Tools used in the U.S. Seasonal Drought Outlook (SDO) include the Climate Prediction Center (CPC) temperature and precipitation outlooks for July and July-August-September (JAS), various short- and medium-range forecasts and models such as the 7-day quantitative precipitation forecast (QPF) totals from the Weather Prediction Center (WPC), the 6-10 day and 8-14 day CPC extended-range forecasts (ERFs), dynamical models at the monthly and seasonal time scale, climatology for JAS, and initial conditions such as soil moisture. The U.S. Drought Monitor valid on June 18, 2024 was used for initial drought conditions. La Niña conditions are likely (with 65% chance) through much of the JAS season.



During the past month, the Western region has experienced a combination of both degradation and improvement of abnormal dryness (D0) and drought (D1-D2), as depicted in the U.S. Drought Monitor (USDM). The degradation of abnormal dryness and drought was located over parts of the Pacific Northwest and central-eastern Montana, where snowpack is running below normal and soil moisture has continued to decline due to many locations seeing below normal precipitation over the past 30 days. Meanwhile, sporadic 1-2 class drought improvement was observed across northern and southeastern portions of the region. Elsewhere from the northern Great Basin southward to the Four Corners region, the antecedent snowpack is near to above normal and deep soil moisture is above normal for most locations. Looking forward to the July-August-September (JAS) season, warmer and drier than normal conditions are favored for most of the interior West. Persistence is broadly favored for the existing drought throughout the West, with likely drought development across parts of the Pacific Northwest, Northern Rockies, central and eastern Montana, and the Four Corners, where soil moisture conditions have begun to deteriorate in several locations.It is important to note that the onset of the North American Monsoon (NAM) typically occurs in late-June and early-July in the Southwest, which increases uncertainty in the JAS drought outlook for the Four Corners region due to the sporadic nature of thunderstorm activity during the monsoon season. Areas not seeing adequate precipitation will likely experience degrading or expanding drought conditions.



Forecast confidence is moderate to high for central and northern parts of the Intermountain West and low to moderate for the Four Corners in the Western region.



The High Plains region also has experienced a combination of both degradation and improvement of abnormal dryness (D0) and drought (D1-D3) during the past 30 days over parts of North Dakota, Wyoming and the southeastern region. Looking ahead to the JAS season, warmer and drier conditions are favored across much of the region for the JAS season, persistence is forecast for existing drought over the region, where antecedent dryness exists at the onset of the JAS period, drought development is also favored despite JAS being a wet time of year for these regions.



Forecast confidence is moderate for the High Plains region.



During the past 30 days, parts of southern Texas, western Oklahoma, northeastern Arkansas and parts of Tennessee Valley have received beneficial rainfall and resulted in 1-3 class drought improvement or removal. However, much of the rain fell over areas not experiencing drought conditions and some areas (e.g. southern and western Texas and Oklahoma, northern Mississippi) missed meaningful rainfall and have seen 1-2 class degradations as well. Looking ahead to JAS, drought improvement or removal is likely in parts of Southern Texas and northern Mississippi, due to favorable precipitation in all range forecasts. Conversely, warmer and drier conditions are favored for July and JAS across the western Southern Plains and given the antecedent dryness already in place, portions of northern Texas and western Oklahoma are likely to see drought persist and expand in coverage through the end of September, despite being a climatologically wet time of year. The existing small drought over northern Arkansas is likely to persist, due to lack of wet signals in precipitation outlooks.



Forecast confidence is moderate to high for the Southern region.



During the late spring, the Midwest became drought-free for the first time since June 2020. Unfortunately, two small areas of drought have just developed with increasing anomalous dryness across parts of the region again. Degradations are likely to continue through the JAS season and drought redevelopment is favored by the end of September, due to the lack of above-normal precipitation signals in the forecasts coupled with above-normal temperatures across much of the region. The eastern Corn Belt is vulnerable to the rapid onset of drought during the next few weeks due to: low topsoil and likelihood of above-normal temperatures with high evapotranspiration rates.



Forecast confidence is moderate to high for the Midwest region.



In the Southeastern region, abnormal dryness (D0 as depicted in the USDM) has popped up in the southern Appalachians and portions of the Piedmont and Coastal Plain of Virginia, parts of the Carolinas and Georgia recently. Moderate to severe drought (D1 to D2 depicted in the USDM) rapidly developed in the Florida Peninsula. However, more than 15 inches precipitation was observed over most of the southern Florida Peninsula during last week, causing flooding and existing drought to be wiped out. Looking ahead to JAS, warmer than normal temperatures are favored throughout the region during JAS and above normal precipitation is also favored throughout the Southeast. The existing drought in the Florida Peninsula is forecast to be removed. However, the newly developed drought in western Virginia is likely to persist, due to lack of wet signals in short to extended range forecasts and monthly outlook coupled with forecast above-normal temperatures and a favorable time of year for soil moisture discharge. It should be noted that there is an increased risk of rapid onset drought across Virginia and Carolinas during the next few weeks. Based on the JAS precipitation, any drought that develops is expected to be eliminated by the end of September.



Forecast confidence is high for the Southeast region.



The Northeast has seen some abnormal dryness (D0 as depicted in the USDM) at the start of the JAS season across portions of the Mid-Atlantic and parts of the central and northern New England (due to deteriorating soil moisture, stream flows, and subnormal snowpack), newly developed moderate drought (D1 as depicted in the USDM) has popped up over parts of the Delmarva. However, there could be some extended dry and wet periods during the JAS season, so some periods of localized degradation and improvement cannot be completely ruled out as the season progresses along. Nonetheless, the Northeast is forecast to be drought-free by the end of the JAS season due to favorable JAS precipitation predicted across much of the region.



Forecast confidence is moderate for the Northeast region.



Parts of eastern mainland Alaska and the southeastern Alaska Panhandle have experienced abnormal dryness (D0 as depicted in the USDM) for a while, as below normal snowpack and rainfall deficits accumulating over the past 4 months resulted in the antecedent dryness. Looking ahead to JAS, Alaska is forecast to continue drought by the end of September, as near to above normal precipitation being favored throughout the JAS season coupled with the region entering into its wet time of year climatologically.



Forecast confidence is moderate to high for Alaska.



For the Hawaiian Islands, drought persistence is forecast, with additional drought development also likely on the leeward slopes of the islands. Antecedent dryness, dry seasonal precipitation signals, and JAS being a climatologically dry time of year support this persistence and development forecast. Additionally, summer rainfall is typically diminished during ENSO-neutral to La Niña transitions (i.e. transition to cooler than normal SSTs in the tropical Pacific), further supporting the degradation potential.



Forecast confidence is high for Hawaii.



Puerto Rico is drought-free at the start of the JAS season and is forecast to remain drought-free by the end of September, as antecedent soil moisture and stream flows are above normal, long-range forecasts show enhanced probabilities of above normal precipitation , it is a climatologically wet time of year, and these areas will be more vulnerable to tropical activity as the season progresses.



Forecast confidence is high for Puerto Rico.



Similar to Puerto Rico, the U.S. Virgin Islands (USVI) are likely to remain drought-free by the end of September, due to the antecedent conditions, the favorable long-lead precipitation outlook, and the potential for a more favorable tropical activity supporting an increased likelihood that the islands will remain drought-free by the end of the season.



Forecast confidence is high for the U.S. Virgin Islands.



Forecaster: Yun Fan



Next Seasonal Drought Outlook issued: July 18, 2024 at 8:30 AM EDT