Wednesday, August 19, 2015

Tropical Storm Danny: August 19, Update A

Just enough time to squeeze in a quick update before my next flight! :-)

I see Tropical Storm Danny-boy is churning away out there...He is currently at around 12N, 42W, with a central pressure of 1000mb and winds of 5ph:

He is currently at around 12N, 42W, with a central pressure of 1000mb and winds of 50mph.

First, his circulation... there is still a good vorticity signal in the lower half of the troposphere, with a small signal in the upper troposphere. This means that the storm still has pretty good circulation. 

Second, his convection... he is skirting the southern edge of that Saharan Air Layer I mentioned yesterday (the red and yellow area in the map below): 

which means that he is running into dry, dusty air and so his convection is still not as strong as it would have been otherwise for a storm with his circulation... BUT, sea surface water temperatures are over 27 deg C, with the upper 50-75m warmer than 26 deg C, so he does have enough from the ocean to sustain him. 

Second, in addition to the SAL, he is also bumping into a that high pressure I mentioned yesterday. This is why he has slowed and is now moving at 10mph (generally WNW). This means that the track is a little harder for me to predict, but the NHC has been generally good at the track from 1-2 days out last year, so I will go with this (for the next couple of days) - for the track part only, not the intensity!:

I would say that everyone, including the folks in Bermuda should keep an eye on Danny. I think there is a chance that he will move north of this track by Sat/Sun - but it depends on how that high pressure acts. 

That's the basics. Must run!
Ciao 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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