Subtropical Storm Alberto Makes Landfall in Northwest Florida

Subtropical Storm Alberto made landfall in northwest Florida late on Monday afternoon.  According to the National Hurricane Center the center of Subtropical Storm Alberto officially made landfall near Laguna Beach, Florida.  At 5:00 p.m. the center of Subtropical Storm Alberto was located at latitude 30.3°N and longitude 85.9°W which put it about 15 miles (25 km) west-northwest of Panama City, Florida.  Alberto was moving toward the north at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 994 mb.  A Tropical Storm Warning was in effect for the portion of the coast from Aucilla, River, Florida to the border between Florida and Alabama.

Subtropical Storm Alberto weakened slowly as it approached the coast of northwest Florida.  Several factors contributed to the weakening of Alberto.  Drier air spiraled into the core of the circulation.  The drier air inhibited the development of taller thunderstorms in the eastern and southern quadrants of the circulation.  Most of the stronger storms developed north and west of the center of circulation.  Daytime heating of the land made the atmosphere more unstable and the instability contributed to the development of thunderstorms in rainbands in those parts of Alberto.  Subtropical Storm Alberto also mixed cooler water to the surface as it moved slowly toward the coast of Florida.  The Sea Surface Temperature near the coast was about 26°C before Subtropical Storm Alberto arrived.  However, the layer of warmer water was very thin.  The winds caused by Alberto mixed the water in the upper levels of the Gulf of Mexico.  The mixing brought cooler water to the surface and the Sea Surface Temperature cooled to near 24°C.  The cooler water meant there was less energy to support the circulation around Subtropical Storm Alberto.

The circulation of Subtropical Storm Alberto will weaken slowly as it moves inland.  Winds blowing water toward the coast will continue to produce a storm surge of 3 to 4 feet (1 to 1.3 meters) east of the center of circulation for another 12 to 24 hours.  A large surface high pressure system over the Atlantic Ocean will steer Subtropical Storm Alberto slowly toward the north during the next several days.  Locally heavy rain could produce flooding as Alberto moves northward.  Flood Watches have been issued for areas between the Gulf Coast and the Lower Ohio River Valley.  Flood Watches have also been issued for places as far east as the Carolinas and Virginia.  The risk of flooding is even greater for locations that already received heavy rain from previous weather systems.