A cold 500 mb low in central California Tuesday has caused scattered showers and thunderstorms in the lowlands and rain, snow and thunder in the mountains. Accumulating snow fell in spots down to almost 6,000 feet Tuesday morning before snow levels rose to above 7,000 feet in the afternoon.
The closed low initially will head east into Nevada late Tuesday night and Wednesday. However, energy on the western side of the low will drag this low back to the south-southwest Wednesday night and Thursday with the low moving into southwestern California by Thursday. This is going to set the stage for potentially some interesting weather. As the low starts southwestward Wednesday night, there could be a shower in spots from the western upper deserts to the mountains and adjacent valleys by late at night. Then on Thursday, with the low over the area, instability can lead to a few scattered showers and thunderstorms developing. The best chance is in the afternoon and evening hours.
There is not a lot of moisture to work, but our computer models do show a rather unstable air mass. The following may be a little too technical for some but informative for others. Below is what the MUCAPE is forecast by late afternoon which is at, or somewhat above, 500 j/kg. Also the Lifted Index goes negative to -1 to -2. This is certainly unstable enough to support showers to develop.
Lifted Index (red lines):
Any shower or thunderstorm that does get going can bring quick downpours, gusty winds and even some small hail. Showers will end quickly Friday night after the sun sets.
With the low moving slowly away Friday and over the weekend and a ridge building in for the weekend, look for considerable warmer weather by the weekend.
Catch me on Twitter at @Kenwxman
Comments that don't add to the conversation may be automatically or manually removed by Facebook or AccuWeather. Profanity, personal attacks, and spam will not be tolerated.
Dangerous heat will build across the Southwest through the middle of next week putting some records in jeopardy.
Parts of the West will bake in the heat over the next few days but cooler weather will arrive by the start of the weekend.
Models have been consistent on bringing a rigorous system from the Northwest to the Southwest this weekend.
The pattern next week will favor unsettled and cool weather for the Northwest.
Rain and mountain snow will highlight just about every day this week in the Northwest.