Is it generally true.......

[dixiebreeze]

that the larger a storm is coming off Africa, the less likely it is to curve NE or NNE, etc.?

[wxmann_91]

I thought it was more likely. A large sized storm would weaken the subtropical ridge, and therefore more likely move poleward, while a smaller storm could tuck beneath the ridge and continue moving westward.

Just an amateur newbie opinion, so if you want a more accurate/detailed answer, ask Derek Ortt or senorpepr or just a pro met.

[ncweatherwizard]

Well, a larger storm won't weaken so much that it would curve northeastward, but the lower pressure of the storm, and thus the higher pressure difference between the ridge and the storm, causes the storm to move more poleward.

A larger storm, of course, can extend into a ridge to the north, so that the pressure gradient is more spread out (how strong it is, of course, depends on the ridge strength and the pressure of the storm), but the ridge still needs weakening (usually [ahead]) of the storm to move the storm northward and eventually northeastward.

Scott

[Brent]

Not sure about that... but I do know the slower they move the more likely they will recurve and this one is certainly moving slower than normal.

[Jim Cantore]

I dont think it matters

I think what matters the the location of the ridge and eventually the burmuda high

[Derek Ortt]

the larger the storm, the greater the beta effect, the farther north it will go if all else is equal

[Aslkahuna]

We saw that with a Supertyphoon in 1977. It was a very large and intense strom with virtually no steering whatsoever so the internal forces just sent it slowly north until it finally encountered a steering flow and turned NW.

Steve

[weatherwindow]

certainly agree with derek and asl...size implies greater beta effect..howver, that said, the contribution of beta effect to steering is normally neglible vis-vis that contributed by the synoptic flow, upstream and down, in the vicinity of the cylone. beta becomes an issue in a weak or ill defined steering environment. all in all, even a reasonably large trop system is normally dwarfed by the synoptic scale features around and thru which it travels.......................................rich

[vacanechaser]

gnerally the rule of thumb is the stronger it gets, the more likely it is to recurve... Thats what I have noticed... It seems if we can get a storm to develop once it gets past 50W there is a likely threat to the U.S. coast.. But of course not always true to form..

Jesse V. Bass III
http://www.vastormphoto.com
Hurricane Intercept Research Team

[weatherwindow]

re: jesse's point..........the 50deg w "tipping point" may be a function of the average location of the mid ocean TUTT. in an "typical" synoptic setup(which i might add is currently in place), the subtropical ridge axis is interrupted by a mid ocean UL trof whose position varies east to west and north to south. in many cases, that trof is located over or near the lesser antilles. a westward moving storm encountering this trof would likely recurve. west of the trof axis, the ridge tends to rebuild and dominate the steering flow. a system forming west or south of this axis would have a much better chance of a long westerly track, perhaps threatening the u.s.....rich

[dixiebreeze]

Thanks to everyone for all the very interesting information.

[Kitesailor]

What is the beta effect?

[deltadog03]

actually, this system is moving much slower than they usually do down here...I wouldn't be suprised if this MISSES the trof...

[OuterBanker]

20 60 rule. Just my own obs that if a storm is above 20 n before 60 w it is almost always a fish. Every model has Irene above 20 n by 50 w a sure fish.

[DESTRUCTION5]

20 60 rule. Just my own obs that if a storm is above 20 n before 60 w it is almost always a fish. Every model has Irene above 20 n by 50 w a sure fish.

I agree...Fish most defineately...

[Guest]

What is the beta effect?

Comes right after the Alpha effect!

[jax]

20 60 rule. Just my own obs that if a storm is above 20 n before 60 w it is almost always a fish. Every model has Irene above 20 n by 50 w a sure fish.

you might be right... but then again... how many models are
right 5 days out and before a storm has an official clasification/center?

hmmm... if if where a skiff... we'd all be fishing...

[Guest]

actually, this system is moving much slower than they usually do down here...I wouldn't be suprised if this MISSES the trof...

Heres your song....to the tune of Deltadawn

"Deltadog whats that theory you have now? could it be a wish, for days gone bye? and did I hear ya say? that Irenes meetin the U.S. someday. To take us to that Cat 5 storm and die."

Sorry, left the airplane glue open again..sniff..sniff

[dwg71]

actually, this system is moving much slower than they usually do down here...I wouldn't be suprised if this MISSES the trof...

Heres your song....to the tune of Deltadawn

"Deltadog whats that theory you have now? could it be a wish, for days gone bye? and did I hear ya say? that Irenes meetin the U.S. someday. To take us to that Cat 5 storm and die."

Sorry, left the airplane glue open again..sniff..sniff

That is too funny....

[x-y-no]

What is the beta effect?

The beta effect is a cosequence of the fact that the Coriolis effect increases with latitude, and the interacion of a vortex with that gradient.

The net effect is that cyclones in the northern hemisphere will tend to move northwest absent other steering.

Jan