Will 2014 Be California's Hottest Year in History?

With just two months left in the year, there’s a better than 99 percent chance that 2014 will be the warmest year on record for California, according to National Weather Service meteorologists.

The state has been baking in above-average temperatures all year — setting a record for the warmest first six months of any year this June — thanks to a persistent atmospheric pattern that has also mired California in a major drought. The heat has only exacerbated the drought’s effects, and the state is in dire need of a really wet winter, an uncertain prospect  right now.

The year is also on pace to be the warmest on record globally, edging out 2010 thanks to large pockets of warmth in the oceans. Nine of the 10 warmest years on record have occurred in the 21st century, a mark of the steady climb of Earth’s average temperatures as greenhouse gases increasingly accumulate in the atmosphere.

The NWS office in Hanford, Calif., tweeted a graphic on Monday that showed the likely scenarios for how the average temperature of the year would play out. Based on observed temperatures, and the climatological history of the last two months of the year for the state, there is a better than 99 percent chance that 2014 will easily top 1934 as California’s warmest on record, going back to 1895.

The reason for the perpetual warmth is a persistent atmospheric ridge, or high-pressure system, that has steered storms away from the state and kept temperatures elevated. (This same pattern has led to a persistent trough over the eastern U.S., where temperatures have been cooler-than-average for much of the year.)

The heat likely exacerbated the already dry conditions in the state, which took root after three straight dry winters, normally the rainy season in California.

This probable hottest year follows the driest year on record for the state, 2013, and both of those conditions feed on each other. The heat can speed evaporation and can cause more precipitation at higher elevations to fall as rain instead of snow, said Mark Svoboda, a climatologist with the National Drought Mitigation Center at the University of Nebraska-Lincoln. The mountain snowpack is critical to replenishing the state’s reservoirs.

Link: http://www.wunderground.com/news/2014-california-hottest-year-history-20141106