November 21, 2019 – Relatively quiet conditions expected through Sunday with a gradual warming trend as highs will be around 6 to 12 degrees above average. A trough of low pressure passing to the east will bring a period of dry, northerly winds to the Valley on Monday, which may bring elevated fire weather concerns. The focus quickly shifts to a likely pattern change late Tuesday as a strong Pacific system reaches the West Coast. Rainfall is forecast to begin by Tuesday afternoon or evening and spread toward the south and east. Heavier precipitation would fall on Wednesday with the potential for significant snowfall accumulations at or below pass levels. Valley rainfall may be impactful given it has been several months since the region saw widespread rains. The weather becomes more showery on Thanksgiving Day with cool temperatures and low snow levels.
Impacts
- Easier fire starts
- Potential for major travel delays due to snowstorm during peak holiday travel
- Slick roadways given lack of recent rainfall
Forecast Confidence
- Medium for fire weather conditions
- Medium for next week’s winter storm
- Medium for low snow levels
Timing
- Monday
- Increasing northerly winds over the Valley; gusts around 25 to 35 mph, locally higher in wind prone locations
- Minimum daytime humidities in the upper teens to low 20s; moderate overnight recoveries
- Tuesday afternoon – Thanksgiving
- Precipitation spreads through the region by the afternoon to evening hours
- Heavy snow more likely by Wednesday with snow levels at or below pass level
- Rain/snow showers persist on Thanksgiving with low snow levels
