"I Keep a Weather Eye on the Horizon"

To borrow a line from Mark Knopfler's "Cleaning My Gun".  Lots of my fellow Florida bloggers are keeping an eye on Irma and feeling a bit uncomfortable.  This morning, Irma has gone fully beast mode with sustained winds at 180 mph.  That said, it's not expected to stay Cat 5 for more than the next couple of days, and the models are having difficulty predicting what it does beyond three days. It's important to remember the area of the highest winds is actually pretty small, just the eyewall of the storm, but that lower winds can cover a large area over water.  McThag posts some computer runs from one of the good models (the GFS) for a couple of days that show how the wind fields can work out.

The current National Hurricane Center guys put up this 5-day forecast this morning:  

The way this is supposed to be read is that the storm can be anywhere in the stippled area at 8AM on Sunday.  The end location is about 500 miles in diameter, saying the center could be over the center of the state, or over southern Cuba which is the difference between hurricane winds over all of south Florida or not even having a nasty day.  

The morning spaghetti plot of all the models shows almost unanimous agreement that the storm is going to get picked up by an approaching low pressure system and turn north; the question is how soon it gets picked up and where it ends up hitting. 

Several of the models; the consensus if you will, have it turning right in the last 24 hours of that plot, and coming ashore somewhere on the southern tip of the state.  Some models have it turning much sooner, a few have it turning in the Gulf.  The largest difference is just where it tracks.  If it tracks along the center of the state it will weaken markedly.  If it tracks off either coast, it will be over some rather warm water and will weaken less.   

There's a difference between forecasting and reading computer models, but the NHC is pretty good.  Granted, they have a tendency to be melodramatic when a storm is close, they forecast a much, much worse scenario for Hurricane Matthew last October than we really got, but they still get pretty close.  I've read that they overstate the forecasts deliberately, saying that people won't evacuate unless they overstate it, but IMO that just feeds the cycle.  People see the overstated forecast (cat 4 hurricane onshore, death and destruction) vs. the reality (cat 3 storm well offshore, barely hurricane force winds onshore) and ignore the "official" forecasts. 

It takes two days to evacuate the keys, so folks down there should be getting out of town by Friday, maybe Thursday.  For us, midway up the East Coast, evacuation depends on what kind of storm we're getting and I don't see a way to know that for a few days.  I really doubt it could be a Cat 5 with any substantial land interfering with wind inflow, but if it stays off the East Coast, it could remain a Cat 4.  That would be exceedingly unpleasant, but I'm pretty sure the house would make it barring bad flying debris, a tornado, or something like that.  If it comes up the center of state, or rides the coast, I think it's cat 2 or cat 3.  I recall some storm in around '07 or '08, maybe Fay in '08, where the forecast called for it to intensify coming up the center of the state - I remember joking about that with co-workers wondering what planet something like that could happen on.  It did not intensify.

To steal a meme from Gunfree Zone. 

It looks like the next few days are going to be spent watching the path and how the big picture steering pattern develops.  Waiting to see when the storm turns right.  I think I've spent a couple of months of my life watching storms like this and trying to see when they turn right.