Hurricane SeasonApril 28th, 2009 at 11:30 pm by Bill Steffen under Bill's Blog, Inside WOOD TV8, Uncategorized, Weather
This is a map of current (well, a few days ago) sea surface temperatures relative to average. Go here and you can click on this image and make it zoom in to a particular area. You can check a map of sea surface temperatures (not relative to average) here (see if you can find the Gulf Steam off the E. Coast of the U.S., the cold currents off the W. Coast of the U.S. and Chili – places that don’t get hurricanes because of the relatively cold water) On the map above, the blue color indicates where the water is cooler than average and the yellow indicates where the water is warmer than average. First, note that the La Nina (cooler than average water in the Equatorial Pacific) is ending and a weak El Nino (warmer than average water in the Equatorial Pacific) is beginning. “WEAK” is a very important word here. When we have a strong El Nino (1982-83) we have warmer weather and less snow in the winter. That is NOT the case with a weak El Nino. In fact, some of the coldest winters in Michigan (1976-77) occurred with a weak El Nino. A weak El Nino usually (not always, but usually) brings slightly cooler than average temperatures in the summer to Michigan (hint here on our long range weather) – but more on that in later posts.Now, look at the map above. The water in the western Gulf of Mexico is relatively warm. That could mean early (June) tropical activity coming into Texas, Louisiana and/or NE Mexico. The water off S. Florida into the Bahamas down into Cuba is cooler than average. So is the water just west of Africa. These areas would be (not totally, but) less inclined to get early or major hurricane activity early in the season. The water is warm near the Leeward and Windward Islands, where activity could be near average levels. Last year the Atlantic/Caribbean/Gulf of Mexico area (which by the way is the most variable of the world’s tropical storm basins) had 16 named storms, 8 hurricanes – of which 2 reached Category 4 (Gustav and Ike – both of which came north to dump a lot of rain on Michigan and even spawn several small tornadoes). This year the experts like Dr. Gray at Colorado St. (the most famous of hurricane forecasters) and Joe Bastardi of Accu-Weather are forecasting fewer storms in the Atlantic Basin (12 named storms, 6 hurricanes and 2 intense hurricanes is Dr. Gray’s prediction) and that looks like a good forecast to me.
There is warmer than average water off the West Coast of Mexico. This region might see above average tropical activity this season. Storms here tend to move WNW away from land (so affecting fewer people), but can still hit the west coast of Mexico with rain and wind. Last year this area had 17 named storms, 7 hurricanes – one of which reached Category 4. Those numbers could be higher this year.
The area to watch is the Western Pacific. This area sees more hurricanes (called typhoons west of the International Dateline) than any other part of the world. Last year the Western Pacific had 28 named storms, 12 hurricanes and 5 that reached Category 4. The only storm to reach Category 5 in the world in 2008 was Super Typhoon Jangmi off the coast of Taiwan on Sept. 27. This year that count should be higher, with the real possibility of more Category 5 storms. If you know someone in this area (Philippines, Taiwan, China, etc.) they should be alert and be able to take safety measures if threatened.
The water in the Bay of Bengal is a little cooler than average. This area gets some deadly storms (called cyclones in the Indian Ocean). Last year there were an estimated 146,000 fatalities and 12 billion in damage mainly from Cyclone Nargis, which hit Burma. First there is a lot of population in this region that lives in coastal areas. Second, the shape of the bay means that the area is prone to major flooding from storm surge caused by the strong onshore winds on the right side of the storm. Hopefully, the water will stay relatively cool here and that will help keep the intensity of storms a bit lower than average.
Finally, here’s a list of hurricane names for this coming season and beyond (there’s a “Bill” this year!) and check out the FAQ about hurricanes (lots of good info. here) If you’re interested in the effect of any human-induced global warming on hurricane activity, read this from the Bulletin of the American Meteorological Society. If you don’t have time to read the article, here’s the last sentence, “…it is reasonable to conclude that the significance of any connection of human-caused climate change to hurricane impacts necessarily has been and will continue to be exceedingly small.”