National Conditions: May 24, 2023 - May 30, 2023
While the Southern Plains improved again, the Midwest, Northeast, Mid-Atlantic, and South saw a huge expansion of Abnormal Dryness (D1) with some drought. Parts of eastern South Dakota and Nebraska worsened too.
As of May 30, 2023, 15.84% of the U.S. and Puerto Rico and 18.95% of the lower 48 states are in drought, according to the U.S. Drought Monitor.
This Week's Drought Summary...
The upper-level circulation over the contiguous U.S. (CONUS) during this U.S. Drought Monitor (USDM) week (May 24-30) was dominated by three features: a trough over the West, a ridge that extended from the southern Plains to the Great Lakes, and a cutoff low over the Southeast. This pattern resulted in targeted areas of precipitation, some of it heavy, while large parts of the CONUS received little to no precipitation. Pacific weather systems moved across the West, but their fronts stalled out when they ran into the ridge over the Plains. The northwesterly flow associated with the trough inhibited precipitation across parts of the West, so the week was wetter than normal only from the Great Basin to northern Rockies. A southerly flow over the Plains was created between the western trough and eastern ridge. This flow funneled Gulf of Mexico moisture across the Plains. The moisture fed thunderstorms and weather complexes that developed along the stalled-out fronts and dry lines, resulting in above-normal precipitation across western portions of the Great Plains from Texas to Montana. Several inches of rain fell with some of these thunderstorms, resulting in localized flooding.
The ridge inhibited precipitation, so a large part of the country from the Mississippi River to the Northeast received little to no precipitation. The exception to this was the Southeast, where the cutoff low pulled in Gulf and Atlantic moisture to spread above-normal precipitation across much of Florida and the Carolinas to Appalachians. Weekly temperatures averaged cooler than normal from the southern Plains to East Coast, but they were warmer than normal across the northern Plains and northern parts of the West. Abnormal dryness or drought spread across a large part of the Midwest and Northeast, and in parts of the Pacific Northwest, Puerto Rico, and Hawaii. Drought or abnormal dryness contracted across the Florida peninsula, across large areas in the western Great Plains, and in northwest Puerto Rico.
Looking Ahead...
For June 1-6, an upper-level ridge will dominate the middle part of North America, bringing above-normal temperatures to the north central states and Pacific Northwest. Upper-level troughs and closed lows will cover much of the West and New England, bringing cooler-than-normal temperatures to New England and southern parts of the West to the southern Plains. Like the last 7 days, a southerly flow of Gulf of Mexico moisture will feed showers and storms that develop from the Rockies to the Mississippi River during the next 7 days. An inch or more of rain is forecast from the southern Plains to northern Rockies, with locally 4 inches or more from the Texas panhandle to southern Kansas, and locally 2 inches or more in parts of Colorado to Montana. A fourth of an inch or more can be expected from California’s Sierra Nevada to the Great Basin, across the northern Plains to Mississippi Valley, in the Tennessee Valley, across the Gulf of Mexico coast, and along the Appalachians to Northeast. New England may see over an inch of rain, while much of the Florida peninsula will be inundated with another 2+ inches of rain. Little to no precipitation is predicted for the eastern Great Lakes to Ohio Valley, the interior Southeast, and southern and western portions of the West.
For June 6-14, a warmer-than-normal pattern is likely for the Pacific Northwest to western Great Lakes, the northern half of Alaska, and the Alaska panhandle, with cooler-than-normal temperatures across southern portions of the West, the southern Plains, and from the Appalachians to New England. Odds favor wetter-than-normal conditions across the West, southern Plains, western portions of the central to northern Plains, and the southwest half of Alaska, with drier-than-normal conditions across the Great Lakes, Upper Mississippi Valley, Ohio Valley, and northeast Alaska.
