Overview

• A Heat Advisory remains in effect north of Yuba City, with valley highs near 100°F on Tuesday.
• Tuesday’s incoming low-pressure system will collapse the high-pressure ridge, cutting afternoon temperatures in the Sacramento Valley to the low 90s.
• Strengthening Delta Breezes and onshore marine flow will bring cooler mornings, lower daytime highs and clearing wildfire haze.
• Southerly winds into the Sierra are expected to draw moisture that fuels afternoon and evening thunderstorms starting Wednesday.
• Despite relief in much of Northern California, the Bay Area stays 3–6°F below normal while Chicago, Northeast Ohio and Boston face worsening air quality, rising humidity and scattered storm threats.