INLAND EMPIRE METRO: Partly cloudy Friday leading to a chance of rain Saturday afternoon and Sunday. Temperatures trending cooler. Highs Friday near 72, 60s on Saturday and 50s Sunday. Overnight lows in the 40s.

MOUNTAINS: Winter Storm Watch Saturday evening until Tuesday. A chance of rain beginning Saturday afternoon and increasing Sunday. Snow levels 5,000 feet but dropping to 3,500 on Sunday with accumulations of several inches. Windy and colder. Resort-level highs Friday 55-65 but much cooler over the weekend.

DESERTS: Mostly sunny Friday with winds becoming light. Partly cloudy Saturday with rain spreading south. A chance of rain Sunday and Monday ending Tuesday. Highs Friday and Saturday in the 50s and 60s. Cooler Sunday.

SUMMARY: Southern California’s whiplash-style weather is about to stage another turnabout.

KEY POINTS
• Gusty Santa Ana winds and low relative humidity with elevated fire weather conditions is coming to an end.
• An abrupt change this weekend into early next week with colder air, widespread rain/snow showers.
• An uptick of onshore winds for the mountains and deserts this weekend.
• A Winter Storm Watch kicks in Saturday night through Tuesday morning in the San Bernardino and San Jacinto Mountains

This season’s exceedingly dry weather and destructive Santa Ana winds are about to sign off probably for the rest of the month.

As the Red Flag Warnings come down Friday, they’ll be replaced by a new weather system rolling down the West Coast. Forecasters have increasing confidence of widespread light to moderate rain for all areas into early next week. A slight chance of thunderstorms is also in the mix.
It’s timed out to begin Saturday afternoon or evening likely lasting through Monday and possibly Tuesday. The chances are 60% to 90% from the coast and into the valleys and mountains. There is a 70% chance rainfall will exceed a half-inch. At resort-levels of the mountains, snowfall will make travel hazardous. Snow levels will start at 5,000 feet dropping to around 3500 feet Sunday evening into Monday.