Severe And Extreme Drought Eases In California

The U.S. Drought Monitor released May 12 shows some minor improvement in California drought conditions and the removal of the short-term drought designation.

But the seasonal outlook shows drought persisting through the dry season as California’s drought continues for a fifth consecutive year.

"Based upon recent conditions and discussions that started last week, areas of D2 (severe) and D3 (extreme) were improved over southern Nevada and southern California," according to weekly report. "For all of the West, the indicator type was changed to "L" (long-term drought) as the areas of short-term impacts have improved enough to remove that designation."

The extreme northwest portion of the state, along the coast north of San Francisco to the Oregon border, accounts for the roughly 10 percent of California where there is no drought. (This area is depicted in yellow and white on the California state graphic).

The only changes in California this past week (the report cutoff is 8 a.m. EDT Tuesday) were two-percent reductions in the level of severe (72.7 percent) and extreme (47.9 percent) drought. In February 2016, extreme drought covered 61 percent of the state.

But 95.7 percent of California remains abnormally dry, with 89 percent in moderate drought. Exceptional drought is 21 percent, a significant decrease from three months ago when it was nearly 39 percent.

Most of the heavy precipitation came to northern California, not southern California, in winter 2015-16 and reservoir storage and statewide snowpack relfects that difference.

Statewide Sierra Nevada snowpack May 12 is 47 percent of normal. The southern Sierra is 36 percent of normal, compared to 43 percent for the northern Sierra and 58 perrcent in the central Sierra.

Looking ahead, the report says "a wetter than normal pattern looks to be likely as there are above-normal chances for precipitation above normal over areas from the Pacific Northwest, Central Plains, and most of the eastern United States."

But, as spring gives way to the dry summer in California, drought conditions will likely see minimal improvement as water managers look ahead to next winter.

The National Weather Service/NOAA Climate Prediction Center issued an update for La Niña May 12. 

"Overall, La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75 percent chance of La Niña during the fall and winter 2016-17," according to the La Niña Watch diagnostic discussion. 

La Niña is a cooling of the water in the equatorial Pacific that occurs at irregular intervals and is associated with widespread changes in weather patterns complementary to those of El Niño. 

La Niña conditions have tended to cause a dryer winter for southern California and southern Nevada.