Drought Monitor-Heavy Rains Bring Improvements01/20/2017
Several areas of heavy precipitation brought drought improvement to parts of the Northeast, Midwest, Plains, and Far West while drought conditions were essentially unchanged elsewhere. Nowhere in the country did dryness intensify enough to worsen the Drought Monitor depiction from last week.
Moderate to locally heavy precipitation (generally 1.5 to nearly 4.0 inches) fell across most of Kentucky and adjacent northwestern Tennessee, with light to moderate totals reported over the rest of Tennessee and in southwestern Virginia.
Farther south and east, little or no precipitation fell. As a result, the small areas of dryness in southwestern Kentucky and adjacent Tennessee were removed, and conditions improved to D0 in a small part of southwestern Virginia and adjacent North Carolina, based in part on a re-assessment of the effects of prior weeks’ precipitation.
Conditions were unchanged elsewhere, including through the areas of Severe to Extreme Drought from northern and central Alabama northeastward through the western Carolinas. Conditions across the southern half of Georgia will be monitored for additional potential improvement resulting from earlier rainfall as well, but no changes were made this week. Over the past 90 days, precipitation totals are 4 to 7 inches below normal in the most seriously affected areas.
Substantial precipitation brought improvement to many of the dry areas from Iowa and northern Missouri eastward through Ohio, and enough fell elsewhere to prevent any deterioration. Generally 1.5 to locally over 3.0 inches dampened much of northern and southern Illinois, most of Indiana, and northern Ohio, prompting removal of D0 from Ohio and Indiana, with smaller areas of improvement noted farther west.
Central Illinois, northern Missouri, and most of southeastern Iowa remained in D0 to D1. Less than half of normal precipitation fell during the last 30 days across much of northern Missouri and parts of central and southern Illinois.
Light precipitation at best was reported from Nebraska and eastern Colorado northward to the Canadian border, leaving dryness and drought unchanged. In contrast, moderate to heavy precipitation pelted most areas from the southern half of Kansas and southwestern Missouri southward across much of Oklahoma and into parts of the Texas Panhandle and northeastern Texas.
Between 3.5 and 5.0 inches fell along some areas near the Kansas-Oklahoma border. This brought improvement from D3 to D2 to a small part of southeastern Oklahoma, and broader improvements to many former areas of D0 to D2 elsewhere.
Still, 90-day precipitation was generally 4 to 8 inches below normal from eastern Oklahoma and parts of eastern Texas eastward across southern Missouri, the northern half of Arkansas, and areas in and near northern Louisiana.
Near to above normal precipitation on time scales ranging from 30 to 90 days or more prompted removal of the D2 areas in north-central and southeastern Colorado. Across the remaining areas of dryness and drought from the Rockies through the Intermountain West and Southwest, scattered to isolated areas of moderate to heavy precipitation weren’t enough to prompt any changes from last week.
In contrast, very heavy precipitation ranging from 4 to 8 inches was recorded throughout the Sierra Nevada and isolated parts of the higher elevations in west-central and southwestern California.
Elsewhere, 1.5 to 3.5 inches of precipitation fell in a swath from San Francisco southward to Monterey and eastward to the Sierra Nevada, and on areas along and near the eastern slopes of the Sierra Nevada, including part of western Nevada. Given the protracted nature of conditions from much of the San Joaquin Valley southward to Mexico, no improvement was introduced there, including the persistence of D4 conditions in part of southwestern California.
In sharp contrast, all D0 to D3 areas in the central Sierra Nevada and adjacent west-central Nevada were improved this week as a pattern of well-above-normal precipitation continued.
Alaska, Hawaii, and Puerto Rico
Conditions remained unchanged in these areas, keeping much of southeastern mainland Alaska in D0 and maintaining the small patchy areas of D0 to D1 intact along the western sides of Kauai, Oahu, Maui, and the Big Island. A drying trend, including reduced mountain snowpack, has been noted in south-central Alaska and through the Panhandle. No changes were introduced this week, but these regions need to be monitored for intensification in the near future.
There is currently no dryness or drought in Puerto Rico.
During the next five days (January 19-23), above-normal precipitation (2-5 inches) is expected across most of the Gulf Coast states from far eastern Texas to and including northern Florida, most of the southern Atlantic Coast region, the Tennessee Valley, and southwestern portions of Kentucky and Virginia. Excessive precipitation amounts (liquid equivalents of 9-13 inches) are forecast for coastal California and most of the Sierras.
These anticipated areas of heavy precipitation are likely to result in additional improvements to next week’s U.S. Drought Monitor depiction. Little if any relief, however, is forecast for most of the Great Plains and Northeast. For the ensuing five-day period (January 24-28), there are elevated chances for above-median precipitation across much of the contiguous U.S.
However, odds favor below-median precipitation across the south-central states. Taking the two periods as a whole, Oklahoma and most of Texas are the least likely areas to receive beneficial precipitation.
Source: Ernst Undesser, AgFax