Monday, July 20, 2009

Blobette in the Atlantic: July 20 Update A

Woo hoo... we have a blobette! :) I've been watching this system as it
nonchalantly crossed the Atlantic over the past week, trying to decide
whether it would stay in one piece. It did. Over the past couple of days
it has improved in both circulation and convection, so my spidey-senses
are telling me to send out an update.

It is currently at about 58W, 14N, just east of the Caribbean Windward
Islands. Convection is strong, and there's pretty good circulation in
the lower part of the troposphere (ooh... scientific jargon. Isn't that
thrilling?!? :) I'll give a brief description below). Water temperatures
are 28-29 deg C, certainly warm enough for a storm, and as it heads into
the Caribbean, temperatures warm up a tad more. The major factor
inhibiting this system is very strong wind shear. I agree with the NHC,
it's unlikely to develop further any time soon, but I'll be keeping an
eye on it.

*Science Alert*. The troposphere: this is the lowest section of our
atmosphere and extends up from the earth to about 15-16km in the
equatorial regions, and to about 8km in the polar regions of the planet.
All our 'weather' essentially occurs in the troposphere. It is defined
by decreasing air temperature with increasing height. You would know
this if you climbed a mountain. Or the easier option, of course, is to
just look at pictures of mountains and see the snow at the top. :) The
top of the troposphere is called the tropopause. The height of the
tropopause varies from place to place. Strong tropical storms have
clouds that reach as high as the tropopause - and in a few very strong
cases, they can extend even higher into the next layer up. The layer of
the atmosphere above the troposphere is the stratosphere, which is
defined by air temperature increasing with height. The ozone hole is in
the stratosphere. *End Science Alert*

Phew... now I need to go and have a nap. ;)

I'll send out another update tomorrow.
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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