Tools used in the Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for January and January-February-March (JFM) 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 (ERFs), dynamical models at the monthly and seasonal time scales, climatology for the JFM season, La Niña composites, and initial conditions such as soil moisture. The U.S. Drought Monitor (USDM), valid on December 13, was used for initial drought conditions.

Drought conditions covered two-thirds of the Western Region as of the December 6th USDM. This is a substantial amount, but is in fact the least coverage in this region since August 2020 (median coverage since 2000 is not quite 46 percent). A few storm systems moved through the region in the past 4 weeks, with the most substantial crossing late in the period. This brought multiple feet of snow to some higher elevations in California, wind gusts to 103 mph south of Lake Tahoe, and 5 to 7 inches of rain along the central California coast south of San Francisco. But following two lackluster winter wet seasons across California due to La Niña conditions, drought conditions are long-entrenched, with impacts felt across the soil, groundwater, and reservoir systems. Looking forward, JFM is the heart of the wet season along the West Coast and parts of adjacent states. California has a particularly pronounced wet season with 45 to 60 percent of annual precipitation typically falling during JFM. These 3 months typically bring 30 to 40 percent of the annual total to the western halves of Washington and Oregon, and a large swath across central Idaho. Moving eastward across the region, JFM is actually a drier time of year closer to the Plains. In eastern portions of Montana and New Mexico, less than 10 percent of the annual precipitation falls during JFM. The outlook is based primarily on the 3-Month Precipitation Outlook, which relied heavily on La Niña composites. Along the northern tier of the region, above-normal JFM precipitation seems likely. Conversely, drier than normal weather is significantly favored along the southern tier or the region. La Niña composites do not favor dryness or wetness in the central stripe across the region. The delineation between the dry southern tier and the wet northern tier is difficult to determine, and may shift north or south at times. The dry climatology across eastern New Mexico adds additional uncertainty. During drier seasons, precipitation anomalies are smaller than during wetter seasons, and the moisture budget is not as sensitive to precipitation during these periods. The bottom line is that surplus precipitation and drought improvement along the northern tier is made with fairly high confidence, and deficient precipitation is expected to cause deterioration across most of the southern tier outside the climatologically dry region in the southern High Plains and adjacent southern Rockies. Some drought expansion is possible across portions of New Mexico and Arizona, although relatively wet antecedent conditions may dampen development.

Forecast confidence is moderate to high across the northern and most of the southern tiers of the Western Region, but low in central sections and in areas with dry JFM climatology.

Drought coverage has slowly increased since summer across the High Plains Region, although there was a slight decline this past week. Nearly 75 percent of the region is experiencing some degree of drought, up from about half the region in August 2022. More recently, a winter storm brought heavy snow and blizzard conditions to a large part of the northern Plains. About 2 feet was reported in Deadwood, South Dakota by the morning of December 15, and totals of 12 to 18 inches fell on a few spots across the rest of South Dakota, North Dakota, Nebraska, and Wyoming. The area affected by this storm is also an area where La Niña composites favor surplus JFM precipitation, so at least some improvement seems likely there. But confidence is tempered by the dry climatology this time of year (typically 5 to 15 percent of the annual precipitation) and uncertainties regarding the seasonal increase in precipitation which begins around late March. Farther south, La Niña composites and the 3-Month Precipitation Outlook favor subnormal JFM precipitation, generally from Nebraska southward and westward. Drought is expected to remain entrenched across the central Plains through the period, expanding into the higher elevations of central and southern Colorado by the end of the period.

Forecast confidence is high for the northern High Plains Region, and moderate elsewhere.

Prevailing warm, dry conditions earlier this year engendered gradual drought development during summer and autumn in the Midwest region. In early June, less than 1 percent of the Midwest Region was in drought, but coverage progressively increased until drought covered about half the region in late October - the most expansive coverage since early 2013. Over the past 6 to 8 weeks, there has been a slight decline in coverage, now at 44 percent. JFM is a relatively dry time of year across the northwestern half of the region, bringing on average 5 to 15 percent of the annual precipitation. Closer to the Ohio River, JFM precipitation is about the same as most other times of the year. A mid-December storm system should bring heavy precipitation to the northern reaches of the region, much of it in the form of snow. Meanwhile, a trailing frontal boundary is expected to bring heavy precipitation into the Ohio River Valley and Great Lakes Regions. Continued ample precipitation is favored across all but the western tier of the region for JFM, consistent with the 3-Month Precipitation Outlook and La Niña composites. As a result, drought improvement or removal is forecast for all but the western tier of the region, with no significant relief anticipated from western Missouri northward into southwestern Minnesota. Drought coverage should continue to slowly decline.

Forecast confidence is moderate to high for the Midwest Region.

Drought coverage has been extensive across the South Region since late autumn 2021. Less than 3 percent of the region was experiencing drought in mid-September 2021, but a warm and dry end to the year left about half the region in drought at the start of 2022, and drought has covered nearly or more than half the region since. Coverage peaked in late October 2022, when over 80 percent of the Midwest was experiencing drought, but conditions have generally improved somewhat since then. As of mid-December, 57 percent of the Midwest was enduring some degree of drought - the least coverage since the beginning of autumn. JFM is climatologically a drier time of year in western parts of the South Region, with 5 to 15 percent of annual precipitation typically falling on western Texas and much of Oklahoma. From the Mississippi Valley eastward, however, JFM is normally about as wet as any other time of year. Over western parts of the South Region, the forecast seems fairly straightforward. The La Niña composites show a strong dry signal in the southwestern Plains during JFM, and the 3-Month Outlook reflects this correlation. Drought is expected to persist across the southern Plains, but the potential for deterioration and expansion is tempered somewhat in far western sections by the cooler and dry JFM climatology (which has a smaller effect on the moisture budget than warmer and wetter seasons) and above-normal precipitation over the last few months. But the rest of Oklahoma and Texas are likely to see drought persist or perhaps worsen, with some development in currently drought-free areas of central and southern Texas. The forecast is more complicated farther east. Mid-December has been wet across the Lower Mississippi Valley and Tennessee, and additional precipitation - moderate to heavy in some areas - is expected before the end of the year. But La Niña composites and the 3-Month Precipitation Outlook show enhanced odds for below-normal precipitation in this area, especially near the Gulf Coast. Given these contradictory signals, any forecast will be low-confidence here. At this time, it looks like abundant December precipitation - with several more inches expected before the end of the year - is likely to bring improvement to drought areas and reduce chances for re-intensification.

Forecast confidence is high in western parts of the South Region, and low to moderate in the Lower Mississippi Valley and Tennessee.

Hot, dry conditions during the first half of autumn resulted in widespread drought degradation across the Southeast Region, with flash drought occurring across the Florida Panhandle, and rapid development across Georgia and the southern Appalachians. Less than 3 percent of the Southeast Region was in drought from August through mid-September 2022, dryness slowly intensified and expanded until coverage exceeded 30 percent in early November. Scattered areas of precipitation over the last 4 to 6 weeks have reduced coverage to around 25 percent as of mid-December 2022. Similar to other areas across the southern tier of the U.S., La Niña composites and the JFM 3-Month Outlooks favor warmer and drier than normal conditions during JFM, but the western part of this region - specifically, western Alabama and the Florida Panhandle - are expected to receive moderate to heavy precipitation through later December, then odds favor drier than normal weather for JFM. Enough precipitation is expected across central Alabama to bring improvement, and odds do not favor re-intensification there by the end of March. But antecedent conditions are drier to the south and east across the Florida Peninsula and adjacent locales. Drought is more intense here (D2) than in other parts of the Southeast, and has been in place longer. In addition, the odds for subnormal JFM precipitation are higher here closer to the Gulf Coast than farther north in Alabama. As a result, drought persistence is forecast on the Florida Peninsula despite moderate to heavy precipitation in mid- to late-December. Farther east along the South Atlantic coastal states, less precipitation is anticipated for the last half of December and abnormally warm and dry JFM conditions are favored in La Niña composites and the 3-Month Outlooks. Drought from northern Florida through North Carolina should continue where it exists, and expand to cover most other parts of the Carolinas, eastern Georgia, and northeastern Florida by the end of March.

Forecast confidence is low to moderate in western parts of the Southeast Region, and high over the South Atlantic Coastal states.

The Northeast is the one region where conditions have predominantly improved since mid-September. About 20 percent of the Northeast was experiencing drought at that time, but now drought is restricted to a few patches across southeastern New York and central New England. A few episodes of moderate precipitation are anticipated for the last half of December, along with some intrusions of Arctic air. Most guidance does not favor either precipitation extreme for JFM. Given the potential for a few episodes of precipitation, and with seasonably cold air preventing any substantial water loss in the moisture budget, the drought areas are expected to continue improving, with very little if any drought remaining in the Northeast at the end of March.

Forecast confidence is moderate for the Northeast Region.

Increased moisture across Hawaii reduced drought coverage in Hawaii from over 90 percent in late September to around 30 percent in early November, remaining about constant since then. La Niña winters tend to be wet across Hawaii, with the core of the wet season commencing in January and February. Based on this outlook, continued drought improvement and removal are forecast.

Forecast confidence is high for Hawaii.

No drought or abnormal dryness is currently in place across Alaska and Puerto Rico, and drought is not favored to develop in either location during the JFM period. JFM is a relatively dry time of year in Puerto Rico, and La Niña composites show rainfall averaging about 10-15 percent less than during neutral or warm ENSO episodes. The Commonwealth has received only light precipitation since early November, but given wet antecedent conditions, and with only a modest tilt of the odds toward slightly less than normal precipitation, no drought development is anticipated. 

Forecast confidence is high for Alaska and moderate Puerto Rico.

Forecaster: Rich Tinker

Next Seasonal Outlook issued: January 19, 2023 at 8:30 AM EST