In South Florida, we’re all familiar with forecast cones that show where a hurricane or tropical storm is likely to go during the next three to five days. But how they’re made and exactly what they mean is not as well known.
Forecast cones are graphic representations of the National Hurricane Center’s latest forecast, and a lot of data is needed to make the forecast and construct the cone. Meteorologists rely on data from satellites when a tropical system is well out to sea, and that’s supplemented by radar data when a tropical storm or hurricane is within radar range (usually a couple of hundred miles or so). But often the most useful data will come from hurricane reconnaissance aircraft that fly into a storm – what the public calls “hurricane hunters.” Actually, there are two organizations that fly hurricane-related missions: NOAA and the 53rd Weather Reconnaissance Squadron of the U.S. Air Force Reserve.
NOAA’s aircraft are based in Lakeland, Florida. Its fleet consists of two WP-3D Orions (nicknamed Kermit and Miss Piggy) and a Gulfstream G-IV jet (known as Gonzo) – but this “Muppet Show” is serious about its missions. Kermit and Miss Piggy are equipped with radar and drop instrument packages called dropsondes into a tropical system as they fly a clover-shaped pattern. They’re the mainstays of the fleet, and they send back data that’s critical in track and intensity forecasting. Gonzo can fly above a hurricane to measure the atmosphere around it – important in forecasting hurricane intensity. By late 2022, NOAA will get a new Gulfstream G550 jet to join the fleet.
The 53rd Weather Reconnaissance Squadron (known as the “Hurricane Hunters”) flies hurricane missions from Keesler Air Force Base in Biloxi, Mississippi. It carries on a tradition that dates back to the first U.S. Army Air Forces hurricane reconnaissance flights during World War II. But today’s “Hurricane Hunters” squadron is made up of U.S. Air Force Reserve officers and ten WC-130J (Super Hercules) aircraft, each with a five-person crew. The planes are specially equipped with radar and meteorological instruments. The 53rd’s pilots, navigators, and meteorologists may be part-timers, but the work they do is always important in making forecasts when hurricanes or tropical storms threaten the U.S. coast.
Once the data is transmitted from a plane, it’s run in several computer models maintained by the National Weather Service. Computer model runs help the hurricane specialists at the National Hurricane Center make their forecast.
To construct the forecast cone graphic, the hurricane specialists’ forecast track is “bashed” against the latest analysis of track forecast error (how far off the forecast has been from a hurricane’s actual track, which is adjusted each hurricane season). The forecast cone that’s created is a great graphic which is much better than the old straight-line track forecast, because it indicates the level of uncertainty (possibility of error) that is a part of every weather forecast. But just what the cone really means is often misunderstood. The National Hurricane Center explains what it does and doesn’t do in this video:
So the next time you see a hurricane forecast cone online or on your TV, you’ll know what you’re looking at – and why it’s so important to keep up with the latest information.