JUDY WOODRUFF, CNN ANCHOR: Heat waves, drought and severe hurricanes. CNN's Natalie Pawelski reports on what looks to be a season of extremes this summer in the United States.</s>NATALIE PAWELSKI, CNN CORRESPONDENT (voice-over): Time was San Francisco baseball fans sometimes had to bundle up in winter coats. This week dozens of fans are treated for heat exhaustion as the field thermometer hit 103 degrees. The streets of San Francisco are buckling in the heat. Across the country, Florida is burning and crops are dying as the Southeast enters its third year of drought. And forecasters are calling for a tough hurricane season. Welcome to summer 2000. Some of this strange weather can be blamed, at least in part, on La Nina.</s>JIM ST. JOHN, GEORGIA INSTITUTE OF TECHNOLOGY: Over the winter it looked like it was going away, but then it just kind of hung in there.</s>PAWELSKI: The current La Nina, a weather system marked by a band of cold water in the tropical Pacific, turns two this summer. Researchers have seen signs of weakening, but La Ninas have been known to last for three years. (on camera): Forecasters say we can expect a summer's worth of weird weather, and keep in mind officially summer doesn't even start until next week.</s>VERNON KOUSKY, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION: During La Nine, the areas that are normally wet become wetter, and those areas that are normally dry become dryer.</s>PAWELSKI: The National Weather Service says La Nina's fingerprint are on the droughts in the Southeast and the Midwest. It also makes hurricanes more likely to hit land. But La Nina is not implicated in Northern California's heat wave or for that matter flooding in Texas or storms in Ohio. Forecasters say that's just nature being its predictably unpredictable self. Natalie Pawelski, CNN.
La Nina Contributing to Nation's Weird Weather