South-Central U.S.: Despite dry, warmer-than-normal weather (temperatures averaging up to 14°F above normal), little if any change was made to the drought designation from Texas northward into southern Kansas. In fact, locally heavy rain has been falling over the region since the data cutoff time (12z Tuesday, January 24) for this week’s drought depiction; impacts from the rain will be addressed in next week’s U.S. Drought Monitor. A small increase in D0 (Abnormally Dry) was made in northeastern Oklahoma to reflect 60-day precipitation deficits up to 3 inches (locally more).
Central and Northern Plains: Seasonably cold conditions prevailed, with some snow falling from the northern High Plains eastward across northern South Dakota toward Sioux Falls. To the south of this area of snow, D0 (Abnormally Dry) conditions were expanded to include much of northern Nebraska. Precipitation in this area has totaled locally less than 50 percent of normal over the past 60 to 90 days, with the 3-month Standardized Precipitation Index (SPI) highlighting this same area as being unfavorably dry.
Midwest: Drought areas of the Midwest - which extend from northwestern Iowa into Minnesota and eastern-most portions of the Dakotas - reported mostly dry weather and seasonable temperatures (averaging within 2 to 4°F of normal) during the past week. Changes to drought designation were generally minor, and included expansion of Moderate Drought (D1) across northwestern Minnesota and northeastern North Dakota. Standardized Precipitation Indices (SPI) out to 6 months indicated increasingly dry conditions in this region. Likewise, 90-day precipitation totals are running 25 percent of normal or less north of Grand Forks, and soil moisture percentile rankings are in the 10th percentile or lower across much of northern Minnesota. On the other hand, drought impacts at this time of year are generally negligible and difficult to ascertain due to the cold; should drier-than-normal conditions continue, this area will have to be closely monitored as we ease into spring.
Western U.S.: Locally heavy, much-needed precipitation in western and northern portions of the region contrasted with ongoing dryness and increasing drought from the southern Great Basin into the central Rockies. A series of Pacific disturbances generated moderate to heavy rain and mountain snow from central California northward into the Pacific Northwest. Heavy snow was reported in the Sierra Nevada (3-8 inches liquid equivalent, locally more) and from the Klamath Mountains (10 inches or more liquid equivalent) into the Cascade Range. Snow-water equivalent in the Sierra improved, although many stations were still in the 20th percentile or lower. Nevertheless, the precipitation provided a 1-category improvement in drought designation in the Sierra, with D2 (Severe Drought) reduced to D1 (Moderate Drought). This area, however, will need to be closely monitored over the upcoming weeks, with water-year-to-date precipitation still averaging 50 percent of normal or less. The heavy precipitation in the Klamath Mountains likewise resulted in modest improvements to Abnormal Dryness (D0) and Moderate Drought, with water-year-to-date precipitation ranging from 50 percent of normal in the southern portions of the Klamath to near normal closer to the Oregon border. Heavy precipitation in the Cascades boosted snow-water equivalents into the 50th to 75th percentile (locally higher), with drought not a concern in the mountains of the Pacific Northwest at this time. Valley locales east of the Cascades largely missed out on the rain and snow, although a half inch or more in the D1 area from southern Washington into north-central Oregon provided beneficial moisture for winter wheat. In northern and central Idaho, moderate to heavy snow (2-6 inches liquid equivalent, locally more) boosted mountain snowpacks and alleviated Abnormal Dryness (D0). By week’s end, snow-water equivalents had jumped above the 40th percentile across much of the region, with yet another storm poised to provide additional relief to the southern portions of the state.