[UPDATED 2021-05-26 1340 UTC] The Atlantic Hurricane Season, which starts on June 1, promises to be a busy time for amateur radio volunteers on the Hurricane Watch Net (HWN) to report ground-level storm conditions in real time for use by National Hurricane Center (NHC) forecasters, and for SKYWARN volunteers, many of whom are hams. The National Oceanographic and Atmospheric Administration (NOAA) has forecast a likely range of 13 to 20 named storms (winds of 39 MPH or greater), of which six to ten could become hurricanes (winds of 74 MPH or greater), including three to five major hurricanes (Category 3, 4, or 5, with winds of 111 MPH or greater) expected. NOAA projects these ranges with a 70% confidence level.
“2021 is looking to be another active season,” said HWN Manager Bobby Graves, KB5HAV. “We can only hope we don’t have a repeat of 2005 or 2020. The sea surface temperatures throughout the normal areas of tropical cyclone activity are already near or just above 80 °F, just what storms like. The current forecast for 2021 is on the high side. The adjusted average is 14 named storms, with seven hurricanes and three of those at Category 3 or stronger.”
When activated, the HWN operates on 14.325 MHz during daylight hours and on 7.268 MHz after dark. When required, however, the net will use both frequencies simultaneously.
The net’s primary mission is to disseminate tropical cyclone advisory information to island communities in the Caribbean, Central America, along the US Atlantic seaboard, and throughout Gulf of Mexico coastal areas. It collects observed or measured weather data from participating radio amateurs in storm-affected areas as well as any post-storm damage reports and passes that information along to forecasters at the National Hurricane Center via its amateur radio station, WX4NHC. The HWN typically activates whenever a storm system has achieved hurricane status and is within 300 statute miles of a populated landmass — although this can vary according to the storm’s forward speed and intensity or at the request of NHC forecasters.
http://www.arrl.org/news/view/amateur-radio-gearing-up-for-another-active-atlantic-hurricane-season