Danielle now a Category 1 hurricane. Watch its birth below
Update 8/23: I replaced the original global image with this close up of the North Atlantic. It depicts the formation of Danielle more clearly, and also doesn’t take as long to load! Second update, morning of 8/24: According to the National Hurricane Center, the second wave of low pressure flowing out of Africa — in the wake of Hurricane Danielle — stands a 90 percent chance of itself becoming hurricane.
Third update, evening of 8/24: The hurricane center has downgraded Danielle to a tropical storm. Literally in its wake, the second wave of low pressure is still estimated to have a 90 percent chance of becoming a hurricane. On the subject of hurricanes, I interviewed Judith Curry of Georgia Tech today for a future radio spot. “Everybody was predicing a very active hurricane season, but so far we haven’t seen very much at all,” she said. This has partially been the result of the blocking pattern thought principally responsible for the heat wave in Russia. According to Curry, it has also made the atmosphere dry in the tropical North Atlantic region. “But now that blocking pattern has broken, so we may see hurricane activity resume, and in fact we have already seen it with Hurricane Daniellle.”
Fourth update, 10:30 a.m. 8/25: Danielle is now a hurricane again, and now a third wave of low pressure is flowing out of Africa. See Jeff Masters’ Wunderground.com blog for more details. Note: This will be the last update on this post. For updated information, continue going to the National Hurricane Center and Jeff’s excellent blog.
The original post begins here:
The animation above shows the evolution of “total precipitable water” in the North Atlantic over the course of 72 hours, ending this evening (August 23) Boulder time. I offer it here simply because I think it is impossibly cool — and beautiful.
And for one other reason: It shows the development of the second Atlantic hurricane of the season, Hurricane Danielle. More about that in a minute. But first, what are we looking at here, and what’s “total precipitable water”?
The atmosphere contains an enormous amount of moisture that circulates around the globe. However, not all of it actually condenses into rain, sleet, or snow since the right balance of pressure and temperature are needed to create precipitation. Total precipitable water (TPW) in the atmosphere is the amount of water that can be obtained from the surface to the “top” of the atmosphere if all of the water and water vapor were condensed to a liquid phase.
The animation was produced by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin. It is based on data from microwave sensors on a number of polar orbiting satellites. What I find most intriguing is the river of atmospheric moisture flowing out of Africa into the Atlantic.
When I was growing up along the Gulf Coast, all we had were some weather maps to log latitude-longitude as reported on the news. Now we can follow the storm from off the African coast.
One fun fact to remember is that the same conditions that made Russia so hot and probably made Pakistan so wet have been keeping hurricanes from forming in the Atlantic. Now that that barrier has dissipated, we could be in for a wild ride the next month.