Much of the western half of the lower 48 states remained in drought throughout May. However, several locations across the Pacific Northwest, Northern Rockies, and Great Plains saw some improvement and removal of drought.
Conversely, drought persisted or intensified across much of the Southwest and Four Corners since the start of May. Across eastern parts of the lower 48 states, improvements to ongoing drought were observed across parts of the Lower Mississippi Valley, southern Florida, and the Mid-Atlantic.
Areas near the Tennessee Valley have experienced abnormally dry conditions over the past month, but recent precipitation has helped to curb that dryness.
Looking forward, drought is likely to persist across much of the West, from southern parts of the Pacific Northwest, extending eastward to the Central Plains, and southward to the Four Corners and Southern Plains.
Along the periphery of this region of persistence (interior Pacific Northwest, Northern Rockies, and parts of the Plains), drought improvement is likely due to favored below-normal temperatures and near to above-normal precipitation during June. Drought persistence is favored across the central Gulf Coast and into south-central Georgia, where extended-range forecasts favor above-normal temperatures and below-normal precipitation throughout the month.
Conversely, extended-range forecasts and the potential for tropical activity early in June make drought improvement and removal likely along the East Coast.
Abnormal dryness (D0) has popped up across parts of southern Mainland Alaska in recent weeks due to unseasonably warm temperatures and below-normal precipitation. Warm temperatures are likely to exacerbate these conditions through the end of June. Antecedent dryness, below-normal precipitation, and a climatologically dry time of year in Hawaii favor drought persistence, with additional development likely.
Recent precipitation deficits coupled with favored below-normal precipitation through at least the middle of June also favors drought persistence and expansion across much of Puerto Rico.
Forecast confidence is high for the southwestern CONUS, and moderate to high for the remainder of the Western Region.
- As of May 24, drought is covering much of the western contiguous U.S. (CONUS). As of May 24, just under 90 percent of the Western Region was experiencing some degree of drought (moderate to exceptional drought; D1-D4).
- Since the May 2022 release of the monthly drought outlook, an active storm track and below-normal temperatures resulted in improvements to drought conditions from the Pacific Northwest to the Northern High Plains.
- Extended (through week-2) and medium-range (weeks 3-4) forecasts favor near to above-normal precipitation and below-normal temperatures for many of these same areas throughout the month. Therefore, drought improvement is likely by the end of June for parts of the Pacific Northwest and Northern Rockies, where recent improvements were observed and favorable temperature and precipitation outlooks favor the continuation of these improvements.
- Elsewhere across the Western Region, drought persistence is broadly favored. In the Southwest, there is also the potential for drought development across parts of Arizona and New Mexico, as this region experienced warmer than normal temperatures and below-normal precipitation over the past 30 days, with conditions likely to continue through much of June.
- However, uncertainty in the Four Corners region increases toward the end of the month and into early July, coinciding with the climatological start of the North American Monsoon.
Forecast confidence is low to moderate for the High Plains Region.
- The High Plains Region experienced almost a 5 percent reduction in drought coverage over the past month, associated with a climatologically active storm track during much of May.
- During the first half of June, below-normal temperatures and near to above-normal precipitation are favored across much of the region. However, toward the middle of the month precipitation signals disagree somewhat, particularly across the central CONUS. Additionally, La Niña signals for May-June-July (i.e. the season centered on June) are very inhomogeneous across the Great Plains.
- Climatologically, June is a wetter time of year for much of the Great Plains, extending into the Midwest. Therefore, drought persistence is favored across much of the High Plains Region, where antecedent soil moisture anomalies are greatest and drought is more intense, while drought improvement is likely along the eastern and northern boundaries of the areas currently entrenched in drought.
- Improvements extend slightly farther westward into Oklahoma and Kansas, where 7-day QPF estimates from the WPC indicate the potential for more than 3 inches of rain to fall.
Forecast confidence is high for the Southern Region.
- Drought persistence is favored across much of the Southern High Plains, extending to the western and central Gulf Coast. Warmer and drier than normal conditions are favored through much of June.
- Drought development is also likely across parts of southern and western Texas, where above-normal temperature and below-normal precipitation signals are strongest during the month.
- Conversely, drought improvement is favored for much of central Oklahoma, extending into central Kansas, where close to 3 inches of rainfall is forecast during the first 7 days of June, with near to above-normal precipitation and seasonal temperatures favored through at least the middle of the month.
- Farther east in the Southern Region, precipitation signals at all leads out to 1 month are favorable for no drought development.
Forecast confidence is moderate for western Iowa, and high elsewhere for the Midwest Region.
- In sharp contrast to areas farther west, less than 1 percent of the Midwest Region is currently experiencing drought, which is confined to parts of western Iowa.
- In addition to June being a climatologically wetter time of year for much of the region, extended-range forecasts favor below-normal temperatures and near to above-normal precipitation through at least the middle of the month.
- Despite the antecedent short and long-term dryness and negative soil moisture anomalies across parts of the central and western Corn Belt, cooler and wetter signals through much of June suggest improvements are likely by the end of June.
Forecast confidence is low for south-central Georgia and moderate to high elsewhere for the Southeast Region.
- Drought has persisted across parts of the Atlantic Coastal Plain and the southern Florida Peninsula during May.
- During June, above-normal temperatures are broadly favored and above-normal precipitation signals are mainly confined to the Atlantic Coastal Plain and the Florida Peninsula.
- Additionally, there is the potential for an area of low pressure, associated with the remnants of Hurricane Agatha that made landfall in southern Mexico, to bring immediate drought relief to the southern Florida Peninsula toward the end of the first week of June. However, it is uncertain whether this feature will regain tropical characteristics at this time. Nonetheless, heavy rainfall is forecast across drought-stricken areas in Florida.
- Along the Coastal Plain of Georgia and the Carolinas, drought improvement is also favored, as above-normal precipitation is favored throughout June. However, just inland from the coast in south-central Georgia, precipitation signals dissipate. Given the favored above-normal temperatures, drought persistence is likely.
Forecast confidence is moderate to high for the Northeast Region.
- Long-term drought continued to improve during May across northern New England. However, moderate (D1) drought did develop across parts of southern New England, which has observed 2 to 3 inch precipitation deficits over the past 30 days and stream flows falling below the 24th percentile of the historical distribution (below the 10 percentile in some cases).
- Extended-range forecasts favor wetter than normal conditions and seasonable temperatures through the middle of the period, with those signals becoming less prominent at longer lead times.
- In favor of the extended-range outlooks and wetter trends during La Niña years for this time of year, drought removal is favored by the end of June for the Northeast Region.
Forecast confidence is moderate for Alaska.
- Areas of abnormal dryness (D0) have increased in coverage across parts of western and southern Mainland Alaska in the weeks and months leading up to June, associated with unseasonably warm temperatures and below-normal precipitation.
- Precipitation signals are lacking during much of June while above-normal temperatures are favored. Additionally, Alaska doesn’t begin to approach its climatological peak in annual rainfall until July.
- Given the antecedent dryness, favored above-normal temperatures, and weak to absent precipitation signals, drought development is likely by the end of June in areas across the Mainland that are currently experiencing abnormal dryness.
Forecast confidence is moderate to high for Hawaii.
- In Hawaii, antecedent dryness, a climatologically drier time of year, and below-normal precipitation probabilities favored in the long-range dynamical and statistical model guidance favors drought persistence. There is also the possibility for drought development in areas currently experiencing abnormal dryness (D0).
Forecast confidence is moderate for Puerto Rico.
- Drought conditions have deteriorated over the past 30 days across parts of Puerto Rico. The North American Multi-model Ensemble guidance favors near-normal temperatures and near to below-normal precipitation.
- Despite the climatological start of the Atlantic Hurricane Season beginning June 1, with La Niña conditions likely to persist through the end of the month, drought conditions are likely to persist due to the antecedent dryness (30-day precipitation deficits exceeding 4 inches in many areas, per AHPS) and below-normal precipitation estimates through the middle of June.