Drought

California

Record warm and dry weather has hit California this month, as one of the worst drought in state history continues to intensify. San Francisco Airport observed its warmest January day on record on Wednesday: 73°. This beat the previous all-time January record of 72° set twice before (on January 13, 2009 and January 24, 1948). Oakland hit 77° on Wednesday, and Monterey topped out at a remarkable 83° -- which would be a daily record on many summer days.

The record January heat has been accompanied by record dryness. California recorded its driest year in its history during 2013. The most widely used measure of drought in the U.S. shows that December 2013 drought conditions in California were the 2nd most intense for any December going back to 1895, with only December 1898 being worse.

Less than an inch of precipitation has fallen over more than 95% of the state so far in January 2014, and the prospects for significant rain for the next ten days look bleak. A large and persistent ridge of high pressure has set up over the West Coast and shows no signs of budging. Since rain-bearing low pressure system tend to travel along the axis of the jet stream, these storms are being carried well to the north of California into Southeast Alaska, leaving California exceptionally dry.

Thursday's U.S. Drought Monitor showed that the area of California experiencing extreme drought expanded from 28% to 63% over the past week, and January 2014 drought conditions are expected to challenge 1899 for the dubious honour of worst January drought in state history.