Drought Monitor: Wet weather offers relief to Plains

Drought Monitor: Wet weather offers relief to Plains

Storms move across southern Great Plains and Mississippi Delta, bringing some drought improvement

Storms across the lower 48 states over the past Drought Monitor week brought drought relief to some areas, and a little too much rain to others, according to this week's drought map author David Miskus of NOAA.

In Texas, for example, flash flooding in Austin created dangerous situations for the area's residents, while moderate to heavy rain also descended upon the Southeast, west-central Corn Belt and western Great Lakes region, Ohio and Tennessee Valleys, much of the Atlantic Coast States, and the Pacific Northwest, northern Rockies, and Sierra Nevada.

William Cannon Drive is closed after heavy flooding October 30, 2015 in Austin, Texas. (Photo by Drew Anthony Smith/Getty Images)

In the Northeast, showers and thunderstorms dropped moderate to occasionally heavy rain on the region, ending a 3-week stretch of relatively dry weather. Since the past few weeks were mostly dry, this week's rains were not enough to make many improvements except where the heaviest rains fell on D0 areas.

Into the Southeast, the upper-air low that inundated Texas and the Delta gradually tracked into the region late in the week, dumping heavy rains on the central Gulf northeastward across Georgia, the Carolinas, and into Virginia.

The rains, however, missed most of Florida and southeastern Georgia. The flash drought that had affected the southern Plains and Mississippi Delta for 3 months was slowly expanding eastward, but this week's precipitation put a damper on the dryness.

From western Alabama into east-central Georgia, most of the D1 to D0 was improved, and rains eliminated some of the D0 where the amounts were largest.

According to NASS/USDA, topsoil moisture rated short to very short for both Alabama and Georgia stood at 30% as of Nov. 1, down from 58% and 42% a week prior, respectively.

Midwest, Great Lakes region and Southern Plains >>


In the Midwest and Great Lakes region, widespread light to moderate and occasionally heavy rains fell, halting or ending a general expansion of abnormal dryness or drought.

With lower temperatures, little or no evapotranspiration, and (still) unfrozen ground, rainfall during the autumn can go a long way in recharging the soil moisture. As a result, D1 was improved 1-2 categories in northwestern Tennessee, western Kentucky, and south-central Indiana where a large band of 2-6 inches of steady, all-day rains greatly eased or erased short-term deficits.

Similarly, 2-4 inches in central Kentucky, southeastern Indiana, and southwestern Ohio eliminated abnormal dryness.

In southwestern Wisconsin, 2-3 inches of rain was enough for a 1-category improvement, but not so in southwestern Minnesota and northeastern Iowa where totals up to 1.5 inches were not enough to significantly reduce deficiencies.

Light to moderate rains also halted the expansion of short-term dryness and drought in the western Great Lakes region, and actually trimmed away some of the D0 and D1 edges where the totals were large enough.

In Missouri and southeastern Iowa, bands of moderate to heavy rain allowed for some trimming of the D1 edges, along with a bit of D0 and D1 improvement in central Illinois.

Not surprisingly, the NASS/USDA statewide topsoil moisture rated short to very short improved 10-34 percentage points on Nov. 1 from the previous week in Wisconsin, Iowa, Missouri, Illinois, Indiana, Ohio, Michigan, Kentucky, and Tennessee, although Missouri, Illinois, and Indiana was still at 42, 38, and 38%, respectively.

Extreme precipitation events in the Mississippi Delta and Southern Plains seem to be the norm, nearly ending the 3-month flash drought. After the sufficient rainfall, remaining D1 and D0 were alleviated across south-central and southeastern Texas and the southern two-thirds of Louisiana.

In addition to these incredible totals, widespread moderate to heavy rains were measured across the eastern two-thirds of the state, south-central Oklahoma, central Arkansas, nearly all of Louisiana and the southern two-thirds of Mississippi.

Short to very short topsoil moisture dropped to 16, 19, 5, and 16% in Texas, Arkansas, Louisiana, and Mississippi, respectively, as of Nov. 1, down from 32, 48, 39, and 58% the previous week, according to NASS/USDA.

Plains, West, Southwest >>


Weekly totals were much lower across the northern and central Plains as compared to areas to the south and east; however, in North Dakota, timely rains helped improve the condition of the winter wheat while farmers utilized the dry weather to continue harvesting corn and sunflower seeds which were done well ahead of normal.

Even though little or no rain fell on South Dakota, 90-day surpluses, lower temperatures, and minimal evapotranspiration have kept the D0(S) from worsening. In southern Nebraska and eastern Kansas, light to moderate (0.3-0.9 inches) rains generally kept conditions stable, although a reassessment of short-term tools led to a slight redraw of the D1 areas in Kansas and D0 in southwestern Nebraska.

In southwestern Colorado and southwestern Kansas, 0.6-1.5 inches of rain, locally to 2.5 inches, plus heavy rains from last week, were enough to eliminate the D0 Colorado and Kansas counties.

Although precipitation was generally light across Arizona and New Mexico, slight adjustments were made; D1 was improved to D0 across northern and central Arizona and a bit in northwestern New Mexico.

Based upon the Oct. 1 USDA/NRCS statewide reservoir storage data, Arizona and New Mexico were still below normal – 35% and 28% capacity versus normal of 49% and 42%, respectively.

An early-season, moisture-laden Pacific storm system brought beneficial precipitation to extreme northwestern and central California, an early bonus to the 2015-16 Water Year in the Sierras.

However, with four consecutive years of drought, this precipitation was just a start to moisten the soils for hopefully more (frozen preferred) precipitation this winter, thus no changes were made in the Sierras.

Meanwhile, in the Pacific Northwest and Northern Rockies, a constant barrage of Pacific moisture and storm systems brought daily precipitation, quite heavy during mid-week, to coastal Washington, northwestern Oregon, the northern Cascades, and northern Rockies.

For the week, totals ranged between 6-15 inches in the first three areas, and 2-6 inches in the latter region. With this week's copious amounts and wet weather during the past 3-4 months, 1-category improvements were made to areas with the greatest amounts, namely western Washington and northwestern Oregon, central coastal Oregon, western side of Cascades, northeastern Washington, northern Idaho, and northwestern Montana, and north-central Montana.

Similarly, some D0 was removed from eastern Montana as the short-term indices were either normal or wet.

Drought Monitor: Wet weather offers drought relief to Plains

Read the full Drought Monitor upate at droughtmonitor.unl.edu.

Source: David Miskus, NOAA/NWS/NCEP/CPC

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