Unsettled pattern for the end of the month; large precip deficits persist

The extraordinary mid-winter dry spell in California continues this weekend. Most parts of the state have seen only very light precipitation thus far in 2013. For much of NorCal (and especially the Bay Area), January-February 2013 was the driest early-winter interval on record. While late November and early December 2012 brought very heavy precipitation to more northern parts of the state, the near-total lack of subsequent storm activity has dropped water-year totals well below average across the entire state. With the climatological peak of the rainy season now behind us, the question becomes: how much of a dent can we put in our accrued precipitation deficit before the Pacific storm track shifts north for the season?

Well, it does appear than  a more unsettled pattern is headed toward California over the coming week–with a higher potential for meaningful rainfall in most areas than has been experienced in quite some time. A cutoff low will approach from the north and west by next weekend, and although there’s always a lot of uncertainty associated with features removed from the mean flow it does appear that this system will have sufficient moisture and potential instability to get some decent precip going over at least some parts of the state.

Depending on the particulars of where the low sets up and the degree of synoptic-scale forcing available, it’s also possible that there could be a fairly widespread thunderstorm outbreak. We’ll have to keep an eye on that as we get closer to the main event. Stay tuned!

© 2013 WEATHER WEST