2009

This has been a confounding pattern to predict more than a few hours out, and even then it has been giving forecasters a fair bit of trouble over the past 48 hours. Significant rainfall did occur over parts of Central California–including the Sacramento Valley and the southern Sierra foothills. As much as 2 inches of rain has already fallen in some local areas, even producing a little urban or small stream-type flooding in these areas. SoCal, however, largely escaped significant precipitation except the higher terrain near Santa Barbara. Certainly…this rainfall has been very beneficial to areas that ave received it, but snow levels are extremely high with the precipitation event (>7500 feet) and the current rainfall deficits are so large that it will take quite a bit more rainfall than this to even put a significant dent in the current drought. The extremely moist but dynamically weak subtropical plume responsible for this recent precipitation will peter ut overnight, leaving only scattered showers for Saturday. A new and colder system will drop down from the north on Sunday, but since it will have a mostly over-land trajectory expect precipitation, if any, to be light. Snow levels will be fairly low with any precipitation that does develop–in the 2500-3500 foot range.

After this secondary cold system has moved through, the pattern appears that it will become quite dry again by the middle of next week. This is not the kind of drought-busting pattern that we desperately need right now, and we are beginning to run out of time for heavy precipitation events to occur to replentish the water supply. The most recent update of the Climate Predicition Center’s Drought Assessment indicates that a significant portion of NorCal is now experiencing “extreme” drought conditions, and the majority of the state is facing “severe” hyrdological defecits. Currently, the outlook for the rest of the water year does not look good. More on that later.