Thursday, March 22, 2018

National Drought Mitigation Center

Drought and Climate for May 2016: Conditions improve in northern California, western Nevada

Access the latest monthly drought outlook from NOAA's Climate Prediction Center.
The two maps above are from the High Plains Regional Climate Center.
Find these and other products related to the U.S. Drought Monitor on the USDM website.

By Deborah Bathke, NDMC Climatologist


In May, the West saw the biggest decreases in drought areas while the Southeast saw the biggest increases.  A steady improvement in conditions in northern California and western Nevada led to a reduction of extreme (D3) and severe (D4) drought in these areas.  Extreme southeastern California and the northwestern parts of Arizona, Utah, and New Mexico also saw changes for the better with some removal of moderate drought conditions. The exception to the West’s improvements was in the Pacific Northwest, where above-normal temperatures combined with below-normal precipitation, soil moisture, and streamflow led to an expansion of abnormally dry (D0) conditions.  In much of the Plains and Mid-Atlantic states, abundant precipitation during May improved many of the areas of drought and abnormal dryness.  Conditions continued to dry out in the Upper Great Lakes and New England, leading to an expansion of abnormally dry conditions.  Much of the Southeast saw a deterioration of conditions during May.  Below-normal precipitation in Tennessee, northern Alabama, and northern Georgia caused an expansion of moderate drought (D1) and an introduction of severe drought (D2). By the end of May, 12.73 percent of the contiguous United States was experiencing moderate drought conditions or worse, compared to 14.56 percent at the beginning of the month.  Other categorical changes were also relatively small.  Severe drought improved from 5.46 to 4.18 percent, extreme drought improved from 3.44 to 2.46 percent, and exceptional drought remained the same at 1.11 percent of the contiguous United States. Outside of the contiguous United States, conditions in Alaska and Puerto Rico remained unchanged for May.  In Hawaii, the Big Island saw a slight expansion of severe drought, while the other islands generally saw an improvement in their abnormally dry areas.  The number of people being affected by drought increased from 49.8 million at the beginning of May to about 54.8 million by the end of the month.

Drought Outlook

With the exception of the central Plains states, the  summer (June, July, August) temperature outlooks issued by the NOAA-Climate Prediction Center (CPC) call for increased chances that temperatures will be warmer than normal across the United States, with the highest anomalies in the West and New England.  This outlook, combined with current dry conditions, leads to an expected development of drought over Washington, Oregon, and portions of the upper Midwest and southern New England.  Although drought conditions have improved in recent weeks, projected warmer than normal temperatures and climatologically dry conditions during the summer months favor the persistence of drought in northern California and northwestern Nevada as well as in Hawaii. A ramping up of the Southwest monsoon during the summer months is expected to alleviate drought across much of western New Mexico. The removal of drought conditions is also projected for parts of Tennessee, northern Georgia, the far western Carolinas, and Puerto Rico.


Temperatures in May generally deviated within 4 degrees of normal over most of the United States.  Above-normal temperatures were recorded in the Pacific Northwest, the Dakotas, the upper Midwest, and New England.  The largest anomalies were recorded in northern North Dakota with temperatures in excess of 5 degrees above normal and parts of the southern Plains with temperatures lower than 3 degrees below normal.


Precipitation in May was highly variable across the United States, ranging from less than 25 percent of normal along the west coast, the Southwest, parts of the Plains, and Mississippi and Alabama to more than 200 percent of normal in parts of Nevada, Arizona, Texas, Missouri, Louisiana, and the Atlantic coastal region.


Regional Overviews


Most of the Northeast started out cool, but temperatures warmed up near the end of the month. At the end of the month, average temperatures ranged from more than 3 degrees above normal in parts of New England to more than 3 degrees below normal in parts of Maryland and Virginia.  A stalled storm track over the southern half of the region in the first half of the month had stations in Maryland and Virginia recording rain on 20 or more days in May.  By month’s end, precipitation ranged from 25 percent of normal in parts of New York and New England to more than 200 percent of normal in parts of Maryland. Stations in these areas ranked in the top 10 driest and wettest, respectively.


Temperatures in the Southeast ranged from slightly below normal to slightly above normal in May. Mean temperatures were 1 to 3 degrees above normal in southern Florida and parts of Alabama, Georgia, Mississippi, Tennessee, and South Carolina.  The average temperature of several stations in southern Florida fell within the top ten warmest on record.  Conversely, each state in the Southeast also had areas where temperatures were 1 to 3 degrees below normal and the average temperatures fell within the top 10 coolest on record. Precipitation was above normal in Florida and along the Atlantic coast, in part due to the drenching showers and thunderstorms brought by Tropical Storm/depression Bonnie at the end of the month.  Many locations in these areas had precipitation amounts that were as much as 200 percent of normal, falling within the top 10 wettest Mays on record and alleviating the drier than normal conditions that existed at the beginning of the month.  Precipitation along the Gulf coast and interior parts of the region ranged from 5 to 70 percent of normal, with amounts at stations in eastern Mississippi, Alabama, western Georgia, and Tennessee falling within the top 10 driest on record.

Movers & Shakers for May 2016

Percent area May 3, 2016

Percent area May 31, 2016 Status Percentage point change
Biggest increases in drought
Alabama 1.50
Moderate 25.34
Georgia 12.32
27.96 Moderate 15.64
Tennessee 24.49
Biggest improvements in drought
Moderate 7.33
89.68 83.91
Moderate 5.77
74.37 59.02 Severe 15.35
Hawaii 60.92 57.36 Moderate 3.56
Missouri 8.25 0 Moderate 8.25
Nevada 62.33
34.25 Moderate
23.17 5.39 Extreme 17.78
New Mexico
Utah 12.35
Virginia 3.67
 0 Moderate
West Virginia
Moderate 20.76


Temperatures for May ranged from more than 4 degrees above normal in northwestern Minnesota to more than 4 degrees below normal in the southern parts of Missouri, Illinois, Indiana, and Kentucky.  Precipitation was variable across the region.  Multiple storm systems across the southern part of the region led to monthly rainfall totals across parts of western Iowa and western and southeastern Missouri that were more than 150 percent above normal. Drier conditions were observed across the remainder of the region, with the driest locations in northern Minnesota receiving as little as 5 percent of their normal precipitation amount.

High Plains

May temperatures across the High Plains ranged from more than 5 degrees above normal in northern North Dakota to 5 degrees below normal in western Nebraska, eastern Colorado, and Kansas. Several rounds of severe thunderstorms across the central Plains resulted in monthly precipitation totals that were more than 150 percent of normal across parts of eastern Nebraska and Kansas, southeastern South Dakota, and western Iowa.  Parts of southwestern Wyoming and northwestern Colorado recorded totals in excess of 300 percent of normal, keeping these areas drought-free.


Temperatures were below normal across much of the South in May.   Parts of northern and central Texas, central Oklahoma, northern Arkansas, and northeastern Louisiana recorded temperatures more than 3 degrees above normal while a few small areas in southern Texas, Arkansas, and Louisiana recorded temperatures of 2 degrees or more below normal.  Once again, slow-moving storm systems brought heavy rains and flooding to parts of central and eastern Texas, with some areas receiving in excess of 300 percent of their normal precipitation.  Southern Louisiana also had significant rainfall during May with totals more than 200 percent of normal.  The remainder of the South was dry, with parts of Oklahoma, western Texas, southern Arkansas, and northern Louisiana receiving less than 50 percent of their normal precipitation.


May brought above-normal temperatures to the Pacific Northwest and primarily below-normal temperatures everywhere else.  The warmest locations in Oregon and Washington were more than 4 degrees above normal, while the coolest locations in Utah, Arizona, and California were more than 4 degrees below normal.  As is typical for the West, precipitation in May was highly variable.  May once again brought drier than normal conditions to the Pacific Northwest and much of California, with the driest areas receiving less than 25 percent of their normal precipitation.  Locations such as Southern California and the San Francisco Bay Area, areas near Puget Sound, and Tucson all set records for the driest May.





May 2016 impact summary: California continues water conservation efforts, prepares for wildfire season

The two charts above summarize information from the Drought Impact Reporter.
The two charts above summarize information from the California Department of Water Resources Water Conditions page.

By Denise Gutzmer, NDMC Drought Impact Specialist

Drought intensified in the Pacific Northwest and the Southeast, with other areas of dryness developing across the nation during May. Rain eased dry areas in the central eastern United States and from northern California to Utah and brought flooding to Kansas and Texas.  With the Climate Prediction Center predicting a 75 percent chance of a La Niña developing during the fall and winter 2016-17, no relief seems to be on the horizon for the California drought.

The dry, warm spring melted snow early and quickly across the western United States, turning what appeared to be healthy snowpacks into a thin patchy layer of snow with little runoff to offer during the summer months. This was not the expected aftermath of a strong El Niño that was hoped to bail California out of a years-long drought and replenish reservoirs, but the Shasta and Oroville reservoirs and Lake Folsom were full, making northern Californians feel like the drought was over, while in Southern California, reservoirs had more space than water.  California’s 31 May entries in the Drought Impact Reporter record some of the changes in perspective and operation as the state partially experiences some relief from the past four plus parched years.  Nevada enjoyed some easing of drought during May also, with eight impacts mostly related to plants and wildlife.  Washington had three impacts, and Arizona, Texas and Utah each had two impacts, while more than a dozen states had a single impact.

California prepares for continued drought

Governor Jerry Brown issued an executive order on May 9 to establish a new framework for water use efficiency, making permanent the emergency drought regulations set forth in January 2014 and warning water providers to prepare for a drier future.  Some of the emergency rules include not washing off pavement with potable water or watering lawns within 48 hours of a rainstorm.  The governor’s administration also announced plans to do away with statewide mandatory water conservation targets that took effect in June 2015.

“California Braces for Unending Drought,” by Ian Lovett, The New York Times, May 9, 2016 and San Jose Mercury News, May 9, 2016

 Executive Order B-37-16, Making Water Conservation a California Way of Life

Water districts allowed to set own conservation rules

Later in May, California water districts gained the right to set their own conservation standards when the State Water Resources Control Board finally dropped their mandatory conservation targets.  Water providers must, however, ensure that they have three years’ worth of water in reserve, and, if not, adopt water-savings targets to have a three-year supply.  A number of statewide conservation measures were extended through January 2017. Residents, for example, must not allow water runoff when irrigating their lawns or wash cars without a shut-off nozzle.

“California drops mandatory water cutbacks for cities and towns,” by Kurtis Alexander, San Francisco Chronicle (, May 18, 2016

California marks continued conservation success

Californians remained steadfastly conservation-minded in April as they used on average 77 gallons of water daily, a decrease of 26.1 percent compared to the 104 gallons used daily in April 2013, according to the State Water Resources Control Board.  During the past 11 months of intensive conservation, the state’s residents have saved enough water to serve 18 percent of California’s 40 million people for one year.

“Californians beat drought-time conservation target for April,” by Associated Press, The Washington Post, June 6, 2016

Dry landscape exacerbates ongoing fire danger

As drought persists into its fifth year, fire danger remains high in California.  The Department of Forestry and Fire Protection responded to nearly 1,344 wildfires that blackened 6,810 acres from the start of 2016 through June 4, according to the Cal Fire website.  The landscape remains dry and primed to burn, and more than 29 million standing dead trees still offer fuel for wildfires.  Homeowners were urged to create a defensible space of 100 feet around their homes as the state looks at another potentially devastating year of wildfires as fire season becomes a year-round concern.

“Cal Fire Urges State to Prepare with "Ready, Set, GO" Campaign,” by Kaitlin Lewis, KSTE-AM 650 (Rancho Cordova, Calif.), May 2, 2016

Recovering Nevada rangeland could be used for grazing; large mustang roundup needed

Nevada, like California, has endured more than four years of drought, and the landscape and its wildlife bear the marks of it.  After a wetter winter, Governor Brian Sandoval urged the U.S. Bureau of Land Management to reassess the need for livestock grazing restrictions in the northeastern part of the state since precipitation improved forage and water resources.

A lifting of the restrictions was unlikely, apart from removing 4,000 wild horses in Elko County in the northeastern corner of the state, which John Ruhs, the Nevada director for the U.S. Bureau of Land Management, felt was needed.  Funding for the mustang roundup was lacking, but the drought-affected rangeland in four herd-management areas covering more than 600 square miles had deteriorated.

 “Nevada governor urges relaxed grazing limits,” by Scott Sonner, Associated Press, Salem Statesman-Journal (Ore.), May 28, 2016

  “US agency's Nevada boss urges roundup of 4,000 mustangs,” by Associated Press, Capital Public Radio (Sacramento, Calif.), May 2, 2016

Coyotes encroaching into Las Vegas for food, water

The lengthy drought in southern Nevada and disrupted desert habitat had more coyotes venturing into Las Vegas in search of food and water since there were fewer rodents, reptiles and other traditional prey available for coyotes.  The creatures prey on cats and dogs and forage for garbage in urban areas.

“Wily coyotes can thrive in the city and suburbs,” by Jesse Granger, Las Vegas Sun (Nev.), May 2, 2016

Washington state streams trending low again; fire danger rising in north central part of state

Ample snowfall earlier in 2016 made it seem as though Washington was escaping the drought that had held the state for the past two years, but warm weather and low snowfall since have created problems for Washington state fish, according to Teresa Scott of the Fish and Wildlife Department. Some streams have fallen to mid-summer lows and are preventing growing fish from traversing shallow stretches. Some bodies of water were heating up rapidly as they did in 2015, which led to fish kills.  Vulnerable fish may struggle during migration again this year.

With snow cover quickly disappearing, the landscape has become drier than usual for this time of year, leading to an early start to the fire season.  A large wildfire broke out west of the Cascades on May 13 in Gold Bar, six weeks earlier than the first large wildfire in 2015.  Campers in north central Washington were warned by the state Department of Natural Resources to be careful with fire because forests were still vulnerable to wildfire owing to drought in 2015 and the warm, dry spring this year.

“Record snowpack melt causing a host of woes,” by Derrick Nunnally, The Bellingham Herald (Wash.), May 31, 2016

 “Campers warned of closed roads, fire danger,” by K.C. Mehaffey, The Wenatchee World (Wash.), May 26, 2016


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