This Week’s Drought Summary
The storm track remained active across much of the contiguous U.S. (CONUS) this week. Much of the Northern Tier states experienced beneficial rainfall and near to below-normal temperatures, predominantly leading to drought improvements from the Pacific Northwest to the Northern Plains. Storm systems and clusters of thunderstorms also resulted in some improvements from the Mississippi Valley to the East Coast. However, where the heaviest rains did not fall, there was some deterioration and slight expansion of abnormal dryness or drought conditions, particularly in parts of the Southeast and Ohio and Tennessee Valleys. Above-normal temperatures and below-normal precipitation was the main story across much of the southwestern CONUS, extending into Texas, leading to general persistence and degradation of drought conditions. Weak trade winds in Hawaii and below-normal precipitation in Alaska have continued, resulting in degradations this week. Warm and dry conditions also contributed to worsening conditions in Puerto Rico.
Short-term (30 to 60-day) rainfall deficits continue to mount across parts of the Lower Mississippi and Tennessee Valleys. Coverage of D0 (abnormal dryness) was generally expanded, although coverage is sporadic. Seasonal temperatures in these areas helped keep evapotranspiration rates at bay this week. However, daily soil moisture anomalies continue to become more negative, particularly over the past couple of weeks from northern Louisiana, extending northeastward toward the Tennessee Valley, as several locations have seen continued declines in surface moisture. Similar to the Carolinas, these areas will need to be watched in the coming weeks, as potentially excessive heat and below-normal precipitation is forecast through the end of the month. Drought deterioration is also warranted across much of Texas, which saw another week of much above-normal temperatures, high winds, and below-normal precipitation. Some of these degradations extended into western Louisiana also. However, in eastern Louisiana, a cluster of thunderstorms provided some relief to abnormally dry (D0) and moderate drought (D1) areas. Improvements are also warranted in western Oklahoma, particularly in areas that received at least 1 inch rainfall surpluses this week. Some 2-category improvements occurred in areas where year-to-date precipitation deficits declined and daily soil moisture estimates improved to near-normal down to 200 cm.