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Drought and Climate for May 2018: Drought continues its grip on southwestern United States

by Curtis Riganti

Drought


During May, drought was eradicated in south Florida as rainfall from multiple storm systems in the Gulf of Mexico affected the area. Drought was also eliminated in southeast Georgia. Meanwhile, drought in the southern High Plains continued, although parts of western Oklahoma and the Texas Panhandle improved. Drought conditions worsened or persisted roughly from Midland, Texas through Arizona, New Mexico, and southern California. At the end of May, national coverage of moderate drought had decreased from 28.60 to 26.42 percent, severe drought coverage had increased from 16.32 to 16.92 percent, extreme drought coverage had increased from 8.89 to 9.24 percent, and exceptional drought coverage had slightly decreased from 2.20 to 2.09 percent.

Drought Outlook


During June, the ongoing drought in the Southwest and southern and central Plains is forecast to persist and expand eastward into parts of Louisiana, Arkansas, northern and western Missouri, southern Iowa, and west-central Illinois. The northern and eastern sections of the ongoing Dakotas drought are forecast to improve and, in some areas, be removed. The drought in eastern Oregon is forecast to expand slightly to the north and west. A small area of drought may also develop in southwest New Hampshire. Elsewhere, no categorical changes in drought status are forecast.

Temperatures


Aside from parts of coastal California and parts of the Florida Peninsula, much of the rest of the continental United States saw much warmer than normal temperatures. In particular, the areas from the upper Ohio Valley through the middle Missouri Valley southwest to the Texas Panhandle sweltered in temperatures 6 to 10 degrees above normal. The anomalously warm temperatures, particularly in the central United States, took place in stark contrast to the very cool conditions experienced in much of this region during April.

Precipitation


Precipitation varied widely in the continental United States during May; the most notable wet areas were Florida, Georgia, the Carolinas, and Virginia, where precipitation was more 8 inches above normal in isolated areas. Meanwhile, western Washington and Oregon were very dry. Other notable dry areas on a national scale included southwest Arkansas through north-central Texas and central and western Colorado.

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.

Regional Overviews


Northeast

During May, above-normal precipitation fell in the Mid-Atlantic region and in much of Pennsylvania and parts of southern New York. Meanwhile, the rest of New England received below-normal precipitation; southern Vermont, New Hampshire, and Maine largely received less than 50 percent of their normal May precipitation. Temperatures in May were above normal across nearly the entire region. The warmest areas, where temperatures exceeded 6 degrees above normal, were found in western Pennsylvania, West Virginia, Maryland, Delaware, western New York, and parts of Massachusetts.

Southeast

Much of the Southeast received above-normal rainfall in May, with large swaths of the region seeing at least double their normal rainfall for the month. In particular, the Florida Peninsula, the western Carolinas, and Virginia were very wet, where rainfall met or exceeded 200 percent of normal. Isolated drier pockets (<75 percent of normal) occurred in northeastern Alabama and northwestern Georgia. Temperatures in the Southeast were mostly above normal, with the warmest readings (temperatures 6 degrees or more above normal) being found in parts of the Carolinas and Virginia. The Florida Panhandle was near normal or below normal during the month.

South

Precipitation across the South during May varied widely, although on a large scale it was below normal. The driest areas were in parts of southern Texas, the western Texas Panhandle, northeastern Texas, parts of Louisiana, and southern Arkansas. These areas saw 25 to 50 percent or less of their normal May rainfall. Isolated spots in central and western Texas, western Oklahoma, the eastern Texas Panhandle, and Mississippi received more than 150 percent of their normal May rainfall. The coverage of the wetter than normal conditions was spotty, though, as other surrounding locales received near-normal or below-normal rainfall. May temperatures were above normal across nearly the whole region; temperatures rising to 6 degrees or more above normal took place in the Texas Panhandle, the northern two-thirds of Oklahoma, roughly the northern half of Arkansas, and much of Tennessee. Warm, but more moderate conditions, occurred closer to the Gulf Coast.

Midwest

Swaths of dry and wet conditions were found over the Midwest in May. Mostly below-normal rainfall occurred from northwestern Missouri eastward to western Ohio, with some areas in this area receiving less than half of their normal May rain. To the north, in northern Iowa, southern Minnesota, southern Wisconsin, northern Illinois, and lower Michigan, many areas received more than 150 percent of their normal May rainfall. Dry conditions prevailed in central, west-central, and northeastern Minnesota, while rainfall elsewhere in the Midwest was highly variable. May temperatures in the Midwest were much warmer than normal; with few exceptions, temperatures were at least 4 degrees above normal during the month, many areas were at least 6 degrees above normal, and the region from northwestern Missouri eastward through Ohio had widespread readings of at least 8 degrees above normal.

High Plains

Precipitation amounts varied in the High Plains during May. The most notable dry areas, where precipitation was generally at or below half of normal, were in southeastern, south-central, and western Colorado, northeastern South Dakota, west-central North Dakota, east-central and southeastern Nebraska, and the Interstate 70 corridor in eastern and north-central Kansas.  Most of Wyoming received well above normal precipitation for May; some parts of the state received more than 150 percent of normal precipitation. This wetness extended into western and central portions of Nebraska, as well as parts of northeastern Colorado. Temperatures were generally warmer than normal in the region during May. The hottest weather was focused in southeastern Nebraska and much of Kansas, as well as parts of the Dakotas, where temperatures were 6 degrees or more above normal for the month.

West

A notable lack of precipitation occurred over much of western Oregon and Washington during May. Elsewhere, precipitation was generally within an inch of normal. Parts of south-central Montana saw 3 or more inches above normal precipitation, and a few wetter spots were also scattered about the Sierra Nevada range in California and over parts of Nevada, Utah, and the Snake River Plain in Idaho. Most of southern and central California experienced near or slightly below normal temperatures for May, while parts of Arizona, Nevada, and Utah were slightly warmer than normal. Eastern Washington and Oregon, much of Idaho, and parts of Montana (particularly the eastern high plains) had above-normal temperatures. Parts of these regions reached 6 degrees or more above normal for the month of May.

Alaska, Hawaii and Puerto Rico

Alaska, Hawaii and Puerto Rico are not currently in drought.

Movers and Shakers for May 2018
StatePercent Area
May. 1, 2018
Percent Area
May. 29, 2018
StatusChange
Biggest increase in drought
Arizona95.9897.05Severe1.07
Arizona60.3573.61Extreme13.26
Arizona9.6215.71Exceptional6.09
California13.9920.75Severe6.76
Colorado30.8933.67Extreme2.78
Colorado5.027.79Exceptional2.77
Missouri16.5417.52Moderate0.98
Nebraska2.265.37Moderate3.11
Nevada31.0331.80Moderate0.77
New Mexico98.5699.35Moderate0.79
New Mexico80.8489.39Severe8.55
New Mexico45.0662.86Extreme17.80
New Mexico10.5918.27Exceptional7.68
North Dakota39.0153.30Moderate14.29
North Dakota3.4613.95Severe10.49
Oregon39.9245.30Moderate5.38
South Dakota19.2621.17Moderate1.91
Utah90.4392.67Moderate2.24
Utah58.4659.75Severe1.29
Utah3.744.02Exceptional0.28
Wyoming2.462.47Moderate0.01
Biggest decrease in drought
California37.1037.08Moderate0.02
California2.802.78Extreme0.02
Colorado67.9863.92Moderate4.06
Colorado53.6550.55Severe3.10
Iowa14.188.97Moderate5.21
Kansas84.8869.40Moderate15.48
Kansas59.4745.96Severe13.51
Kansas27.1615.85Extreme11.31
Kansas7.201.47Exceptional5.73
Oklahoma47.4445.53Moderate1.91
Oklahoma42.0740.54Severe1.53
Oklahoma34.8429.71Extreme5.13
Oklahoma23.939.81Exceptional14.12
Texas49.3640.06Moderate9.30
Texas25.5021.93Severe3.57
Texas13.947.82Extreme6.12
Texas4.311.17Exceptional3.14
Utah27.8027.75Extreme0.05

May 2018 impact summary: Water restrictions and burn bans increase in U.S. Southwest

by Denise Gutzmer

Drought persisted in parts of the Great Plains and intensified in the Southwest during May, which was an unusually hot month for the country.  Those hot temperatures stressed wheat and pastures and generally dried the landscape.  In the drier parts of the nation, notably in the Southwest, counties and municipalities enacted water restrictions and burn bans in preparation for a dry summer. 

In May, the NDMC added 152 impacts to the Drought Impact Reporter, with 35 for New Mexico, 31 for Colorado and 30 for Texas, cataloguing instances water shortages, poor crop prognoses and challenges for livestock producers.

 

Smaller wheat crop expected in southern Plains

The wheat crop was expected to be the smallest in more than 10 years as drought gripped the southern Plains, damaging crops, and a global surplus kept prices down.  According to the National Agricultural Statistics Service, the 2018 wheat crop was forecast to be 1.19 billion bushels, 6 percent lower than in 2017.  Drought and a late freeze damaged Oklahoma’s wheat crop, leading the U.S. Department of Agriculture’s National Agricultural Statistics Service to forecast a harvest of 52 million bushels, 47 percent lower than the 98.6 million bushels harvested in 2017. 

State, national wheat crops down, by Enid News & Eagle (Oklahoma), May 11, 2018

Oklahoma wheat producers expecting modest returns after a tough year, by Leilana McKindra, Southwest Farm Press, June 6, 2018

 

Fire restrictions implemented in Southwest

The arid Southwest appeared to be headed toward a difficult summer, given that two-thirds of the region was already in drought as summer began.  Some areas were experiencing near-record and record dryness.  With the dryness came heightened fire danger, numerous fire restrictions and forest closures throughout the Southwest.  Several forests in Arizona, including the Tonto and Coconino national forests, were closed to visitors.  In New Mexico, the Carson National Forest, Santa Fe National Forest and other national forests, grasslands and monuments were also closed.  Fire restrictions in southern Colorado were widespread in many counties and public lands where drought conditions were worst. 

Experts: ‘Alarming’ drought conditions hit US Southwest, by Susan Montoya Brown, The Associated Press, May 23, 2018

Area closures on Tonto National Forest begin Wednesday, Eastern Arizona Courier (Safford, Arizona), May 21, 2018

Large swaths of national forest near Flagstaff to close due to fire danger starting Wednesday, by Emery Cowan, Arizona Daily Sun (Flagstaff, Arizona) May 21, 2018

Given dry forecast, Carson forest faces more fire rules, by Sarah Halasz Graham, Santa Fe New Mexican (New Mexico), May 21, 2018

Fire bans enacted across Southern Colorado, by The Pueblo Chieftain (Colorado), May 16, 2018

 

Colorado River Basin experiencing continued drought

After a winter of below-average snowpack and drought, the U.S. Bureau of Reclamation announced that Arizona, Nevada and Mexico faced a 52 percent chance that they may receive less water from the Colorado River in 2020, because of ongoing drought, as the level of Lake Mead continued to drop.  The chances of a shortfall rise to 64 percent in 2021 and 68 percent in 2022.  Lake Powell was expected to receive just 43 percent of its typical inflow in 2018.

The flow of the Colorado River peaked weeks early just before mid-May and lower than normal in Colorado at the Utah state line.  The flow was about 8,500 cubic feet per second, ranking in the five lowest flows in 85 years of record.  With river flows being so low, water restrictions were rampant in the southern part of the state. 

The dry winter also left New Mexico’s water supplies in bad shape with reservoir levels falling low enough to activate the Rio Grande Compact provision, which prohibited the storage of additional water in upstream reservoirs.  The total amount of water stored in Elephant Butte and Caballo fell to less than 400,000 acre-feet on May 20.  Water from Elephant Butte and Caballo is used for irrigation in southern New Mexico and West Texas, industrial and municipal use in El Paso and to supply water to Mexico.

In eastern New Mexico, streamflow in the Pecos River as measured by the U.S. Geographical Survey found that the river was flowing at 21.5 cubic feet per second, about a sixteenth of the mean of 339 cfs for May 15.  Farther downstream at Anton Chico, no flow was recorded on the same day.  The low water levels prompted New Mexico Game & Fish to stock fewer fish on the Pecos River and take the remaining fish elsewhere, such as to the San Juan River and Heron, Storrie, Eagle Nest and El Vado lakes.

Mexico, 2 US states could see Colorado River cutback in 2020, by Dan Elliot, The Associated Press, May 9, 2018

River's peak more of a bump, by Gary Harmon, The Grand Junction Daily Sentinel (Colorado), May 12, 2018

NM drought worsening despite recent rainfall, by Ollie Reed Jr., ABQJournal Online (Albuquerque, New Mexico), May 25, 2018

‘This is really bad:’ Flows in Pecos River are tiny, by T.S. Last, Albuquerque Journal (New Mexico), May 18, 2018

 

Texas agriculture, water supplies affected by drought

Drought in Texas was worsening, with rangelands and pastures deteriorating and cattle sales occurring in the Panhandle and South Texas toward the end of May.  Crops and rangelands were not faring well with the early heat and need for irrigation.  Some were selling cattle early, given the pasture condition and waning water supplies. 

Declining aquifer levels led the Edwards Aquifer Authority to announce Stage 1 pumping restrictions after the 10-day average level of an index well fell below the minimum 660 feet trigger.  Some cities in South Texas began restricting water use, with permit holders in Bexar, Atascosa, Caldwell, Comal, Guadalupe, Hays and Medina counties being told to limit their pumping.  Outdoor watering restrictions began in San Antonio and San Marcos. 

Texas Crop and Weather Report – June 5, 2018, by Adam Russell, The Bryan-College Station Eagle (Texas), June 5, 2018

San Antonio among cities with drought water use restrictions, by Associated Press, May 22, 2018

 

For more details, see the Drought Impact Reporter

http://droughtreporter.unl.edu/map/

 

 

The images above summarize information from the Drought Impact Reporter.