Gov. Rick Scott (R-Fla.) has declared an emergency in 42 counties in Florida in preparation for Tropical Depression Nine, which has been upgraded to Tropical Storm Hermine. (Reuters)

At 2 p.m., the National Hurricane Center upgraded the depression to Tropical Storm Hermine. This post has been updated.

Tropical Storm Hermine is forecast to hit Florida’s vulnerable Big Bend area on Thursday. A storm surge is the biggest threat to the coast, while heavy rain and flooding will inundate inland areas. Isolated tornadoes are also possible as the storm comes ashore.

On Wednesday, a tropical storm warning, hurricane watch and storm surge warning are in effect for the Big Bend area of Florida. Though the storm appeared to be strengthening, the Hurricane Center believes this is just a temporary flare-up of thunderstorm activity, as opposed to organized intensification into a hurricane.

Top winds in Hermine are 40 mph and they could increase to 60 or 70 mph as the storm nears Florida. With just 24 hours before it begins to interact with land, Hermine is running out of time to intensify much more before it makes landfall.

The center of the storm is expected to come ashore on Thursday night, but as with any tropical cyclone, never focus on just the exact landfall point and time. Flooding rains, storm surge, gusty winds and tornadoes will accompany the storm well in advance and far away from the exact center crossing the coastline.


(NOAA)

Coastal flooding due to storm surge, strong winds, and tornadoes are all possibilities in Tropical Storm Hermine.

Storm surge is a special concern in this part of Florida because the shape of the coastline leaves water nowhere to go but onto the land when strong winds are blowing onshore (it’s worse for areas to the right of the storm center’s motion).  The storm surge — coastal erosion and flooding — should not be underestimated even if it’s “only” a tropical storm. This same area was impacted by Tropical Storm Colin’s storm surge in June.

The storm surge warning stretches from Franklin County to Hernando County in Florida. “There is a danger of life-threatening inundation within the next 36 to 48 hours … from Aripeka to Indian Pass,” the National Hurricane Center wrote on Wednesday morning.

Storm surge forecast

Indian Pass to Ochlockonee River — 2 to 4 feet
Ochlockonee River to Chassahowitzka — 3 to 5 feet
Chassahowitzka to Aripeka — 2 to 4 feet
Aripeka to Bonita Beach (including Tampa Bay) — 1 to 2 feet

In addition to low-lying areas being inundated with the surge, minor damage to marinas, docks, boardwalks and piers is possible. Some small boats could break away from their moorings, says the National Weather Service.

The three-day rainfall forecast for Hermine paints a heavy rain swath. The National Weather Service is calling for 6 to 10 inches of rain in parts of northwest Florida. It also calls for up to the same amount along the coastal Carolinas as the storm tracks up the East Coast on Friday into Saturday morning.


Three-day rainfall forecast. (NOAA)

Tropical Storm Hermine is the season’s eighth named storm, three weeks ahead of the average date of eighth named storm formation. If the storm reaches hurricane intensity, it would also be three weeks ahead of the average date of the season’s fourth hurricane formation, and it would be the first hurricane to make landfall in Florida since Wilma in 2005.

Though the future of this storm depends heavily on how much it intensifies over the next 24 hours, the next area of concern is the southeast coast, from Georgia up through the Outer Banks, on Friday and Saturday morning.

The Post’s Angela Fritz contributed to this report.