Putting the eye in Irene

Bad Astronomy
The entire universe in blog form
Aug. 25 2011 9:26 AM

Putting the eye in Irene

Over the past few days, hurricane Irene has grown as it approaches the United States. The NASA/NOAA Earth-observing GOES 13 satellite has been keeping an eye on the storm, and images it has taken have been put together into this dramatic video showing Irene from August 23 at 10:40 UTC to 48 hours later... just a few hours ago as I write this:

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Pay attention about 20 seconds into the video (August 23 at about 20:00 according to the clock at the top of the video). You can see the eye wall region burst into existence, and a few seconds later the eye itself suddenly appears. Also, a surge of white clouds appears to the right of the eye and wraps around the hurricane. That's where warm air has risen strongly, overshooting the cloud tops, and producing intense rainfall (5 cm/hour according to TRMM!). Overshooting tops, as they're called, happen frequently in tropical storms as they intensify. For what it's worth, something like that happens in stars as well as hot plasma rises rapidly from under the surface, though astronomers tend to call it "convective overshoot".

Irene is currently a strong Category 3 hurricane (with sustained winds at 200 kph (120 mph)), and is expected to start affecting the east coast today. If you live along the coast, take precautions, and please, stay safe.

Video credit: NASA/NOAA GOES Project

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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