A heatwave from the Rockies to the Mississippi Valley is pushing south toward the Gulf Coast and increasing strain on regional power grids and cooling demand. The NWS has extended extreme-heat warnings from Montana to Texas, including Dallas where highs are forecast near 100°F (38°C) through at least next Wednesday and heat index values could reach about 107°F. A separate hot dome covers Southern California and Arizona; Phoenix highs may reach 117°F. A senior branch forecaster at the Weather Pre

A heatwave from the Rockies to the Mississippi Valley is pushing south toward the Gulf Coast and increasing strain on regional power grids and cooling demand. The NWS has extended extreme-heat warnings from Montana to Texas, including Dallas where highs are forecast near 100°F (38°C) through at least next Wednesday and heat index values could reach about 107°F. A separate hot dome covers Southern California and Arizona; Phoenix highs may reach 117°F. A senior branch forecaster at the Weather Prediction Center said the pattern is fairly persistent, likely into next week, with only minor day-to-day variation and overall persistence through the end of the month.