Sea surface temperature data is from satellite microwave data.
The image above shows the recent track of Hurricane Bertha across the Atlantic Ocean. It also shows the sea surface temperatures from July 14.
Notice the wake of cooler water that the storm left behind as the high seas caused the upwelling of cooler waters from below. Around July 14, when the storm was still to the southeast of Bermuda, it slowed its forward speed and nearly stalled. The longer duration of the storm over that particular region resulted in very high seas for a prolonged period, which enabled even colder water to get upwelled to the surface. Note the cool patch.
As the surface water continued to cool, the storm's energy source was diminished, causing Bertha to weaken. Once Bertha got northeast of Bermuda, it started to move along once again, and the upwelling was reduced. Bertha eventually regained strength and became a hurricane for a short time before hitting the colder waters in the northern latitudes.
So remember, if a hurricane spins around in the same area for a couple of days, chances are that its own wind (causing the high seas) will eventually cause it to weaken.
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Hi Brett,
Greetings from Halifax, Nova Scotia. That graphic of sea surface temps as Hurricane Bertha moved around last month was very interesting. It's too bad something like that didn't happen before Hurricane Juan.
I agree, Juan was moving along, which limited the upwelling of cooler waters.
Posted by Brian Phillips | August 1, 2008 7:40 PM
Brett,
Can you explain to me some of the factors that affect the UV index. I assume it will be higher with clear as opposed to cloudy skies, and the angle of the sun is important too. But what about temperature and humidity?
Thanks,
Neil
Neil, Temperature and humidity have little if any impact on the UV index. Sky cover, time of year and time of day, elevation are the main factors.
Posted by Neil C. | July 31, 2008 11:00 PM
How do we know that global warming is so terrible. With much of the US CORN MARKET GOING TO BIO-FUELS MAYBE THIS GLOBAL WARMING WILL GIVE US MORE LAND TO GROW FOOD AND A LONGER GROWING SEASON TO FEED THE WORLD. Just an observation
Reply: Feel free to comment in the global warming blog. Remember, this is the Canadian weather blog.
Posted by Mike Schroeder | July 30, 2008 9:21 PM