Tools used in the U.S. Seasonal Drought Outlook (SDO) included the official Climate Prediction Center (CPC) temperature and precipitation outlooks for April 2016 and April-June 2016, various short- and medium-range forecasts and models such as the forecast 5-day and 7-day precipitation totals from the Weather Prediction Center (WPC), the 6-10 day, 8-14 day, and weeks 3-4 CPC forecasts, the NAEFS precipitation outlooks, the soil moisture tools based on the Constructed Analog on Soil Moisture (CAS), dynamical models (CFSv2, NMME, IMME, IRI, and IMME), the 384-hour total precipitation forecasts from several runs of the GFS, the four-month Palmer drought termination and amelioration probabilities, April and AMJ climatology, the MAM16 and JJA16 Caribbean Regional Climate Center (Caricof) Climate Outlooks (for Puerto Rico), and initial conditions. El Nino composites were also considered, although its influence should be decreasing as spring progresses.

The forecast for the small D1 areas in western Oklahoma depends on the April-June precipitation climatology and the 3-month LLF precipitation outlook. Precipitation normally increases as spring progresses, reaching a maximum during the summer months. Forecasts call for dry and warm weather for the next 2 weeks, but enhanced odds for above-normal precipitation thereafter (weeks 3-4, 1- and 3-month precipitation outlooks).
Forecast confidence for south-central High Plains is moderate.

The small D1 area of drought in North Dakota should improve by late June. Extended Range forecasts (Days 6-10 and 8-14) call for enhanced odds of above-median precipitation, but weeks 3-4, April, and AMJ precipitation forecasts slightly tilt toward sub-median amounts. Most of the concern was for the lack of March snow cover in the Dakotas due to the unseasonably mild weather that may cause green-up early, causing plants to draw somewhat limited topsoil moisture. However, the wetter time of year is getting underway in the northern Plains (late spring to early summer), and conditions are not that dire so that near- normal April or AMJ totals should be enough for drought removal.
Forecast confidence for the Northern Plains is moderate.

In the north-central High Plains and adjacent Rockies, odds favor wetter than normal weather in south-central Montana and central Wyoming at 5-days, 6-10 and 8-14 days, (weeks 3-4 EC), and at 1- and 3-months even though the D0, D1, and D2 areas have recently expanded during the past month due to a dry and mild winter. In addition, AMJ is a climatologically favorable (wet) time of the year in the region, bringing better chances for improvement than deterioration. Farther north, however, in northwestern Montana, worse initial conditions (WYTD precipitation 70%, snow water content 68-80%), less favorable climatology, and no tilt (EC) in the 1- and 3-month precipitation outlooks equates to less confidence for improvement, although the 6-10 and 8-14 day forecasts have favorable chances for above-median precipitation.  
Forecast confidence for the northern High Plains and adjacent Rockies is moderate; northwestern Montana is low.

The recent storms in early to mid-March brought welcome precipitation to most of California, especially the northern half, after a very dry February and first few days of March. The first storm (March 5-7) basically made-up for the previous 3 weeks of dry and warm weather as WYTD conditions had stagnated or declined, but returned to early February levels. The second storm (March 10-13) provided a boost to the WYTD statistics with a good jump in the accumulated precipitation indices, stream flow and reservoir levels, and Sierra snow water content, especially across the northern half of California. Farther north, the Northwest had experienced a decent WYTD as storms had been more frequent across this region, leading to drought removal and improvement during this winter. But additional improvements in the West strongly depend on the April outlook (as precipitation climatology rapidly drops after April, with May and June dry as temperatures rise) and initial conditions. Based upon this, the 5-day, 6-10 and 8-14 day keep northern California and the Northwest wet, while the April and AMJ outlooks have a slight tilt toward wetness in northern California, the Great Basin, and south-central Rockies. Although weeks 3-4 and the 1- and 3-month outlooks slightly favor above-median precipitation in parts of the Southwest, the climatology is rather low during the spring, and short-term conditions in southern California, Arizona, and New Mexico are dry. With NRCS/USDA average basin snow water content extremely low in Arizona and western New Mexico (0-49%), minimal spring snow melt is expected. Overall, northern sections (southeastern Oregon, northwestern Nevada, northern California, northwestern Utah)  should see some additional improvement with favorable spring snow melt, filling reservoirs, and near to above normal WYTD precipitation. In contrast, the southern half of California, southwestern Nevada, most of Arizona, and western New Mexico have entered a climatological dry time (between the winter and late summer monsoon peaks), have short-term dryness (initial conditions) and a drier Water Year than northern areas, and minimal snow pack for spring snow melt, therefore development and persistence is expected during the next few months.
Forecast confidence for The West is generally moderate to high, with most northern areas expected to see some improvement in the next month or so, and southern areas to persist or deteriorate.  

El Nino conditions favor continued dryness across most of Hawaii, so persistence or deterioration, including substantial drought expansion, is expected. Even the normally wet windward sides have seen below normal rainfall this year, and although the El Nino is expected to rapidly fade by summer, its atmospheric effects should linger a bit longer. Recent reports from the state have indicated a sharp rise in negative impacts from the recent dryness. 
Forecast confidence for Hawaii is high.

El Nino conditions favor a wetter than average dry season across Puerto Rico, and recent heavy rains in mid-February were enough to make improvements across the island. The most recent rainfall forecast from the Caribbean Regional Climate Center for MAM16 and JJA16 indicated elevated odds for near to above normal precipitation due to above-normal Caribbean and Atlantic basin sea surface temperatures near Cuba, Hispaniola, and Puerto Rico, the demise of El Nino that should allow for summer tropical systems (more rain) to develop and intensify in the basin, and increased precipitation climatology as the island progresses into the summer months. As a result, the expected increase in rainfall should lead to improved drought conditions by the end of June.
Forecast confidence for Puerto Rico is moderate.

Forecaster: David Miskus

Next Seasonal Drought Outlook issued: April 21, 2016 at 8:30 AM EDT