According to today's Drought Monitor report of the U.S. Department of Agriculture (USDA), a large shift in the weather pattern occurred this week across the lower 48 states. Early in the week, low pressure exited the Great Lakes region, allowing temperatures to gradually moderate during the latter half of the week across portions of the eastern contiguous U.S. (CONUS). In the western CONUS, high pressure broke down as a strong storm system moved into the Pacific Northwest heading into the weekend. As this storm system moved eastward into the Great Plains through the weekend and leading up to Tuesday, October 25, many locations across the western and central CONUS experienced above-normal precipitation, with cooler than normal temperatures in the system’s wake.
In the Midwest, in a similar fashion as the Southern Region, antecedent short-term (30 to 60-day) dryness has resulted in the widespread expansion of abnormally dry (D0) and moderate (D1) to severe (D2) drought conditions. Given the much of the region experienced above-normal temperatures and below-normal precipitation again this week, it warranted another round of 1-category degradations, particularly across the Ohio Valley.
Soil moisture ranks in the bottom 20 percent of the historical distribution, according to various soil moisture products. In addition, 30 to 60-day standardized precipitation indices (SPIs) range anywhere from D1-equivalent (moderate drought) to D4-equivalent (exceptional drought), with 30-day SPIs indicating the more severe designations. Parts of Missouri and the central Corn Belt were the only areas that received enough rainfall to improve drought conditions or stop ongoing degradation this week. More than 2 inches of rain fell across the western Ozarks leading to broad 1-category improvements to the drought depiction in affected areas, as rainfall totals improved short-term precipitation deficits and topsoil moisture and 7-day average stream flows responded favorably.
For the full USDA report for Oct. 27, click here.