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Drought and Climate for December 2018: Southern U.S. sees above-normal precipitation

by Claire Schirle and Curtis Riganti

Drought


During December, areal coverage of all drought categories decreased slightly on a national scale.  Coverage of moderate drought was reduced 0.79 percent to 18.69 percent.  Severe drought was reduced 0.74 percent to 9.13 percent.  Extreme and exceptional drought were reduced 0.82 percent and 0.15 percent, respectively, leaving 2.75 percent of the country in extreme drought and 0.95 percent of the country in exceptional drought.  The total population within drought areas also decreased slightly, from 55.1 million to 51.4 million.

Drought Outlook


In January, the areas of drought in far northwestern Oregon, northeastern Oklahoma, southwestern Missouri and northwestern Arkansas are likely to be removed.  Drought removal and improvement is also expected in parts of central California, far southern California, and southwestern Arizona.  Drought is expected to persist in Florida, North Dakota and the remaining portions of the West.

Temperatures


Temperatures in much of the country were above normal during December.  The northern plains and parts of the Midwest were the warmest areas, with temperatures 6 to 10 degrees above normal.  Exceptions to the warmer than normal temperatures were found in parts of the Intermountain West, Texas, and northern New England, and in small pockets of southern Georgia and central Florida.  Temperatures in these areas ranged from 6 degrees below normal to near normal.

Precipitation


The southern and southeastern regions, as well as large portions of the plains, were much wetter than normal during December.  Many locations in these areas saw precipitation amounts over 200 percent of normal thanks to multiple heavy precipitation events.  Many areas of the West, on the other hand, saw drier or slightly drier than normal conditions, with many areas seeing precipitation amounts between 5 and 100 percent of normal.  However, eastern Montana, northeastern Wyoming, the Four Corners region, parts of New Mexico, far southern California, northwestern Nevada and parts of Washington saw precipitation amounts between 100 and 400 percent of normal.  The Midwest and Northeast saw variable precipitation totals ranging from 50 percent of normal to 200 percent of normal.

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

Precipitation totals ranged from 25 percent of normal in a small pocket of New York to over 200 percent of normal in sections of Maine and Pennsylvania. The majority of the region, however, saw precipitation totals ranging between 70 and 150 percent of normal.  Temperatures in much of Pennsylvania, New York and New Jersey were between 2 and 6 degrees above normal, while temperatures in New Hampshire, Vermont, Massachusetts, Connecticut and Rhode Island were closer to normal—between 2 degrees below normal and 3 degrees above normal.  Maine was the coolest state in the region, with temperatures ranging between 2 degrees above normal and 5 degrees below normal.  The entire region remained drought free during December.

Southeast

With the exception of southern coastal Florida, the Southeast received much above normal precipitation for December. Many areas saw at least 150 percent of normal precipitation for the month, while many locations in northeastern Florida and coastal Georgia received at least three times their normal December precipitation. Most of the Southeast was 4 to 6 degrees warmer than normal during December. Moderate drought was eliminated from northeastern Florida to southern South Carolina, resulting in a regional increase in moderate drought from 2.6 to 4.43 percent. Outside of southern Florida, the Southeast was drought free at the start of 2019.

South

Near- or above-normal precipitation fell in most of the South during December, with a few drier spots showing up in the western Texas Panhandle and Lower Rio Grande Valley. Numerous locations in central and northeastern Texas and in Oklahoma received at least 150 percent of their normal December precipitation. Aside from the western half of Texas, most of the South experienced near or warmer than normal temperatures. Many locations in Louisiana, Arkansas, Mississippi, and Tennessee were 4 to 6 degrees above normal for December. Moderate drought was removed from northwestern Arkansas and northeastern Oklahoma, while moderate drought developed in the Lower Rio Grande Valley. Across the South, moderate drought coverage decreased slightly, from 0.93 to 0.67 percent.

Midwest

Near- or above-normal precipitation for December was common in most of Missouri and Iowa (excluding southeastern Iowa and northeastern Missouri), Minnesota, and southern portions of Illinois, Indiana, and Ohio. Drier than normal conditions were common in much of Michigan, northern Wisconsin, and spots in northern Indiana and northern Ohio. The entire region was warmer than normal during December, with temperature departures of 3 to 9 degrees above normal being common across the Midwest. The Midwest was drought free at the beginning and end of December, with a few pockets of abnormal dryness lingering at the beginning of 2019 in southwestern Missouri and northwestern Minnesota.

High Plains

Dry conditions occurred during December in eastern Colorado and southeastern and central Wyoming, while above-normal precipitation fell in much of the rest of the High Plains region. Parts of central Nebraska received much above normal (4 to 8 times) their normal December precipitation. Most areas of the High Plains were warmer than normal in December. The warmest areas compared to normal were northern South Dakota and North Dakota, where temperatures soared to 6 to 10 degrees above December normals. Moderate drought was eliminated in central South Dakota and reduced in North Dakota. Across the High Plains states, exceptional drought coverage decreased from 2.73 to 2.29 percent, extreme drought coverage decreased from 6.84 to 5.54 percent, severe drought coverage slightly increased from 11.84 to 11.85 percent, and moderate drought coverage decreased from 20.49 to 18.27 percent.

West

Precipitation departures in the West during December were variable. The wettest areas (compared to December normals) were in eastern Montana, southeastern California, northwestern Nevada, and parts of New Mexico. The driest areas were in central and north-central Colorado, northwestern Wyoming, and western Montana. Warmer than normal conditions occurred in eastern Washington, northern Idaho, and much of Montana, where some areas saw temperatures reach 6 to 8 degrees above normal for December. Elsewhere, generally warmer than normal conditions were common, except for parts of Utah, northern Nevada, southwestern Wyoming, and central and southwestern Colorado. Over the course of December, exceptional drought coverage dropped from 3.35 to 2.88 percent, extreme drought coverage decreased from 10.84 to 8.35 percent, severe drought coverage dropped from 28.95 to 27.22 percent, and moderate drought coverage dropped from 55.06 to 53.25 percent.

Movers and Shakers for December 2018
StatePercent Area
Nov. 27, 2018
Percent Area
Dec. 25, 2018
StatusChange
Biggest increase in drought
Arkansas0.901.22Moderate0.32
Colorado54.8254.91Severe0.09
Florida9.4420.55Moderate11.11
Idaho10.3810.46Severe0.08
Nevada65.9781.09Moderate15.12
New Mexico35.8535.92Severe0.07
Oklahoma3.275.08Moderate1.81
Wyoming3.263.27Severe0.01
Biggest decrease in drought
Arizona73.9969.79Moderate4.20
Arizona34.4132.67Severe1.74
Arizona4.333.30Exceptional1.03
California83.6675.17Moderate8.49
California18.3316.24Severe2.09
California3.782.10Extreme1.68
Colorado33.4627.11Extreme6.35
Colorado13.3511.22Exceptional2.13
Idaho25.7525.59Moderate0.16
Nevada12.9212.84Severe0.08
New Mexico20.6719.89Extreme0.78
New Mexico15.0514.50Exceptional0.55
North Dakota26.5516.72Moderate9.83
Oregon98.6593.34Moderate5.31
Oregon86.2180.46Severe5.75
Oregon34.2624.77Extreme9.49
Utah76.1073.31Severe2.79
Utah17.797.70Extreme10.09
Utah3.011.80Exceptional1.21
Washington32.5930.47Moderate2.12
Washington0.380.17Severe0.21

December 2018 impact summary: Reduced hydropower production affecting Alaska

by Denise Gutzmer

As drought intensified slightly in parts of Nevada, Idaho, Texas and Florida, the NDMC added 11 impacts to the Drought Impact Reporter in December.  Alaska had the most drought impacts, documenting low water supplies and issues with energy production.  California, Rhode Island and New Mexico had two impacts apiece. 

 

Alaska

Southeast Alaska has been in severe drought, with 2018 being Ketchikan’s fourth driest year on record. 

The Ketchikan area received a little more than 96 inches of rain and snow water equivalent during the year, leaving the area nearly 36 inches below normal for 2018.

The poor rainfall meant water supplies were lower than normal, threatening hydropower production.  Alaska Electric Light & Power announced that its customers will see higher electricity rates, probably through June 2019, because of low rainfall and insufficient hydropower production.  AEL&P also produces surplus power, which is usually sold to several other entities, such as Princess Cruise Lines, with the understanding that the supply is interruptible when water supplies are low. Since reservoir levels were low, there was not enough surplus electricity to sell to these customers, fully interrupting their supply for the first time in five years.

A Weird Severe Drought Is Affecting Alaska in One of the Wettest U.S. Locations, by Chris Dolce, The Weather Channel (Atlanta, Georgia), Dec. 11, 2018

Electric rates about to rise, by Alex MeCarthy, Juneau Empire (Alaska), Dec. 17, 2018

 

Rhode Island

Drought was partly responsible for the dearth of Christmas trees in southeastern Massachusetts and Rhode Island.  A tree farm manager in Attleboro, Massachusetts, reported a shortage of Christmas trees in his area and noted that people from the Cape, Rhode Island and Braintree were calling in search of trees. The financial crisis in 2008 when tree growers planted fewer trees and several hot, dry summers that slowed tree growth were reasons for the shortage.

Rhode Island’s forests were also affected by the lack of rain.  Episodes of drought in past years resulted in roughly 13 percent of the trees in the state’s forests dying.  Heat and insect infestations also played a role in the tree deaths.  Many of the dead trees were located across the western part of the state from Burrillville to Hopkinton, on Prudence Island and the Sakonnet Peninsula.  The area of dead trees covered about 45,000 to 50,000 acres, according to The Providence Journal. 

Slim pickings at Attleboro area tree farms as Christmas nears, by Judee Cosentino, The Attleboro Sun Chronicle (Massachusetts), Dec. 16, 2018

State: About 13 percent of Rhode Island forest trees dead, by The Associated Press, Dec. 6, 2018

 

New Mexico

Northern New Mexico enjoyed some snow in late October, but snowfall has been below normal since then.  The precipitation outlook remained average to above average, with the hope of an El Niño bringing more snow. 

With thin snowpack, the Elephant Butte Irrigation District in southwestern New Mexico issued a warning that customers might receive as little as a few inches of water per acre, given that Elephant Butte Reservoir dipped to just 3 percent of capacity in late September. Subsequent snowfall boosted the reservoir level a little, but far more precipitation was needed for a decent irrigation season. 

Early Santa Fe-area snow yields to drier conditions, Sarah Halasz Graham, Santa Fe New Mexican, Dec. 18, 2018

New Mexico farmers brace for meager water allocations, by Susan Montoya Bryan, The Associated Press, Albuquerque Journal (New Mexico), Dec. 20, 2018

 

Colorado River Basin Drought Contingency Plan

Colorado River water managers met in Las Vegas in December as southwestern states tried to devise drought plans to sustain the Colorado River system as its reservoirs declined.  A drought contingency plan was meant to be completed by the end of the year, but the deadline was not met.  Arizona and California were still striving to work out details among stakeholders.

Bureau of Reclamation Commissioner Brenda Burman gave water managers until January 31, 2019, to finalize a drought plan for the basin.  If the deadline is not met, the Bureau of Reclamation may impose unprecedented restrictions on water supplies.

Southwest states eye drought plans ahead of expected Lake Mead shortages, by Yvonne Gonzalez, Las Vegas Sun, Dec. 12, 2018

Correction: Colorado River Water-Drought story, by Ken Ritter, The Associated Press, Dec. 18, 2018

US water official: Feds will protect Colorado River without state drought plans, by Tony Davis, Arizona Daily Star (Tucson, Arizona), Dec. 13, 2018

 

For more details, visit the Drought Impact Reporter

The images above summarize information from the Drought Impact Reporter.