As always with a hurricane, the two questions are where and how bad. The where part has always been pretty straightforward with this storm. Here’s the major models (along with the watch and warning areas) – that’s a really tight grouping, and the meteorology on it is very straightforward that Michael will continue north, then start to turn northeast as it gets caught up in a frontal system that is presently over the southeast (the rain over Georgia yesterday and today is from that, not the Hurricane).
The how bad part has changed from yesterday, maybe not as much as the hype of going from category 2 to category 4 might indicate although the dollar value did take a big jump. Yesterday morning the intensification had paused, and there was a descent chance it would stay at the high 2/low 3 range (that’s what I thought would happen), but outflow increased and shear decreased and the intensification picked up again. But it’s important to keep perspective, especially away from landfall. Right at landfall, yes, that 20 or 30mph wind increase makes a big difference. But that should be in an area where people have evacuated (anyone who stayed on the Florida coast in the warning area was unbelievably foolish). What you do for a Cat 3 and a Cat 4 are the same: get out.
Although landfall will be near Panama City, Storm surge will actually be worst in places like Port St. Joe and Apalachicola, both because surge is worst to the right of landfall (where the winds stay onshore and the water piles up) and due to the unusual shape of the Big Bend of Florida, that kink in the shore line caused by Apalachee Bay just south of Crawfordville to Perry. Surges could be as much as 18 feet in Apalachicola bay where the water piles up. Here’s one storm surge estimate:
The economic impact estimate doubled from approximately $7 Billion yesterday to nearly $16 Billion based on this morning’s simulation. Will take a closer look at that in the next post. Here is my Haetta/TC impact swath estimate, based on the 5am National Hurricane Center forecast:
So what about inland? This is a potentially a bit worse for far south Georgia, but the storm should rapidly decay once inland and as it interacts with the front. Trees down, power outages, those in any mobile home in the southwest corner of Georgia (the area SW of a line from Columbus-Albany-Valdosta, such as the Moultrie and Thomasville or Bainbridge areas), and anyone in the orange band in this map in a mobile home that is not securely strapped down, or in an older mobile home – 25 years or older – or RV type vehicle should move to a secure shelter. Tornadoes are always a concern with this kind of storm so keep your weather alert radio nearby. As for the coast of GA/SC/NC, tides will run 2 or 3 feet above normal, and right now “normal” is already about a foot above average due to the fall equinox (“King Tides”). Here local knowledge is key, so check with the products from your local National Weather Service office (www.weather.gov). In the Savannah area, for example, that means places like US80 (the road to Tybee Island) will flood around high tide, other low-lying areas near the marsh or on Tybee itself will get some shallow flooding. Given the speed the storm is moving it shouldn’t be nearly as bad as storms the last few years like Irma and Mathew, but if you are near the water beware. Otherwise, gusty winds, rains (and street flooding or inland flash floods on creeks in the usual vulnerable areas), and again the occasional tornado must be watched for. Power is going to go out. Sigh. Glad I have a 15kw solar backup system …