Hurricane Wilma's 90-deg turn

Why is Wilma forcasted to turn 90 degrees? What would make it do that?

A pressure front plus prevailing currents. This is not at all unusual, just annoying. We had one just sit of the coast here for several days once, then go somewhere else (Hurricane Elena).

Hurricane paths are a combination of Coriolis force and prevailing wind directions, adapted according to the particular meteorological circumstances in place at a given period of time. (High off the coast will make it move up the coast, for example.) The typical movement of a hurricane describes a large C, moving westward and curving north from point of formation, then continuing to the north and east. There have been a few rare instances where former hurricanes, now downgraded to tropical storm status or lower, have struck coastal areas in Northern Europe, including one storm that held together all the way into the Arctic, causing extensive precipitation in northern Norway and Murmansk.

But the track of any given hurricane is, within those bounds, enormously influenced by relatively small meteorological factors. (The Butterfly Effect is of course an enormous exaggeration of an actual truth.) Hurricane Dennis (the 1999 one, not the one earlier this season) executed a K-turn* in the Atlantic after describing most of the traditional C-shaped path, came back inland and drenched North Carolina, becoming a contributing factor to the devastation wrought by Floyd soon afterwards. (Since soils were still largely saturated from Dennis, they were unable to deal with the rainfall from Floyd, giving rise to the widespread flooding that was Floyd’s biggest damaging effect.)

  • Ignore the “404 Not Found” that first appears on the page; this page displays the best map I could Google of Dennis’s path, and it was apparently preceded by a link to a different item which has apparently been deleted, which is what the 404 reference applies to. The map will load below the 404 alert.

Not really an answer but something cool: http://www.wunderground.com/tropical/tracking/at200524_climo.html

This is a historical map of the paths of some hurricanes that started in the same vicinity of Wilma. As you can see hurricanes historicaly make a 90 degree turn.

Because Fort Meyers sucks :smiley:

Its been twenty years since I studied meteorology, but I don’t recall the Coriolis force having anything to do with hurricane tracks. In fact, hurricanes move in the opposite direction the Coriolis force would suggest they should. The Coriolis force is responsible for the counterclockwise circulation (Northern Hemisphere) of low pressure systems, but hurricane tracks are determined by the prevailing winds in the lower tropics where hurricanes form.

Google Bermuda High to see why Caribbean hurricanes follow the “C” pattern that they do.

So does Fort Myers.

doh :smack:

You can see the path of all 2004/ 2005 hurricanes at MSNBC’s Hurricane tracker. Charley (linked) made that curve. It’s interesting to see the convolute tracks that a hurricane follows.

There is a large and quite deep low-pressure cell up in Oklahoma/Kansas. This creates a strong westerly wind south of it. As Wilma moves north and the cell moves east the storm gets into the west wind and is blown to the east.

Tropical Storm Vince a few weeks ago, was the first tropical storm to hit mainland Europe in recorded history, when it hit Spain just south of the Portugal border as a weak tropical storm.

However in this case, the storm formed between the Azores and Canary Islands as a cut-off low, then stalled for a few days, before finally acquiring enough tropical characteristics to become a tropical storm/hurricane.

And now, it’s already a Cat 5? Holy cow.

You may well be right; I recall reading some time ago about remnants of hurricanes moving past the British Isles and Scandinavia in the past, but I have no cite to offer. Perhaps there is a meteorologist around the board who might offer some clarity on this?

I think Viscera is one, as am I, although I only hold the degree, no actual working experience.

Not only that, but it is the strongest storm ever recorded.

That said, it’s expected to weaken before hitting the US.