Zeta has significantly strengthened and grown in size for its trip north across the Gulf of Mexico. The center of the storm is forecast to make landfall over southeastern Louisiana near New Orleans late this afternoon. But Zeta will impact the coastline as far east as the Florida Panhandle.
When the storm passed over Mexico’s Yucatán Peninsula, the core was disrupted, diminishing the peak winds. But this had the effect of spreading the storm’s energy over a wider area. Now the core has redeveloped, and an eye has formed. The strengthening process should continue for the first half of today, with Zeta reaching Category 2 strength.
As Zeta gets farther north in the Gulf, there is less energy to draw from the Gulf water, and the upper-level winds are forecast to become more hostile. On the other hand, the storm is picking up forward speed. Those effects should cancel out each other to some degree, so a relatively steady state is expected, with Zeta coming ashore at or near Category 2 strength.
The larger radius of strong winds on the right side of the circulation will produce a higher storm surge over a wider area. The current National Hurricane Center forecast calls for the Gulf water to rise 5 to 9 feet above normal high tide from Louisiana through Mississippi and into Alabama. This means the storm surge will push well inland into the bays, rivers, and bayous that feed into the Gulf.
In the western Florida Panhandle, the forecast is for a water rise of 2 to 4 feet above the normal high tide level. In Pensacola, they are still recovering from Hurricane Sally, and now they are under a Tropical Storm Warning and a Storm Surge Warning again. Unless something unexpected happens, however, like happened in slow-moving Sally, they should be on the edge of the storm.
A last-minute change in this track is very unlikely in this case. The steering pattern is very well established.
New Orleans is about 50 miles inland, so winds there shouldn’t be quite as strong as at the coast, but Zeta is moving so fast, hurricane-force is now expected. The New Orleans area with its rich tree canopy is quite vulnerable to high winds. Damage from falling trees and power outages are likely.
The giant flood-protection system that surrounds the city will not be challenged by this storm. In unprotected outside of the levees in Louisiana and along the Mississippi and western Alabama coast, however, storm surge flooding will be a major threat.
Zeta is going to be propelled north by an unusually large and strong upper-level storm system coming across Texas. This will speed it inland, meaning the high winds will occur well north of the coastline, hundreds of miles from the coast. Also, the upper system and Zeta will team up to generate a corridor of very heavy rain from the Gulf coast, across the Midwest, and into the Northeast.
Tornadoes are also possible in the South as Zeta makes landfall.
The remnants of Zeta are forecast to be absorbed by a cold front associated with the upper-level storm on Thursday. Once that happens, a weak version of the front will be pushed south and is expected to pass through South Florida around Halloween. We should notice the humidity drop along with cooler morning temperatures.
The long-range computer forecast models continue to insist that a season-changing front will push south through Florida early next week. If the forecast holds up, Election Day should be clear and relatively cool across the state.
At the same time, the weather pattern over the extreme southern Caribbean is forecast to be supportive of a tropical system, so we’ll have to keep an eye to the south. But, the evolution of the fall weather pattern, with northern air pushing through Florida, should keep any tropical developments, if they occur, well to the south for the foreseeable future.