Tools used in the U.S. Monthly Drought Outlook (MDO) include the Climate Prediction Center (CPC) updated temperature and precipitation outlooks for August 2023, 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, dynamical model output, August climatology, and initial conditions such as soil moisture and snowpack. The U.S. Drought Monitor valid on July 25, 2023 was used for initial drought conditions. El Niño conditions have developed across the Equatorial Pacific, and the atmospheric response to these conditions is anticipated to impact the forecast.

On the heels of several weeks of excessive heat (in several cases record-setting warmth) across portions of the western U.S., monthly outlooks favor predominantly above normal temperatures and below normal or equal chances of above, below, and near normal precipitation. As such, drought persistence is favored throughout the West. In the Southwest, the North American Monsoon (NAM) circulation has appeared to finally establish itself over the past few weeks, although later than it normally does annually. However, short-range model guidance suggests a suppression of NAM precipitation at least through the middle of August, particularly over Arizona and New Mexico. Therefore, drought development is also favored across parts of the Four Corners region. In the Pacific northwest, above normal precipitation is favored through the middle of August. However, precipitation anomaly forecasts are not impressive enough to curb the trend of degradation, and the favored above normal temperatures throughout August are likely to result in drought development across that region as well. Central portions of the Intermountain West have experienced improvements to drought conditions since the start of 2023 and leading up to mid-July. Antecedent wetness, the potential for additional rainfall in the extended-range, and weak temperature signals for August favor no additional drought development for the central Great Basin and central Intermountain West by the end of August. Favorable temperature and precipitation signals, especially over the next couple of weeks, favor drought removal in areas experiencing moderate drought near the vicinity of Yellowstone National Park.

Forecast confidence is moderate for the Pacific Northwest, northern Intermountain West, and central Great Basin, and high for the Four Corners and Desert Southwest.

Below normal temperatures and near to above normal precipitation are favored over the next couple of weeks and through the remainder of August across much of the Great Plains, increasing the potential for drought improvement and removal from northern Oklahoma to southeastern South Dakota. Additionally, ENSO composites and climatology favor wetter than normal conditions across much of the central U.S. and, with the establishment of the NAM ridge over the Southwest, there is an increased potential for several rounds of clusters of rainfall and thunderstorm activity (known as mesoscale convective systems, or MCSs) on its northeast periphery. Conversely, from central South Dakota northward to the Canadian border, drought is forecast to persist, as precipitation signals are weaker across the Northern Plains and Upper Midwest and temperatures are forecast to predominantly be below normal during August.

Forecast confidence is high for the High Plains region.

Antecedent short and long-term dryness, in addition to favored above normal temperatures and below normal precipitation through the end of August, favor drought persistence and development across much of southern Texas and southern Louisiana. Elsewhere, antecedent wetness, ENSO composites, the potential for MCS activity, above normal precipitation favored over the next couple of weeks, and equal chances of above, below, and near normal to above normal chances of precipitation through the end of August favor drought improvement and removal from northern Oklahoma eastward to the Tennessee Valley.

Forecast confidence is high for the Southern region.

August is a climatologically wetter time of year for much of the Midwest. Additionally, with the NAM ridge having established itself across the Four Corners region, there is an increased risk of MCS activity across the central U.S., along its northeastern periphery. The monthly temperature outlook for August predominantly favors equal chances of above, below, and near normal to above normal chances, and the precipitation outlook favors equal chances of above, below, and near normal to above normal chances. ENSO composites, centered on the month of August also indicate wetter signals when El Nino conditions are present, although potential contributions from El Nino may be lagged a bit, given its recent onset. Across the upper Midwest and northwestern Great Lakes, drought persistence is broadly favored, although there could be localized areas of improvement and degradation by the end of August.

Forecast confidence is high for the eastern Corn Belt and southern Great Lakes, and moderate elsewhere in the Midwest region.

In the Southeast, extended-range precipitation outlooks favor drought removal across northern Alabama, despite above normal temperatures being favored through the middle of August. In Virginia, generally seasonal temperatures and above-normal precipitation are favored throughout the month of August, favoring drought removal there. In the Florida Peninsula, despite above-normal temperatures being favored throughout the month, August is a wet time of year due to the summertime sea breeze circulation. In addition, sea surface temperatures (SSTs) are much warmer than normal, allowing the atmosphere to remain rich with moisture. Therefore, drought removal (in moderate to severe drought areas) and improvement (in extreme drought areas) are forecast in the Florida Peninsula. Additionally, the risk of tropical cyclone activity cannot be ruled out as the Atlantic Hurricane Season progresses toward its historical peak in September.

Forecast confidence is moderate for Florida and high elsewhere in the Southeast region.

The Northeast has been the beneficiary of several episodes of heavy rainfall over the past month, associated with the passing of strong storm systems and a consistent jet stream pattern that has resulted in persistent daytime thunderstorm activity, in addition to the warm Atlantic SSTs helping to keep moisture plentiful across the region. With the improvements in drought conditions over the past month and favorable temperature and precipitation outlooks for all periods through the end of August, the Northeast is primed for complete drought removal by the end of the month.

Forecast confidence is high for the Northeast region.

Some abnormal dryness has developed over the past one to two months across portions of the southern and eastern Alaska Mainland. However, there have been recent improvements as a result of above-normal rainfall in drier areas in recent weeks. Despite above normal temperatures being favored, weak precipitation signals, and the potential for short-term drought development, August is climatologically a wetter time of year. Favoring the wet time of year, Alaska is favored to remain drought-free by the end of August.

Hawaii has seen short-term improvements to drought across windward portions of the Maui and the Big Island with the passage of Tropical Storm Calvin on July 19th. However, this improvement is likely to be short-lived, as below normal precipitation is strongly favored during August for the islands. Therefore, drought persistence is forecast, with an increased potential for drought development, particularly in areas already experiencing abnormal dryness.

Despite antecedent short-term abnormal dryness and moderate to severe drought in Puerto Rico, long-range precipitation tools favor near to above normal precipitation through the end of August. In addition, as the Atlantic Hurricane Season progresses, the possibility for tropical cyclone activity cannot be ruled out. Therefore, drought improvement and removal is favored for Puerto Rico.

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

Forecaster: Adam Hartman

Next Monthly Drought Outlook Issued: August 31, 2023 at 3:00 PM EDT