A subtropical storm is classified also as a subtropical cyclone. The requirement to be a subtropical storm/cyclone is maximum sustained winds of 39mph or higher for an average of a full minute. Their centers are cooler than standard tropical storms but they can develop into tropical storms and hurricanes with the right conditions.
Subtropical Storm Alberto is anticipated to range from Louisiana to Florida along the Gulf Coast, affecting western Cuba and parts of the Yucatan Peninsula with maximum sustained winds of 40mph. This storm is slow moving at 2mph, with an average 10-15 inches of rain and 25 inches in northeastern Yucatan and Cuba. Southwest Florida and the Florida Keys can expect rains ranging 4-12 inches. A storm surge watch (defined by the National Hurricane Center, NHC, and National Oceanic and Atmospheric Administration, NOAA, as the possibility of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 48 hours, in association with a tropical, subtropical, or post-tropical cyclone) has been issued from Horseshoe Beach in Florida to the mouth of the Mississippi River. Prospective flooding increases early in the week with potential for flash floods and mudslides.
An average season (June 1st to November 30th) generally produces 12 storms, 6 hurricanes, and three major hurricanes (major hurricanes are category 3 or higher). AccuWeather Hurricane Expert, Dan Kottlowski anticipates 12-15 tropical storms during this hurricane season with 6-8 becoming actual hurricanes and 3-5 of those becoming major hurricanes. Reports from the NOAA estimate 10-16 named storms this season, with 5-9 developing into hurricanes and 1-4 of those becoming major hurricanes.