Drought swallowed 59 per cent of the Lower 48 in a single month

Drought coverage across the Lower 48 jumped by roughly 10.5 percentage points in under a month, reaching 59.1 per cent of the contiguous United States as of September 1, according to the U.S. Drought Monitor’s weekly map released September 3. The expansion was concentrated in a band running from the southern Plains through the Mississippi Valley and into the Corn Belt, where hot, dry weather triggered what monitor authors classify as flash drought: conditions that develop and intensify over weeks rather than months.

Flash Drought Spread From Texas Into the Corn Belt

The Drought Monitor’s weekly summary describes flash-drought conditions occurring across a wide swath spanning Texas northeastward through Oklahoma, southern Kansas, southern Missouri, Arkansas, northern Mississippi and portions of far western Tennessee. Burn bans were enacted across much of western Oklahoma, and officials in Oxford, Mississippi asked residents to conserve water because of high demand combined with recent extreme heat. Streamflow across much of central and western Oklahoma and northern Texas ran low alongside depleted soil moisture, a combination the report ties directly to short-term precipitation deficits rather than a longer multi-year dry spell. Degradation was especially prevalent in southwestern and northern Texas, deep south Texas, northern Mississippi and eastern Oklahoma, where hot, dry weather worsened conditions in areas already carrying a range of drought impacts to agriculture and water supply.

Temperatures Made a Dry Month Worse

Warmer-than-normal conditions compounded the rainfall shortfall in several of the hardest-hit areas. Oklahoma and the northern half of Texas ran 6 to 10 degrees hotter than normal for the week, continuing what the report calls a very hot August across much of Oklahoma. Kansas saw similarly elevated readings, 6 to 10 degrees above normal, which raised atmospheric demand for moisture and worsened conditions in the southeastern part of the state. That heat-drought pairing mirrors the pattern behind the record-warm summer NOAA reported for the country as a whole, though the drought map itself is built from a separate set of precipitation, streamflow and soil-moisture indicators rather than temperature rankings alone. Fire danger also grew in step with the dryness: the weekly report notes continued worsening of fire risk and vegetation stress across southwest Missouri and neighboring Arkansas as conditions there degraded alongside the broader southern Plains expansion.

Why Some Regions Improved While Others Degraded

The national total masks sharp regional swings. Widespread improvement occurred from Wyoming and the eastern Colorado plains northeast into Nebraska’s Sandhills and southern South Dakota, where recent heavier rainfall either eased conditions directly or prompted a reassessment of earlier ratings. Parts of Colorado west of the Front Range and western Utah also saw drought ease slightly after recent rain reduced long-term precipitation deficits. At the same time, moderate drought expanded in northern California, where a lack of winter snowpack combined with recent hot, dry weather, and conditions worsened further in north-central Montana and west-central Minnesota as short-term rainfall deficits mounted. Short-term precipitation shortfalls and poor streamflow also pushed drought conditions lower in parts of the Idaho Panhandle, the Spokane, Washington area and nearby northwest Montana, while parts of the Northeast, including southern New England and sections of New Jersey and southeastern Pennsylvania, saw localized improvement after rain totals locally topped 2 inches.

Puerto Rico’s Extreme and Exceptional Drought

Conditions off the mainland were more severe in places. More than three-quarters of Puerto Rico remained in drought, with over 40 per cent of the island classified as extreme drought, even after heavy rainfall from the remnants of Tropical Storm Dolly brought localized relief to the island’s east. In the U.S. Virgin Islands, groundwater levels on St. Croix, St. John and St. Thomas all remained well below where they stood a year earlier despite scattered rain, with monitoring wells on St. Croix and St. John both reading several feet deeper than their September 2025 levels. St. Thomas fared worst for rainfall among the three islands, with its main airport gauge recording just 0.01 inch for the week, underscoring how unevenly the same tropical moisture source can affect drought status across a small island chain.

How the Weekly Map Gets Built

The Drought Monitor is produced jointly by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the U.S. Department of Agriculture, NOAA and NASA. Each week’s map uses a Tuesday 8 a.m. Eastern data cutoff and is released the following Thursday morning, blending precipitation records, streamflow gauges, soil moisture readings and on-the-ground reports submitted by farmers, water managers and other observers. The classification scale runs from D0, abnormally dry, through D4, exceptional drought, and each area is tagged for whether impacts are short-term, long-term or both, which is why a single state can carry both improving and worsening designations in the same week.

What the Coming Week Is Expected to Bring

The U.S. Drought Monitor’s current conditions page points to continued dry weather across much of the central and south-central country through the following Monday evening, especially from southeast Nebraska through Oklahoma, Arkansas and western north Texas into southwest Texas, eastern New Mexico and Colorado. Some relief is forecast elsewhere: the remnants of Tropical Storm Edouard were expected to bring heavy rain to east-central and southeast Texas, and the Florida Peninsula was positioned for rain totals of 2 to 3 inches or more. For the hardest-hit southern Plains and Mississippi Valley region, though, forecasters favor a continuation of the warmer- and drier-than-normal pattern that produced the past month’s rapid expansion.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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