Heavy precipitation across much of US, but little received in High Plains
Heavy precipitation affected large parts of the nation last week, with heavy snow in the central Rockies bringing some relief to the dry areas there. The broadest area of heavy precipitation stretched from the Middle Atlantic States southwestward into the Lower Mississippi Valley and the Southeast. At least 2 inches fell from the Ohio River to near the Gulf and southern Atlantic Coasts, with 7 to 10 inches measured across the much of the interior Southeast.
On the other side of the 48 states, heavy precipitation covered parts of the Northwest. Near the coast in Washington and northern Oregon, most locations recorded at least 4 inches of precipitation, with isolated amounts to 10 inches in higher elevations. Just to the east, along the Cascade Range from central Oregon northward, a broad swath received at least 5 inches of precipitation, and most of a strip through central Washington reported 10 to locally 15 inches.
Well inland, in the central and northern Rockies, precipitation was largely elevation-dependent,. The more elevated regions observed 2 to 5 inches, with lesser amounts in adjacent areas of lower elevation. Heavier amounts more broadly covered central Idaho and adjacent areas in Washington and Oregon, with totals of 4 to locally 8 inches common.
It was another week of above-normal temperatures in the East and part of the interior Northwest, while subnormal readings were recorded in the central Rockies where the heavy snowfall dominated the week. Temperatures were 10 to 15 degrees F warmer than normal in the east-central States and part of the interior Southeast, and most sites east of the Mississippi River were at least 4 degrees F above normal. Many locations across the Country averaged 2 to as much as 5 degrees F above normal since mid-November 2019, especially east of the Mississippi River and the interior Rockies and Far West.
Abundant rainfall eliminated D0 in relatively small parts of southeastern Louisiana and southernmost Mississippi, but most areas of dryness along the central Gulf Coast missed the bulk of the precipitation, keeping most of the D0 area unchanged. Farther west, moderate to heavy precipitation (1 to locally 4 inches) eliminated almost all dryness across western Louisiana and southwestern Arkansas, and induced improvement across the D0 to D2 conditions in eastern Texas as well.
In addition, moderate rains in north-central Texas as well as the Red River Valley removed D0 from those regions, but left moderate drought largely intact across southwestern Oklahoma. But farther south, most areas of dryness and drought across central and southern Texas received little if any precipitation, prompting areas of drought intensification and expansion. Severe drought now covers large portions of central and southwestern Texas, and the D3 along parts of the Rio Grande Valley expanded into neighboring counties. Over the last 90 days, precipitation deficits reached 5 to 7 inches across interior eastern Texas, and less than 25 percent of normal has fallen around the areas of extreme drought in southwestern Texas.
Heavy precipitation (over 2 inches) was restricted to the Ohio Valley, with most of the region recording a few tenths of an inch, if any. Still, longer-term surplus moisture covers most of the region, and no areas of abnormal dryness or drought have been identified.
Most of the region saw little to no precipitation this past week, leaving the Drought Monitor unchanged in south-central Kansas, and prompting some limited expansion of the D0 to D2 conditions in western Kansas and eastern Colorado. Farther west, most lowland areas received only light precipitation, but heavy snows blanketed the higher elevations from central Colorado into western Wyoming. Snowpack is now near to above normal for this time of year in western Wyoming, and considerably above normal from central Wyoming southward through most of the higher elevations in central Colorado. This prompted removal of the D0 area that had covered southwestern Wyoming. More limited improvement was noted in the D0 and D1 areas in central and western Colorado, where dryness is more entrenched.
