are issued for all Atlantic tropical or subtropical cyclones, and for eastern Pacific tropical or subtropical cyclones that are threatening land. Public advisories are normally issued every six hours. They may be issued every two or three hours when coastal watches or warnings are in effect. Special public advisories may be issued at any time due to significant changes in warnings or in the cyclone.
The most current Public Tropical Cyclone Advisories are found on the Active Storm Advisories page and the Tropical Cyclone Products page. They issued under the following World Meteorological Organization (WMO) and AFOS headers:
Atlantic: WTNT31-35 KNHC MIATCPAT1-5
Pacific: WTPZ31-35 KNHC MIATCPEP1-5
The numbers 1-5 are assigned by cyclone number, i.e., advisories on the first, sixth, or eleventh cyclones of the Atlantic season would be sent under the WMO header WTNT31 KNHC; advisories on the second, seventh, or twelth cyclones of the Atlantic season would be sent under the WMO header WTNT32 KNHC, and so on.
The Tropical Cyclone Forecast/Advisory contains a list of all current watches and warnings on a tropical or subtropical cyclone, as well as the current latitude and longitude coordinates, intensity, and system motion. The advisory contains forecasts of the cyclone positions, intensities, and wind fields for 12, 24, 36, 48, and 72 hours from the current synoptic time. The advisory may also include information on any pertinent storm tides associated with the cyclone. All wind speeds in the forecast advisory in given in knots (nautical miles per hour).
Forecast/Advisories are issued on all Atlantic and eastern Pacific tropical and subtropical cyclones every six hours. Special Forecast/Advisories may be issued at any time due to significant changes in warnings or in the cyclone.
The most current Tropical Cyclone Forecast/Advisory is found on the Active Storm Advisories page and the Tropical Cyclone Products page. They are issued under the following WMO and AFOS headers:
Atlantic: WTNT21-25 KNHC MIATCMAT1-5Pacific: WTPZ21-25 KNHC MIATCMEP1-5
The numbers 1-5 are assigned by cyclone number, i.e., advisories on the first, sixth, or eleventh cyclones of the Atlantic season would be sent under the WMO header WTNT21 KNHC; advisories on the second, seventh, or twelth cyclones of the Atlantic season would be sent under the WMO header WTNT22 KNHC, and so on.
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The Tropical Cyclone Discussion explains the reasoning for the analysis and forecast of a tropical or subtropical cyclone. It includes a table of the forecast track and intensity.
Tropical Cyclone Discussions are issued on all Atlantic and eastern Pacific tropical and subtropical cyclones every six hours. Special tropical cyclone discussions may be issued at any time due to significant changes in warnings or in the cyclone.
The most current Tropical Cyclone Discussion is found on the Active Storm Advisories page and the Tropical Cyclone Products page. They are issued under the following WMO and AFOS headers:
Atlantic: WTNT41-45 KNHC MIATCDAT1-5
Pacific: WTPZ41-45 KNHC MIATCDEP1-5
The numbers 1-5 are assigned by cyclone number, i.e., discussions on the first, sixth, or eleventh cyclones of the Atlantic season would be sent under the WMO header WTNT41 KNHC; discussions on the second, seventh, or twelth cyclones of the Atlantic season would be sent under the WMO header WTNT42 KNHC, and so on.
The Tropical Cyclone Strike Probabilities give the percentage chance of a tropical or subtropical cyclone passing within 75 nm to the right or within 50 nm to the left of a specified point, looking in the direction of cyclone motion. The probabilities are give for the time periods 0-24, 24-36, 36-48, and 48-72 hours, with a 0-72 hour given by adding the indivdual probabilities together.
Tropical Cyclone Strike Probabilities are normally issued for Atlantic tropical or subtropical cyclones every six hours when the system is forecast to be within 72 hours of landfall. Special Strike Probabilities may be issued if Special Public/Forecast Advisories are issued.
The most current Tropical Cyclone Strike Probabilities are found on the Active Storm Advisories page and the Tropical Cyclone Products page. They are issued on WMO headers WTNT71-75 KNHC and AFOS headers MIASPFAT1-5.
The numbers 1-5 are assigned by cyclone number, i.e., probabilities on the first, sixth, or eleventh cyclones of the Atlantic season would be sent under the WMO header WTNT71 KNHC; probabilities on the second, seventh, or twelth cyclones of the Atlantic season would be sent under the WMO header WTNT72 KNHC, and so on.
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Tropical Cyclone Updates are brief statements issued in lieu of or preceding special advisories to inform of significant changes in a tropical cyclone or to post or cancel watches or warnings. Tropical Cyclone Updates for the Atlantic are issued under WMO header WTNT61 KNHC and AFOS header MIATCUAT. Tropical Cyclone Updates for the eastern Pacific are issued under WMO header WTPZ61 KNHC and AFOS header MIATCUEP.
The most current Tropical Cyclone Update is found on the Active Storm Advisories page and the Tropical Cyclone Products page.
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Tropical Cyclone Position Estimates are issued between 2-hourly intermdiate advisories whenever a tropical cyclone with a well-defined radar center is within 200 nautical miles of land-based radar in the United States. These estimates give the center location in map coordinates and distance and direction from a well-known point.
Atlantic Tropical Cyclone Position Estimates are issued under the WMO header WTNT51 KNHC and AFOS header MIATCEAT. Eastern Pacific Tropical Cyclone Position Estimates (a rarely used product) are issued under WMO header WTPZ51 KNHC and AFOS header MIATCEEP.
The most current Tropical Cyclone Position Estimate is found on the Active Storm Advisories page and the Tropical Cyclone Products page.
The Tropical Weather Outlook is a discussion of significant areas of disturbed weather and their potential for development out to 48 hours. It includes (when possible) a nontechnical explanation of the meteorology behind the outlook.
Tropical Weather Outlooks also include a brief descriptions of any tropical or subtropical cyclones in the region. It also includes the WMO and AFOS headers of where to find more information on an active cyclone during the first 24 hours of existence.
Tropical Weather Outlooks are issued four times a day during the hurricane season. Atlantic outlooks are transmitted under WMO header ABNT20 KNHC and AFOS header MIATWOAT. Eastern Pacific outlooks are transmitted under WMO header ABPZ20 KNHC and AFOS header MIATWOEP.
The most current Tropical Weather Outlook is found on the NHC home page and the Tropical Cyclone Products page.
Special Tropical Disturbance Statements are used to furnish information on strong formative, nondepression systems. These are usually issued for systems strong enough to produce heavy rains and strong winds that do not yet meet the criteria of tropical or subtropical cyclones. These products are transmitted only as needed.
Atlantic Special Tropical Disturbance Statements are issued under WMO header WONT41 KNHC and AFOS header MIADSAAT. Eastern Pacific Special Tropical Disturbance Statements are issued under WMO header WOPZ41 and AFOS header MIADSAEP.
The most current Special Tropical Disturbance Statement is found on the Active Storm Advisories page and the Tropical Cyclone Products page.
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The Monthly Tropical Weather Summary is issued on the first of every month during the hurricane season. It describes the previous month's tropical cyclone actvity and gives details on the cyclones as known at that time. The last Tropical Weather Summary of the season gives an brief account of the whole season.
Atlantic Tropical Weather Summaries are issued under WMO and AFOS header ABNT30 KNHC and MIATWSAT. Eastern Pacific Tropical Weather Summaries are issued under WMO header ABPZ30 KNHC and AFOS header MIATWSEP.
The most current Monthly Tropical Weather Summary is found on the NHC home page and the Tropical Cyclone Products page.
The Reconnaissance Plan of the Day (52K GIF) is a coded description of planned reconnaissance flights into Atlantic or central Pacific tropical cyclones, subtropical cyclones, or suspect areas on a given day. This includes operational missions by the Air Force Reserve Hurricane Hunters< and research missions by the Hurricane Research Division. It also includes a second day outlook of potential flights. The product is also issued outside the hurricane season for flights under the National Winter Storms Operations Plan.
The Reconnaissance Plan of the Day is normally issued once a day under WMO header NOUS42 KNHC and AFOS header MIAREPRPD. Amendments are issued as needed.
The most current Plan of the Day is found on the NHC home page and the Reconnaissance page.
Vortex data messages are coded reports issued whenever a reconnaissance aircraft penetrates the center of a tropical or subtropical cyclone. They give the position of the cyclone as well as the time of the fix. They include information on winds, temperatures, pressure, and dewpoints encountered during penetration. They also include information on the eye size, shape, and status if an eye is present. There are three types of vortex messages. Detailed Vortex Data Messages ( Frames version, No frames version ) are the standard coded message issued when an aircraft penetrates a cyclone. Abbreviated Vortex Data Messages use the same format as the Detailed messages, but they leave out some of the groups. Supplementary Vortex Data Messages give wind, temperature, pressure, and dewpoint data at 15 nm intervals during the penetration into the cyclone and subsequent depature. Note: the vortex message decoding links are courtesy of the 53rd Weather Reconnaissance Squadron - The Hurricane Hunters.
Vortex messages are transmitted whenever they are received from a reconnaissance aircraft. An Air Force Reserve reconnaissance aircraft typically makes four penetrations during a flight and transmits four detailed and four supplementary messages. Atlantic vortex messages are transmitted under WMO header URNT12 KNHC and AFOS header MIAREPNT2. Central Pacific Vortex Messages are transmitted under WMO header URPN12 KNHC and AFOS header MIAREPPN2.
The most current Atlantic Vortex Data messages are found on the NHC home page and the Reconnaissance page.
Reconnaissance observations are coded reports detailing the pressure, wind, temperature, and dewpoint at roughly 30-minute intervals along a reconnaissance aircraft's flight track. Reconnaissance observations are the primary observations sent during the initial investigation of a potential tropical cyclone and during practice missions. They are also transmitted during tropical cyclone missions: 1) during the trip to and from the cyclone, and 2) at the turning points during the flight through the cyclone. Note: the reconnaissance observation decoding link is courtesy of the 53rd Weather Reconnaissance Squadron - The Hurricane Hunters.
Atlantic reconnaissance observations are transmitted for routine missions under WMO header URNT10 KNHC and AFOS header MIAREPNT0. Atlantic tropical cyclone reconnaissance observations are transmitted under WMO header URNT11 KNHC and AFOS header MIAREPNT1. Pacific tropical cyclone reconnaissance observations are transmitted under WMO header URPN11 KNHC and AFOS header MIAREPPN1.
The most current Reconnaissance Observations are found on the NHC home page and the Reconnaissance page.
Dropsondes are instrument packages ejected from reconnaissance aircraft to take vertical profiles of pressure, wind, temperature, and dewpoint. Dropsonde observations are coded reports of these profiles taken in the center of a tropical cyclone, enroute to or from a tropical cyclone, or on a winter storm mission. Note: the dropsonde observation decoding link is courtesy of the 53rd Weather Reconnaissance Squadron - The Hurricane Hunters.
Atlantic dropsonde messages are transmitted under WMO header UZNT13 KNHC and AFOS header MIAREPNT3. Pacific dropsonde messages are transmitted under WMO header UZPN13 KNHC and AFOS header MIAREPPN3.
The most current Reconaissance Observations are found on the NHC home page and the Reconnaissance page.
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