CURRENT CONDITIONS

After improved regional drought conditions throughout this winter 

into spring, as of June 1st a mere 8.24% of California and none of Nevada 

remains in moderate to severe drought (D1-D2) according to the U.S. 

Drought Monitor. This is a marked improvement compared this time 

last year (86% in California, 62% in Nevada). The lingering areas of 

drought remain near the southern central coast and southeast corner of 

California. Few changes in the U.S. Drought Monitor classes have occurred 

in California and Nevada in the last two months, 

with most improvement having taken place 

through February. On April 7, California Governor 

Brown lifted the statewide drought emergency 

except for a few counties in the San Joaquin Valley 

(Fresno, Kings, Tulare, and Tuolumne).

Almost all of California and Nevada received 

above- to much-above-normal precipitation this 

winter. At the end of May 2017, regions of the 

Sierra Nevadas and northern Nevada have been 

the wettest on record for the 2016-17 water year 

(Oct. 1-Sept. 30). These amounts resulted in part 

from continued landfall of large precipitation 

events called atmospheric rivers (ARs). ARs are 

narrow corridors of high water vapor transport 

in the lower 2 km of the atmosphere. In the short 

term, California and Nevada generally have seen 

an overall drying trend.

Snowpack levels have decreased since April 

1 but remain above normal. As of May 31, Nevada SNOTEL sites are 

well above normal (300-400%) snow water equivalent for this time of 

year, while California Department of Water Resources (CA DWR) north, 

central, and south automated snow sensors show above-average snow 

water content in the Sierra Nevada (42%, 74%, and 59% of April 1 normal, 

respectively). April brought warmer than normal temperature to southern 

California and Nevada, and cooler than normal temperatures to the 

northern part of the region, with the opposite temperature pattern in May. 

Many reservoirs in California are near or above historical normal levels, 

with some near flood control release levels before the additional summer 

snowmelt. Streamflows in California and Nevada are running normal to 

above normal, with flood stage potential in western Nevada. Forecasts for 

above-normal streamflow volume have persisted since February. 

CLIMATE OUTLOOK

Following a transition from weak La Niña conditions to neutral this 

past winter, ENSO neutral conditions persisted through April and May 

with near-average equatorial sea surface temperatures (SST) near the 

central Pacific and above-average SSTs in the eastern Pacific. Currently 

ENSO-neutral conditions are present, and are favored to continue through 

early summer 2017. The official probabilistic ENSO forecast shows near 

equal chances (both >40%) of neutral or El Niño conditions developing 

through late summer into fall. A clear shift to El Niño conditions is lacking 

in observational data.

The Climate Prediction Center (CPC) seasonal outlooks as of May 18 

show equal chances of above, below, or average precipitation in JuneNATIONAL INTEGRATED DROUGHT INFORMATION SYSTEM

CALIFORNIA-NEVADA 

DROUGHT OUTLOOK MAY 2017 

US DROUGHT 

MONITOR 

MAY 30, 2017

Severe drought

Abnormally dry

Moderate drought

NEVADA PRECIPITATION (INCHES)

OCTOBER 2016 - APRIL 2017

CALIFORNIA PRECIPITATION (INCHES)

OCTOBER 2016 - APRIL 2017

OCTOBER-APRIL 2017 PRECIPITATION 

PERCENTILE
July-August (JJA) and July-August-September 

(JAS) in California-Nevada. Above-normal 

temperatures are favored across the region, with 

a 40-60% chance of above normal temperatures 

in summer into early fall. According to the North 

American Multi-Model Ensemble (NMME), 

these temperatures could be 0.25-1 ̊C above 

normal through summer to fall. Highlighted in 

this webinar was recent work by Shrad Shukla 

(CNAP/UCSB) that showed historically the 

NMME is relatively skillful in forecasting JJA and 

JAS temperatures for the interior of CaliforniaNevada. Through August, drought is expected 

to persist in the south central California coast 

as well as near the southern California-Arizona 

border. 

FIRE POTENTIAL OUTLOOK 

Despite improved drought conditions 

throughout California and Nevada, significant 

wildland fire potential exists through the 

summer and is dependent on several factors. 

These include various dead fuel moistures and 

http://www.cpc.ncep.noaa.

OUTLOOK: 

PRECIPITATION

JUNE-JULY-AUG

JULY-AUG-SEPT

OUTLOOK: 

TEMPERATURE

JUNE-JULY AUG

JULY-AUG-SEPT

A = chances of abovenormal precipitation

EC = Equal chances of 

above, below, normal

33-40% probability 

of above normal 

precipitation

40-50% probability 

of above normal 

precipitation

Source: https://www.predictiveservices.nifc.gov/outlooks/outlooks.htm

EC = Equal chances of 

above, below, normal

33-40% probability 

of above normal 

temperature

40-50% probability 

of above normal 

temperature

50-60% probability 

of above normal 

temperature

environmental conditions. A significant grass crop, or 

10-hour fuels, across Nevada and California have created 

potential for wildland fire throughout the summer. 

For example, 10-hour fuel moisture over Nevada is in 

the 1-2% and 3-4% range. In the short-term, there will 

likely continue to be a burst in fire activity across the 

cured grassy areas in California.Most of these fires will 

not result in a significant drain on regional firefighting 

resources, but could require high resource demand at the 

local level. 100-hour fuel moisture (such as sagebrush) 

in the region is lowest in southern Nevada due to recent 

warming and drying. 

On the other hand, 1000-hour fuel moisture (such 

as from timber) is high due to a large snowpack, and as 

a result the higher elevation areas have below-normal 

wildland fire potential until later in the summer. With 

the combination of a robust grass crop and significant 

tree mortality, the Sierra foothills in the 3000-6000 foot 

elevation will be the most likely area for large fire activity 

this summer. 

Recent work by Gina McGuire from the Great Basin 

Geographic Area Coordination Center has shown that 

during the last 15 years, the years when Nevada entered 

or exited drought were those with the highest number 

of acres burned. In California, live fuel moisture is above 

average for this time of year, and will likely stay above 

average or close to average throughout much of the fire 

season. Therefore, significant fire activity (apart from 

the initial grass fire surge) will be slow to develop, and 

large fire activity within the heavier fuels may not start 

until later in July or August. Atmospheric conditions will 

determine coming wildland fire potential including the 

monsoon and Santa Ana winds in southern California.

ABOUT PREDICTIVE SERVICES 

Predictive Services is a national program operating out of the 

Geographic Area Coordination Centers (GACC) (https://gacc.

nifc.gov/) throughout the United States and is comprised of 

meteorologists, fire intelligence coordinators, and fire behavior 

analysts. Predictive Services combines weather, fuels, and 

resource availability to provide a comprehensive look at fire 

potential (where and when large fires occur). They provide this 

information through their web portal and products, monthly/

seasonal outlooks, and webcast briefings.

ABOUT THIS OUTLOOK

On May 30th, 2017 NIDIS and its partners held a CaliforniaNevada DEWS Drought & Climate Outlook Webinar as part 

of a series of regular drought and climate outlook webinars 

designed to provide stakeholders and other interested parties 

in the region with timely information on current drought status 

and impacts, as well as a preview of current and developing 

climatic events like La Niña.

A video of and presentations from this webinar can be 

accessed here: https://www.drought.gov/drought/calendar/

events/california-nevada-drought-climate-outlook-webinarmay-30

CONTRIBUTORS

David Simeral, WRCC/DRI

Shrad Shukla, CNAP/UCSB

Gina McGuire, BLM

Thomas Rolinski, USFS

Amanda Sheffield, NIDIS/SIO/

UCSD