Monday, August 25, 2014

Tropical Storm Cristobal: August 24, Update A

Mother Nature pulled a fast one in Iceland yesterday! Today the scientists over yonder said that there was no sign of a sub-glacial eruption at Bardarbunga after all and something else is afoot (my leading theory is that the rumblings are caused by an alien spaceship. Obviously. ;-)). Hmm... maybe this volcano-eruption malarkey is just a ploy to make us all learn another Icealandic word?

On the other hand, a magnitude 6.0 earthquake hit the Napa region of California!! Aaagh! The WINE!!(Warning: following image may be disturbing):
(image credit: D. Duncan, via C. Kellogg)

Quelle horror!

Breathe. Breathe. Ok, I'm back...

So... at least the storms are behaving in a somewhat predictable manner. The blob in the Atlantic turned into a weak Tropical Storm Cristobal today. (Historical Note, thanks to Mr. Locke: Cristobal Colon (minus accent aigu) was the real name (in Spanish) of Christopher Columbus. His REAL real name is Cristoforo Colombo since he was Italian; however he discovered the Americas on Spanish ships so Cristobal Colon is it.)

Cristobal's winds are officially at 50mph (TS range: 39-74 mph), central pressure is 996mb. Here are the vorticity maps so we can see his circulation (and hence, structure) in the troposphere. There's something really cool in these maps... not only is there a poorly defined Tropical Storm in the Atlantic, but you get the rare privilege of seeing the structure of a cat 5 hurricane in the Pacific!

Near the surface (850mb):
In the middle troposphere (500mb):
In the upper troposphere (200mb):

He is barely a Tropical Storm because the vorticity is not an isolated blob, but is connected to low pressure to the north and south (like a front) - this is an indication that he is not very well-organized. Another indication that he is only a Tropical Storm at the most is that there is no blob in the upper troposphere (you only see that in hurricanes). In comparison, in the Pacific just southwest of Mexico you can see the vorticiy signal for Hurricane Marie (lower left quadrant) - she is a cat 5 storm with winds of 160mph! The circulation is so strong (the force is strong with this one ;-)), that it is white in the lower and mid troposphere, and almost white in the upper troposphere. That, my friends, is the vorticity (circulation) signal of a pretty darn-tootin strong storm!

Because he is so poorly defined, the NHC estimate Cristobal's center to be at 24.5N, 72.9W and he is stationary at the moment. He was drifting slowly to the north earlier today. It looks like the pressure fields have changed since yesterday and are opening up a path for him to move northward and stay out in the Atlantic, away from the US. He is stationary at the moment because he is bumping up against high pressure (it's like climbing uphill for him), but it looks like he should move northwards tomorrow and then to the northeast.

He does have a fair bit of rain in him... I think the Turks and Caicos are getting a bit of a washing!
This is because the sea surface water temperature is a very warm 29-30 deg C, with the upper 50-100m warmer than 26 deg C. That's enough to keep him happily fed for now.

And for those who asked... I thought the new Dr. Who was ok. Not a strong an opening episode as a couple of other Doctors as it was a bit heavy handed on the differences between this Doctor and the previous one and it was a bit chaotic. I'm not sure I like all the opening sequence changes yet either. I am also curious to see how going back to a more avuncular Doctor plays out with the new audiences. I, for one, enjoyed the old Dr. Who, and don't mind at all. :-)

More tomorrow!

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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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