Nationwide
Abnormal dryness (D0) and short-term moderate (D1) to severe (D2) drought continued to expand across the Lower to Middle Mississippi Valley, Ohio Valley, Central Appalachians, Northeast, and Southeast.
However, heavy precipitation (2 inches or more) resulted in a 1-category improvement to central and eastern portions of Kentucky and Tennessee. Enhanced moisture, associated with Hurricane Lorena in the East Pacific, led to locally heavy precipitation and drought improvements in parts of the Desert Southwest. Following a relatively wet week for this time of year, minor improvements were made to parts of Oregon. Elsewhere, little to no changes were warranted for the Pacific Northwest and California.
A strong cold front for early September triggered heavy precipitation and drought improvements across New Mexico and the Rio Grande Valley of Texas. Much of the Central to Northern Great Plains and Upper Mississippi Valley remained drought-free. 7-day temperatures (Sept. 2-8) averaged below-normal across most of the central and eastern U.S., with above-normal temperatures limited to the Pacific Northwest, Northern Intermountain West, Great Basin, and California.
The West
Heavy precipitation (1- 2.5 inches) supported a decrease in severe (D2) to extreme (D3) drought around the Albuquerque, Santa Fe, and Las Cruces areas of New Mexico. In addition, the National Drought Mitigation Center (NDMC) long-term drought blend was used as guidance. Locally heavy precipitation led to improvements across portions of southeastern Nevada, southwestern Utah, and western to southern Arizona.
Conversely, the continued drier-than-normal Monsoon (60-day precipitation averaged 50 percent below normal) supported an expansion of extreme drought (D3) for eastern Arizona. A favorable response to heavy precipitation (2-2.5 inches) two weeks ago led to the removal of extreme drought (D3) in southwestern Montana. Further to the north, a 1-category degradation was made in northwestern Montana after a reassessment of longer-term metrics, including the NDMC blend. A slight increase in extreme drought (D3) in eastern Washington was made to better align with the 6-month Standardized Precipitation Index (SPI). An unusually wet start to September resulted in small areas of improvement in Oregon. Elsewhere across the Pacific Northwest and California, no changes were needed.
The High Plains
Heavy precipitation (more than 2 inches) occurred in D-nada areas of central Kansas, but significant precipitation (1.5 to inches) led to a minor decrease in abnormal dryness (D0) in southwestern Kansas.
Conversely, a slight increase in D0 and moderate drought (D1) was made to eastern Kansas. Significant precipitation (more than 0.5” and locally 2-3”) supported improvements across southern Colorado, while worsening SPIs led to a slight expansion of severe (D2) to extreme (D3) drought for northern Colorado. A majority of the Dakotas, Nebraska, and eastern Wyoming remain drought-free.
The South
Heavy precipitation (1.5 to 2 inches or more) supported a 1-category improvement to central and eastern Tennessee, while 30 to 60-day SPI, along with soil moisture indicators, resulted in the expansion of severe drought (D2) across western Tennessee, northern Mississippi, and northeastern Arkansas.
Increasing 30 to 60-day precipitation deficits supported extending abnormal dryness (D0) south to the Mississippi Gulf Coast. For the long-term drought areas designated in Texas, a round of heavy precipitation (more than 1.5 inches) this past week resulted in 1-category improvements. Based on the 120-day SPI and NASA SPoRT soil moisture, D0 was expanded across southwestern Oklahoma with the addition of a small moderate drought (D1) area. 30 to 60-day SPIs along with declining soil moisture supported an increasing coverage of D0 across the Texas Panhandle and Edwards Plateau. — UNL Drought Monitor
