Weather provides 5 reasons to bring Olympics to Bay Area

BY JAN NULL
Special to the Mercury News

If weather were a five-event Olympic pentathlon, the Bay Area would surely walk away with the gold.

The Bay Area Sports Organizing Committee, a private non-profit organization, has submitted a bid to bring the Olympic Games to the San Francisco Bay Area in 2012. I have been fortunate to be part of the process, and put together the meteorological and environmental section of the 700-page report.

The other U.S. cities bidding for the 2012 Summer Games are Los Angeles, Cincinnati, Dallas, Houston, New York, Tampa and Washington, D.C. In the weather competition, they all finish far behind the Bay Area.

The 2012 games will run from July 27 to Aug. 12. In the summer, the Bay Area's mild Mediterranean climate sets it apart from its steamier counterparts across the country in the first weather event: lack of hot weather. From July 26 to Aug. 12 Palo Alto has an average high temperature of 77 degrees; the other bidders range from 84 to 96. Additionally, the persistent afternoon and evening sea breeze cools the Bay Area at night, but the other areas tend to stay warm and sultry.

More important for athletes and fans alike would be the Heat Index competition. This index combines the temperature and humidity to give a level of comfort (or discomfort) and relates to the body's ability to cool itself. The HI for San Francisco is a pleasant 80 degrees; the closest contender is Los Angeles at 87 degrees. The other six cities are even warmer, with an average HI of 103 in Tampa and 110 in Dallas!

The Bay Area would run away with the lack of smog event as well. The other cities, with their high temperatures, provide a great environment for the development of summertime smog and ozone. The average number of ``unhealthy'' air days due to ground-level ozone for the San Francisco Bay Area is less than one a year. Los Angeles tops the list with 90 days. The rest of the bidders range from four unhealthy days in Tampa to 41 in Houston.

Our Mediterranean climate brings our natural summertime drought in which rain is extremely rare. The lack of rain category would also belong to the Bay Area. Looking at the past 30 years of weather records for the proposed time period of the games, it has rained only one day out of the 480 days -- or about 0.2 percent of the time. Compare this with an average of one day for the period in L.A., two days in Dallas and as many as seven in Tampa.

The final event in our weather pentathlon would be for Olympic-quality winds in the sailing events. Here our brisk and predictable sea breeze through the Golden Gate provides world-class sailing conditions in an area of the bay already called the Olympic Circle between Alcatraz and Berkeley. None of the other sites even comes close to this quality of winds.

So the gold goes to the San Francisco Bay Area's weather. Backers of bringing the games to the Bay Area will know next spring whether the region makes the short list winnowed from among the eight U.S. cities vying for the 2012 Summer Games. In the fall of 2002, the International Olympic Committee will select one to compete against locales from other countries. In fall 2005, a host city will be named.

Q Your July 3 column talked about high-pressure areas in the Pacific and the Atlantic. How does air accumulate over an area in the open ocean? Is it in response to higher gravity? It would seem that air, being a fluid, would flow away from a pile-up of the atmosphere as quickly as it formed. George Godlewski - Saratoga

A Yes, the air is always in motion and trying to reach equilibrium by flowing from areas of high pressure toward areas of low pressure. These high- and low-pressure areas describe the conditions near the Earth's surface, but we have to think about the atmosphere in three dimensions. Consequently, while air flows outward from areas of high pressure, it is replaced from aloft by sinking air.

Q I enjoy your column in the Mercury News and learn a lot about the weather. It seems to me that the summers here in San Jose are getting warmer than they used to be, or is it just that I am tolerating the heat less? Have we been having more heat waves, or higher-than-normal temperatures? Vivian Brundage - San Jose

A You don't say what your time of reference is, but I took a look at average high summertime temperatures and the number of 90-degrees days in San Jose for the past three decades. During the 1970s, the average high temperature from May through September was 79.5 with 18 days of 90 or above. In the 1980s, this rose to 80.3 with 19 days exceeding 90 degrees. The 1990s saw an average of 80.7 degrees and 24 days of 90 degrees. However, these numbers should be taken with a grain of salt because of the effects of urbanization in the area and the warming it can bring.

Jan Null, founder of Golden Gate Weather Services and Adjunct Professor at San Francisco State University, is a retired lead forecaster with the National Weather Service. Send questions to him c/o WeatherCorner, San Jose Mercury News, 750 Ridder Park Drive, San Jose, Calif. 95190. You also can telephone questions at (510) 657-2246, fax them to (510) 315-3015 or e-mail them to weathercorner@ggweather.com.