2004-09-03 FCST: Ivan (Atlantic)

[Jeff Snyder]

Well, the rapid strengthening/deepening continues, as a special intermediate 8pm advisory upgraded Ivan to CAT 4, with 135mph winds and 948mb central pressure. It looks like there is a legitimate possibility that this will be the first Cat 5 of the season... Recon missions start on Tuesday, and there's a scheduled synoptic mission (for model ingestion) for the 0z runs that day also...

 

[Robert Dewey]

For what its worth, I'm going to say that this hurricane probably won't be too intense when (or if) it hits the U.S. mainland - Looks like it will be the most intense across Haiti and through ol' Castros back yard. The terrain over those regions combined with the angle at which the hurricane is projected to move will minimize it's time over water, so it is quite possible that it could weaken dramatically.

Then again, as others have mentioned, hurricane forcasting is far from accurate that far in advance...

 

[Kevin Walter]

Who. Freaking. Knows.

Not the NHC. Not us. Not the models (have you seen the 00z Kate Moss???). Not Castro. Surely not Castro.

I'm going to agree and say that it won't be a major hurricane when (and if) it makes landfall. However, rather than say it's due to topography, I'll say it's just as with Isabelle last year and Frances this year; statistics are heavily against a storm remaining a major hurricane for very long. It's just too far away. Although, it is moving at Mach 10, and it may only have another 6 days over open water.

Sigh. Here's to another week of checking NHC updates religiously. (What's that honey? [distracted].....feed the cat?.....yeah, yeah...I'll get it in juuuust a minute. [emaciated meow]).

 

[JR Hehnly]

Forcast track from various models:
http://www.midatlanticwx.com/cyclone/AL092004.gif
[Broken External Image]:http://www.midatlanticwx.com/cyclone/AL092004.gif

http://www.sfwmd.gov/org/omd/ops/weather/p...ts/storm_09.gif
[Broken External Image]:http://www.sfwmd.gov/org/omd/ops/weather/plots/storm_09.gif

 

[Chris Sokol]

Ivan could end up as the biggest player of the seaon. Current trends indicate minimal decrease in strength due to interaction with the islands, and plenty of time to recover before striking the conus. Still looks like a south Florida strike, possibly in the Miami area. One question I have is how far south the waters are cooled due to Frances.

 

[Shane Adams]

Down to a Cat 3 this morning. Not reporting because I care, but it's on every channel 24-7 so I hear about it whether I'm trying to or not. After Frances, I don't see how anyone can get too excited about Ivan since tropical systems tend to be letdowns, and if it were to be a badass, it would devastate an already wrecked area - don't see how that could be fun.

I think with hurricanes, you've got a window where it's fun then it becomes a nightmare; two in three weeks have caused havoc and I just don't see how even hurricane fans can wish another upon the state of Florida, which is where everyone seems to think it's headed. Once again, I'm thinking the stringers will be dancing in the streets (what's left of them), but other than those folks, I just don't see the draw.

 

[Chris Sokol]

http://www.caribbean-weather.net/hurricaneIVAN.html

Lots of good info and graphics.

This is an interesting snippet from a local forecast page:

LOCAL WEATHER SYNOPSIS/DISCUSSION
=================================

The hurricane is breaking all the known rules, in that it has intensified rapidly
whilst clipping along at near 20 mph and at such a low latitude south of or near 10N.

At around 3 pm. it was closer to 10.4N 47.2W and while that may seem like reasonable jog
to the north-west, the lastest animated loops suggest that a more westerly track has
started back for now. Ivan is getting larger as we speak and could a major Cat. 4 hurricane
by the time it gets the Eastern Caribbean by early Tuesday morning - now only 36+ hours away.

A Hurricane Watch will probably be raised for Barbados by 5 pm., as I think 11 pm. would be
too late! However, that is up to the relevant authorities.

 

[Jeff Snyder]

Eek... Recent recon reports show that Ivan is considerably weaker than previously thought. The reported central pressure is 969mb, and the NHC has set winds at 115mph, a weak Cat 3, on a special 2pm advsisory.

 

[Zach Bailey]

Eek... Recent recon reports show that Ivan is considerably weaker than previously thought. The reported central pressure is 969mb, and the NHC has set winds at 115mph, a weak Cat 3, on a special 2pm advsisory.

I don't see how the NHC can set the winds at 115mph...for two reasons. One, does 969mb even support winds of 115mph? I would think it would need to be at least 15-20mb lower. And second, the most recent hurricane hunter vortex message (the one which reported the pressure of 969mb) reported... MAX FL WIND 53 KT SW QUAD 1728Z, which using the .9 reduction only gives 48kt at best. What is the NHC thinking here? Do they not want to admit they're wrong even though they've seen the empirical results from the hurricane hunter? Or do they just think that the hurricane hunter didn't sample the strongest winds? :?

 

[Tim Vasquez]

I have added the model paths to our own forecast plot. Updated every 30 minutes. Interesting that the UKMET wants to take it into the western Gulf, though the track change at 72 hours or so makes me wonder if a different set of parameterizations are used from there on out.

http://www.stormtrack.org/ivan.gif

 

[Carrie Halliday]

I am thinking along the same lines as Tim. Think Ivan will go much farther west than anticipated. But I said the same thing with Franny and went bust.

 

[Jeff Snyder]

The approach angle with Cuba could be a big issue for the storm. A split between the GFDL and the official forecast would put the eye over Cuba for an extended period of time, which, given the terrain, would cause signficant weakening. The UKMET, for what it's worth, brings Ivan in a very similar path as Gilbert, the great 888mb monster Cat 5 of years ago. I don't think there's been a single hurricane in the Gulf this year, so....

 

[Tim Vasquez]

A bunch of the numerical models are now trending westward -- south of Cuba and towards the Gulf. Strange how they all changed in unison.

 

[Nick Smith]

I don't see how the NHC can set the winds at 115mph...for two reasons. One, does 969mb even support winds of 115mph? I would think it would need to be at least 15-20mb lower. And second, the most recent hurricane hunter vortex message (the one which reported the pressure of 969mb) reported... MAX FL WIND 53 KT SW QUAD 1728Z, which using the .9 reduction only gives 48kt at best.

The normal pressure/wind relationship hasn't applied very well this season. Surface pressures have been running above the normal for the Atlantic basin. Therefore, the central pressure in this seasons TCs has been higher than you'd expect for the given wind speeds.

The strongest flight level wind would of been found in the northeast quadrant of the hurricane. An FL wind of 106 knots, in the northeast quadrant, was found at 2056Z, which reduces to approximately 95 knots for a surface wind.

 

[Thomas Loades]

Ivan is now a strong category 2, with 110-mph sustained winds, and Trinidad now has a hurricane warning out (for what must be the first time ever). It will be interesting to see just how this pans out as it crosses the Caribbean; and if it does head for the Gulf, the Yucatan Peninsula may — as it usually does — take the punch out of it.