National Drought Summary -- May 19, 2020

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilized include the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14 Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast web page used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

The southern Plains, Mississippi Valley, Pacific coast and south Florida were the recipients of the greatest rains this week, with some areas of Louisiana and south Florida recording 5+ inches of rain for the week. Dryness over the East and West was also coupled with warmer than normal temperatures over the West. Temperatures were 3-6 degrees above normal over the Nevada, Utah, Colorado and New Mexico regions while the northern Plains was 6-9 degrees below normal. Many dry areas of the Plains and Midwest have not had drought development due to the unseasonably cool temperatures in May.


Alaska, Hawaii, and Puerto Rico

Hawaii has been dry recently, which allowed the expansion and introduction of abnormally dry conditions over most of the state. On Kauai, abnormally dry conditions were added to the southern half of the island. In Oahu, abnormally dry conditions were expanded to cover the southwestern half of the island. Abnormally dry conditions were expanded to cover the rest of Maui and the Big Island. On Molokai, moderate drought was expanded eastward to Kaunakakai and on the Big Island, moderate drought was pushed to the east to include the leeward slope of the Kohala Mountains and south to Waikoloa. In Puerto Rico, abnormally dry conditions were expanded to the north with a new area introduced in the northeast part of the island. With short-term dryness impacting the southern portions of the island, a new area of moderate drought was added this week. No changes were made in Alaska this week.


High Plains

Temperatures over the region were generally 6-8 degrees below normal, with portions of Colorado and Wyoming the outliers with temperatures 2-4 degrees above normal. Most of the region was fairly dry for the week with many areas below normal for precipitation during one of the wettest months of the year. Portions of western South Dakota, western Nebraska, northeast Colorado, and southeast Kansas did record precipitation that was well above normal with 150-400 percent of normal for the week. With the dryness throughout much of the area, abnormally dry conditions were expanded and moderate drought was introduced to portions of western North Dakota and into South Dakota. Abnormally dry conditions were expanded through central and southeast Nebraska and portions of northeast Kansas. These areas will be ripe for drought development without rain, especially if temperatures become more seasonable. Northeast Colorado did see some improvement due to recent heavy rains as the severe and moderate drought as well as the abnormally dry conditions shifted south slightly. The abnormally dry pocket in southeast South Dakota was also removed this week after some locally heavy rain.


Midwest

Cooler than normal conditions again dominated the region with temperatures 2-4 degrees below normal in the southern portions of the area and 4-6 degrees below normal in the north. A slow-moving storm system affected the eastern areas of the region, with many areas recording 2-3 inches of rain with locally greater amounts. There are several dry pockets in the region, and areas of Wisconsin, Minnesota and northeast Iowa all had abnormally dry conditions expand this week due to the dryness over the short-term. Abnormally dry conditions were also expanded over southeast Iowa and into northwest Missouri. The lack of above-normal temperatures has kept drought from developing, but conditions are being monitored.


Northeast

Cooler than normal temperatures dominated the region, with most areas at least 2-4 degrees below normal for the week and the northernmost portions of the region 6-8 degrees below normal. Precipitation was mixed for the week, with the southern areas remaining dry while portions of the northern areas of the region recorded normal to slightly above normal precipitation. Ongoing dryness in portions of northeastern New York did allow for the introduction of D0 this week, which was based upon the short-term indicators.


South

Temperatures over the region were near normal to slightly below normal where the most precipitation took place. Areas of west Texas were 3-6 degrees above normal for the week. It was an active week over much of the region for precipitation, which allowed for improvements over much of the area. Most of southern, central, and eastern Texas as well as southern Louisiana had a full category improvement as these areas recorded the greatest precipitation, which shifted the drought indices, allowing improvement to take place. Some areas of southern Louisiana had 10+ inches of radar-estimated rainfall. Areas of the Texas and Oklahoma panhandles, west Texas, and southwest Oklahoma did not receive any of this rain and conditions continued to deteriorate. Portions of western Oklahoma have had all winter wheat zeroed out as producers did not get a crop to grow and did not even see enough growth for grazing purposes. In southwest Oklahoma, moderate drought and abnormally dry conditions expanded this week. Some areas of the Texas panhandle did see improvements to the abnormally dry conditions while other areas missed out on the rain and saw conditions decline. Abnormally dry conditions were also expanded over west Texas this week.


Southeast

For the region as a whole, the week was mostly dry. Spotty precipitation throughout the area did bring near-normal precipitation with it, but those who missed out were mainly dry for the week. Portions of southern Mississippi, southern Florida, and the panhandle of Florida did see 200+ percent of normal precipitation. Temperatures were cooler than normal over most of the area with most locations right at normal to 3-6 degrees below normal for the week. Due to the significant rains in south Florida, a full category improvement was made as the short-term dryness has been improved upon greatly over the last several weeks. The drought area of central Florida was split from that of southern Florida where lingering abnormally dry conditions were eliminated. With dryness over the last several weeks, abnormally dry conditions again returned to northern Florida into southern Georgia. In the panhandle region, abnormally dry conditions and moderate drought were expanded northward in response to short-term dryness. The dryness gradient remained in place over portions of southern Mississippi and southern Alabama with the severe drought areas pushing slightly northward this week. The areas of the region with sandier soils with lower capacity to hold moisture are in need of precipitation to stave off a widespread expansion of abnormally dry conditions. The cooler temperatures have lessened demand, but that can change rapidly in this region.


West

Most of the region was dry for the week with the exception of the Pacific Northwest and northern California, where 150-200 percent of normal precipitation was recorded. Temperatures for the region were 3-6 degrees above normal over central Nevada, Utah, Colorado, and eastern New Mexico, with most of the rest of the region near normal to 3 degrees below normal for the week. In the Pacific Northwest, the recent rains helped to slow down further degradation in Oregon and Washington, with portions of the abnormally dry areas of western Washington improved this week. Oregon has some improvement to the severe and extreme drought over the southwest portions of the state but did see moderate drought expand slightly over portions of the western areas of the state. Conditions in Nevada and Utah continue to decline with an intensification of moderate and severe drought over northern portions of both states as the short-term dryness is starting to combine with the long-term issues in these areas. New Mexico had an expansion of moderate, severe, and extreme drought in the northern portions of the state as some of the recent dryness is coupled with longer-term issues in the drought indicators. Abnormally dry conditions were expanded over most of eastern New Mexico as a result of short-term issues. Southwest Colorado had an expansion of extreme and severe drought conditions while moderate drought was expanded northward over the central portion of the state.


Looking Ahead:

Over the next 5-7 days, it is anticipated that the Plains states will remain in an active pattern, with the greatest precipitation to occur over portions of Nebraska, Kansas, Oklahoma and into Texas. The Mid-Atlantic is also anticipating precipitation amounts of up to 3-4 inches during the period. Dry conditions will dominate the Southwest and into most of the Pacific Northwest and West Coast. Temperatures during this period will be near normal over most of the country with below-normal temperatures over the Northwest and northern Rocky Mountains. Areas that receive the most rain will also have the coolest temperatures over the Mid-Atlantic into the Northeast.

The 6-10 day outlooks show a high probability of greater than normal temperatures over the West, northern Plains, Midwest, Northeast and Alaska. The greatest probabilities are over the Southwest. There are also high probabilities of cooler than normal temperatures over the southern Plains and into the South. The precipitation outlook has the northern Plains and Pacific Northwest with the greatest likelihood of below-normal precipitation. The best chances of above-normal precipitation will be over the South and Southeast but may also include the Midwest and Southwest.


Author: Brian Fuchs, National Drought Mitigation Center

Dryness Categories
D0...Abnormally Dry...used for areas showing dryness but not yet in drought, or for areas recovering from drought.

Drought Intensity Categories
D1...Moderate Drought
D2...Severe Drought
D3...Extreme Drought
D4...Exceptional Drought

Drought or Dryness Types
S...Short-term
L...Long-term