Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for December 2021 and December 2021 - February 2022 (DJF, or winter season), 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 Weeks 3-4 outlooks and related tools from CPC, dynamical models at the monthly and seasonal time scales, the 384-hour total precipitation forecasts from several runs of the GEFS, climatology for the DJF season, and initial conditions such as soil moisture. The USDM valid on November 16 was used for initial drought conditions. 

Drought has eased slightly in central and northern sections of the West Region, though the short-term heavy precipitation was not as beneficial as it might seem, given the long-term, protracted nature of the drought here. The vast majority of the region remains in drought, including broad areas of severe (D2) to exceptional (D4) drought. The outlook here is driven primarily by the expected La Niņa and its observed past effects on conditions during the winter. The forecast is approximately divided into two areas: above-normal precipitation and an easing of drought conditions are expected across the northern half of the region while lesser amounts will maintain or worsen drought severity there. The northern and southern tiers of the region have the most forecast confidence, as La Niņa conditions most strongly correlate with observed conditions here. The middle of the West Region, around the dividing line between drought improvement/removal and persistence, is the most uncertain. In addition, forecast confidence generally increases from east to west because of the precipitation climatology. Over 35 percent of the annual precipitation total typically falls along the West Coast, topping 50 percent along the California coastline and in the central valleys. Farther east, where winter usually contributes a smaller proportion of the annual precipitation, the sufficiency of precipitation to impact multi-month (or longer) drought conditions is less certain, whether the DJF outlook favors dryness (southern tier) or wetness (northern tier). The area of expected drought improvement approximately coincides with the area with enhanced chances of above-normal precipitation in the DJF outlook.

Forecast confidence is high along the northern and southern tiers of the West, and low-to-moderate across the central parts of the region.

Similar to the West, the northern and western portions of the High Plains Region remain entrenched in drought, while the southern High Plains Region has more localized dryness. The DJF outlook favors drier-than-normal conditions in southern sections of Kansas and Colorado, but odds favor above-normal precipitation in central and western Wyoming and adjacent areas. Drought improvement or removal is expected in those areas, but persistence or worsening is expected elsewhere, with some expansion possible in the southernmost reaches of the region. From central Kansas northward through the Plains, winter is a relatively dry time of year, with much of the region typically accumulating only 5 to 15 percent of the annual precipitation total then. The climatological dryness reduces the chances for drought-improving precipitation in any case, so persistence is the only logical forecast there.

Forecast confidence is moderate-to-high for the High Plains Region.

Drought changes were highly variable in the Southern Region since mid-October 2021. Widespread improvement was noted across eastern Oklahoma, and lesser areas of central and southern Texas also saw drought Conditions ease. Meanwhile, drought developed and expanded across the ArkLaTex region eastward to the Mississippi River, and worsening conditions also impacted much of the Rio Grande Valley, and areas from the Big Bend to the Red River. La Niņa favors subnormal precipitation during DJF across most of Texas and Oklahoma, and southern sections of Louisiana, and none of the tools depict impactful surplus precipitation anywhere in the Southern Region. Drought is expected to persist region-wide, expanding to fill in areas of abnormal dryness (D0) from central and western Texas northward through Oklahoma and New Mexico. These areas have the greatest odds of observing subnormal precipitation.

Forecast confidence is moderate to high for the Southern Region.

Drought covers the northern reaches of the Midwest Region, except for the Upper Peninsula of Michigan, while only patchy moderate drought is established farther south in the middle Mississippi and lower Ohio Valleys. The DJF outlook favors enhanced precipitation across all but the western tier of the region. As a result, drought is expected to improve throughout the region except along the western tier of the Midwest, where climatological dryness lowers the chances for broadscale heavy precipitation. Persistence is most confidently favored in parts of northern Minnesota, where drought is more severe and more entrenched than farther to the south and east, and where the climatology tilts the driest.

Forecast Confidence is high across the northern parts of the Midwest Region, and low-to-moderate elsewhere. 

The Southeast Region is largely drought-free, with patches of moderate drought (D1) restricted to portions of the Carolinas and adjacent southeastern Virginia. Both the official DJF outlook and La Niņa composites favor a drier-than-normal winter from southern Louisiana to eastern North Carolina and southward across Florida, with the greatest forecast confidence over southern Georgia and Florida. Odds tilt slightly toward a dry winter in the he existing moderate drought areas of the Carolinas, so persistence is forecast. Development is not depicted, but it could also occur anywhere from South Carolina through northern Florida with a dry winter, but antecedent conditions are favorable, and no specific area appears particularly vulnerable at this time.  

Forecast confidence in the Southeast Region is moderate-to-high.

In the Northeast Region, drought is limited to a small area of western Maine, where DJF and other outlooks are nondescript. But DJF outlooks favor surplus precipitation just west of there, and a few tools bring modest chances farther east into the drought region. This is neither a particularly wet nor dry time of year, but with reduced moisture demand from humans and most environmental processes, a forecast of improvement or removal seems the best bet, though with very low confidence.
  
Forecast confidence in the Northeast Region is low.

La Niņa winters typically bring surplus precipitation to Hawaii, and the DJF outlook shows a strong tilt of the odds in that direction, easing drought. Only small areas of moderate drought exist in northeastern and southwestern sections of Puerto Rico; below-normal precipitation is marginally favored here, consistent with La Niņa composites, so drought persistence is expected, though no significant expansion of drought seems likely given the mild tilt of the odds. Alaska is drought-free and should remain that way.

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


Forecaster: Richard Tinker
 
Next Seasonal Drought Outlook issued: December 16, 2021 at 8:30am EST