Another Weekend Storm for California

An interesting last 24 hours for weather forecasters in the West. GOES-15, the western satellite that provides all sorts of data from satellite pictures to cloud and sounding data, failed late yesterday and stopped transmitting. It took until later Thursday for the problem to be isolated, but the satellite will not be back into commission any earlier than later Friday morning. This is important because it means the weather has a blind spot in satellite data and computer models will not have as much data in them until the satellite is back up and running. With another storm set to come inland across California this weekend, there is just a little less confidence than normal at this point on timing and precipitation amounts.

It’s not a question as to whether it rain and snows, it is now a question about when the important rain develops and moves away and how much precipitation there is. Today’s models did a flip flop on the timing with the European now faster with rain moving in than the GFS. For days it has been the other way around. I am going to stick with the European as at least it has been consistent.

Rain will move into the central coast of California later Saturday night and will spread east and south late Saturday night and Sunday. Good rain and snow amounts are likely from about central California into southwest California. The heaviest precipitation may again be in parts of the southern third of the state. This will also be a pretty cold storm or at least become that way. The resorts in the south-central Sierra will get the most snow probably 15 to 25 inches above 7,000 feet with a foot down to 5,000 feet. Snow levels drop by late Sunday and Sunday night down to 3,500 feet. In Southern California, snow levels start out at around 6,000 feet or a little higher but drop to 5,000 feet late and 4,000 feet at night. Resorts in Southern California pick up 1-2 feet with the highest amounts probably in the San Gabriel Range.

Rainfall amounts in central and southwest California will average 0.75 to 1.50 inches but with local amounts of 2-3 inches up favored topographical areas.

One thing this storm will not do is bring anywhere near the kind of precipitation to Arizona as the one did late last week into Monday. Because the storm is plowing east, it will lift northeast toward Utah. This could be a good precipitation producer for the Wasatch Range, but snow and rain amounts are going to be far, far less than the last storm in northern Arizona.

More details coming tomorrow.