The cold, closed low I have been talking about for almost a week now is on schedule for Southern California and then into the Southwest later tonight and tomorrow. The low this afternoon was just off the coast of San Luis Obispo by mid-afternoon Thursday and will go south of Pt. Conception tonight, turn east tomorrow and move across the LA Basin tomorrow afternoon then to near the Colorado River by Friday morning. There will be two distinct maximum areas of rainfall with this storm. The first will be over Southern California especially from the mountains on west and in the Upper Deserts and the second in Arizona north into Nevada and Utah. Thunderstorms will be locally heavy, and there is the potential for locally severe weather in the form of strong, gusty winds, heavy downpours and hail. There is even the slight chance of a waterspout in the coastal waters of Southern California and a funnel cloud or weak tornado over land.
Precipitation will end tomorrow night in Southern California except near the Colorado River where a shower or thundershower could linger in spots late tomorrow night and to start on Friday. Precipitation in Arizona, southern Nevada and Utah continue on Friday with the heaviest activity in the morning hours.
This one storm is the only one the area will see for some time to come. Longer-range computer models show a big ridge building in California and the Southwest over the weekend and next week and temperatures rise back to above-normal levels.
This will make for a very hazardous period for firefighters into early Friday night.
With such high heat and low humidity, the fire danger will be as high as it can get.
For the second time this week, parts of northern California will get some rain.
With such high amounts of water vapor, thunderstorms will bring locally very heavy rain that can cause flash flooding.
Many areas east of the Cascades this weekend will be over 100 F.
some of the moisture from Andres and newly formed Blanca could influence the weather in the Southwest