Thursday, July 03, 2008

[Jyo_hurricane] Tropical Storm Bertha: July 3 Update B

As expected, the 11am NHC advisory upgraded TD2 to TS Bertha. She has
winds of around 40 mph (TS: 39-74 mph), and they have a better handle on
her center of circulation they say, which is at 13.3N, 24.7W, located
190 miles south-southwest of the Cape Verde Islands. She's still moving
in a WNW direction at about 14 mph and her minimum pressure is now 1006 mb.

And now for a bit of background science before the track discussion. For
those of you who have been with me for the start of previous seasons,
this is a refresher.

In the northern hemisphere, things move clockwise around a high pressure
system, and counter-clockwise around a low pressure system. These
storms are generally steered by the larger scale atmospheric pressure
fields. Over the Atlantic there is a large pressure system called the
Bermuda/Azores High and this is a factor in the general steering and
track of these storms. Imagine a clock-face over the Atlantic. The storm
is currently moving from the 6 to 7 on the face, which is the W-NW
track. It will then shift to a NW track (7-8 numbers on the face), then
N-NW (8-9) and so on as it curves out and away from the N. American

At the moment, this high pressure is confined to the eastern Atlantic.
So, I agree with the computer models and the NHC that given the current
large scale atmospheric pressure fields this storm will curve out in the
Atlantic in a few days.

If anything changes today, I'll send out another update otherwise you'll
hear from me tomorrow. Have a lovely day :)

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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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