Widespread Drought Improvement For The South, Midwest
Following a drier-than-normal winter, March came in like a lion for much of the U.S. Widespread drought improvements were made to the Midwest and South, but worsening precipitation deficits and low snowpack caused there to be a mix of improvements and degradations elsewhere.
Northeast
A series of weather systems moved across the Northeast last week. Temperatures were generally warmer than normal, so wintry precipitation in the form of snow, sleet and freezing rain was generally limited to the mountains and higher elevations. Otherwise, the rest of the region saw rain. Widespread liquid precipitation totals of 1 to 2 inches fell in parts of New York, northern New Jersey, Pennsylvania and West Virginia, leading to 1-category improvements.
Most notably, an area of extreme drought (D3) contracted across northern New Jersey, severe drought (D2) also improved for the rest of northern New Jersey into eastern Pennsylvania. Moderate drought (D1) also improved in western and southeastern New York, central and eastern Pennsylvania and eastern West Virginia. Abnormal drought (D0) was reduced in western Pennsylvania.
Despite the recent beneficial precipitation since late February, a long-term drought of varying intensity persists for much of the Northeast. Some 28-day average streamflows remain low (below the 10th percentile) from the northern Mid-Atlantic into New England. Any improvements this week were made to long-term drought as short-term drought has mostly ended.
Southeast
The Southeast saw occasional rain showers and thunderstorms over the past week. Interior portions saw the most rainfall for the week, with some locally heavy rain seen in spots. Mobile, Ala., picked up around 5 inches of rain for the week! However, there continues to be mounting precipitation deficits due to a fairly dry winter. Therefore, improvements were very localized this week. There were also a few spots that had abnormally dry and drought conditions worsen. Overall, conditions were generally status quo over the past week as the precipitation was enough to slow down drying and worsening drought.
Improvements were noted to moderate drought (D1) in localized areas of northwestern, east-central and southwestern Alabama as well as a small portion west-central Georgia and southwestern Virginia.
Meanwhile, localized degradation occurred in southeastern Alabama, northeastern Georgia, southwestern Virginia and the Florida Peninsula. A new area of extreme drought (D3) was added to northeastern Georgia, while extreme drought worsened in east-central and southeastern Florida. Severe drought (D2) expanded across southeastern Alabama and central Florida, while moderate drought (D1) worsened in southwestern Virginia.
Consistent with a La Niña winter, drought has worsened the past few months across Florida with more than two-thirds of the Sunshine State designated with extreme (D3) drought. According to the National Interagency Fire Center, a wildfire at Florida’s Big Cypress National Preserve has grown to over 35,000 acres burned.
South
A frontal boundary was stalled over much of the South this week, which led to frequent rounds of rain and thunderstorms. Despite the locally heavy rainfall across the southern Plains and Lower Mississippi Valley, only modest improvements were warranted as precipitation deficits over the winter remain large.
Precipitation amounts up to or even exceeding 2 inches were recorded generally across the eastern half of the region. Improvements were made in eastern Oklahoma and isolated spots of eastern Texas to moderate to extreme drought (D1-D3). Severe to extreme drought (D2-D3) contracted across northern Arkansas, while central Louisiana and southwestern Mississippi saw improvements to abnormally dry to severe drought (D0-D2) conditions. Southeastern Tennessee saw moderate drought (D1) contract slightly.
In areas that missed out on the beneficial rainfall, drought intensified for parts of west-central Oklahoma and the Oklahoma Panhandle. Both severe and extreme drought (D2-D3) intensified. Much of South Texas remains in Extreme to Exceptional (D3-D4) drought.
A majority of the South Region has received less than half their normal precipitation with a temperature departure of more than 6 degrees above normal during the past 90 days. These 3-month precipitation and temperature observations are consistent with a La Niña wintertime pattern.
Midwest
The Midwest was quite active over the last week as a couple low pressure systems and associated cold fronts moved across the region. Rain was the predominant precipitation type throughout the region. Though, some parts of the Upper Midwest did experience some snow or a wintry mix of snow, sleet and freezing rain at times. Widespread drought improvement was seen throughout the Midwest as a result, with every state seeing some type of improvement. Given the time of year, this recent precipitation was very beneficial in recharging soil moisture.
Improvements were made to Minnesota’s Arrowhead (moderate drought D1), southwestern Wisconsin (moderate drought D1), much of Iowa (abnormal dryness to moderate drought D0-D1), much of Missouri (moderate to extreme drought D1-D3), the southern half of Illinois (moderate to extreme drought D1-D3), the southern half of Indiana (abnormal dryness to extreme drought D0-D3), central and southeastern Ohio (abnormal dryness D0) and southern parts of Michigan’s Lower Peninsula (abnormal dryness to moderate drought D0-D1).
High Plains
A potent low pressure system impacted the High Plains region toward the middle of the drought monitoring period. This brought snow to Wyoming and Colorado, while rain generally occurred elsewhere. Parts of Wyoming, Colorado, Kansas and Nebraska had heavier precipitation amounts (up to 1 to 1.5 inches), which includes some very wet snow in the Denver metro area. Lighter precipitation was recorded in the Dakotas. However, precipitation deficits remain large over much of the High Plains region, while snowpack is critically low in the central Rockies of Wyoming and Colorado.
As a result, there were only localized improvements this week. Most notably, extreme drought (D3) was completely removed in and around the Denver metro area, while severe to extreme drought (D2-D3) contracted across southern Wyoming. Moderate drought (D1) has slight improvement in far eastern Nebraska, while abnormally dry conditions (D0) shrunk in southeastern Kansas.
Extreme drought (D3) expanded from central Colorado into north-central Colorado, while moderate drought (D1) worsened in southwestern Colorado. Severe drought (D2) expanded in east-central Wyoming as well as from northeastern Nebraska into southeastern South Dakota.
The low snowpack throughout the Central Rockies, especially Colorado, remains a major concern heading into the spring. As of March 10, snow water equivalent for the river basins of Colorado is running below 70 percent of the 1991-2020 average.
West
The Northwest into parts of the Great Basin had a fairly active week of weather thanks to a parade of storm systems. Coastal areas and lower elevations saw rain, while the mountains and higher elevations picked up some snow. Then, in the Southwest, dry weather prevailed for the first half of the monitoring period, then a weather system brought some small chances of rain to southern California, Arizona and New Mexico.
Despite the overall active weather pattern last week, there were only degradations made to the drought depiction. The low snowpack throughout much of the West continues to be a major concern heading into spring. As of March 10, snow water equivalent is less than 40% of normal from the Cascades of the Pacific Northwest southward through the Great Basin and Four Corners region. Temperatures over the last two week have averaged above normal. Not only did this cause snow to be limited to the tallest peaks, but the warmer than normal weather has also led to an early onset of snowmelt for parts of the West. Although California remains free of drought, snow water equivalents is 53% of the normal statewide according to the California Department of Water Resources.
Based on increasing 60-day precipitation deficits and to reflect the low snowpack, abnormal dryness (D0) was added to parts of northern California. Moderate drought (D1) expanded into southeastern Utah while intensifying to severe (D2) and extreme (D3) drought across northeastern and western portions of the state. Moderate (D1) drought was expanded across north-central to northeastern Washington along with central Oregon due to 30 to 90-day precipitation deficits and low snowpack.
Looking Ahead
A cold front moving through the eastern U.S. early in the forecast period is expected to bring sharply colder temperatures. Another, stronger cold front will sweep east from the Great Plains to the East Coast by the end of the forecast period, pushing subfreezing temperatures as far south as Oklahoma and the Texas Panhandle.
More than an inch of precipitation is forecast across the Great Lakes and New England, while drought-stricken Florida is expected to receive much-needed rainfall. In contrast, the Ohio Valley, Middle to Lower Mississippi Valley, and Great Plains are likely to stay mostly dry. At the same time, dry weather will be accompanied by an increasing chance of record heat across California, the Great Basin, and Southwest.
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Source: U.S. Drought Monitor