Thursday, July 28, 2011

Tropical Storm Don: July 27, Update C

The hurricane hunter plane found that our little Caribbean/GOM blob had a good enough structure to become Tropical Storm Don this afternoon. He is in the Gulf, just north of the Yucatan peninsula, with a center officially around 22.8N, 88.1W. Because he is not very well organized yet, it is difficult for me to see this center and I would hazard a guess that he is actually a little south of this location, which would make him a little closer to the Mexico landmass. Because of this proximity to land his convection has decreased a little this afternoon/evening and he is barely a TS with a wind speed of 40mph (TS range: 39-73mph) and central pressure of 1000mb. As he moves away, he should get a bit stronger.

He is moving WNW at 12mph. The forecast has him making landfall on the central Texas coast on Friday night as a Tropical Storm. I think he’s got a good chance of carrying on in a more westward direction than the forecast currently shows, so this landfall might be a little too far north. It could be a Mexico/south Texas landfall, but I won’t be able to tell until I get more data tomorrow.

Someone (Jack) sent me a question today about why this was being called a tropical cyclone and not a tropical storm. This is an excellent question that I’ve never had to try an explain in writing before, and nope, it’s not to scare people ;-) … it’s just meteorological jargon to keep us on our toes. Hopefully this is where I’ll only lose about 99% of you… here goes…

1. All low pressure systems have what is called <jargon alert> cyclonic motion <end jargon alert>, regardless of which hemisphere they are in (I’ll go into hemisphere and direction of movement some other time).

2. So tropical cyclones (lower case), which are low pressure systems, are the generic name for all tropical storms (also lower case) regardless of which ocean basin they develop in. The terms ‘tropical cyclone’, ‘tropical storm’, and sometimes ‘tropical system’ are interchangeable (so long as they are all pronounced with a lower case of course) and do not have names.

3. However, (and here’s a magic trick so pay attention otherwise you’ll miss it), if these tropical cyclones (lower case) develop in the Indian Ocean, they are called Tropical Cyclones (upper case) and have a name. (Did you like that very subtle lower case/upper case trick, huh? ;-) ). In the Atlantic and eastern Pacific, named tropical cyclones (lower case) are called Hurricanes (upper case), and in the western Pacific, named tropical cyclones (lower case) are called Typhoons (upper case). And of course, just to make things absolutely crystal clear for you, if a tropical storm/cyclone (lower case) has winds of 39-73mph and develops in the Atlantic or eastern Pacific, it is called a Tropical Storm (upper case) and given a name. So if you catch someone pronouncing a lower case tropical cyclone/storm in an upper case, or vice versa, then you should report them to the Ministry of Incorrect Case Usage, located next to the Ministry of Silly Walks ;-).

4. This terminology is well established and came about historically. It is beyond even the Power of Grayskull to change this now so we just have to live with it.

Well that was fun. Are you still with me? Hello? <chirp chirp> Er… hello…? <tumbleweeds> Hmm… I think I’ve lost you all. It must be time to go. I’ll give you time to read that again and I’ll be back tomorrow (did I mention the test at the end of this season? ;-)).


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DISCLAIMER:These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

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