Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for September and September-October-November (SON), 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 scales, climatology for the SON season, and initial conditions such as soil moisture. The U.S. Drought Monitor (USDM) valid on August 16, 2022 was used for initial drought conditions. La Niña conditions are present at the start of the SON season, with strongly enhanced chances that La Niña will persist through the autumn months. Therefore, temperature and precipitation composites from historical La Niña episodes during SON were also considered.

Drought conditions remain prevalent across the Western and Southern climate regions of the CONUS, with just over 70 percent of the Western Region and over 77 percent of the Southern Region experiencing moderate drought or worse as of the 11 August 2022 USDM. The Southwest Monsoon has been highly active this Summer, resulting in drought reductions across portions of the California deserts, the Great Basin, and the Four Corners states. As is typical during the monsoon, the heaviest convective thunderstorms resulted in flash flooding, while other regions have largely missed out on rainfall so far. Further east, a tropical disturbance (98L) brought drought relief to southern Texas. In contrast, abnormal dryness coupled with periods of extreme heat across the southern Plains resulted in widespread drought expansion and intensification, with portions of central Oklahoma experiencing a 3-class degradation on the USDM depiction over the last 4 weeks. Seasonable dryness prevailed across the remainder of California, resulting in little change to the drought depiction, while some periods of precipitation brought relief to interior Washington and the Oregon Cascades. Over the next two weeks, forecasts from WPC and CPC indicate a continued active monsoon pattern, with widespread rainfall extending eastward across the south-central CONUS. Recent runs of the ECMWF show a potential for widespread heavy to excessive rainfall across northern or central Texas, with the latest WPC 7-day QPF forecast showing a swath of 5-7 inches of rainfall across northern Texas and southern Oklahoma. Beyond the final weeks of August, the CPC September outlook favors equal chances (EC) for below-, near-, and above-median precipitation across the southern Four Corners region, Texas, and Oklahoma, with above-median precipitation slightly favored for southern Arizona and Louisiana. The SON seasonal outlook shows a somewhat drier solution, but precipitation climatology in these regions is heavier at the beginning of the period, and decreases markedly by the end of November. Therefore, based on the widespread wetness favored in the short and medium range, widespread drought reduction is favored across Arizona, New Mexico, southern Utah and Colorado, and eastward across the entire Southern Region. Despite the widespread drought conditions currently in place, localized flooding may be possible in areas that receive the heaviest rainfall.

Forecast confidence is moderate to high for the Western and Southern regions.

While convective systems brought localized relief to portions of central South Dakota and Nebraska, drought conditions worsened in general across the High Plains region under frequent heatwaves and dry conditions, with the most significant drought impacts existing across Kansas, Nebraska, and northeastern Colorado. Further east, following a rapid onset of drought conditions across much of the Corn Belt, increased rainfall over the last month resulted in widespread improvements, though close to 40 percent of both Missouri and Iowa still remain in moderate drought or worse as of the 11 August USDM. Further east, periods of extreme rainfall brought historical flooding to mountainous communities in eastern Kentucky, while pockets of moderate drought remain across portions of the Great Lakes region. Climatological precipitation decreases rapidly across the Plains and Midwest during the autumn months, limiting the potential for substantial drought relief, though decreasing evapotranspiration rates also reduce the potential for further drought expansion. During the next 7 days, widespread rainfall is favored to overspread the northern Mississippi Valley, which may bring some spotty drought relief and hold off further degradations. Drier conditions are favored for the Week-2 period, and both the September and SON outlooks from CPC favor below-median precipitation and EC to above-normal temperatures across the northern Plains and upper Midwest. Therefore, drought persistence is favored across almost all of the High Plains and Midwest regions, with pockets of development possible in already abnormally dry portions of the Northern Plains. Drought improvements are possible along the southern extent of these regions due to a potential for heavy rainfall in the short term, as discussed above in regards to the Southern Region. 

Forecast confidence is moderate for the High Plains and Midwestern regions.

Flash drought conditions were also common across the Southeast during early Summer, but a return to a more widespread convective regime eliminated most of the drought conditions across the region. As of the 11 August USDM, less than 2 percent of the Southern Region was experiencing moderate drought, with small pockets remaining in upstate South Carolina and eastern North Carolina. During the next 7 days, the WPC QPF forecast shows a continued pattern of generous rainfall, with the heaviest amounts (1.5 to 4 inches) focused over the Piedmont and coastal Plain regions of the Carolinas. The CPC 8-14 day ERF slightly favors above-average rainfall, and the September outlook favors above-average rainfall along the Gulf Coast and along the Georgia and Florida border. Enhanced chances for above-average rainfall shift to the Florida peninsula on the SON outlook. Based on these forecasts, removal of the small remaining drought areas is likely, and no additional drought is favored to develop. Uncertainty increases across the Florida peninsula, where a somewhat lackluster seabreeze convective regime combined with periods of abnormal heat have resulted in decreased streamflows. With the peak of the Atlantic hurricane season still to come and several months remaining of the wet season, there are ample opportunities to boost moisture across Florida. However, should no tropical systems affect the state through the end of November, the region will be vulnerable to drought development beyond this outlook period in the upcoming dry season. 

Forecast confidence is high for most of the Southeastern Region, and moderate for Florida.

Slowly increasing dryness during the Spring accelerated into the development of an unusually stubborn drought across much of the Northeast, with the greatest impacts (D3, severe drought) felt across eastern Massachusetts and parts of Rhode Island. Increased rainfall brought some relief to northern and western Maine over the past several weeks, but precipitation events continue to miss coastal areas of the northern mid-Atlantic region and southern New England. Streamflow values are extremely low (below 10 percent) across much of southern New England, and groundwater levels have begun to drop. The autumn months are typically a great opportunity for soil moisture recharge across the Northeast, as a southerly shifting mean storm track maintains a generous precipitation climatology and ET rates decrease as trees go dormant. In the short term, increasing impacts across portions of central Pennsylvania, upstate New York, and New Jersey may result in further drought expansion, but the WPC QPF forecast has trended wetter, with the latest outlook bringing widespread 0.5 to 1.5 inches of rain across the region, which may be sufficient to stave off widespread degradations. The CPC ERF forecast slightly favors above-average precipitation, while the CPC monthly and seasonal outlooks favor EC for precipitation and above-average temperatures. Despite the potential for seasonable moisture recharge, the severity of the current impacts and the potential for further short term degradations makes substantial improvements less likely in the absence of a clear wet signal. Therefore, persistence is maintained across the region.

Forecast confidence is low for the Northeastern Region.

Drought conditions eased across Alaska following periods of enhanced precipitation and below-average temperatures. A rapidly decreasing sun angle and temperature climatology during SON makes drought formation less likely. Therefore, drought development is not anticipated during the outlook period. Drought conditions continue to plague much of Hawaii, and enhanced trade winds associated with the ongoing La Niña provide little opportunity for substantial relief. Therefore, drought persistence is favored through the end of November. In contrast, drought improvement is the most likely outcome for Puerto Rico, as the peak late summer wet season and hurricane season approach.

Forecast confidence is high for Alaska, and moderate for Hawaii and Puerto Rico.

Forecaster: Adam Allgood

Next Seasonal Drought Outlook Issued: September 15, 2022 at 8:30 AM EDT.