Overview

• Lightning and brief heavy downpours arrived overnight into Thursday, with minor flooding reported in parts of San Bernardino County as flood watches cover mountains, deserts and burn-scar areas including Altadena and Pacific Palisades.
• Showers and thunderstorms are expected to continue into Friday before easing, and officials caution that conditions can shift rapidly with the potential for upgraded flash-flood warnings.
• Rainfall will be highly uneven, ranging from a few hundredths of an inch to 1–2 inches where training storms set up, increasing flash-flood and debris-flow risk on vulnerable terrain.
• Moisture and storm bands are expanding beyond the Los Angeles and San Diego areas, with rain chances and watches reaching the Central Coast, Central Valley and Sierra Nevada, and into southern Nevada including the Las Vegas valley.
• Daytime temperatures have cooled but humidity is elevated, keeping nights warmer than normal and creating slick, slower commutes where heavier cells pass.