Tools used in the U.S. Monthly Drought Outlook (MDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for June, 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), the Week 3-4 outlooks and tools from CPC, dynamical models at the monthly time scale, the 384-hour total precipitation forecasts from several runs of the GFS, climatology for June, and initial conditions such as soil moisture. The U.S. Drought Monitor, valid on May 25 at 12Z, was used for the initial drought conditions. 


Long-term drought remains entrenched and continues to expand throughout a majority of the West. According to the U.S. Drought Monitor valid on May 18, nearly 45% this region is designated with severe (D2) to exceptional (D4) drought. Since June is in the dry season for much of the West, persistence is likely. Based on low soil moisture (below the 20th percentile) and the June outlook calling for elevated probabilities of below normal precipitation and above normal temperatures, development is forecast for the current D0 areas in Washington, Oregon, Idaho and Montana. 

Forecast confidence for the Western Region is high.  


The wet April continued into May across western Wyoming and Dakotas, eastern Colorado and adjacent high Plains where 30-day precipitation surpluses are 1 to 5 inches. Based on improving conditions such as soil moisture, generally above the 20th percentile, and additional precipitation forecast for the June, drought removal is likely for parts of southeastern Colorado. Please note that the seasonal outlook (June-July-August) favors below normal precipitation and above normal temperatures. Therefore, worsening drought conditions may return in late June, July or August. The remainder of the northern Rockies and Great Plains have received near to below average precipitation during May. Persistence is more likely for the northern and central Great Plains and redevelops in central Wyoming due to most forecast tools favor near to below normal precipitation and above normal temperatures. However, forecast confidence is low since June is one of the wetter months of the year when the northern and central Great Plains receive 14 to 24 percent of their annual precipitation. 

Forecast confidence is moderate for southeastern Colorado but low for the remainder of the High Plains Region. 
 

Widespread, heavy rainfall (1 to 8 inches, or more) in May along with additional rainfall forecast in the June are likely to result in drought improvement or removal across the Texas Panhandle, central and southern Texas and Oklahoma. Farther to the west, persistence is forecast for areas that largely missed out on this beneficial rainfall and soil moisture is below the 5th percentile, and elevated probabilities of below normal precipitation and above normal temperatures during the June. The remainder of the Southern Region is expected drought free due to CPC ERF and monthly outlooks favoring above normal precipitation and near to below normal temperatures.

Forecast confidence is moderate for the Southern Region. 


Drought is more likely to persist across parts of Minnesota, Iowa, Illinois, Wisconsin and Michigan due to lack of wet signals in precipitation outlooks and above normal temperatures favored at various times scales. However, forecast confidence is low given the wet time of year and mixed precipitation forecast tools.

Forecast confidence is low for the Midwest Region.


Abnormal dryness (D0) expanded across parts of Georgia, the Carolinas and Virginia due to increasing 30 to 90-day precipitation deficits. However, based on relatively wet singals in different precipitation forecast tools at variaous time scales, development is less likely for most of the current D0 area. Drought removal is expected for the current D1 areas in the Carolinas and southeastern Virginia which is consistent with the June precipitation outlook. As the convection season ramps up around the beginning of June and above normal precipitation is favored at various time scales, any lingering dryness across the Florida Peninsula is likely to be short-lived. 

Forecast confidence is moderate for the Southeast Region.

 
Recent Beneficial rainfall brought some relief for the dryness areas (D0) in Pennsylvania and New York. However, drought persistence is more likely across the current D1 areas in New England due to larger precipitation deficits (more than 8 inches) dating back 3 months, lack of wet singal in precipitation outlooks at various time scales and its time of the year favoring soil moisture discharge.  

Forecast confidence is moderate for the Northeast Region.


Due to a lack of snowfall this past winter, abnormal dryness (D0) is designated for parts of northern and eastern Mainland Alaska. Based on an increasingly wet climatology during June and predictions favoring equal chance for both precipitation and temperatures, this D0 area is unlikely to worsen to moderate drought (D1). Alaska is likely to remain drought-free.

Forecast confidence is high for Alaska.

 
Abnormal dryness (D0) expanded in coverage across the Hawaiian Islands during May. Persistence is expected for the ongoing drought areas and development is likely across the leeward sides of the Islands due to the areas entering their dry season and lack of wet singal in precipitation outlooks for the June. Forecast confidence is low to designate development for any specific area on a monthly time scale.  

Forecast confidence is low for Hawaii.


During May, moderate drought (D1) was persisted in eastern Puerto Rico and Vieques and slightly expanded across southwest Puerto Rico. Since the latest model guidance indicates a continued drier-than-normal pattern through the June and the region enters its wet season, persistence is likely.
 
Forecast confidence is low to moderate for Puerto Rico.


Forecaster: Yun Fan
 
Next Monthly Drought Outlook issued: June 30, 2021 at 3pm EDT