This past week brought substantial precipitation (over 1.5 inches) to parts of the continental United States.
Western Washington, the central and southern Sierra Nevada, southwestern California, portions of the western Mississippi Valley from southern Minnesota into Louisiana and eastern Texas, a swath across the Gulf Coast and South Atlantic States, and the eastern tiers of the mid-Atlantic and Northeast were beneficiaries.
The highest totals (3 to locally 8 inches) were recorded across northern Florida and adjacent Georgia, and northwesternmost Washington. More than 3 inches also fell on scattered small patches of the Sierra Nevada, in a swath from central Mississippi through western Georgia, and central South Carolina.
In contrast, only a few tenths of an inch of precipitation barely dampened most of the Ohio Valley and adjacent Appalachians, and from the central and western Plains to the Pacific Coast, although some of the higher elevations of the central Rockies recorded moderate amounts.
Central and southern portions of the Florida Peninsula also recorded a few tenths of an inch at best. Meanwhile, it was an abnormally warm week across the entire northern tier of the country outside far western Washington, from the central Plains eastward through the mid-Atlantic, and across central and southern Texas. Daily maximum temperatures averaged 12 to 15 degrees Fahrenheit above normal for the seven-day period over the central and northern Dakotas and adjacent Minnesota.
Somewhat below-normal temperatures were observed from the central Rockies westward to the Pacific Coast and southward to the Mexico border.
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the U.S. Department of Agriculture and the National Oceanic Atmospheric Administration. (Map courtesy of NDMC.)
South
Subnormal precipitation in eastern and southern Tennessee led to some expansion of D0 and D1 there, but most of the central and eastern South Region, from eastern portions of Oklahoma and Texas through Mississippi and western Tennessee, is free of dryness and drought.
There are a few isolated areas of dryness and abnormal dryness that is affecting extreme northwestern Arkansas. Some degree of dryness covers the central and western sections of Texas and Oklahoma. Rainfall along the Red River (south) led to some improvements across southern Oklahoma and adjacent Texas, but some degree of dryness remains.
Other parts of Texas and Oklahoma saw little or no precipitation, leading to areas of dryness and drought intensification. The greatest drought intensity (D4, exceptional drought) covers a large part of the Big Bend and portions of central Texas, were patches of D4 are surrounded by a large area of D3 (extreme drought). Since mid-December, less than 5% of normal precipitation has fallen on the Big Bend while large sections of central, southern, and western Texas reported less than half of normal since mid-January.
Generally 20 to 50% of normal for the two-month period was also observed across the Oklahoma Panhandle and adjacent areas. With dry weather, seasonably increasing temperatures, and periods of high winds, conditions could deteriorate rapidly across central and northwestern Texas, reaching into parts of adjacent Oklahoma and New Mexico.
Midwest
Variable precipitation totals took drought conditions in different directions over disparate parts of the region. Moderate to heavy precipitation brought sizeable areas of improvement to central and southern Iowa, and much of Missouri.
Farther north, a part of the northern Great Lakes also saw improvement, but most of the precipitation missed Minnesota, causing deterioration in west-central parts of the state.
During the past six months, precipitation has totaled 3 to locally 8 inches below normal across the region including central and southwestern Minnesota and a northeast-to-southwest swath through Missouri.
High Plains
Light to moderate precipitation fell on parts of the High Plains region this past week, reducing dryness and drought severity in the middle of the region across several patches in Wyoming, adjacent northern Colorado, part of north-central Nebraska, and a small area in northwestern Kansas and adjacent areas.
Farther south, continued subnormal precipitation induced a broad area of deterioration in central and western Kansas and smaller portions of southern Colorado, but heavier amounts eased conditions in eastern Kansas.
The depiction across the Dakotas did not change. During the last 90 days, less than half of normal precipitation was measured across south-central and southwestern Kansas, southeastern Colorado, and a few patches across the Dakotas.
At the same time, much of Wyoming, central and northeastern Colorado, and a few swaths from northern Kansas through Nebraska and southwestern South Dakota recorded above-normal amounts.
Southwestern Kansas and southeastern Colorado were particularly dry during the last 90 days, receiving less than 25% of normal.
West
Similar to the situation across central and western Texas, dryness and drought may be intensifying at a fairly quick clip across New Mexico, and a large part of the state deteriorated by one category this week. That includes a larger area of D3 along the southern tier of the state, with a small area of D4 introduced in the state’s southwestern interior.
The lowest totals (just 2 to 25% of normal) extend across the southern Four Corners area. Conditions are considerably better north of Utah and central Nevada, with D3 restricted to a small part of western Montana, and more than half of the area free from dryness and drought.
Looking ahead
The March 13 to 17 period starts out unusually mild in a large part of the central and eastern U.S. while relatively cool weather stretches from the Rockies to the Pacific Coast. On March 13, temperatures may reach the upper 70s degrees as far north as central South Dakota. Portions of central and southern Texas are expected to top 90 degrees.
As the period progresses, warm air pushes south and east toward the Atlantic Ocean while a shot of cold air invades the northern Plains. Lows are expected to drop into the teens in parts of the northern Plains that are expected to top 75 degrees two days earlier. The cold intrusion looks to be short-lived, with the air mass moderating as it pushes east.
On March 17, warmer weather is expected to again build into the Plains. Meanwhile, the western half of the CONUS remains relatively cool. Elsewhere from the Rockies westward, fairly widespread light to moderate precipitation is forecast, with heavier totals of 1.5 to locally 4 inches falling on some of the higher elevations (particularly in central and northern Idaho).
Farther east, a swath of heavy rain is anticipated from the lower Ohio Valley southward into portions of the Gulf Coast states. In the middle of the country, at least a few tenths of an inch of precipitation are forecast for the east-central and northeastern Great Plains with amounts approaching of slightly exceeding an inch over most of Minnesota and adjacent portions of South Dakota and Iowa.
Dry weather is anticipated across the High Plains and the southern half of the Great Plains, with a few tenths of an inch falling at best.
The Climate Prediction Center’s 6- to10-day outlook from March 18 to 22 favors a continuation of below-normal temperatures from the Rockies westward, and warmer than normal weather over most of the central and eastern states. Meanwhile, subnormal precipitation continues to be favored across most of Texas and Oklahoma, and there are slightly enhanced chances for drier than normal weather over part of North Dakota.
The rest of the country should average near- or wetter-than-normal moisture.
Richard Tinker is with the National Oceanic Atmospheric Administration, National Weather Service, National Drought Mitigation Center, National Centers for Environmental Prediction, and Climate Prediction Center.
