This Week’s Drought Summary
Short-term drought continued to rapidly expand across the Ohio, Tennessee, and Middle Mississippi Valleys along with parts of the Corn Belt. Thunderstorms brought locally heavy rainfall and drought relief to parts of the central to northern Great Plains. However, 7-day temperatures averaged above-normal throughout the Great Plains. A tropical disturbance in the western Gulf of Mexico and a trough of low pressure resulted in heavy rainfall and improving drought conditions to southeast Texas and southwest Louisiana. Convective rainfall was highly variable this past week across the Southeast with isolated amounts exceeding 3 inches while other areas remained mostly dry with worsening drought conditions. New England experienced a week of mostly dry weather and expanding drought coverage. Following the unusually heavy Monsoon rainfall during late June, heavy amounts were more localized this past week across New Mexico. Seasonal dryness prevailed throughout California, while much of the Pacific Northwest became drier after a wet spring. Drier-than-normal conditions persisted for much of Alaska into the beginning of July. A tropical wave of low pressure tracked northwest from the central Atlantic and brought heavy rainfall to eastern Puerto Rico.
The rapid onset of drought continues to affect parts of the Tennessee and Lower Mississippi Valley with a continued increase in coverage of short-term moderate drought (D1). Western Tennessee and northern Mississippi were especially dry the past two weeks with many areas receiving less than 0.25 inches of rainfall. This dryness was combined with above-normal temperatures. Therefore, severe drought (D2) was added to parts of northern Mississippi and western Tennessee. 30-day SPEI, EDDI, and soil moisture indicators were used as guidelines in these degradations. Likewise, D0-D1 was also expanded across northeast Texas, southeast Oklahoma, and Arkansas. The number of Arkansas counties, designated with burn bans, continues to increase. In the 6 week period since May 25, Jonesboro, Arkansas has recorded 1.17″ of precipitation, or about 25% of normal. This is the driest such period since 1952. SPI values, starting at 120 days through the past 24 months, along with CPC’s leaky bucket soil moisture (lowest percentile) supported an expansion of D4 across the Texas Panhandle.
Closer to the Gulf Coast, heavy rainfall (more than 1.5 inches) resulted in widespread 1-category improvements to southern Louisiana and southeastern Texas. In areas that received more than 5 inches of rainfall such as southwest Louisiana, a 2-category improvement was justified. A small 2-category improvement was also made to northeastern Texas that received 3 to 6 inches of rainfall. Recent, heavy rainfall also led to a trimming of the extension of moderate drought (D1) across central Mississippi.