US Drought Monitor and Summary, Aug. 10, 2018
South: Moderate rainfall was less common in this region than farther east, with 7-day rainfall exceeding an inch restricted to portions of southeastern Texas, west-central and southeastern Louisiana, southern and east-central Mississippi, eastern Tennessee, and small pockets in the western Oklahoma Panhandle and adjacent Texas. Large portions of western Tennessee, northern Mississippi, northeastern Louisiana, Arkansas, Oklahoma (excluding the Panhandle), and interior Texas received little or no rainfall. As a result, dryness and drought improved across the northwestern Oklahoma and the northern Texas Panhandle, but persisted or intensified farther south and east.
Small areas of D4 were introduced in central and southwestern Texas and southwestern Oklahoma (mostly based on large multi-month rainfall shortages and (in central Texas) depleted moisture in grass, shrubs, and even large trees that could serve as efficient fuel for wildfires).
D3 expanded to cover a large area from southwestern to northeastern Texas, and smaller regions of D3 now cover several patches in northwestern Louisiana, along the Red River Valley, and in northwestern Texas.
Across Texas, primarily outside the Big Bend and the northern Panhandle, mandatory water use restrictions have been imposed by 665 public water supply authorities according to the Texas Drought Preparedness Council, with a few mandating moderate to severe restrictions. Voluntary cutbacks have been requested by another 400 authorities.
90-day rainfall totals below two-thirds of normal are common in the D3 areas, and across the D2 regions of northwestern Texas. A few patches in southwestern and interior northeastern Texas recorded less than 25 percent of normal during this period. Substantial multi-month rainfall deficits are less widespread (scattered to broken in coverage) north and east of the Red River Valley.
Looking Ahead: Through Aug. 14, a broad area of moderate to heavy precipitation is forecast in central and southeastern Arizona, across southern and eastern New Mexico, and from northern and Central Texas eastward to the Atlantic Coast. Rainfall totals exceeding an inch should be widespread, with two or more inches expected in the eastern half of the Carolinas and from southern Arkansas westward through the northern tier of Texas (excluding the Panhandle), part of the Big Bend, and southeastern New Mexico.
Similar amounts (one to locally two inches) are expected in western and northern Maine. Heavy to excessive amounts (three to five inches) are forecast in western Texas in a region bounded by the Pecos, San Angelo, Wichita Falls, and Lubbock areas. In contrast, light rain at most is anticipated from the Lower Ohio Valley, the central Plains and Rockies, and northern Arizona northward to the Canadian Border and westward to the Pacific Coast, though a little more may fall on parts of the Great Lakes Region.
Nationally, above-normal temperatures will cover most of the country. Daily nighttime lows should average near or slightly above normal across most of the Plains and Mississippi Valley, and at least 3°F above normal from the High Plains westward to the Pacific Coast, across the northern Plains and Great Lakes Region, and from the Appalachians through the Eastern Seaboard. But despite unremarkable minimum temperatures, daytime highs should average significantly below normal (anomalies -3 F or lower) where persistent rainfall is forecast, specifically in the swath from the upper Southeast and interior Lower Mississippi Valley westward through Oklahoma, central and northern Texas, New Mexico, and southern Arizona.
Highs will average 6°F to locally 10°F below normal across southern Oklahoma, central and northern Texas, and eastern New Mexico. Meanwhile, anomalous heat will continue across areas from the central and northern Rockies westward through the Intermountain West. Daily highs averaging 9°F or more above normal are forecast in western Montana, the northern Intermountain West, and northern Great Basin.
Surplus precipitation is favored for the ensuing five days of Aug. 14 – 18 in the Desert Southwest, southern Rockies, central Great Plains, Texas (outside the southeast tier), middle Mississippi Valley, Ohio Valley and adjacent Great Lakes Region, and central and northern sections of the Appalachians and Eastern Seaboard. All but the western and northern tiers of Alaska are also expected to record above-normal precipitation. Meanwhile, subnormal rainfall is favored in the South Atlantic States, central Gulf Coast, and in a swath from the northern Intermountain West eastward into the western Great Lakes Region.
Enhanced chances for warmer-than-normal conditions cover much of the contiguous 48 states, with only the region north of the immediate Gulf Coast extending from the central and southern Appalachians westward through the lower Ohio Valley, middle and lower Mississippi Valley, most of Texas, and the southern Rockies excluded. Odds favoring abnormally cool weather are limited to areas from the southern tier of Arizona and New Mexico eastward through the Big Bend, central and northern Texas (excluding the Panhandle), central and eastern Oklahoma, and adjacent Arkansas.