Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for December 2019 through February 2020 (DJF), 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 the DJF season, and initial conditions such as soil moisture. The drought areas on the U.S. Drought Monitor, valid on November 19, were used. ENSO-neutral is favored to continue through the Northern Hemisphere winter (around 70-percent chance), with a 55 to 60 percent chance of ENSO-neutral continuing through summer 2020.
During past 30 days, widespread rainfall exceed 2 to 8 inches across much of the Ohio Valley, Mid-Atlantic and Southeast. As a result, drought conditions were greatly improved or even ended over the areas. A number of factors favor improving drought conditions during the outlook period. These factors include the likelihood of additional rainfall (1 to 2 inches, locally more) during the next 2 weeks, and the short-term nature of the drought. The next three months is a favorable time of year for soil moisture recharge as evapotranspiration rates decrease. Based on these factors, drought removal across the areas is forecast for short-term moderate (D1) drought areas on the U.S. Drought Monitor, valid on November 20.
Forecast confidence is high for the Southeast Region.
The Northeast region is back to drought-free, due to a recent period of above normal precipitation and below normal temperatures. Drought is unlikely to develop during the outlook period based on the time of year and the lack of a dry signal among any precipitation tools.
Forecast confidence is high for the Northeast Region.
Above normal rainfall during past 30 days wiped out short-term drought over the Ohio Valley. Given the absence of any dry signal among seasonal precipitation tools and a favorable time of year for soil moisture recharge, drought-free conditions are likely to persist through the end of February.
Forecast confidence is high for the Midwest Region.
During the past 30-days, precipitation amounts ranged from 2 to 15 inches over the Lower Mississippi Valley which resulted in drought removal. However, drought continues to plague parts of Texas. A relatively dry climatologly supports broad-scale persistence for the ongoing drought in Texas. A slight expansion of the drought is based on the seasonal outlook calling for increased chances for below normal precipitation.
Forecast confidence is moderate for the lower Mississippi Valley and low for Texas of the Southern Region.
A lack of summer monsoon rainfall resulted in drought development across the Four Corners region since July. 90-day precipitation deficits exceed 4 inches in parts of Arizona, southwest Colorado, western New Mexico, and Utah. Ongoing precipitation along with increased chances for above normal precipitation through the end of Week-2 support improvment or removal of drought across much of the Four Corner Region. Drought development is forecast for parts of central California due to below-normal precipitation since the beginning of October along with the seasonal outlook favoring below normal precipitation.
Forecast confidence is low for the West.
The Missouri River Basin remains excessively wet with many areas receiving 200 to 400 percent of normal precipitation during the past 90 days. Soil moisture ranks in the 99th percentile from North Dakota south to Nebraska. Therefore, drought development is unlikely for the northern and central Great Plains. A small area of moderate to severe drought is ongoing across southwest Kansas, and south and western Colorado. Although the seasonal outlook favors above normal precipitaton across northern and central parts of this region, drought persistence is forecast given the relatively dry time of year across southwest Kansas. This persistence extends west to include southeast Colorado.
Forecast confidence is high for the High Plains Region.
Mainland of Alaska is back to drought-free. Removal or improvement for the Alaska Panhandle is consistent with a wet climatology and the seasonal precipitation outlook. Although long-term drought impacts, such as hydro power, continue for parts of the Alaska Panhandle, the recent increase in precipitation has raised lake levels.
Forecast confidence is high for Alaska.
Drought improvement continues across Hawaii. Based on a wetter climatology during the winter along with the seasonal precipitation outlook, continued improvement and removal of drought are likely by the end of February.
Forecast confidence is high for Hawaii.
Only abnormal dryness (D0) is designated for Puerto Rico. The climatology becomes increasingly drier during the outlook period. Forecast confidence is not high enough to warrant development at this time for Puerto Rico.
Forecast confidence is low for Puerto Rico.
Forecaster: Yun Fan
Next Seasonal Drought Outlook issued: December 19, 2019 at 8:30 AM EST