Central Florida Hurricane Center 2012

The turn poleward comes from the usual "from the west" pattern on the weather, and the presence of a trough.

Hurricanes, generally speaking, move into a weakness in the weather pattern. They will ride up the front of a trough if they get "caught" by one, for example, and this is the usual reason for the move poleward - that or getting caught on the front side of a low pressure system (which turns to the left.) The stronger the trough the earlier and more pronounced the move poleward.

The Bermuda High also frequently causes storms to recurve because the back side of the high pressure is moving northward; as the storm comes "around" the high it tends to move into that weakness, and gets "sucked" north. This only happens, however, if there is no ridging that blocks off that path - as there is now. That's why you get a lot of fish spinners off the Atlantic Coast.

Ridging, on the other hand, tends to drive hurricanes west (and in extreme cases, south of west), because the weakness is in that direction and they are "blocked" northward. This is what happened originally with Katrina - but then the ridge broke down as the storm got into the gulf and we all know what happened after that.

There is no "troughiness" in the forecast; ergo, there's nothing to allow the storm to move northward. There IS a lot of ridging currently and in the forecast, which is where the westerly motion comes from.

The problem with long-term forecasts is that the weather environment has a way of radically changing - and the models are frequently wrong more than 48 hours out. So if, for example, the ridging breaks down 3-4 days from now, you could get a poleward turn out of the storm - then its Katy Bar The Door for whoever happens to be north of where it is at that point in time.

A storm like this is potentially menacing to a huge number of people precisely because if it does not get ripped apart by Hispanola (which is looking increasingly unlikely as the current WNW motion continues) it is more and more likely to hit someone. Once it gets into the gulf, if it does, its virtually guaranteed to hit someone as something - we are then arguing about who and how strong, not if.

But - we are talking about a mid to end of next week impact if this goes into the gulf. That's a long way off and way too far out to be making predictions as to where its going to go. Once the storm gets into the Florida Straits I'd be willing to go out on a limb and take a "best guess" at where (within 100 miles either side) its headed, but right now there's a decent shot of it not getting into the gulf at all. But if it does, then its bad news as conditions over the gulf, both in terms of SSTs and atmospherics, are quite favorable for intensification - and if it goes over the warm eddy, the possibility of an explosive increase in strength cannot be ruled out.

The sad part is that I don't see a recurvature before the Florida Coast in the next 3-4 days, which is when it has to happen if its going to avoid land. A southerly deviation that takes it over the DR/Haiti is probably the "best" possibility in terms of harm, in that this will rip up the storm - but that is looking increasingly unlikely. The other day I gave it a 50/50 shot at making it past Hispanola - now I think the odds are better than 80%, which is not a good thing.

If you're south of roughly Canaveral I'd be prepared for this thing on the east coast and especially in the Keys, as you could have an unwelcome visitor over the weekend. If the WNW track holds in particular then the gulf needs to be really "on watch" as there won't be a lot of interaction with land to disrupt it, and the amount of time over water from any disruption it DOES suffer will be much longer than if it were to go in somewhere mid-Florida, for example, and then come out into the gulf (a scenario that would leave the storm far less time to regenerate before a second hit.)

For right now the best option is to have your hurricane kit prepared, figure out what you're going to do IF it comes your way, and be ready - but not freaked out.

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