Drought degradations were centered on the Pacific Northwest and Southeast in this week's Drought Monitor update, while the change map also showed improvements across the Northeast quarter of the U.S. and smaller improvements in the Central Plains.
About 40.1% of the contiguous U.S. is in some form of drought or dryness currently, compared to 39.6% last week and 45.3% one year ago. About 2.9% is in the most extreme rating, compared to 2.9% last week and 2.9% one year ago.
Drought map update author Richard Tinker of NOAA said up to 3 inches of precipitation fell on parts of the Northeast, leading to improved conditions across portions of the region.
In the Southeast, there were areas of moderate rain and isolated locations with heavy amounts, but most areas reported less than a normal week's worth of precipitation, and hotter-than-normal conditions exacerbated dryness.
Overall, despite some small areas of improvement, dryness and drought either persisted or worsened
In the Ohio Valley, the remnants of Tropical Storm Bill along with a frontal boundary brought copious amounts of rain to the area.
Locations from the Mississippi and Ohio Rivers' confluence to the central Appalachians received 2 to 6 inches of rain, resulting in widespread dryness and drought relief. Moderate rain brought improvement as far south as central Kentucky, western West Virginia, and south-central Virginia.
Light to moderate precipitation fell on the dry areas along and northwest of the Great Lakes Region, and across parts of the southeastern Great Lakes region.
No tangible change in dryness severity was noted in Wisconsin and Minnesota, but in combination with moderate to heavy rains over the past few weeks, D0 was removed from part of south-central Michigan.
Light to moderate rainfall fell on most of the dry areas in the Plains, though little or no rain fell on dry areas from northern Kansas into southeastern New Mexico. A second week of significant rainfall led to reductions in the extent of D0 and D1 conditions in southeastern South Dakota and adjacent Nebraska, and there was further reduction in the D0 area still lingering in central Texas. Otherwise, conditions remained essentially as they were last week.
From the Rockies westward to the Pacific Coast, little precipitation fell last week. Overall, there was little change in conditions except along the northern tier of states from Montana westward through Washington and Oregon.
Continued dryness and exceptionally hot weather kept dryness and drought increasing most significantly across eastern Washington, central and northern Idaho, and western Montana. The entire state of Washington is now covered by D0 conditions or worse, and D2 was pulled northward along the Oregon coastline, and expanded across a large part of central Idaho and adjacent Montana.
In contrast, recent heavy precipitation in west New Mexico and adjacent northeast Arizona led to additional improvements in these areas despite the dry week.
Source: U.S. Drought Monitor/The U.S. Drought Monitor is produced through a partnership between the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration.