Hurricane Bertha: July 10 Update A

I should never have called her Boring Bertha a few days ago. I'm sorry
Mother Nature. I take it back.

Intensity:
So... the Really Very Incredibly Interesting Bertha is now weakening
again and has winds of 90mph, making her a strong cat 1 (74-95mph
range). I hope you all remembered my 'warm cloud top' discussion from
yesterday? Well, that was a sign of the weakening, and since then the
cloud tops have become warmer so there is not a lot of convective
activity going on in this system. She is still surrounded by dry air,
and some of that is getting entrained. However, she is still over waters
of 27-28 deg C and in a low wind-shear environment, and dynamically she
is still very good looking (she still has an eye), so I am not sure if
she will weaken much more today and she there is a good possibility that
she'll get a bit stronger - and that is also the thinking of the NHS,
who are finally not solely relying on the models:

"THE INTENSITY FORECAST IS A CONUNDRUM. <talk about models>... THE
INTENSITY FORECAST WILL BUCK THE MODEL GUIDANCE AND CALL FOR SLIGHT
STRENGTHENING DURING THE FIRST 24-36 HR."

Track:
This is also becoming trickier by the hour. Given her slower forward
speed of 9mph it looks like she is moving against an area of higher
pressure (going up hill slowly). There are three scenarios:
1. there is now an area of low pressure moving off the US and into the
Atlantic. IF that moves fast enough and she gets north enough in the
next day or two, she will interact with it and move northward - but
where exactly that interaction will occur is uncertain. However, the
computer models at the moment are predicting that she will not interact
with this low.
2. she manages to get around the high she is now bumping against and
moves N-NW and then N soon
or,
3. she will continue to move in a NW direction and to the west of her
current track as she tries to get around this high pressure system
(remember, in the Northern Hemisphere, things move clockwise around a
high pressure system).

Her forward speed provides a clue about the state of the atmosphere -
slower speeds indicate that she is encountering a high pressure ahead of
her, and so the chance that the track will be to the left of the current
center of the cone is greater.

Let's see what happens during the rest of today.

I hear that the surf is now good in Bermuda - and tomorrow the east
coast of Florida should see some nice surf...
J.

Blogs archived at: http://www.jyotikastorms.blogspot.com/
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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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