Published Tuesday, March 11, 2003 in the San Jose Mercury News

Lights, camera, climate!

The Academy Awards are less than two weeks away, but they rarely acknowledge a starring factor in many movies -- the weather. Here's a look at some of the roles the weather has played on the silver screen.

Award-winning moments for weather effects range from adding ambience like the foggy final scene of ``Casablanca'' to providing a scene's entire backdrop -- where would ``Singin' in the Rain'' have been without its signature downpour? In some films, weather has provided a story's critical turning point, such as the fog-shrouded iceberg field in ``Titanic'' or the tempest of ``The Perfect Storm.''

Screenwriters need drama, and many seem particularly fond of extreme weather events such as hurricanes and tornadoes. The 1937 John Ford disaster epic ``The Hurricane'' pits man against the elements, and in 1939 probably the most famous tornado of all time spirited Dorothy (and Toto, too) off to the Land of Oz.

Advances in special effects have made on-screen weather more realistic. But as far back as 1939, ``The Rains Came'' captured the first Academy Award for special effects. Ten thousand gallons of water were poured on the cast to reproduce the India monsoon.

More recently, spectacular tornadoes were the centerpiece of the exciting, albeit scientifically marginal, 1996 film ``Twister.'' After the special effects of ``The Perfect Storm'' in 2000, I felt like reaching for a towel.

Forecasters have also made an appearance on the big screen -- though hardly in ways they would in real life. In 1991's ``L.A. Story,'' Steve Martin played wacky Los Angeles weatherman Harris Telemacher in his search for the meaning of life, or at least a meaningful relationship. Two years later in ``Groundhog Day,'' Bill Murray played a TV weatherman named Phil Connors who kept finding himself stuck in Feb. 2 until he figured out what was really important in life.

Real-life meteorologists usually have other preoccupations -- and maybe not too much time for Hollywood. When I asked a good friend and KGO meteorologist about his knowledge of weather on-screen, he cracked: ``I used to think that `Gone with the Wind' was a weather movie.''

Persian Gulf weather:  For those who want to monitor weather conditions in the area of the Persian Gulf as talk of war grows, I've set up a weather Web site for the region at http://ggweather.com/sw_asia.htm.

Q.  My wife asked me why storms always seem to be more intense at night. I told her that this was simply her perception. But I got to thinking that maybe there is something I don't know. Are storms in Northern California more intense at night? James Miner - Tracy

A.  This is mostly an issue of perception. At night, there is less traffic noise, fewer planes flying over and things are quieter at home. The types of weather systems that we usually see in the Bay Area are fronts, which do not vary a great deal in intensity from night to day. But they could be slightly stronger in the daytime, when there are greater differences in vertical temperatures.

Q.  Why isn't the hottest day of the year around June 22, the summer solstice, and the coldest day of the year around Dec. 22, the winter solstice? Dave Bastacky - Mesa, Ariz.

A.  The warmest and coolest seasonal temperatures are indeed four to six weeks after the solstices. This temperature lag is caused by the fact that air is warmed not by the shorter wavelengths of solar radiation, but rather by the longer wavelengths emitted by the Earth and other objects. The Earth and oceans give up their accumulated heat at a slower rate than it arrives. This, coupled with continued incoming solar radiation that exceeds the outgoing, accounts for the lag. Conversely, the largest negative energy balance is reached toward the end of January.

This same sort of slow response accounts for the daily maximum temperature occurring several hours after noon and the daily minimum occurring shortly after sunrise.

Q.  How predictable are thousand-year storms or floods and hundred-year storms or floods? Do they fairly often, rarely or never follow a pattern? Rebecca Pattenaude - Windsor

A.  The concept of hundred- and thousand-year storms is one of the most misunderstood in meteorology. First, these are statistical calculations and have nothing to do with the predictability of an individual weather event. Also, keep in mind that the longest actual weather records in the United States go back about 200 years, and in California from 100 to 150 years. To be more precise, what a hundred-year storm really tells us is that, based upon the available past weather records, there is a 1 percent probability of an event occurring in a given year.

To illustrate, a 25-year one-day rainstorm for San Jose is calculated to be 2.97 inches of rain. This means that there would be a 4 percent chance of this amount of rain occurring in a year. There are similar calculations for floods, windstorms and extreme temperatures.

Jan Null, founder of Golden Gate Weather Services, is a retired lead forecaster with the National Weather Service. Send questions to him c/o Weather Corner, 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 or fill out a form online at http://ggweather.com/questions.htm