PERSONAL
Laid in supplies today. Water and bread shelves at Publix Market were already stripped bare. No matter to us, our go bag has a case plus 5 days of freeze dried meals and a small camping stove and cookware. If we stay and are in the path, we fill all the large kithen pots for drinking plus the guest bedroom bathtub for flushing. Gas the cars tomorrow. Make decision on stay/go Thursday night or Friday morning after the cone of uncertainty narrows. We stay if we will experience Cat 2 or less. So far, not even taking the precaution of bringing in balcony stuff, always a pain physically and because clutters the condo inconveniently. No need to do so if less than TS winds expected. The building management will make that call probably Thursday for Friday.
TRACK
Each successive ensemble has the track a bit more west before turning north. CFAN (Judy Curry’s company) has the adjusted track even a bit west of ECMWF, which has a better track record than GFS. So if that holds, we may experience nothing at all except rain from outermost bands. But Naples, Sarasota, Fort Meyers, Tampa look to be in real trouble on Irma’s dirty side if CFAN is correct. Current CFAN track has Irma then recurving and hitting Orlando as a Cat 1-2 then Daytona Beach as a 1. CFAN called Harvey perfectly.
Keys are going to get clobbered with high certainty. Mandatory evacuation starting 7 am for tourists and 7pm for residents tomorrow with schools closed from tomorrow until further noice. They have to move 80000 people up US 1 (only way out), always a mess. Miami (65 miles south of Ft Lauderdale) will likely have at least TS conditions given Irma’s size. The mayor is already urging people to evacuate known flood prone areas starting Thursday.
BACKGROUND
the Saffir-Simpson scale was developed by US meteorologist Saffir in the 1960s based on ‘eyewall’ sustained 1 minute windspeed, then refined by US engineer Simpson in the 1970’s for 10 meter height (essentially three stories tall, the ~roofridge of most two story homes. The ratings are based on likely structural damage to ‘ordinary’ structures (think stick built homes) struck by the eye. A Cat 5 destroys these structures completely (google image Hurricane Andrew Homestead Florida damage for vivid examples). Hence there is no meaningful S-S Cat 6 except for scary PR purposes, no different than there is any tornado rated stronger than an Enhanced Fujita scale EF5 for the same reason. There is no meaningful damge number beyond total destruction.
For what its worth, if a cat 1 is 1x wind energy, a Cat 2 is 10x, a Cat 3 is 50x, a Cat 4 is 250x, and a Cat 5 is >500x. Hence my Wilma Cat 3 survived/derived evacuation rule of thumb: cat 2 we stay as the building is designed for minimum Cat 5 (post Andrew building codes). Cat 3 up, we are outa here.
The S-S definition is intentionally sustained winds just outside the eyewall, which is sometimes just 10 miles across.
