Monday, October 13, 2008

TD 15 and other Blobs and Blobettes: October 13 Update B

Things no-one expects:
1. The Spanish Inquisition (Monty Python)
2. Jar-Jar Binks (Star Wars/George Lucas)
3. A Tampa Bay pro-baseball team in the play-offs against the Boston Red Sox
4. FOUR blobs and blobettes to pop up in about 24 hours in October when
the hurricane season is, supposedly, in the home stretch.

Fortunately, we are done with blobette Nana. There is another little blob
just to her south, way out there in the Atlantic, but that doesn't look
like it will amount to much either. There is not much circulation, and the
convection is disorganized. So those two I will ignore. Just like that.
Poof. Gone. I wish.

That leaves the Caribbean. My my, what a year they've had. And now they
have TD15 in the eastern Caribbean, and so no-one is left out, a blobette
in the western Caribbean. Of the two, TD15 has the leading edge in terms
of organization (barely).

A plane was just in that system and has not yet found tropical storm force
winds, so the NHC are keeping it as a TD. However, TS watches etc have
been posted on the islands and I expect it to become TS Omar tomorrow. In
this, I'm in agreement with the NHC. There is a lot of rain and
thunderstorm activity in this system, predominantly to the east and north
of the center of circulation. The center is stationary at 14.6N, 69.4W.
Winds are still near 35 mph, central pressure has dropped to 1001mb.

As you know from previous storm updates (e.g. Fay), stationary system
tracks are (in my humble opinion) a little trickier than moving storms,
because as the storm sits still, the pressure fields around it continue to
evolve. And, of course the intensity depends on the track. The current
forecast center of cone track takes this system right over Puerto Rico on
Weds. evening as a Tropical Storm, and then makes it a hurricane in the
Atlantic by Thursday.

My data access problems continue. Alas, the wind information is still not
available because they are switching to a new processing machine. Bad
timing indeed.

However, we can look out for certain signs. At the moment the center of
circulation is removed from the main convection because of westerly wind
shear. If those two begin to coalesce before it moves much, then there's a
chance it will become stronger than a TS because wind shear will be
reduced, and it will have plenty of warm water to move over. On the other
hand, if the storm remains disorganized and stays where it is then it will
cool the waters underneath and may weaken a tad.

As for the track, I still don't have good enough information on that
either – at least not from the pressure fields. But we can look for signs
in other places. If you look at the satellite water vapor movie, you'll
see that a low-pressure front moved over central Florida today (and very
nice and cooling it was too) and is indicated by the dry/moist air. I
think the model tracks expect that to move south and 'pick up' the storm –
hence the forecast north-east motion tomorrow and on Wednesday. If the
storm stays stationary, there's a good chance that it won't interact with
the front as previously forecast. At the moment (to me anyway) it doesn't
look like the front will get south enough to meet this stationary little
storm, so I'm not as sure about this NE turn towards PR/VIs. But you can
all keep an eye on that interaction. Tricky. Stationary storms. Very

(To see satellite info, instructions are in the satellite image primers:
part one in here
and part two in here

I got this note from our reporter on the ground in St. Thomas earlier today:
"We got plenty of rain here yesterday from this TD system....starting at
around a six pack and a half of Coronas (translated that is around 5:30pm)
and continuing into the night.......heavy rain. I cannot believe that this
darned thing is now going to come back at us from the southwest and travel
northeast and be a I have to scramble to get

And speaking of signs, here's one… I got this from our reporter on Bermuda:
"Hiho, we sail to Puerto Rican on Wed. A seven day cruise. Should I make
my will out or will I be safe?"

Oh dear. I suppose that research cruise during Hurricane Bertha was just
too easy...

Western Caribbean Blob:
There's some circulation and some convection, but not as much as in TD15.
Central America: Expect Rain. Actually, almost the entire Caribbean can
expect clouds and rain from one system or t'other this week. I've blabbed
on about blobs enough for now, so I'll write about this tomorrow.

Night night,

Blogs archived at:
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.

1 comment:

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