WASHINGTON: A widespread and dangerous heat wave was building across the US on Saturday, with triple-digit highs expected in the Southwest and Great Plains this weekend before spreading eastward under a dome of high pressure that meteorologists say could trap oppressive temperatures for a week or more. Forecasters advised people to stay hydrated and find places to cool off, warning of temperatures 15 to 25 degrees Fahrenheit (8 to 14 degrees Celsius) warmer than normal in many areas, including at night — especially bad for people’s health because their bodies won’t have a chance to recover.

Most of America’s Lower 48 states are about to swelter under an unusually large, strong and long-lasting heat dome.

Most of America's Lower 48 states are about to swelter under an unusually large, strong and long-lasting heat dome that will spike temperatures in a way that the National Weather