Above-normal precipitation and subnormal conditions continue in some areas of High Plains while drought expands in Kansas

According to the U.S. Drought Monitor for April 3 released April 5, with a blocking ridge of high pressure anchored over the Southwest, a series of cold fronts tracked across the eastern two-thirds of the nation. The fronts, however, slowed their southeastward advance across the South and Southeast, and after picking up Gulf moisture, produced numerous and widespread showers and thunderstorms with heavy precipitation (more than 2 inches) from the southern Great Plains northeastward into the northern Appalachians. This was similar to the weather pattern back in mid- to late February when the lower Mississippi, Tennessee, and Ohio Valleys were deluged. Lighter precipitation also occurred across the northern halves of the Rockies and Plains, the upper Midwest, Great Lakes region, western New England, the central Gulf Coast States, and along the Pacific Northwest Coast. Little or no precipitation fell on the remainder of the Far West, Southwest, southern halves of the Rockies and High Plains, western Corn Belt, along the eastern Gulf and Atlantic Coasts, and most of Alaska. Weekly temperatures averaged below normal in the northern Rockies, northern and central Plains, Midwest, mid-Atlantic, and Carolinas, and above-normal in the Far West, Southwest, southern Plains, along the Gulf Coast, and in northern New England. In Alaska, readings were much-above normal in western and northern sections and near to below normal in southern and eastern portions. Most of Hawaii and Puerto Rico observed showery weather.

In the High Plains, the persistent fall and winter pattern of above-normal precipitation and subnormal temperatures continued this week across Montana, Wyoming, and the western Dakotas, building up the existing snow cover and gradually providing additional relief from long-term drought. In eastern Montana, SPIs out to 9-months were wet except in the extreme northeastern part of the state (Daniels and Sheridan counties) where D2 lingered. Similarly in extreme western Dakotas and northeastern Wyoming, additional precipitation allowed for a slight nudge of the D0-D2 areas to the east (improvement). However, since this drought goes back to 12 to 15 months ago, it will take more precipitation to remove these long-term deficits (6 to 10 inches) and subsoil impacts where D1 and D2 are currently depicted, hopefully during the upcoming wet season (April-July). In central and eastern North Dakota where the drought was short-term, snow totals of 1 to 2 inches in the central and 4 to 6 inches in the east added to 90-day surpluses. Even though soil moisture conditions are less than desired (ground barely frozen at 4-inch depth), 90-day percent of normal precipitation has shown significant improvement. Therefore, some D1 was improved to D0 in central parts of the state while D0 was erased from eastern areas. In Nebraska, moderate snows fell across southern sections of the state, but D0 was kept as subsoil dryness lingered due to frozen ground earlier in the year that limited infiltration of melting snow or rain. As conditions thaw and additional storms occur, infiltration should increase. Farther south in Kansas, little or no precipitation meant another week of growing deficits, and based upon indices going out to a year, D3 conditions were common in central and northeastern portions of the state; therefore D3 was expanded northeastward.