ATL: ISAAC - Models

[Meteorcane]

Looks like the 00z GFDL wants this to ramp up pretty quickly about 10mb lower than HWRF at 24h

[WxGuy1]

What category would a 983mb hurricane be?

CAT 1

Here are the conversion tables:

http://hypertextbook.com/facts/StephanieStern.shtml

It's important to note that these are only rough guidelines. Hurricane intensity as we referr to it using the Saffir-Simpson scale is based upon sustained wind speed. Wave height, minimum central pressure, or other measures are not used to "rate" a tropical cyclone when using the SS scale. This also means that the potential for damage and destruction is not determined by the SS category alone, as we've seen in the past.

So, a 983 mb tropical cyclone doesn't tell you much about maximum wind speeds and the category of the hurricane. If it's a huge storm, there's a possibility that 983 mb could even be only a tropical storm. The wind speed is essentially a function of the pressure *gradient*, or how the pressure changes with distance from the center of the cyclone. If the surrounding "base state" sea level pressure is ~1013 mb, a very large cyclone that's 300 miles in diameter with a central pressure of 983 mb (resulting in a pressure perturbation of -30 mb) spreads out that pressure deficit over a large distance (1 mb / 10 miles or 0.1 mb/mi). In contrast, a very small cyclone with the same minimum central pressure may spread that perturbation out over only 30 miles (1 mb / mi). As a result, even though the minimum central pressures are the same, the small cyclone may have much stronger winds than the large cyclone. Of course, the real world isn't this simple, but the point stands.

[Dean4Storms]

00z GFS Ensemble Means... Panama City...

https://www.facebook.com/photo.php?pid= ... 8134807369

[SunnyThoughts]

0z hwrf landfall Pascagoula at 96 hrs

Here in Mobile, I would almost rather take the direct hit than have him move in at Pascagoula because of how much water would be pushed up the Bay and the beach erosion we would have (especially Dauphin Island, which already super eroded). Obviously, I don't wish a storm on anyone, just saying for us here in Mobile, landfall in Pascagoula could be our worst case scenario.

I know what ya mean smw, I don't wish it on anyone else either. Maybe we will get lucky and there will be something in the gulf that the models haven't picked up on yet to knock it down to minimal strength. I know we always wish for it to come in east of where we are, so we don't have to deal with that eastern side. Hope everything comes out ok for you.

[Meteorcane]

If the GFDL verifies it would be pretty bad for SFLA, barely any time over Cuba than fast intensification over the Straits.

[Ikester]

What category would a 983mb hurricane be?

CAT 1

Here are the conversion tables:

http://hypertextbook.com/facts/StephanieStern.shtml

It's important to note that these are only rough guidelines. Hurricane intensity as we referr to it using the Saffir-Simpson scale is based upon sustained wind speed. Wave height, minimum central pressure, or other measures are not used to "rate" a tropical cyclone when using the SS scale. This also means that the potential for damage and destruction is not determined by the SS category alone, as we've seen in the past.

So, a 983 mb tropical cyclone doesn't tell you much about maximum wind speeds and the category of the hurricane. If it's a huge storm, there's a possibility that 983 mb could even be only a tropical storm. The wind speed is essentially a function of the pressure *gradient*, or how the pressure changes with distance from the center of the cyclone. If the surrounding "base state" sea level pressure is ~1013 mb, a very large cyclone that's 300 miles in diameter with a central pressure of 983 mb (resulting in a pressure perturbation of -30 mb) spreads out that pressure deficit over a large distance (1 mb / 10 miles or 0.1 mb/mi). In contrast, a very small cyclone with the same minimum central pressure may spread that perturbation out over only 30 miles (1 mb / mi). As a result, even though the minimum central pressures are the same, the small cyclone may have much stronger winds than the large cyclone. Of course, the real world isn't this simple, but the point stands.

This. I was just about to post the same thing. A good example of size vs. pressure is Hurricane Ike. Ike had a 950 mb pressure at landfall and was 'only' a 2. It's enormous size (and double eyewall) kept that storm in check.

[meriland23]

Euro 24hr

Uploaded with ImageShack.us

[smw1981]

Sunny, I'm sure you are thinking the same thing about not letting him come in at Mobile Bay! ha. I hope ya'll come out ok as well..we will have to compare stories after all of this if he comes in around here!

[StormClouds63]

Conditions in eastern GOM early next week?
Conducive for rapid intensification ... or shear/dry air? It seems everyone is assuming RI once in Gulf.

[Dean4Storms]

GFDL between Miami and Cuba @ 42hrs at 977mb

[SunnyThoughts]

Sunny, I'm sure you are thinking the same thing about not letting him come in at Mobile Bay! ha. I hope ya'll come out ok as well..we will have to compare stories after all of this if he comes in around here!

Sounds like a plan! And in all honesty, I would hate it to come up mobile bay..I know what that means for MObile. Devastation water wise.

[meriland23]

GFDL between Miami and Cuba @ 42hrs at 977mb

Is JB onto something here?

[Ikester]

I'm all geared up to report live starting Tues. morning. The powers that be are sending me to Panama City Beach as our staging location. We'll use that location as our pivot point to either stay put or push further west.

[meriland23]

do you have a model run link for the gdfl

[Wx_Warrior]

Ikester, by chance does your station stream live on the web?

[meriland23]

euro 048 hr

Uploaded with ImageShack.us

[Dean4Storms]

GFDL/HWRF.....


http://raleighwx.americanwx.com/models/gfdl.html

[Evil Jeremy]

The new GFDL is up on SFWMD. East shift from Mississippi to Panhandle.

[Dean4Storms]

@42hrs....

http://raleighwx.americanwx.com/models/ ... MSL042.gif

[wxwatcher1999]

Euro is really south...I wander how far west it's going to go