Drought 2016: Finally getting out from under?

Lake County Leader

Drier—and warmer-than-normal conditions overspread much of the West, with precipitation confined to the Pacific Northwest and northern Rockies. Despite the mostly favorable Water Year precipitation to date, the warmth and dryness renewed concerns of early snowmelt in the mountains; however, rain and mountain snow were returning at the end of the weekly drought assessment period (which ends Tuesday morning, 7 a.m., EST).

In northern portions of the region, additional rain and mountain snow continued the favorable Water Year and resulted in further drought reductions in southwestern Oregon and western Montana. Mountain Snow Water Equivalents (SWE) continued to improve in western Montana; however, SWE values remain below average east of Flathead Lake, and the eastern slopes of the northern Rockies will need to be closely monitored over the coming weeks. Likewise, snowpack SWE remain unfavorably low in Wyoming’s Bighorn Mountains (50-70 percent of average) and River Range (60-75 percent of average, but locally less than 50 percent). These areas too will need to be followed closely throughout the second half of the Water Year.

Farther south, there were no changes to the drought depiction from the Great Basin into the Four Corners Region. In the areas of Moderate to Severe Drought (D1 and D2) around Great Salt Lake, precipitation since the beginning of the Water Year has been generally favorable, with mountain SWE currently near to above average. However, reservoir storage in these aforementioned areas hovered near or below 60 percent of average for the date, reflecting the lingering impacts of the region’s long-term drought.

In the core western drought areas of California and western Nevada, dry, warm weather during the period resulted in no change to this week’s drought depiction. While much of the region has experienced favorable precipitation during the 2015-16 Water Year — and subsequent removal of the “S” (short-term) drought Impact Type — considerable long-term (L) impacts remain. Furthermore, there are notable pockets of short-term dryness over central and southern California contributing to the long-term drought signal. While current SWE in the Sierra Nevada are near to above average, most reservoirs on either side of the mountains remain well below average. Adding to the drought are localized areas where it has been a drier-than-normal Water Year to date; counties near and west of Sacramento have averaged 60 to 75 percent of normal precipitation since October 1, while coastal locales from Los Angeles north to Santa Barbara have reported on average 35 to 50 percent of normal rainfall during the current Water Year.

Looking Ahead

Mild weather will expand to cover much of the nation, including the previously cold eastern U.S. Warm weather will continue to set high-temperature records across the nation’s mid-section, with warmth peaking in many areas on February 18. On that date, high temperatures could reach 90°F on the southern High Plains. At the height of the southern Plains’ warm spell, gusty winds and dry conditions will lead to an enhanced risk of wildfires. Dry weather will prevail during the next 5 days across the Deep South, as well as the central and southern Plains. In contrast, precipitation totaling 2 to 6 inches — much of which will fall on February 17-18 — can be expected in parts of northern California and the Pacific Northwest.

Toward week’s end, snow can be expected from the upper Great Lakes into northern New England, while rain showers will develop from the mid-South into the Ohio Valley. The NWS 6- to 10-day outlook for February 23 – 27 calls for above-normal temperatures across much of the western and central U.S., with cooler-than-normal conditions largely confined to the Southeast.

Meanwhile, below-normal precipitation is anticipated from southern California and the Great Basin eastward into the Corn Belt and Great Lakes, encompassing the Rockies and Plains. Wetter-than-normal conditions will be confined to coastal areas of the Pacific Northwest and from the eastern Gulf Coast States into New England.

During the four-week period ending Feb. 2, 2016, contiguous U.S. drought coverage fell to 15.48 percent—a decrease of 2.91 percentage points. This also represents the smallest areal coverage of U.S. drought in more than five years, since Oct. 26, 2010. Perhaps not coincidentally, the U.S. drought minimum of 2010 occurred in the wake of the most recently completed El Niño, which lasted from the summer of 2009 to the spring of 2010.

US drought coverage down to least amount in 5+ years

Since mid-October 2015, stormy weather in many parts of the country—in part driven by a strong El Niño—has significantly reduced U.S. drought coverage from 34.78 to 15.48 percent—a drop of 19.30 percentage points.

Where drought remains, mostly in the Far West, there has been incremental improvement. Although long-term concerns still include below-average reservoir storage, groundwater shortages, and tree mortality, winter precipitation has boosted spring and summer runoff prospects, improved rangeland and pasture conditions, cut irrigation demands, pnd reduced the need for supplemental feeding of livestock.          

California’s intrastate reservoirs held just 54 percent of their normal water volume on Dec. 31, and that number may not appreciably improve until high-elevation snow begins to melt in the spring.

On Feb. 2, more than one-third (38 percent) of the western U.S. remained in drought, down from 57 percent in early October 2015. Most (95 percent) of California was still in drought on Feb. 2, down 2 percentage points from the beginning of the water year on Oct. 1, 2015. However, California’s coverage of exceptional drought (D4) has fallen from 46 to 39 percent since Oct. 1. Farther north, coverage of extreme to exceptional drought (D3 to D4) since Oct. 1 has decreased from 67 to 4 percent in Oregon and from 68 to 0 percent in Washington.

On Feb. 2, drought was affecting just 11 percent of the U.S. cattle inventory, down from an autumn 2015 peak of 27 percent.

On Feb. 2, the portion of the U.S. winter wheat production area in drought stood at 7 percent, down from an autumn peak of 29 percent on Oct. 20. At the end of January, USDA’s National Agricultural Statistics Service rated more than two-thirds of the winter wheat in good to excellent condition in several major production states, including Oklahoma (74 percent good to excellent); Ohio (74 percent); Michigan (73 percent); Montana (72 percent); Indiana (71 percent); and South Dakota (67 percent).

Weather outlook:  Unsettled weather will persist across the Northwest into the weekend, following by a transition to mild, dry conditions. Many other areas of the U.S., from California to the middle and lower Mississippi Valley, will experience dry weather during the next five days. In California and the Desert Southwest, a marked warming trend will accompany the dry weather. Elsewhere, precipitation will be mostly light and confined to the nation’s northern tier, except for some heavy snow early next week in the vicinity of the Great Lakes.