Extensive rainfall helps reduced drought’s footprint
Drought coverage and intensity continued its overall decreasing trend this spring across the Great Plains.
To the east across southern Iowa, northern Illinois, and northern Missouri, drought expanded with little to no precipitation from May 27 to June 2. The Desert Southwest had an unusual wet start to June as a low-pressure system, interacting with enhanced moisture from Tropical Storm Alvin in the East Pacific, resulted in locally heavy rainfall and a 1-category improvement to parts of Arizona.
A wetter-than-normal May brought an end to drought throughout much of the Northeast. The rainy season is well underway across Florida and heavy rainfall this past week led to improvements across the central to southern Florida Peninsula. Seven-day temperatures (May 27 to June 2) averaged below-normal across most of the eastern and central United States, while above-normal temperatures prevailed for the West.
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the U.S. Department of Agriculture and the National Oceanic Atmospheric Administration. (Map courtesy of NDMC.)
South
For the second consecutive week, heavy rainfall (more than 1 inch) prompted a 1-category improvement to central and southern Texas. Despite this recent heavy rainfall, levels in the long-term monitoring wells of Bexar and Medina Counties remain near or at all-time lows.
In addition, many of the 28-day average United States Geological Systems streamflows across south-central Texas are below the 5th percentile, supporting the D3-D4 depiction. Since the SPIs dating back six months are mostly neutral to positive, the drought impact is designated as long-term only for central and southern Texas.
Recent precipitation and the NDMC drought blends supported 1-category improvements to northern and eastern New Mexico. Additional rainfall this past week ended drought across Oklahoma and the Sooner State became drought-free for the first time since July 2019.
Midwest
Following a mostly dry week through June 2nd and based on 30 to 60-day SPI along with soil moisture, a 1-category degradation was made to parts of Iowa and northern Missouri.
The largest 60-day precipitation deficit, ending on June 2, is 4 to 5 inches across western to southern Iowa and northern Missouri.
High Plains
From May 20 to June 2, two-week precipitation amounts ranged from 2 to 4 inches, locally more, across much of Kansas, Nebraska and northeastern Colorado.
This precipitation accompanied by cooler-than-normal temperature during the latter half of May led to improving drought for the central Great Plains. The southern half of Kansas is now drought-free.
On June 2, precipitation (more than 0.5 inch) overspread southern Colorado where a 1-category improvement was made. Additional precipitation this past week along with consideration of SPIs dating back 6 to 12 months and the NDMC drought blends supported the removal of severe (D2) to extreme (D3) drought across southeastern Wyoming.
Despite only light precipitation this past week, a 1-category improvement was made to much of the Dakotas to be more consistent with SPIs at various time scales, soil moisture, and the NDMC drought blends. For the northern Great Plains, the drought impact was changed to long-term only given the recent wetness and the drought signal is strongest at 9 to 12 months.
West
The Desert Southwest had a rare wet start to June as a mid-level low-pressure system interacted with enhanced moisture from former Tropical Storm Alvin in the East Pacific.
Based on worsening soil moisture and low 28-day average streamflows, a 1-category degradation was warranted for parts of central and southwestern Montana.
Looking ahead
From June 5 to 7, a slow-moving cold front coupled with a low-pressure system near the East Coast is forecast to bring scattered showers and thundershowers to the East with the heaviest precipitation for eastern North Carolina. Multiple rounds of thunderstorms with locally heavy precipitation are forecast from the central and southern Great Plains east to the Tennessee Valley through June 7.
In the wake of a cold front, mostly dry weather will prevail for the Northern Great Plains and western Corn Belt. A warming trend is forecast across the Pacific Northwest and northern California with potential record highs on June 8 and 9.
The Climate Prediction Center’s six- to 10-day outlook (valid June 10 to 14) favors above-normal precipitation for the Rocky Mountains, Great Plains, Lower Mississippi Valley, and Southeast. The outlook leans toward below-normal precipitation for the eastern Corn Belt.
Above-normal temperatures are favored throughout much of the West, northern Great Plains, Upper Mississippi Valley, and East Coast with increased chances for below-normal temperatures forecast for the southern Great Plains and Middle Mississippi Valley.
Brad Pugh is with the National Oceanic Atmospheric Administration and Climate Prediction Center.
