2 December 2014
Heavy rain and snow is moving into California tonight, as an intense surface/upper level low pressure system taps warm tropical air to the south and shoves it into California. California gets most of its rain in winter and you might be surprised to know that most if it comes from just 5-6 storms.
The water vapor imagery from the GOES shows the storm well. Keep in mind that you are looking at moisture in the mid levels of the atmosphere here, but there’s a lot of moisture in the low levels as well. Rain has already been falling in Southern California, and a mud slide from earlier rain closed the Pacific Coast Highway near Malibu.
The NOAA-NAM model shows some impressive rain totals, which are completely supported by the satellite imagery this evening. This model is a 12 km grid and it smooths out the high elevations of the sierra, so locally there will be feet of snow up high. Three more storms like this (over the winter), and California will be in much better shape next year compared to the last two.
However, the rain deficits are so extreme, that it will take much more than a few storms to bring water levels up by much.