During the early part of last week, an amplified ridge-trough pattern over North America brought widespread late summer heat to the West and south-central US, with milder temperatures overspreading the Corn Belt and gradually shifting to the Northeast and mid-Atlantic states. The north side of the mean ridge provided a focus for convective activity, with narrow swaths of locally heavy rainfall extending across Nebraska and Missouri, while shortwave troughs brought several rounds of storms to the eastern Corn Belt and parts of the mid-Atlantic and southern New England. Underneath the ridge, dry weather combined with excessive heat continued to promote rapid onset drought across much of the South region. Across the Southeast, summer convection competed with enhanced evapotranspirative demand due to hot temperatures, causing some degradation in areas that missed out on thunderstorm activity. Across the West, an active monsoon pattern continued to bring localized relief to parts of Arizona and New Mexico, while excessive heat and drier conditions promoted drought expansion across eastern New Mexico and portions of the Intermountain West, Great Basin, and the Northwest.
Across Alaska, improved rainfall eased drought conditions over the central interior, while drier weather sparked some degradation over the southeast. Across Hawaii, following widespread heavy rainfall from Hurricane Lala in the previous week, Tropical Storm Moke passed well south of the state, bringing enhanced flow and precipitation to the windward sides of the islands. Across the Caribbean, a suppressed convective regime continued to promote gradual drought expansion across Puerto Rico.
Northeast
Two rounds of storminess overspread the Mid-Atlantic states and southern New England during the week, bringing widespread accumulations of 1–2 inches across northern West Virginia, Pennsylvania, and Maryland. Higher amounts fell across parts of New Jersey and Long Island, causing isolated flooding in urban areas and along small streams. The rainfall boosted soil moisture and streamflows across the region, bringing some reduction in the drought depiction across eastern West Virginia, southeastern Pennsylvania, the Delmarva, New Jersey, and Long Island. One limiting factor in broader-scale drought reduction is groundwater conditions, which have been slower to respond following prolonged dryness in prior months. Across Upstate New York and northern New England, rainfall was more widely scattered. While precipitation brought localized relief to central New Hampshire, surrounding areas experienced degradation due to worsening impacts from short-term dryness.
A fairly typical summer convective regime remained in place over the Southeast, with the heaviest thunderstorms occurring in the seabreeze-favored regions of the Gulf Coast and South Atlantic coastal plain, resulting in localized improvements across Virginia and the Carolinas. Convection was more meager across central Alabama and Georgia, where above-average temperatures drove gradual degradation. Small areas of degradation also occurred in North Florida, the Treasure Coast, and portions of South Florida due to persistent heat and a lackluster seabreeze regime. The extent of remaining drought across Florida in late August is extremely unusual, as wet-season rainfall to date has been unable to fully erase the severe deficits built up during the winter and spring.
Under a persistent heat dome ridge maintaining mostly dry conditions and unrelenting heat, widespread rapid drought expansion continued for another week across the South region. Weekly maximum temperatures exceeded 100 degrees F across nearly the entire region - with the exception of Tennessee - and peaked above 110 degrees along the Texas-Oklahoma border. Condition Monitoring Observer Reports (CMOR) submitted to the National Drought Mitigation Center highlighted rapidly worsening impacts, including dry stock ponds, wilting trees, dust storms, and elevated wildfire activity. Drought expansion and intensification were most pronounced across Texas, Oklahoma, Louisiana, and Arkansas, while conditions also began to noticeably deteriorate across Mississippi. Small-scale convection provided only highly localized, brief relief to isolated portions of central Oklahoma and Arkansas.
Following the widespread heavy rainfall that fell across the Corn Belt in the previous week, lighter precipitation and milder temperatures overspread the region. Conditions were adequate to maintain a drought-free status quo across Kentucky, Indiana, and Ohio, while showers brought some relief to Michigan's Lower Peninsula, northern Illinois, and southern Wisconsin. In contrast, another dry week across portions of Minnesota, western and northern Wisconsin, and Michigan's Upper Peninsula aggravated ongoing drought impacts, leading to localized degradation. Severe drought (D3) expanded across northwestern Wisconsin and into eastern Minnesota.
The High Plains saw a mixture of drought degradation and localized improvement. Rapid drought deterioration continued across southern Kansas and southeastern Colorado, where dry conditions and excessive heat aggravated agricultural impacts. Further north, widespread convection brought drought relief east of the Front Range across eastern Colorado, though some deterioration occurred in the Rockies of Colorado and Wyoming where water storage impacts from last spring's limited snow cover are beginning to mount. Organized convection along the northern periphery of the ridge promoted drought reduction in central Nebraska. Showers mostly maintained a status-quo depiction across South Dakota, save for small areas of degradation along its respective borders with North Dakota and Minnesota. More widespread drought degradation was noted across North Dakota, where precipitation was sparser outside of a single, narrow convective event that tracked across the northeastern corner of the state.
West
Seasonal dryness continued across the Pacific Coast states and much of the Great Basin, where persistent above-normal temperatures drove high demand on water resources and led to localized degradation. Extreme Drought (D3) expanded slightly across southern Oregon and northern Washington, where soil moisture and groundwater levels remained critically poor. Extreme to Exceptional (D4) drought also expanded into northeastern Idaho, with degradation noted in small portions of Utah and the southern California deserts. Elsewhere, ongoing monsoonal convection promoted drought relief across much of Arizona and western New Mexico, though persistent heat and dry conditions drove drought expansion across eastern New Mexico.
Caribbean
With a suppressed convective regime remaining in place over the Caribbean basin—due in part to the strengthening El Niño across the tropical Pacific—drought conditions continued to expand and intensify across Puerto Rico. While isolated rainfall fell over existing drought areas and briefly stabilized topsoil moisture, accumulations were insufficient to overcome mounting deficits, and impacts to streamflows, agriculture, reservoirs, and aquifers continue to build. Similar conditions persisted across the U.S. Virgin Islands, where Extreme Drought (D3) remains entrenched. Absent a significant shift in the large-scale weather pattern, conditions are poised to deteriorate even further in the coming weeks.
Short-term extreme drought continued this week across the U.S. Virgin Islands. Rainfall amounts for this week remained paltry, with up to 0.24 inches on St. Croix, up to 0.14 inches on St. Thomas, and up to 0.25 inches on St. John. Vegetation conditions across the area continued to deteriorate, while potable water demand outpaced production on St. Croix and numerous cisterns ran dry, per news reports. Rainfall shortages are especially notable across the U.S. Virgin Islands at the three-month mark, and conditions will continue to be monitored for possible further degradation.
In Alaska, wet weather during the week helped trim the northern extent of recent-onset Moderate Drought (D1) across the central interior. In contrast, drier conditions across the Copper River Basin led to localized expansion of Abnormal Dryness (D0).
Across Hawaii, following the heavy rainfall and strong winds from Hurricane Lala the previous week, Tropical Storm Moke passed well south of the islands. While Moke brought no direct impacts, the system enhanced northeasterly flow over the state, generating locally heavy rainfall on the windward sides of the islands. Because these areas were already drought-free, no changes to the drought depiction were warranted this week.
American Samoa remained in short-term moderate drought this week. In Pago Pago, 0.45 inches of rain were reported, while 0.44 inches were reported at Siufaga Ridge and 0.16 inches at Toa Ridge.
In Palau, short-term abnormal dryness continued this week, though water levels have improved somewhat after weekly rain reports included amounts of 2.09 and 3.43 inches.
The Mariana Islands remained free of drought or abnormal dryness this week. Following a drier week, 1.7 inches of rain fell on Saipan this week. At least 2.97 inches of rain fell on Tinian this week. Rota’s weekly rainfall report came in at 2.36 inches, continuing a recent stretch of wet weather there. In Guam, 3.04 inches of rain were reported this week.
The Republic of the Marshall Islands was free of drought or abnormal dryness this week. Conditions in Jaluit improved from short-term abnormal dryness to normal conditions after receiving at least 3.44 inches of rain. In Kwajalein, at least 3.86 inches of rain fell this week. In Ailinglapalap, at least 3.43 inches of rain fell this week. In Utirik, 1.98 inches of rain fell this week after a pair of much drier weeks, keeping abnormal dryness from developing. Wotje received a total of 4.45 inches of rain. Rain this week in Majuro and Mili totaled 3.66 and 2.02 inches, respectively.
Short-term abnormal dryness in Yap ceased after a deluge of over 22 inches of rain there, including over 16 inches on August 21. After a couple of drier weeks in Ulithi, 4.89 inches of rain fell there, so conditions remained normal. In Woleai, 1.71 inches of rain fell this week, marking the third consecutive week with less than 2 inches but a much higher total than the previous two weeks. Given a quite wet July there, conditions have not yet fallen into abnormal dryness, but this will be monitored moving forward. In Chuuk, at least 3.05 inches of rain fell this week. In Lukunor, at least 3.26 inches of rain fell this week. In Nukuoro, 2.73 inches of rain fell this week. Short-term abnormal dryness developed in Kapingamarangi, where no rain fell this week, marking the third consecutive week with less than 2 inches of rain. In Pohnpei, wet weather continued with 5.15 inches of rain this week. In Kosrae, at least 6.26 inches of rain fell this week after over 13 inches fell last week. No drought monitor depictions were made for Fananu or Pingelap, as no data were available for either location this week.
Looking Ahead
Over the next 7 days, upper-level ridging centered over the western U.S. is forecast to progress eastward, shifting hotter conditions to the East while bringing a potential reprieve from extreme temperatures to the West. Excessive heat will persist across the south-central U.S., which may continue to fuel rapid drought expansion and intensification. Enhanced monsoonal convection is favored across Arizona, with moisture extending northward into Utah and parts of the northern Rockies, while light, early-season precipitation may overspread southern California. Forecast precipitation amounts across the South region would be insufficient to offset ongoing moisture deficits. Across the Midwest, light to locally moderate precipitation is expected. Seasonal convection will linger across the Southeast early in the period before drier conditions move in by the end of the period. Along the Eastern Seaboard, initial storminess will give way to drier conditions, though unsettled weather may return to the Northeast by late week.
For the 8-to-14-day period, below-normal temperatures are favored across the Northwest, while elevated odds for above-normal temperatures extend across much of the remainder of the CONUS. The highest probabilities for excessive heat remain anchored over the south-central and southeastern U.S., maintaining heavy evapotranspirative demand in regions experiencing rapid drought degradation. Above-normal temperatures are also favored across Hawaii and the Alaska Panhandle and southeastern Alaska, while below-normal temperatures are more likely across the rest of Mainland Alaska. The precipitation outlook exhibits a weaker signal for the CONUS, with slightly enhanced chances for above-normal precipitation across the western U.S. and New England, while near-normal precipitation is favored elsewhere. High probabilities for above-normal precipitation extend across Hawaii, with enhanced odds for above-normal rainfall exist across most of Alaska except for the Panhandle.
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