Overview
- Extreme Heat Warnings and Heat Advisories remain in effect across desert and inland Southwest areas through Friday with peak midweek highs forecast in the 110s for deserts and upper‑90s to low‑100s for many inland valleys.
- Nighttime lows will be much warmer than normal, which reduces overnight cooling and increases the risk of heat illness for outdoor workers, older adults and people without reliable air conditioning.
- Hot, dry conditions have prompted Red Flag Warnings in parts of California and the interior West, raising the chance of new wildfires and leading utilities and officials to warn of possible power strain or precautionary shutoffs.
- A front and building trough will push into the central and eastern U.S. midweek, bringing scattered to widespread showers and thunderstorms with isolated severe storms and pockets of heavy rain that could produce localized flooding.
- Forecast guidance trends show the western ridge weakening late Thursday into the weekend, which should bring some cooling for affected areas and coastal swell from offshore Tropical Storm Iselle that could raise marine hazards.