This U.S. Drought Monitor (USDM) week saw improvements on the map in drought-affected areas of the Southwest, Northern Plains, and the Midwest while conditions deteriorated in areas of the Pacific Northwest, Eastern Plains of Colorado and Montana, Southern Plains, and the South. In the Pacific Northwest, a combination of factors (below-normal snowpack conditions, short-term dryness, low streamflows) led to expansion of areas of Abnormally Dry (D0) and Moderate Drought (D1) in western portions of Oregon and Washington. In Montana, poor snowpack conditions in the northwestern and west-central part of the state led to expansion of areas of Extreme Drought (D3) where some SNOTEL stations were reporting record or near-record low snow-water equivalent (SWE) levels. In the Southern Plains, drier-than-normal conditions during the past 30-90-day period in addition to low streamflows, declining soil moisture, and impacts to crops led to expansion of areas of Moderate Drought (D1) and Severe Drought (D2) in Oklahoma and Kansas. Conversely, wetter-than-normal conditions have prevailed during the past 30-60 days in portions of the Midwest leading to widespread improvements across drought-affected areas of Iowa, Minnesota, Wisconsin, and Michigan. Likewise, improvements were made on the map in areas of the Southwest (Arizona and New Mexico) in response to beneficial precipitation received across much of the region since the beginning of the Calendar Year (January 1). In California, snowpack conditions moving into late April (4/24) were near normal levels with the statewide snowpack at 97% of normal, according to the California Department of Water Resources. Elsewhere in the West, below-normal SWE levels have persisted in the mountain ranges of Washington, northern Idaho, Montana, and northeastern Wyoming. According to the Natural Resources Conservation Service (NRCS) SNOTEL network (4/23), region-level (2-digit HUCs) median SWE levels are as follows: Pacific Northwest 75%, Souris-Red-Rainy 76%, Missouri 80%, California 95%, Great Basin 108%, Upper Colorado 87%, Lower Colorado 145%, Rio Grande 78%, and Arkansas-White-Red 79%.

Forecast

The NWS Weather Prediction Center (WPC) 7-Day Quantitative Precipitation Forecast (QPF) calls for moderate-to-heavy precipitation accumulations ranging from 2 to 5+ inches (liquid) across western Washington and Oregon as well as eastern portions of the Southern and Central Plains and lower Midwest. Lighter accumulations (less than 2 inches) are expected in areas of the Central and Northern Rockies and Upper Midwest, while isolated light shower activity is expected in portions of Northern California, the Great Basin, and the Northeast. The NWS Climate Prediction Center (CPC) 6-10 Day Outlooks call for a moderate-to-high probability of above-normal temperatures across most of the conterminous U.S., with the exception of the Far West, and the western Great Basin where cooler-than-normal temperatures are expected. In Alaska, there is a low-to-moderate probability of above-normal temperatures in the southern half of the state and below-normal temperatures north of the Brooks Range. In terms of precipitation, below-normal precipitation is expected across the Eastern Tier of the conterminous U.S. as well as out West in western Colorado, Utah, and southern Nevada. Elsewhere, there is a high probability of above-normal precipitation across the Pacific Northwest, Northern California, eastern New Mexico, Texas, the Plains states, and the Upper Midwest.

Midwest

For the week, light-to-moderate precipitation accumulations (generally less than 2 inches) were observed in the region with the heaviest accumulations logged in isolated areas of southern Minnesota, southern and northeastern Iowa, southeastern Missouri, southern Illinois, and southwestern Indiana. Average temperatures for the week were below normal (2 to 6 degrees F) across the western half of the region with the greatest anomalies observed in eastern Iowa and central Illinois. In the eastern portion of the region, the average temperature hovered within a few degrees of normal. On the map, improvements were made in drought-affected areas of southern Minnesota, eastern and northern Iowa, northern Missouri, Wisconsin, southern Illinois, and northern Michigan. In Iowa, despite improving conditions, two areas of Extreme Drought (D3) remain in the northeastern part of the state due to the lingering impacts of the longer-term drought situation with 12-month precipitation deficits ranging from 12 to 16 inches. According to the latest USDA Iowa Crop Progress and Condition report (4/22/24), the statewide soil moisture (topsoil) condition was rated 37% short to very short and 60% adequate. In southern Missouri, areas of drought expanded on the map where dry conditions have prevailed in the shorter term (past 30-90 days) and have led to a significant decline in streamflow levels with numerous rivers and creeks reporting very low flows during the past week (less than 10th percentile), according to the U.S. Geological Survey (USGS). Moreover, very low soil moisture levels (less than 10th percentile) are showing up on various NASA SPoRT soil moisture products.