Want to know if you'll need your umbrella tomorrow? You can get a daily campus weather forecast right here at SF State.

Posted in the hallways of Thornton Hall are forecasts provided by Gator Weather, a student chapter of the American Meteorological Society. A team of ten student atmospheric and oceanic science majors and a few meteorology students learn about public weather forecasting by working in a weather simulation laboratory here on campus.

To make their predictions, the students use data from weather balloons that are released twice daily by the National Weather Service. The balloons gather data about temperature, humidity, pressure, wind speed and direction. Starting with the current conditions both on the surface and in the middle and upper atmosphere, computer models are used to predict how the weather will shift every twelve hours over the next few days. The lab also receives radar and satellite images.

The group even retrieved pictures of hail around the Santa Cruz mountains during the unusually frigid Bay Area weather this past month.

Extracting a reliable five day forecast from the data and graphics is tricky, said senior Katheryn Saussy, a Gator Weather forecaster. Interpreting the models takes a holistic intuition.

“The most important thing we’ve learned is you can’t always trust them,” she said.

Predicting the weather, said Saussy, is what lead atmospheric scientist Edward Lorenz to pioneer chaos theory in mathematics. His computer models showed small rounding errors in weather data and the underlying principle became popularized as “the butterfly effect”- the idea that a tiny difference in measurement can lead to a major difference in outcome when studying complex systems.

“Anyone can run a computer model,” said John Monteverdi, professor of meteorology and advisor to the Gator Weather program. “You have to look at it as a meteorologist rather than as a technician.”

Monteverdi, a leading researcher of severe weather in California, arranged Gator Weather to mimic the operations at a weather forecast office, one possible employment option that students can pursue.

Students also learn about broadcast meteorology. The class room adjacent to the weather simulation lab is a satellite field office of the Nation Weather Service station in Monterey used to brief Bay Area broadcasters about severe weather systems heading our way. The students have access to a video camera and a green screen. Former Gator Weather forecaster, Eric Gose, is now a weather producer at TV station KPIX in San Francisco.

Monteverdi said that although Gator Weather is focused on producing a weather forecast that is usable by the campus community, by working together they form an “esprit de corps” building friendships centered on meteorology.

Austin Cross, a senior and president of Gator Weather, says it is good to get everyone together, both in the weather lab and on excursions to local TV weather stations. Later this month, Gator Weather will have a charity bowling event to raise money for rainforest preservation.

Although forecasts are only available in Thornton Hall, Gator Weather is working on restoring their Web site for daily forecast information, which Cross said has been down since winter break.

“Were starting from scratch,” Cross said.