Tools used in the U.S. Seasonal Drought Outlook (SDO) included the official Climate Prediction Center (CPC) temperature and precipitation outlooks for January through March 2017 (JFM), 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 (CFSv2, NMME, IRI, IMME, and ECMWF), the 384-hour total precipitation forecasts from several runs of the GFS, weeks 3-4 experimental temperature and precipitation outlooks, the four-month Palmer drought termination and amelioration probabilities, climatology for the JFM season, and initial conditions. Weak La Nina conditions currently exist and this was given some consideration, but ENSO-neutral conditions are expected by the end of the period.

Tools pertinent to the last half of December in the Northeast favor near- to above-normal precipitation, but longer-term outlooks show no tilt of the odds toward abnormally dry nor wet conditions. Climatological considerations lean toward the potential for some improvement, with modeled soil moisture typically increasing during this period despite it being slightly drier than other times of the year. Given the tendency toward soil recharge and snowpack, most of the region is forecast to see improvement or removal. The exception is through parts of southern New England where drought conditions date back up to 2 years; thus, improvement will require consistent precipitation over a longer period.
Forecast confidence for the Northeast is low.

Across the Ohio Valley and Southeast as far west as the lower Mississippi Valley, the Drought Outlook generally followed the 3-Month Outlook, with improvement or removal forecast where odds favored above-normal precipitation, and persistence or deterioration farther south, closer to the Gulf Coast. In areas where soil recharge is more common than not, and where JFM is not a markedly dry time of year, drought was forecast to expand. In these areas below-median precipitation would cause a more significant shift away from climatological conditions than it would in areas that don't rely as much on this time of year for an increase in the moisture budget. The last half of December appears to be near- or wetter-than-normal, but this should not have a significant influence on conditions which prevail during the following three months.
Forecast confidence for the Southeast is moderate.

This is a relatively dry time of the year for the High Plains and Great Plains, especially in northern and western sections. Given the 3-Month Outlook calling for enhanced chances for below-normal precipitation from central Oklahoma and southeastern Colorado southward, this makes the forecast of persistence or deterioration in these regions fairly straightforward. To the north in and near the Black Hills, above-normal JFM precipitation is favored, so despite this being a dry time of year, an enhanced snowpack should begin to bring some relief as spring starts and a slow recharge of water into the soil begins.
Forecast confidence for the Plains is high in southern and central sections, moderate in the northern sections.

This is a marginally drier time of the year across the southern and eastern Rockies' drought areas, but not so farther north. Near- to above-normal precipitation is expected during the last half of December regionwide. JFM is a time of the year when snowpack accumulates across mountainous areas and thus climatologically the moisture budget is recharged. The 3-Month Outlook favors wetter-than-typical weather for most of these drought areas as well. In contrast, the relative dryness of this time of year in combination with a 3-Month Outlook favoring below-median precipitation led to a forecast of drought persistence or intensification in the southern Rockies, with improvement or removal expected farther north across northern Utah, northern Colorado and adjacent Wyoming, and western Montana.
Forecast confidence for the southern Rockies is high.

This is a wet time of year for the West Coast (especially California) and to a lesser extent across western Nevada and eastern Oregon. California gets 35 to over 50 percent of its annual precipitation during JFM from the Sierra Nevada westward, so this is a critical time of year for their moisture budget, as it affects conditions over spring and summer, when little precipitation falls. Drought persistence or intensification is expected in southern California where the 3-Month Outlook favors drier than normal conditions. In northern parts of the region, the 3-Month Outlook calls for enhanced chances of abnormally wet weather, so some improvement or removal is expected in eastern Oregon and northernmost Nevada. In central parts of the region, the forecast is much more difficult. Shorter-term conditions favor significant precipitation and a good increase in snowpack across the Sierra Nevada and through central California through the rest of the year, and with no indicators beyond that period pointing in either direction, improvement or removal is forecast here with very low confidence.
Forecast confidence is high in northern Nevada, eastern Oregon, and southern California, but low to moderate in central parts of the drought region.

The outlook for the Hawaiian archipelago favors above-median monthly and seasonal rainfall with a good degree of confidence, and thus so is a Drought Outlook forecast of improvement or removal. However, the fact that these are leeward areas and normal precipitation is relatively low, a slight change from expected conditions could leave these areas without the anticipated improvement, so confidence is only moderate.
Forecast confidence for Hawaii is moderate to high.

Forecaster: Rich Tinker

Next Seasonal Drought Outlook issued: January 19, 2017 at 8:30 AM EST