Wednesday, July 27, 2011

Caribbean Blob: July 27, Update A

The Caribbean blob and our potential next Tropical Storm, Don, is improving in looks (and perhaps also in personality?). It has very good circulation in the lower troposphere over the Yucatan Strait. It also has circulation in the middle levels of the troposphere, but due to wind shear, that is currently sitting over the western tip of Cuba, so the overall vertical structure is not quite cohesive enough to be a Tropical Storm. However, I have noticed once in a while that little things like physics and nature are not allowed to get in the way of a good story, so I suspect that it will become a named Tropical Storm later today. ;-)

Convection is certainly running amok with lots of good thunderstorms in the area. Here’s an infra-red (IR) satellite image of this blob.

I don’t think I have got around to writing my ‘How to interpret an IR satellite image 101’ this year, although I’ve mentioned that red (and dark grey) are strong thunderstorms, possibly tornado generating, orange is thundery with heavy rain, yellow is just rain, blue is just cloudy, no rain, and light grey/white are lovely, whispy or fluffy bunny-rabbit (that’s a technical term for ‘cumulus’ clouds of course ;-)) summer-day sorts of clouds. <Science Alert> The IR satellite image shows the temperature of the tops of the clouds. In the troposphere, the higher up you go in altitude, the warmer the temperature becomes (this trend changes direction for the next layer in the atmosphere which warms with height. This next layer up is called the stratosphere and is where the ozone layer/hole likes to hang out). The stronger the convective activity, the taller the clouds are, and the warmer the cloud tops will be. So red areas on this IR image is where the cloud top temperatures are warmest, orange are not so high up and so on. <End of Science Alert>

Looking at the larger scale pressure fields, it looks like this blob will continue to move in a general WNW direction for now, and therefore into the Gulf. I’ll report back later with where it’ll be after that. The models are showing the TX/LA region for landfall, which is indeed a likely scenario.

Don is very international as names go. I mentioned India and Italy(US) yesterday, and here’s an Australian, “Don Bradman = legend” (from Steve B.). Sir Donald George Bradman, called “The Don”, was one of the greatest cricket batsmen of all time, with a Test batting average of 99.94, which is “claimed to be statistically the greatest achievement in any major sport.” If you disagree about the statistics (not about whether cricket is a major sport part because it is!!), please take that up with Wikipedia. ;-)

More later… I’m out for now!

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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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