Hurricane Jova is threatening the Pacific coastline of Mexico. The latest forecast shows the storm blowing ashore on Tuesday afternoon local time as a category IV hurricane, with winds of 115 knots if not higher. At the moment, a hurricane warning is in force from Punta San Telmo to Cabo Corrientes and a tropical storm warning from Lazaro Cardenas to Punta San Telmo. Apart from the high winds, Jova will also come with up to 15 inches of rain, which could unleash flashfloods and mudslides, as well as a substantial storm surge.
Jova is the 10th storm of the East Pacific season, and the 5th major hurricane in that basin this year. Irwin is following in its wake, but is a weak tropical storm, beaten down by the outflow from Jova which is not far away to its east.
Hurricanes are Nature's safety valve, serving to funnel excess heat from the ocean in the tropics away to higher latitudes. Whilst the cloud tops may be as cold as -85C (-65F) at 10 miles above the surface, the temperature in the eye at the same altitude can be as high as +19C (66F). A hurricane (typhoon or tropical cyclone, all the same thing) requires water temperatures of at least 26C / 80F and an absence of windshear (winds blowing at different speeds and/or directions at different levels of the atmosphere). Once ashore, a tropical cyclone will rapidly weaken and dissipate.