Tools used in the U.S. Seasonal Drought Outlook (SDO) included the Climate Prediction Center (CPC) temperature and precipitation outlooks for February (Feb'19) and February through April 2019 (FMA'19), 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), 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 FMA season, and initial conditions. El Niño is favored to form and continue through the Northern Hemisphere spring 2019 (65 percent chance). The anomaly pattern favored during El Niño was considered, however, the recent atmospheric anomalies reflected intra-seasonal variability related to the Madden-Julian Oscillation, and have not yet shown a clear coupling to the above-normal ocean temperatures. The late winter and early spring months tend to be the most favorable months for coupling, so forecasters believe weak El Niño conditions will emerge shortly, but even if conditions were to form, the timing and its weakness will not favor major global impacts during the remainder of the winter.
Northeast: There is no drought analyzed anywhere, and although some abnormal dryness is showing up in extreme northern Vermont and Maine, drought development is not expected, especially considering how cold it normally is in FMA and how wet is has been during the past year in much of New England and the mid-Atlantic.
Northeast forecast Confidence is high.
Southeast: Drought was limited to southeastern Florida. It is a fairly dry time of year for the state, but normals year-round are more substantial than in the Plains (where FMA is also a drier time of year), and El Niño development (assuming the atmosphere couples with the ocean conditions) would strongly favor above-normal FMA precipitation as indicated in the 3-Month outlook. Thus drought improvement is forecast.
Southeast forecast confidence is moderate to high.
South: Drought (D1) was restricted to small areas in the northern Texas Panhandle and extreme southern Texas. The D1 in northern Texas was long-term while the southern Texas moderate drought was short-term. With the 5-day QPF showing little or no precipitation, ERFs depicting near-normal chances, Weeks3-4 favoring subnormal rainfall, Feb'19 with equal chances (EC), and FMA tilting toward above normal precipitation, along with the wild card influence of a probable weak El Niño (wet) and a cooler time of year (less evaporation), the odds for improvement slightly outweighed the chances for persistence and development - although in the short-term, conditions may degrade somewhat before improving later in the period as 60-day precipitation was 25-50 percent of normal in southern and western Texas.
South forecast confidence is low to moderate.
Midwest: Similar to the Northeast, there was no drought in this region. All that remained was a small D0 area in northwestern Minnesota, covered under a blanket of snow and frozen in place. After most locations experienced a wet 2018, and are anticipating more moisture in the short-term and extended range, drought development is not expected anywhere.
Midwest forecast Confidence is moderate to high
High Plains: Much of the Great Plains (Dakotas, Nebraska, Kansas) were also drought free with the exception of northern North Dakota (D1). But with the ERFs, Weeks3-4, and Feb'19 precipitation outlooks favoring above-normal precipitation and near- to below-normal temperatures, along with a moderate blanket of snow currently covering its frozen ground, this water in the bank (snow) should be enough by late April to provide ample moisture to the thawed ground. In the High Plains (Wyoming and Colorado), however, it is a different story as long-term D2-D4 drought lingered in Four Corners Region (southwest Colorado) while short-term D0-D2 dryness/drought has been slowly growing in northern Colorado and southern Wyoming. On Jan. 14, WYTD basin average SWC (precipitation) ranged between 75-95 (80-95) percent of normal, but most of this was due to a good start to the Water Year (wet October and November) and a cold Oct-Dec. It has been rather dry the past 60 days. However, the 5-day QPF, ERFs, Weeks3-4, and FMA'19 favored above normal precipitation (Feb'19 EC), thus some improvement is expected in Colorado and southern Wyoming by late April. Note that improvement in southwestern Colorado may still leave some of this area in D3 or D2. And although some improvement is forecast, the Four Corners Region drought has lasted at least a year, so hydrologic impacts will continue into 2019, but at least this winter has started out favorably.
High Plains forecast confidence is moderate.
West: Much of the region (over 71 percent) is in dryness or drought (D0-D4) - which includes CO and WY - with D2-D4 drought extending from Oregon southeastward into the Four Corners Region. Most of this drought is long-term, especially the Four Corners Region (more than a year) and Oregon (6-9 months). During the past 60 days, near to below normal temperatures and surplus precipitation has fallen on most of California, Washington, northern Nevada, and parts of Arizona, Utah, New Mexico, and Colorado. January 14 WYTD basin average SWC (precipitation) responded, with most major basins in these areas at 80-115 (75-115) percent of normal. Major California reservoirs have also increased, with levels in central and southern sections of the state (Melones, San Luis, Millerton, Perris, Castaic, McClure, Don Pedro) near or above the historic Jan. 14 average, and northern reservoirs (Shasta, Trinity, Folsom) slightly below the average. Climatologically, the Far West is currently in their wet season (at least Feb and Mar), with coastal California normally recording 20-26 percent of their annual precipitation during February.
In the short-term (QPF), a potent Pacific storm system is forecast to drop heavy precipitation (1-6 inches) along the West Coast, on the Cascades and Sierra Nevada, and into the Interior West and Rockies. If this precipitation occurs, some short-term improvements are possible. The longer lead outlooks, however, do not look favorable from the extended to long-range (ERFs, Weeks3-4, 1- and 3-month LLFs) for the Northwest and California. A strong ridge is expected to persist over the West with a deep trough over the East, bringing a good chance for warm and dry weather to much of the West during late January into February (normally a very wet time for California). The FMA'19 outlook is still forecasting warm and dry weather, with the center of greatest subnormal precipitation odds centered over southern Oregon and northern California, and EC over southern California and Nevada. As a result, any short-term improvements to the Far West from this ongoing system may be offset by the dry and warm weather expected through February. The unfavorable medium to long-range forecasts, plus subnormal basin average SWC and precipitation, were also responsible for possible development of drought in the Northwest by late April where D0 currently existed. Chances for above normal FMA'19 precipitation, however, was located over the Four Corners Region and the southern Plains, hence the improvement over this area, but even with improvement, many of these locations would still be in D2 or D3 drought. Plus, the uncertainty with respect to the expected weak El Niño and whether atmospheric conditions couple to the Pacific oceanic conditions later in this period is a wild card.
West forecast confidence is low to moderate.
OCONUS (AK, HI, PR): In southeastern Alaska where normals are extremely high (more than 100 inches), subnormal precipitation during the past 6-12 months has accumulated large deficits and gradually have lowered lake levels used for hydroelectric power generation. Fortunately, all time periods (from 5-day QPF to FMA'19) have favorable odds for above normal precipitation, thus a 1-category improvement is expected. In Hawaii, expected El Niño conditions during FMA should cause subnormal rainfall especially on the leeward sides during the normal rainy season, so persistence and development of drought was depicted for the western sides of the islands. In Puerto Rico, recent dryness has gradually enveloped most of the island with abnormal dryness and a few D1 areas, and the expected El Niño favors subnormal rainfall across the Caribbean (as did the CFSv2), therefore development of D1 was placed where the D0 existed.
Alaska and Hawaii forecast confidence is moderate to high; moderate in Puerto Rico.
Forecaster: David Miskus
Next Seasonal Drought Outlook issued: February 21, 2019 at 8:30AM EST