Map released July 23, 2020 | Data valid July 21, 2020
This week’s drought summary: High pressure dominated the southern half of the contiguous U.S. (CONUS) during this U.S. Drought Monitor (USDM) week. Upper-level weather systems tracked across the U.S.-Canadian border, dragging surface lows and fronts along with them. The frontal systems tapped Gulf of Mexico moisture to drop locally heavy rain across parts of the Plains to Midwest, while convective thunderstorms peppered coastal areas of the Gulf. The high-pressure ridge inhibited precipitation across much of the Southern Plains to Southeast, and across most of the West. It also kept temperatures unusually hot, with daily maximums exceeding 90 degrees F across the South throughout the week and across much of the West for most of the week. The excessive heat spread into the northern Plains, Midwest, and into the Northeast as the week wore on. The persistent heat increased evapotranspiration, which dried soils and stressed crops and other vegetation. The locally heavy rains brought temporary relief from the heat and dryness, but only for those areas in the Plains and Midwest lucky enough to receive the rain.
South: Two to locally more than five inches of rain fell across parts of the Texas Panhandle and Northwest Oklahoma, and along parts of the Texas to Mississippi coast. But it was another dry week across much of Texas to Eastern Oklahoma to Northern Mississippi and Tennessee. Moderate to extreme drought contracted in the Panhandles of Texas and Oklahoma, but moderate to severe drought expanded in other parts of Texas, with pockets of extreme drought added to Southwestern Texas and Southwestern Oklahoma. Abnormal dryness or moderate drought expanded further east across parts of Arkansas, Louisiana, and Tennessee.
Looking ahead: For July 23-27, the Southwest Monsoon is predicted to fire up, dropping locally two or more inches of rain across parts of the Four Corners states, and up to an inch of rain is forecast over parts of the Northern Rockies. Otherwise, the West is expected to be mostly dry. A tropical system may bring up to four inches of rain along the western Gulf of Mexico coast and up to two inches over Southern Florida, while frontal systems could leave one to three inches of rain over parts of Nebraska, the northern Plains to western Great Lakes, parts of the Midwest to Appalachians, the Mid-Atlantic coast, and parts of the Northeast. In between these systems, large swaths of the Southern and Central Plains to Southeast and Southern Great Lakes have less than an inch of rain in the forecast. Temperatures are predicted to continue warmer than normal for most of the CONUS.
The outlook for July 28-Aug. 1 calls for wetter-than-normal conditions across the Southwest to Mid-Atlantic region and most of Alaska, and drier-than-normal conditions in the Pacific Northwest to Great Basin, Northern Plains to Great Lakes, and much of the Northeast, as well as Southeast Alaska. Odds favor warmer-than-normal conditions for most of the West, Northern Plains to Great Lakes, eastern Gulf Coast, all along the Eastern Seaboard, and across the Aleutians in Alaska. Cooler-than-normal temperatures are likely across the Southern to Central Plains and across most of Alaska.