Weekly rainfall totals of 5 to 10 inches fell across New Mexico, Arizona, Utah and Colorado this week, delivering a large share of annual precipitation to some Desert Southwest locations and easing drought across the eastern New Mexico and northwestern Texas winter wheat belt.

The moisture came from an El Niño-fueled eastern Pacific hurricane season. Three storms — Nolo, Odalys and Polo — indirectly affected the United States, according to the U.S. Drought Monitor. Nolo dropped heavy rain on east-facing Hawaiian slopes that were already free of drought, while remnant moisture from Odalys and Polo produced a near-record moist environment over the normally dry Southwest. Hurricane Polo curved northeast into Baja California early this week and tracked into southern New Mexico, triggering a second round of heavy rain Monday and Tuesday.

Beneficial rainfall extended into southern and eastern Colorado, western Kansas and western Nebraska, producing nearly across-the-board drought improvement across the High Plains despite temperatures running up to 6 degrees Fahrenheit or more above average. Northern and eastern North Dakota also saw substantial reductions in drought coverage and intensity after heavy rain near the Canadian border.

The South goes the other way

Conditions deteriorated sharply east of the Plains. Much of Texas, Oklahoma and Arkansas, hit by temperatures 6 to 12 degrees above average and virtually no rain through August and September, now sit under severe, extreme or exceptional drought classifications — coverage that intensified again this week. Southern Missouri also worsened.

The Drought Monitor pegs the recovery deficit bluntly: much of Texas and Oklahoma needs 20 to 25 inches of rain over a three-month span to break out of drought. The only exceptions to the deterioration were far western Texas and the western Oklahoma Panhandle, where several inches fell as Odalys and Polo moisture moved through.

For Plains growers, the split matters for both planting conditions and forage and stock-water supplies. Western Kansas and Nebraska ranchers caught measurable relief, while wheat and pasture operators in central Texas, Oklahoma and Arkansas face another week of stress on emerging stands and already-thin soil moisture.

Midwest and West

The Midwest spanned the full spectrum, from extreme to exceptional drought in northern Wisconsin to excessive wetness from Iowa to Ohio after a summer of prolific rainfall. That persistent storm track has effectively separated the southern drought from the northern one. Minnesota's long-term drought eased: up to 5 inches or more fell over severe-to-extreme drought areas near the North Dakota border, and northwestern Minnesota dropped out of drought classification entirely this week.

Elsewhere in the West, conditions held steady, with limited improvement in the northern Rockies, southwest Montana, northwest Wyoming and Oregon. Arizona, New Mexico and Colorado recorded what the monitor described as deep, substantial drought-busting rainfall.

The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska, the U.S. Department of Agriculture and the National Oceanic and Atmospheric Administration. Jonathan Case, who contributed the analysis, is with NASA/MSFC/UAH.

Looking ahead

Rain was still falling Tuesday morning as the new Drought Monitor week began, stretching from Arizona and New Mexico into the central and High Plains. The Weather Prediction Center has flagged moderate threats for excessive rainfall from the Southwest into Texas and Oklahoma and northward into Nebraska and Iowa, with drought-busting rains possible across the South as the Polo-connected system evolves.

The Climate Prediction Center's 6-to-10-day outlook shifts well-above-average temperatures into the western states along with below-normal precipitation chances, while projecting above-average precipitation from southern Texas into the Southeast, including Florida — a forecast that, if it verifies, could begin chipping away at the 20-to-25-inch deficit across the Southern Plains.