Full Notification

...Precipitation Expected Saturday with Low Snow Levels; Continued Potential for Frost/Freeze Saturday and Sunday Nights...

MAIN IMPACTS

Snow and wind across mountain highways - Significant travel problems could develop on mountain passes Saturday into Saturday night due to snow levels dropping to about 3000 feet along with very windy conditions. Snow, blowing snow, and icing are likely along the Grapevine (I-5), highways 2 and 14 across the San Gabriel Mountains, and highway 33 in the Ventura County mountains. Amounts: 1-2 inches near pass levels with 3-6 inches above 5000 feet. Wind gusts >50 mph at times late Saturday.
Rain impacts to outdoor venues Saturday - Although we are not expecting a significant rain event, the timing of the rain on Saturday will likely impact many outdoor venues where exposure could cause problems for unprepared people. Rain slick highways will likely create many traffic slowdowns and/or accidents.
Precipitation amounts will vary from mainly under 0.25" for coastal Ventura and Los Angeles, to 0.50" or greater for the central coast (San Luis Obispo and Santa Barbara Counties), and the foothill communities. Heaviest amounts between 0.50-1.0" will be in the mountains of Santa Barbara Co. eastward into the San Gabriel Mountains. See attached image.
Frost/Freeze - Crops and sensitive plants should continue to be protected across interior valleys tonight and Friday morning, then additional cold air will lead to more freezing temperatures on Saturday night and possibly Sunday night as well. Some areas may not be as cold during this time frame due to either lingering cloud cover and/or north to northeast winds, however most agricultural interests should continue to take measures to protect their crops Saturday and Sunday nights.

SYNOPSIS

A fast-moving and cold storm system will traverse southwest California on Saturday. Rain is likely to spread from the northern counties early in the morning southward across Ventura and Los Angeles by late morning into the afternoon hours. Snow levels will start off near 5000 feet and drop to 3000 feet or less at times Saturday afternoon which could quickly impact travel over mountain passes, especially when gusty winds over 50 mph develop late Saturday. Cold air will follow the storm with another round of hard freeze conditions for many interior valleys and frost for colder coastal valleys Saturday and Sunday nights.

OUTLOOK

High pressure and clearing skies are expected on Sunday. After Sunday night, temperatures will start to rebound for Monday and Tuesday. Gusty northeast winds (offshore) will develop by early Monday morning with rapidly lowering humidities expected, with this trend continuing on Tuesday.

FORECAST CONFIDENCE

High confidence in the precipitation event and snow levels Saturday; medium confidence on freezing temperatures Saturday and Sunday nights.

*Note - the attached image shows the predicted precipitation totals on Saturday.

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