The active weather pattern persisted across most of the nation, though unfavorably dry, hot weather lingered over parts of the South and Southwest. During the 7-day period ending Tuesday morning, areas of heavy to excessive rainfall provided widespread drought relief across the central and southern Atlantic Coast States and from Texas northward into Montana and the Dakotas. Conversely, short-term dryness intensified along the central Gulf Coast, while worsening drought conditions were noted in portions of Arizona and Oregon. Likewise, short-term dryness continued to develop in parts of New England. Please note the wet weather pattern continued through the week; any rain that fell after 12z Tuesday (8 a.m., EDT) will be incorporated into the following week’s drought assessment.
Watch: U.S. Drought Monitor since January 1, 2018.
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The overall trend toward improving conditions in the south contrasting with increasingly dry weather in the far north continued, though some northerly areas benefited from locally heavy rain. In southern Kansas, another week with moderate to locally heavy showers (1-3 inches, as high as 3.72 inches in Longton, KS) led to widespread reductions of drought intensity and coverage. Nevertheless, 6-month precipitation in the state’s lingering Extreme Drought (D3) was less than half of normal, while the Exceptional Drought (D4) in the state’s southwestern corner stood at less than one third of normal over the same time period. Moderate to heavy rainfall (locally more than 3 inches) in northeastern Colorado likewise trimmed the coverage of Abnormal Dryness (D0). In south-central Nebraska and north-central Kansas, heavy rain (2-3 inches; Phillipsburg, KS, reported 3.95 inches) yielded a corresponding reduction of D0. In southeastern Nebraska, increasingly dry conditions over the past 90 days (40-60 percent of normal) led to a modest increase of Moderate Drought (D1) southwest of Lincoln. Farther north, sharply wetter conditions between Bismarck, ND, and Aberdeen, SD, (6.17 inches in Java, SD) resulted in a considerable reduction of D0. Beneficial rain (1-2 inches) was also reported in northeastern Montana, where D0 was reduced accordingly. Meanwhile, D1 and D2 were increased somewhat in North Dakota from Bismarck to the Canadian border, where 60-day rainfall shortfalls (locally less than 30 percent of normal) have added to the region’s lingering long-term drought.
Conditions were largely mixed over the region during the 7-day monitoring period, with generally dry weather in the north contrasting with additional rain in southern portions of the region. Moderate to heavy rainfall (1-4 inches, locally more) led to widespread reductions in Abnormal Dryness (D0) in central Missouri, with a report of 5.52 inches in Appleton City (north of El Dorado Springs). Similarly, moderate to heavy showers (1-2 inches) netted a modest reduction to D0 in southeastern Iowa. Conversely, rain largely bypassed locales from northeastern Missouri into west-central Illinois, with D0 expanded to capture areas reporting half of normal rainfall over the past 60 days. Farther north, the recent tendency toward unfavorable dryness continued, with D0 expanded across northern Wisconsin and environs to capture locales which have reported less than 50 percent-of-normal rainfall over the past 60 days. Nevertheless, rain amounts topping an inch in and around Red Lake in northern Minnesota led to small reductions to Moderate Drought (D1) and Abnormal Dryness (D0).
An active pattern will continue, with two significant areas of wet weather over the next 5 days. Forecast data continues to show a tropical or subtropical system developing over the eastern Gulf of Mexico and lifting slowly northward over the Memorial Day holiday weekend; if this were to verify, the potential exists for another round of heavy to excessive rain (2-6 inches, possibly more) over the lower Southeast. Meanwhile, a pair of slow-moving storms system will produce moderate to heavy rain (1-4 inches) from the northern Rockies eastward across northern portions of the Plains and Upper Midwest. A trailing cold front will trigger showers over the western Corn Belt and Mississippi Valley. Despite the continuation of a generally active weather pattern, the Southwest will remain unfavorably dry. The NWS 6- to 10-day outlook for May 29 – June 2 calls for below-normal rainfall over the Northwest and from Texas and the southern High Plains into the Great Lakes and New England. In contrast, wetter-than-normal conditions are expected from the northern Great Basin into northern portions of the Rockies and Great Plains, with a second higher-likelihood area of above-normal rainfall over the southeastern quarter of the nation. Abnormal warmth is expected over most of the nation save for near-normal temperatures in the aforementioned rainy and cloudy Southeast.