NHC Updates:

Recon Tutorial
This tutorial is about using the mapping available in our aerial reconnaissance system. When a mission is active, or for missions we have archived, you will find some of the following symbols in our mapping products, all of which are clickable.


Wind Barbs icons High density observations (HDOB) are usually transmitted every thirty seconds. For each HDOB message there are usually twenty lines of observations, which would usually mean the message has twenty observation lines from the past ten minutes. The mapping on our site will have a wind barb for each of those twenty observations which will represent the average flight level wind speed over thirty seconds and the wind direction. The winds barbs to the left, from left to right, represent 5 knots, 10 knots and 65 knots. All of them to the left note that the wind direction is from 0 degrees, or from the north. It means that if you were facing north, the wind would be hitting you in the face. Wind Speed Color Legend In addition to decoding a wind barb to determine the wind speed, or simply clicking it to view the wind speed and other data, you can also identify the wind speed, in knots, by color. This legend is included in our Google Earth recon product. For high wind speeds, you will need to click it to get the wind speed or recognize the speed the wind barb represents by looking at it.

Vortex Icon A round white circle with a number in it represents a vortex message with the pressure, in millibars, located in the circle. You can click this icon to view a decoded vortex message which contains information about the center of the storm and often significant observations seen in the storm, such as the highest flight level wind recorded and the highest estimated surface winds.

Sonde Icon This is a picture of a dropwindsonde, which is often just called a dropsonde. A dropsonde is released from the aircraft to sample such things as wind, temperature and pressure. (Visit NOAA's Aircraft Expendables page for more information.) You can click this icon to view a decoded dropsonde message, which contains the previous mentioned things at different levels between the aircraft and sea surface. A dropsonde diagram is also available in the popup window which displays most of the data in the tables in a visual way.

RECCO Icon A pair of binoculars represents a reconnaissance code message (RECCO) which has information that is observed by a person aboard the plane. You can click this icon to view a decoded RECCO message.

AXBT Icon This is a picture of an airborne expendable bathythermograph (AXBT), which is larger than a dropsonde. Like a dropsonde though, this is also dropped from a plane, only it takes its readings once it reaches the ocean's surface. It drops a sensor deep into the water column measuring water temperature at various depths. (Visit NOAA's Aircraft Expendables page for more information.) SST Icon If the sea surface temperature (SST) is available, our site will display the SST, in Celsius, as a color coded icon like the one to the right. If it is not available, then an AXBT icon will appear instead. The color coded icon to the right would appear when the temperature is between 26.00°C and 26.99°C. You can click the icon for temperatures at other depths.


There are a variety of aircraft and agencies that investigate tropical cyclones. The following are the types of aircraft our site usually follows. The aircraft icon for each is what you will see in our mapping products when we have data from that type of aircraft.

Plane Icon

United States Air Force - Lockheed WC-130J Hercules (About)

The Air Force currently uses a fleet of ten of these aircraft. These aircraft fly through hurricanes taking various readings, such as the flight level wind speed, the estimated surface wind speed estimated by the Stepped Frequency Microwave Radiometer (SFMR) instrument and many other readings. This aircraft flies at various levels in a hurricane so it is important to know what level it is flying at when looking at flight level observations. (Air Force and NOAA P-3 aircraft will also often be at higher altitudes when traveling to and from a storm, often descending to the planned operational altitude before entering the storm and ascending once exiting the storm.) These aircraft are also occasionally used like the NOAA G-IV jet, sampling the environment around the storm rather than in it. Air Force aircraft usually follow a set pattern when traveling into a storm. The home base of the Air Force hurricane hunters is Keesler Air Force Base in Biloxi, Mississippi. In the eastern Caribbean, they usually operate out of Henry E. Rohlsen Airport in the U.S. Virgin Islands. In the Central Pacific, they usually operate out of Hickam Air Force Base in Honolulu, Hawaii. They operate out of other locations as needed.

Plane Icon

National Oceanic and Atmospheric Administration (NOAA) - Lockheed WP-3D Orion (About)

NOAA currently uses two of these aircraft, one nicknamed "Kermit" (N42RF) and the other "Miss Piggy" (N43RF). Like the Air Force hurricane hunters, these aircraft also fly through hurricanes taking similar readings. NOAA's P-3's also "participate in a wide variety of national and international meteorological, oceanographic and environmental research programs". These aircraft are very research oriented, often testing various scientific equipment. While these aircraft often follow flight patterns similar to the Air Force, some research missions may involve very different flight tracks depending on the research being done. The home base of the NOAA hurricane hunters is Lakeland Linder Regional Airport in Lakeland, Florida. Prior to mid 2017, they were based at MacDill Air Force Base in Tampa, Florida. In the eastern Caribbean, they usually operate out of Grantley Adams International Airport in Barbados. In the Central Pacific, they usually operate out of Honolulu International Airport in Honolulu, Hawaii. They operate out of other locations as needed.

Plane Icon

National Oceanic and Atmospheric Administration (NOAA) - Gulfstream IV-SP (G-IV) (About)

NOAA currently uses one of these aircraft, nicknamed "Gonzo" (N49RF). This jet samples the high altitude environment around the storm rather than flying into the storm like the NOAA P-3's and the most common Air Force flight tracks into a storm. In the past, our site often received only dropsonde data from this plane rather than high density observations. If this happens, the track will be very approximate as the track line will simply connect the locations of each dropsonde's splash location.

Plane Icon

National Aeronautics and Space Administration (NASA) - Northrop Grumman RQ-4A Global Hawk (About)

NASA has two of these unmanned aircraft systems. NASA872 (also known as AV-6) and NASA874 (which as of 2016 has not yet been used). NASA871 (AV-1) has been retired. Unlike the other aircraft we track, these are unmanned aircraft capable of traveling great distances. Other aircraft cannot reach the eastern Atlantic from North America, which is not a necessity except for research purposes. These aircraft are capable of traveling across the Atlantic and back in missions that could last as long as about a day. These aircraft can fly at extremely high altitudes, well above the other reconnaissance aircraft our site tracks. Our site only tracks Global Hawk dropsonde data that has a WMO header like NOAA dropsondes. (example: UZNT13 KWBC) We do not currently process the raw track files from the Global Hawk aircraft which have a very large file size. The home base of the Global Hawk aircraft is Edwards Air Force Base in California, although the missions investigating tropical cyclones have usually taken place from NASA's Wallops Flight Facility in Virginia.

Plane Icon

National Science Foundation / National Center for Atmospheric Research (NCAR) - Gulfstream V, HIAPER (High-performance Instrumented Airborne Platform for Environmental Research) (About)

NSF/NCAR uses one of these highly-modified aircraft. This jet can sample the high altitude environment around the storm like the NOAA G-IV. While this plane has usually not been tasked by the National Hurricane Center to conduct reconnaissance, it has been previously when the G-IV was unavailable due to unscheduled maintenance. Historically, our site has only ever received dropsonde data from this plane rather than high density observations. The home base of this aircraft is at the Earth Observing Laboratory's (EOL) Research Aviation Facility (RAF) located at Rocky Mountain Metropolitan Airport (formerly known as the Jefferson County Airport) in Broomfield, Colorado, located outside Denver.

Using Google Earth

Google Earth Example Menu If you do not have Google Earth, click here to download it.

This is an example of what the menu in the left column will look like in Google Earth. Once the Google Earth network link opens, "Do not display any missions" will be selected if there is recon available. If there is none available, it will simply say "There is currently no recon available."

Once you select the mission you want, like "Mission 03 into Earl" in the example at the left, that particular network link will open the data for that mission. The storm number will be located in parenthesis next to the storm name. Under that you will find the mission number. Next to that you will find the agency that is investigating the storm, "AF" for United States Air Force, "NOAA" for the National Oceanic and Atmospheric Administration and "NASA" for the National Aeronautics and Space Administration. The number to the right of the agency is the tail number of the aircraft.

The other folders contain information on different observations. You can check a folder to show or hide all observations of that type. When you expand a folder you will be able to view all the observations of that type. From there you can select to show or hide specific observations. For HDOB messages, observations are noted by the message number, like "OB 01", which is the observation number for a set of observations within the message, usually twenty.

To view the latest position of the reconnaissance aircraft, look for the picture of a plane. If you click the icon, you will see the direction the plane is traveling and the distance to a large city nearby.

Missions from the past three hours can be found using our Google Earth network link. Check out our reconnaissance archive for prior missions. Look for the Google Earth symbol in the archive to view mission data in Google Earth for that mission.

When using Google Earth you should usually view recon data looking straight down while the view is oriented north. Wind barbs can be misaligned at times if you are not looking straight down and oriented north. Due to how Google Earth treats icons, this is unavoidable.