Rain.

Filed in Uncategorized by on February 6, 2007 6 Comments

Our historic dry spell is quickly coming to an end. A fast-approaching system will spread rain across NorCal on Wednesday, reaching as far south perhaps as Santa Barbara by evening. Rainfall totals with this first system will be as high as 1.5 inches in the north, 1.0 inches in the Bay Area, and 0.5 inches south to Santa Barbara and interior parts. The Sierras will see 6-10 inches of snow, as well. Thursday will feature continued showers over much of the state north of Santa Barbara. A rather strong storm is expected to approach CA on Thursday night, and with a strong subtropical moisture tap will probably bring some heavy rains and gusty winds to northern and central portions of the state. Rainfall totals with this second system could be as high as 2-4 inches in the Bay Area and Sierra foothills with locally higher amounts, and wind gusts in excess of 50 mph are possible. Areas as far south as Los Angeles could see some rain from this second system, but south of Santa Barbara any accumulation will be fairly light. A moist zonal flow continues to stream into CA over the weekend, and some locally heavy rainfall may develop within this moisture plume. There is some uncertainty as to where this fairly narrow rainband will set up, but right now it looks as if the Bay Area may see the brunt of it. Another 1-3 inches could fall during this period (locally more). It now appears that a third system may approach the coast by late in the weekend. This system will dig further south than the previous two as the once-powerful ridge continues to be supressed even farther to the south and east. As a result, SoCal stands a good chance of seeing some significant, possibly even heavy, rainfall during this timeframe. And…instead of reverting back to a dry and dull pattern after this third storm…the pattern actually gets more interesting. On days 6/7, a longwave trough will develop over the E. Pac. and propagate eastward towards the coast. This could eventually bring a period of cold and unstable weather during the 7-10 day period…with a good change of rain in SoCal. And…although it would be foolish to take the GFS at its word out beyond 10 days, particularly during such a momentous pattern shift…there may be a very strong East Pacific jet in our medium-range future (days 10-16). In short: we’re finally going to see some much-needed precip over most/all of the state. Stay tuned.