Record May heat sent temperatures soaring above 100° in much of Southern California on Wednesday, and fierce Santa Ana winds fanned fires that scorched at least 9,000 acres in San Diego County, forcing thousands to evacuate. For the second consecutive day, the Los Angeles Airport set a record for the hottest May temperature since record keeping began in 1944. Wednesday’s 96° beat the record set on Tuesday of 93°. Other all-time May record heat was recorded at Camarillo (102°) and Oxnard (102°) on Wednesday. In Downtown Los Angeles, the mercury hit 99° on Wednesday, falling short of the all-time May record is 103° set on May 25, 1896. More record heat is forecast on Thursday, and hot offshore Santa Ana winds will bring extreme fire danger.

Figure 1. A firenado in Fallbrook, California at old Highway 395 and Interstate 15 on May 14, 2014. Image credit: Jena Rents via Twitter.

Figure 2. True-color MODIS satellite image of fires burning in Southern California and Northern Mexico on Wednesday afternoon, May 14, 2014. Image credit: NASA.

100% of California in severe to exceptional drought
Today’s U.S. Drought Monitor report showed grim news for California: 100% of the state is now in severe or higher drought, up from 96% the previous week. Though just 25% of California is classified as being in the highest level of drought, “Exceptional”, Erin McCarthy at the Wall Street Journal estimates that farms comprising 53% of California’s $44.7 billion market value lie in the Exceptional drought area. Averaged state-wide, the Palmer Drought Severity Index during April 2014 was the second worst on record, behind 1977. For the 12-month period ending in April, drought conditions in California for 2013 – 2014 were also the second most severe on record, slightly below the 2008 – 2009 drought. To break the drought, most of the state needs 9 – 15″ or precipitation to fall in one month. This amounts to more than a half-year’s worth of precipitation for most of the state.

Figure 3. The May 13, 2014 U.S. Drought Monitor showed 100% of California in severe or higher drought, with 25% of the state in the highest level of drought, “Exceptional.” Image credit: U.S. Drought Monitor.

California’s rainy season is over
The California October through April rainy season is now over. Between October 2013 and April 2014, the state received 10.44″ of precipitation, which is just 51% of average for the period, and the third lowest such total on record. Going back to 1895, the record low mark was set in 1976 – 1977, when the state got just 34% of its average rainy season precipitation. California typically receives less than 10% of its annual precipitation between May and September, and the coming hot and dry summer in combination with a severely depleted Sierra snowpack will cause a severe fire season and significant agricultural damages. The fifth and final snow survey of the season on May 1 found that the statewide snowpack’s water content–which normally provides about a third of the water for California’s farms and cities–was only 18% of average for the date. Already, the 2014 drought has cost the state at least $3.6 billion in agricultural damages, the California Farm Water Coalition estimates. CAL FIRE recently announced it had hired 125 additional firefighters to help address the increased fire threat due to drought conditions.

from:    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2679