Hurricane forecasts/advisories contain more detailed information on the forecast track of tropical storms than contained in the scheduled high seas forecasts and are transmitted 4 times daily at approximately 03Z, 09Z, 15Z and 21Z for each active tropical system
The western part of the North Atlantic Ocean east of the North American coast to 35°W, from 7°N to 67°N, including the Gulf of Mexico, the Caribbean Sea and the sea area between 7°N and the South American coastline at 4°30'N, and Hudson Bay* and Approaches.
*INMARSAT-C broadcasts to Hudson Bay and Approaches use "rectangular area referencing" so as to ensure that INMARSAT-C receivers aboard vessels navigating outside this area do not display marine forecast messages extraneous to the vessels' area of operation.