Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for January (Jan) 2021 and January through March (JFM) 2021, various short- and medium-range forecasts and models such as the 7-day quantitative precipitation forecast (QPF) 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 and seasonal time scales, the 384-hour total precipitation forecasts from several runs of the GFS, climatology for Jan and JFM, and initial conditions for parameters such as soil moisture. Existing drought areas on the forecast are based on the December 15 U.S. Drought Monitor. Conditions currently reflect the presence of a moderate La Nina, with a 95% chance for La Nina to persist through the Northern Hemisphere winter, and forecaster consensus indicated the potential for a strong cold event given the robust ocean-atmospheric coupling already in place.

Mostly dry weather and above-normal temperatures did little to alleviate drought conditions across most of the West, but recent storminess over the Pacific Northwest brought some relief to ongoing drought conditions there during the past several weeks. The short-term pattern looks similar, with storm systems bringing additional coastal rain and mountain snows to the Cascades, northern Rockies, and the northern Sierra Nevadas, with accumulations tapering off toward the south. Both the CPC Jan and JFM outlooks reflect climate anomalies associated with La Nina, favoring above-median precipitation for the Northwest and northern Rockies, below-median precipitation for central and southern California through the southern Four Corners region, and equal chances for near-, below-, and above-median precipitation straddling northern California eastward to most of Utah and Colorado. JFM is a normally a wet time of year for the Far West, and winter moisture is critical to building mountain snowpacks that feed reservoirs from river snowmelt during the typically drier late spring and summer months. Therefore, the wet signal forecast for the Northwest favors further drought reductions across the Northwest and northern Rockies, with drought elimination possible for much of Washington. In contrast, drought persistence is favored for the remainder of the West, with drought expansion possible across southern California due to good odds for below normal precipitation and above normal temperatures during JFM. 

Forecast confidence is high for the Western region.

Across the High Plains, drought conditions worsened during the past several weeks with degradations observed in most states, although some improvements did occur but were fairly localized. The La Nina favored anomalous precipitation dipole is reflected in the seasonal outlook, where above-median precipitation is favored for North Dakota and northwestern Wyoming, while below-median precipitation is favored for much of Colorado, Kansas, and Nebraska. JFM is a dry, cold time of year for the Plains, and any anomalous snowfall during the winter months across eastern Montana and the Dakotas will likely remain above the frozen soils until the spring thaw beyond the JFM period. Therefore, little change in the incipient drought conditions is likely during the outlook period. Further south, despite the normally dry time of year, the potential for subnormal rainfall and above-normal temperatures favors development of drought conditions across Kansas.

Forecast confidence is moderate for the High Plains region.

The most substantial drought development over the past month occurred in Texas due to abnormal dryness and near- to above-normal temperatures. The increasing dryness in southern Texas was interrupted by swaths of heavy rainfall, which brought some relief to the areas. La Nina winters tend to be warm and dry across most of the southern CONUS, and this is reflected in the probabilistic monthly and seasonal outlooks. Therefore, drought development is likely for the rest of Texas and Oklahoma. In addition, the surplus rainfall this summer and fall from several tropical systems affecting the Southeast are gradually becoming a faded memory from southeastern Louisiana eastward across southern sections of Mississippi, Alabama, Georgia, South Carolina, and northern Florida. With this region accumulating growing precipitation deficits out to 60 days and a JFM outlook for subnormal precipitation and above normal temperatures, drought development is likely. However, short-term drought removal is favored for northern Mississippi and western Tennessee due to short-term forecasts of above normal rainfall and favorable time for soil moisture recharge.  

Forecast confidence is moderate to high for the South and Southeast regions.

Small pockets of drought currently extend across parts of northern Missouri, central Illinois, and northern Indiana as these areas missed surplus precipitation that overspread portions of the Ohio River Valley for the past month. Additionally, unusually long-lasting drought has persisted across central Pennsylvania, upstate New York, and coastal New England, though recent storminess brought relief to much of this area. During La Nina winters, the climatological winter storm track typically shifts to the west, favoring the Ohio Valley and interior New England with enhanced precipitation. This is reflected by elevated chances for above-median precipitation in the JFM seasonal outlook. Therefore, drought removal is favored for the eastern half of the Corn Belt, and additional drought improvements are expected across the Northeast. While enhanced chances for above-median JFM precipitation do not extend to coastal New England (Equal Chances-EC), climatology favors frequent coastal storms during the winter, and these storms should be sufficient to erode the ongoing drought. In contrast, with no tilt of odds (EC) for JFM precipitation and with a drier and colder climatology than eastern regions, drought across parts of western Iowa, northwestern Missouri, northern and western Minnesota should persist as the ground will most-likely remain frozen well into March.

Forecast confidence is high for the Midwest and moderate to high for the Northeast.

No drought is currently in place or anticipated to develop across Alaska or Puerto Rico. Persistent dryness and above-average temperatures promoted widespread drought development in Hawaii, with nearly 23% of the state currently experiencing drought conditions. With the start of the wet season in January, as well as enhanced trade winds associated with the La Nina response, above-average rainfall is favored, particularly across the leeward sides of the islands. Therefore, drought improvement or removal is favored during JFM.

Forecast confidence is high for Hawaii.

Forecaster: Yun Fan

Next Seasonal Drought Outlook issued: January 21, 2021 at 8:30 AM EST.