Overview
- A broad ridge of high pressure has kept much of the country dry and pleasant through Friday with cool mornings and lower humidity.
- Models and local National Weather Service products show the pattern shifting Sunday, bringing higher humidity and a renewed risk of scattered to organized severe thunderstorms into early next week according to the Storm Prediction Center.
- Southern California faces active heat alerts with Heat Advisories for coast and valleys and an Extreme Heat Warning for mountains and deserts where daytime highs are forecast in the 113–119°F range through Monday.
- South-central Montana, including the Billings area, is entering an extended heat episode with highs near or above 100°F, warm overnight lows, reduced humidity and a Fire Weather Watch because lightning, gusty winds and dry fuels could spark new fires.
- Monsoon moisture will raise humidity and mountain storm and flash-flood risks across the Southwest while Hurricane Fausto in the eastern Pacific remains a developing threat to Hawaii as a tropical system next week.