Large Scale Summary
- Support for troughs focusing 130-148W. The main governing agent is the MJO with a maximum along about 168-175W.
- Primarily well below average precipitation. A few wet periods: Dec 11-14, 23-26.
- Potentially heavy rains occur in Jan 2026. This looks like a pattern typical for atmospheric river regimes (AR). Typically, the ORWA region is very wet, especially near the coast, including NORCAL-rest of California north of 37N. The portion of California south of 37N has below average precipitation. That is a typical AR-associated pattern of rainfall on a monthly or smaller time scale.
Near Term Forecast
NORCAL
- PRECIPITATION DATES: Dec 6,9, 20-26, 27-31.
- COLD/FREEZES/WINDS: Dec 16-19, 30-31.
- WARM/DRY PERIODS: Dec 8.
- MOUNTAIN SNOWS: Dec 6,9,20-26,27-31.
CENTRAL
- PRECIPITATION DATES: Dec 6, 10-11, 20,25-26.
- COLD/FREEZES/WINDS: Dec 6,10-11, 25-26,31
- WARM/DRY : Dec. 7-8
- Central Sierra SNOWS: Dec 6,10-11,25-26
SOUTHERN
- PRECIPITATION DATES: Dec 26.
- COLD/FREEZES OR COLD SANTA ANAS: Dec 8-10, 16-19
- WARM/DRY PERIODS: Dec 7-8.
- MOUNTAIN SNOWS: Dec,25-26
SOUTHERN CALIFORNIA DESERTS
- PRECIPITATION DATES Dec 6,25-26
- COLD/N-NE WINDS: Dec 8-11, 15-19
- MOUNTAIN SNOWS: Dec 25-26.
Medium Term Outlook: Jan 2026
NORCAL
- PRECIPITATION DATES: Jan 10-15, 25. Below average precipitation.
- MOUNTAIN SNOWS: Jan 10-15, 25. Below average snowfall.
CENTRAL
- PRECIPITATION DATES: Jan 10-14. 24-25. Below average.
- MOUNTAIN SNOWS: Jan 10-15, 24-27. Below average snowfall.
SOUTHERN
- PRECIPITATION DATES: Jan 10-13. 25. Below average.
- MOUNTAIN SNOWS: Jan 10-14, 25-26. Below average snow.
SOUTHERN CALIFORNIA DESERTS
- PRECIPITATION DATES: Jan 10-12, below average.
- MOUNTAIN SNOWS: Jan 10-13, below average snow.
Figures and Text: Alan Fox, Fox Weather, LLC
Copyright © 2025 Fox Weather, LLC.