| Keith234 |
| (Storm Chaser) |
| Sat Sep 25 2004 02:00 PM |
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Soth Atlantic Hurricane Question
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I wasn't sure wether to post it here or the questions and anwsers forum. My question is this, how did a hurricane like this form? Did a trough split in an unusal area or something like that? Thankyou.
| Clark |
| (Meteorologist) |
| Sun Sep 26 2004 08:54 AM |
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Re: Soth Atlantic Hurricane Question
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The storm had extratropical origins, as a blocking pattern set up over the S. Atlantic, resulting in trough fracture and leaving a piece of energy behind in its wake off of the coast of Brazil. With marginally favorable SSTs and a sharp enough temperature difference between the sea surface and top of the troposphere (i.e. the temperatures aloft were cold enough to counteract the marginal SSTs), the system gradually converted to tropical origins much like you sometimes see tropical/subtropical storms form from remnant frontal boundaries (or even upper lows).
Normally, the water temperatures are colder than they were in March, plus the blocking pattern does not exist and storms are relatively progressive throughout the hemisphere. Upper winds are also, in general, not condusive to tropical development. It's possible, but really unlikely. But, as 2004 has proven...anything can - and does - happen.
| Keith234 |
| (Storm Chaser) |
| Sun Sep 26 2004 11:57 AM |
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Re: Soth Atlantic Hurricane Question
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When I was looking at the loops of this storm, I saw a huge mass of clouds to the east of the storm moving southward. It almost looked like a mini-rex block to me, the ridge laying on the poleward side of the "cut-off" low, this one prevented deep-shear and stoped some cool blasts of cold air. Because of this cold air mixing with some warm air (repestively) it created a weak baroclinic system that drifted around waiting for the right moment to make the change. While the water temps were marginally favorable, the shear had relaxed and the intial disturbance was created, telling one that hurricanes always don't need the textbook 79 degree water temp and they require a unique set of parameters. Thanks Clark for your thoughts too, I just wanted to see if anyone else thought what I thought.
Here's a cool link!
http://cimss.ssec.wisc.edu/tropic/brazil/movies/abba/brazil-java.html
| LI Phil |
| (User) |
| Sun Sep 26 2004 09:45 PM |
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Re: Soth Atlantic Hurricane Question
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Keith&Clark,
These boards had considerable discussion on the storm, in a thread entitled "First known tropical storm (or hurricane) forms in South America" or something like that. It's worth reading if you have a few minutes...
http://flhurricane.com/cyclone/showflat....3&fpart=all
If whatever memory I have left serves me, I believe a good deal was made of the position of the ITCZ at the time, which was one of many factors which led to development.
Check it out some time!
| Clark |
| (Meteorologist) |
| Sun Sep 26 2004 10:22 PM |
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Re: Soth Atlantic Hurricane Question
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Took a look through all of that Phil...the ITCZ argument could work for the northern one in January, but not the big storm -- Catarina -- in March, which definitely had extratropical origins. I based my post above on a lot of the studies that have already been done on Catarina, many of which were presented at the Hurricanes & Tropical Met. conference in May that I was able to attend. Cool stuff.
On a side note, I may be giving a presentation in San Diego at the 2005 AMS Conference in January...I'll keep interested parties noted as I find out more.
| Keith234 |
| (Storm Chaser) |
| Sun Sep 26 2004 10:25 PM |
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Re: Soth Atlantic Hurricane Question
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What is AMS Clark, is it a club for a college?
| LI Phil |
| (User) |
| Mon Sep 27 2004 03:01 PM |
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Re: Soth Atlantic Hurricane Question
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AMS= American Meterological Society
San Diego in January...man, I'd love to be there then! Do report back...
| Redbird |
| (Weather Hobbyist) |
| Tue Sep 28 2004 01:54 AM |
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Re: Soth Atlantic Hurricane Question
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If you go there Phl, bring a jacket or sweater as it is chilly there a good part of the year.