Story Summary by Ground News AI:

• On Monday, AccuWeather calculated more than 200 million people were threatened by chaotic weather across the United States, with over half the population in the path and more than 3,000 flight cancellations.
• A strengthening heat dome over the Southwest traps hot air, arriving as blizzards continue in the Upper Midwest and Great Lakes, according to the NWS.
• Regional measurements indicate L.A. and Ventura counties broke 13 daily temperature records on Tuesday, Anaheim hit 100 degrees, Palm Springs reached 103, and there is about a 50% chance Palm Springs could reach 110 degrees on Thursday or Friday, Paul Steward said.
• Emergency officials said over half a million customers lost power, schools closed in Wisconsin and Minnesota, Minnesota Governor Tim Walz authorised National Guard support, and at least one fire-related fatality was reported.
• Despite some moderation, forecasters warn temperatures will remain five to 15 degrees above normal into next week, risking earlier Sierra Nevada snowmelt and fire season, with some relief later this week.