Tools used in the U.S. Monthly Drought Outlook (MDO) include the Climate Prediction Center (CPC) updated temperature and precipitation outlooks for May 2023, various short- and medium-range forecasts and models such as the 7-day quantitative precipitation forecast (QPF) totals from the Weather Prediction Center (WPC), the 6-10 day and 8-14 day CPC extended-range forecasts, dynamical model output, May climatology, and initial conditions such as soil moisture and snowpack. The U.S. Drought Monitor, valid on April 25, 2023, was used for initial drought conditions.

Drought conditions continued to ease across much of the Western Region as the Spring snowmelt follows repeated atmospheric river events during early 2023. Drought coverage was nearly cut in half across the region over the last three months, and the greatest improvements occurred in California, where drought covered over 97 percent of the state at the beginning of the calendar year, and now extends across less than 8 percent of the state. Despite a fairly dry May climatology west of the Rockies, undercutting systems south of an amplified ridge over northern North America are favored to bring late season rainfall to coastal California and additional snowfall to the Sierra Nevadas during early May. The CPC 8-14 day and updated May outlooks show a potential for this unseasonably wet pattern to persist throughout much of the month. This moisture may help ease small lingering drought areas across the northern Sierras and northwestern Nevada. Elsewhere, despite the forecasted enhanced moisture regime, topography and climatology will limit the potential for further drought reduction across the California deserts, southern Great Basin, and Utah ahead of the summer monsoon season. Further north, despite overall near normal snowpack conditions, precipitation accumulations since the beginning of the water year are well below normal across far northern California, Oregon, Washington, and Idaho. Therefore, the late season precipitation boost is unlikely to substantively change the current drought conditions across the Northwest and northern Intermountain West.

Forecast confidence is moderate for the Western Region.

During the past four weeks, deep snow cover across the Dakotas melted fairly rapidly, leading to reductions in lingering drought conditions, though also causing stream and river flooding. Little snow cover now remains across the High Plains states. Further south, a persistent lack of precipitation led to further deterioration, particularly across Kansas and Colorado. Currently, over 60 percent of Kansas is experiencing extreme to exceptional drought, with increasing impacts to winter planted crops. During the past week, widespread heavy rainfall overspread southeastern Colorado and southwestern Kansas, bringing a much needed substantial moisture boost to the region. The impacts of this recent precipitation to soils and streams is still being assessed, but should help yield some relief to the ongoing drought conditions. Over the next 7 days, mostly light precipitation is forecast across the High Plains region, though heavier amounts are forecast across the central Rockies. The CPC 8-14 day outlook shows enhanced chances for above-normal precipitation across western portions of the High Plains region. The updated monthly precipitation outlook maintains equal chances for below-, near-, and above-normal precipitation, with a drier signal across the Dakotas and eastern Nebraska and Kansas. Based on the impacts from recent precipitation and these outlooks, drought improvement is favored for southeastern Colorado and southwestern Kansas. Persistence of existing drought conditions is favored elsewhere, and some development is possible across northeastern Kansas.

Forecast confidence is moderate for the High Plains Region.

Similar to the High Plains region, rapid snowmelt over the past few weeks resulted in some drought reductions and high streamflow values across the upper Midwest, while a lack of precipitation promoted drought expansion across Missouri. Light precipitation (generally less than 0.5”) is forecast across Missouri during the next 7 days, which may help slow further degradations but will not improve the current situation. Both the CPC 8-14 day and updated monthly outlooks favor near to below-normal precipitation across the Midwest region, however, which may promote slow drought development in areas already abnormally dry or becoming dry. With little to no snow cover remaining, additional moisture boosts from melting will not occur during May, though moisture levels should generally remain favorable across Minnesota and northern Iowa. In contrast, drought development is favored for southern Iowa, northern Missouri, and west-central Illinois, where antecedent conditions are drier. Development may also be possible as far east as western Indiana, but wetter antecedent conditions make this less likely to occur during May.

Forecast confidence is moderate for the Midwest Region.

Across the Southern Region, exceptional drought continues to blanket much of northern Oklahoma. Across Texas, drought conditions largely persisted or slowly expanded across the western and central portions of the state, while periods of heavy rainfall eased and eliminated drought conditions across eastern Texas. Other than a small region of moderate drought along Louisiana’s Gulf Coast, the lower Mississippi River Valley and Tennessee Valley are free of drought conditions. Similar to Colorado and Kansas, widespread heavy rainfall fell across much of Oklahoma, northern and central Texas during the past week, bringing a significant moisture boost to areas entrenched in drought. As this precipitation continues to work its way into soils and streams, some drought improvements in the near term are favored where the heaviest rains occurred. During the next 7 days, generally light precipitation is forecast across the Southern Region. Above-normal rainfall is favored for much of the Southern Region during the 8-14 day period, and the updated CPC monthly outlook for May favors above-average precipitation along the Gulf coast into eastern and central Texas, and below-average precipitation for the Tennessee Valley, with enhanced chances for below-average temperatures. May is a climatologically wet time of year for Texas. Based on these outlooks, drought improvements are favored for central Oklahoma, central, eastern, and southern Texas, and Louisiana. Drought persistence is maintained for northern and western Texas, the Oklahoma Panhandle,
 and northeastern Oklahoma.

Forecast confidence is low to moderate for the Southern Region.

Most of the Southeast region is drought free; however, widespread drought developed across the Florida Peninsula during early Spring, following a characteristically dry and warm La Niña winter. Moderate drought also developed across northern Virginia, as moisture deficits became increasingly impactful when vegetation broke dormancy early. Thunderstorm activity has increased markedly across Florida, bringing drought relief south and east of Lake Okeechobee, along with localized flooding and severe weather. Forecasts during May at all time scales favor a continuation of a wet pattern across Florida, due in part to a mean frontal boundary draped across the region, and an early onset of the seabreeze-driven convective season. Therefore, continued drought relief is favored with high confidence. Across Virginia, heavy rainfall fell on April 28, with additional rainfall ongoing at the end of April. Total accumulations of 3 to 5 inches are favored with these events, which should quickly ease the moderate drought conditions. 

Forecast confidence is high for the Southeast Region.

Across the Northeast, small pockets of moderate drought remain across southern New England, southeastern New York, and northern New Jersey, with more widespread moderate drought conditions across the mid-Atlantic states. As mentioned in the Southeast discussion, a series of storm systems are progressing through the region, bringing widespread soaking rains. This near term rainfall should be sufficient to relieve the remaining drought conditions. No additional drought development is currently anticipated for the Northeast region, though forecasts for above-normal temperatures across northern New England may promote areas of increasing dryness during the month.

Forecast confidence is moderate to high for the Northeast Region.

No drought conditions are currently present or anticipated to develop during May across Alaska and Hawaii. Drought conditions have expanded across western Puerto Rico following a fairly dry winter and early Spring. While dynamical models slightly favor a continuation of the dry pattern, an active Madden-Julian Oscillation (MJO) signal and an ongoing transition towards a warm ENSO base state may provide opportunities for periods of wetness. Therefore, drought persistence is maintained for existing drought areas, but no new development is favored on the outlook.

Forecast confidence is high for Alaska and Hawaii, and low for Puerto Rico.

Forecaster: Adam Allgood

Next Monthly Drought Outlook issued: May 31, 2023 at 3PM EDT