Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for February (Feb) 2021 and February through April (FMA) 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 Feb and FMA, and initial conditions for parameters such as soil moisture. Existing drought areas on the forecast are based on the January 19 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 (end of March 2021), and the potential for a transition to ENSO-neutral during the Spring 2021 (55 percent chance during April-June).

The ongoing La Nina event unfortunately favors subnormal precipitation and above-normal temperatures across the southern tier of States where drought is currently severe to exceptional (D2-D4) levels. SNOTEL basin Snow Water Content (SWC) values are less than 75% of normal across much of the southern half of the West, and under 50% in southern Utah, Arizona, and New Mexico, including below 25% in most of Arizona and southwestern New Mexico. In contrast, where near to above normal precipitation and seasonable temperatures have occurred (Northwest), SWC values are better across the northern half of the West, with basins in Washington, northeastern Oregon, northern Idaho, western Montana, and northwestern Wyoming close to normal or slightly above. For the next 2 weeks, however, a change in the long-term weather pattern should bring welcome precipitation and subnormal temperatures to the West, including the Southwest, before the Week 3-4 and 1- and 3-month LLFs revert back to the "typical" La Nina anomaly pattern. This brief favorable weather pattern in the Southwest is likely not enough to make any significant improvements in the long run (end of April), thus persistence was made for much of the Southwest, with development in southern California. In contrast, the Northwest should continue receiving above-normal precipitation and (probably) seasonable temperatures, continuing a wet trend from this Fall for additional improvements in the Northwest. The improvement in northwestern California was based upon recent heavy rains the past 30-days, more heavy precipitation expected during the next 2-3 weeks, and a wet climatology with equal chances (EC) of below, normal, or above precipitation in both the 1- and 3-month precipitation LLFs.

Forecast confidence is moderate to high for the Western region.

In the northern Plains, although the 6-10 day ERF, Week 3-4, and 1- & 3-month LLFs tilt toward above-normal precipitation, the past 30-60 days have been quite dry and very mild there, which has led to minimal or no snow cover. Plus, with climatology quite dry during February and March, any surplus precipitation in the Dakotas most-likely would not eliminate the accumulated deficits and impacts of the past 1-2 months. Thus, persistence (not improvement) is forecast for the northern Plains. In addition, development was not added in South Dakota since the forecasts showed potential for above-normal precipitation. Improvement might have been depicted if this SDO was for MAM or AMJ as the precipitation climatology is much wetter then. Farther south, with the ongoing La Nina, the 3-month LLF favors subnormal precipitation in Colorado, Kansas, and Nebraska, thus persistence for existing drought areas and some development along the eastern drought border (southern Kansas) was drawn.

Forecast confidence is moderate for the High Plains region.

The past 30-days brought surplus precipitation to western parts of the Midwest, with subnormal totals in Wisconsin, Illinois, Indiana, Michigan, western Ohio, and Kentucky. Temperatures have also averaged above normal, leading to diminished snow cover. With the 7-day QPF limiting moderate precipitation to southern sections (Kentucky), only light amounts should occur for much of the region. The 6-10 day ERF favors above-normal precipitation, but by 8-14 days, the odds call for near to below-normal precipitation (with seasonable ERF temperatures). With the Week 3-4, 1- and 3-month LLFs favoring above-normal precipitation, improvement is expected in Illinois and Indiana and northern Minnesota. In western Iowa, with only a weak signal for improvement, a rather dry February and March climatology, and the drought being long-term, persistence was the safest forecast.

Forecast confidence is moderate to high for the Midwest region.

Surplus precipitation, including snow, has fallen on most of the South (Texas, Oklahoma, Louisiana, Arkansas) during the past 30-60 days, prompting drought improvement across most of Texas, Oklahoma, and Arkansas recently. The 7-day QPF continued the ample precipitation across central and eastern Texas, Arkansas, and most of Louisiana, Mississippi, and Tennessee, although drier weather is expected by 8-14 day ERF and into the Week 3-4 forecast. The upcoming rains should be enough to remove the small D1 areas in western Tennessee and northern Mississippi. The 1- and 3-month LLFs favor subnormal precipitation for southern and western sections of the South (and above-normal temperatures), with a southwestward dip of above-normal precipitation probabilities from the Ohio Valley into the lower Mississippi Valley in the FMA precipitation LLF. With subnormal precipitation expected in southern Texas and along the central and eastern Gulf Coast, development was depicted in these areas - but not along the western Gulf Coast where the precipitation outlooks are closer to normal. 

Forecast confidence is moderate for the South region.

Mostly dry conditions have enveloped parts of the Southeast the past 30-60 days, namely the central and eastern Gulf and southern Atlantic Coasts and eastern Tennessee Valley, although a band of surplus precipitation did fall from Apalachicola, FL area northeastward into the Carolinas and southeastern Virginia. Currently, only a few areas of D0 were found on the Jan. 19 USDM in the Southeast. However, the 7-day QPF predicts heavy precipitation (1-4 inches) across much of the Southeast - except drier right along the Gulf Coast and Florida. Then, the extended range forecasts expect precipitation to gradually decrease, with the 8-14 day ERF favoring subnormal precipitation across the region. Similarly, the Week 3-4, 1- and 3-month LLFs also expect subnormal precipitation (thanks to La Nina) mainly along the Gulf Coast - thus, development is expected along (most of) the central and eastern Gulf and southern Atlantic Coasts (including all of Florida) by the end of April. 

Forecast confidence is moderate for the Southeast region.

A wet winter pattern has dramatically improved conditions and stream flows across New England, with only a few small D1 areas left. The 7-day QPF showed light precipitation, 6-10 & 8-14 day ERFs have a slight tilt toward below-normal precipitation, and temperatures will be seasonable out to 2 weeks. The Week 3-4 hinted at above-normal precipitation, while the 1- and 3-month LLFs favored above-normal precipitation in western areas and EC toward eastern areas (above-normal temperatures for both time periods). With minimal soil moisture loss during the winter (low temperatures, no evaporation, frozen ground) and future moisture infiltration (e.g. snow pack), most winter precipitation that occurs should contribute to decent spring moisture conditions by the end of April. Thus, the remaining D1 areas should be gone by the end of April.

Forecast confidence is moderate to high for the Northeast region.

In Hawaii, a La Nina typically brings above-normal rainfall during their climatologically wet winter season, particularly later in the season (Jan-Mar), thus improvement is expected across the islands. In Alaska, no changes are anticipated during their frigid winter hibernation. In Puerto Rico, recent dryness in the north (D0 and D1) may expand somewhat by the end of April based upon some model guidances forecasting subnormal Feb and FMA precipitation; therefore some development was added in north-central sections. 

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

Forecaster: David Miskus

Next Seasonal Drought Outlook issued: February 18, 2021 at 8:30 AM EST.