Tropical Storm Arthur is the first of the Atlantic season and threatens the southern United States with dangerous flash flooding. The National Hurricane Center announced the storm Wednesday and said Arthur would skirt over the Gulf Coast with heavy rain through Friday. The storm loomed over a World Cup match in Houston between Portugal and the Democratic Republic of Congo. It also formed amid days of heavy rain that has been drenching southern Texas. Authorities near Houston said a teenager appears to have drowned in a retention pond Tuesday following a period of heavy rain earlier in the week.

Global warming extinctions usually have people picturing the last polar bears or other furry critters disappearing. But the world of plants also will be decimated by climate change, and they're often overlooked. One new study Thursday says tens of thousands of plant species will likely go extinct as warmer temperatures and shifting rain patterns ruin their habitats. A second study looks at what the world loses when flowering plants blink out of existence. In many cases, it's not just not just one species that is lost, but a giant chunk of the evolutionary tree of life.

Scientists say a record-smashing March heat wave in the U.S. Southwest shows climate change is already driving more dangerous weather extremes. World Weather Attribution said Friday that the heat would have been virtually impossible without human-caused warming. Experts say extremes now hit more often, in odd seasons, and in unusual places. NOAA data shows a much larger share of the country sees extreme conditions than decades ago. An analysis by The Associated Press finds the U.S. breaks far more heat records than in past decades. One former FEMA official said disasters now fall outside old planning models and noted insurers pulling back.

Extreme weather conditions from coast to coast put more than half the U.S. in the path of rough conditions. Storms across the nation's eastern half forced airlines to cancel more than 3,000 flights nationwide Monday. Many schools closed early in the mid-Atlantic states, where high winds and tornadoes were in the forecast. Blizzards buried parts of Michigan, Wisconsin and Minnesota while torrential rains flooded homes and washed out roads in Hawaii. California is dealing with unusually high temperatures for this time of year. Areas near San Francisco could see temperatures in the high 80s.