Click here to go to the US Drought Monitor website. Here’s an excerpt:
[A] series of storm systems tracked across the lower 48 States, dropping light to moderate precipitation on the Northwest and northern half of the Rockies, which eventually entrained ample Gulf moisture into the system while over the lower Mississippi Valley. As a result, widespread moderate to heavy rains (2-6 inches, locally to 10 inches) fell from northeastern Texas northeastward into the southern and central Appalachians, with the greatest totals reported in central Arkansas and western Tennessee. As the systems trekked farther eastward, light to moderate precipitation also fell on the Northeast and the Carolinas as frigid conditions gradually replaced the mild air from earlier in the week across the eastern two-thirds of the Nation. Dry conditions prevailed across the Southwest, southern third of the High Plains, along the Gulf Coast, and in parts of the mid-Atlantic. In Hawaii, very heavy rains (4-10 inches) during December 20-21 in the central islands (western Maui, Lihue, eastern Molokai) interrupted what had been a relatively quiet (dry) December…
Like the upper Midwest, with frigid temperatures, a non-growing season, frozen soils, and a climatological dry time of year (fall and winter), conditions should remained locked in place. With that said, light snow fell across portions of the High Plains, providing a thin to medium blanket of snow across Montana, North Dakota, Wyoming, Nebraska, northern halves of Colorado and Kansas, and southern South Dakota. Snow was lacking across northern South Dakota as readings dropped below 0 degF by week’s end. In more southern locations where temperatures were somewhat warmer and soils not as deeply frozen, short-term D1 and D2 was expanded in southwestern and central Kansas in response to similar drought indices in neighboring Oklahoma. Fortunately, with longer-term conditions not as dire in Kansas as in Oklahoma, impacts were less severe in Kansas…
Significant precipitation (1-4 inches) was limited to along the Washington and Oregon Coasts, in the northern Cascades, and the northern and central Rockies. Little or no precipitation was observed across much of the Southwest, Great Basin, and southern Rockies. While the Water Year-to-Date (WYTD) basin average precipitation was near to above-normal (85-120%) across the northern half of the West, warmer temperatures have reduced the average basin snow water content (SWC) to near or slightly below normal across the Northwest (50-100%), although eastern Idaho, Montana, and Wyoming has fared better (100-150%). With the recent precipitation, some slight reduction (improvement) in the western edges of the D0 and D1 areas in northwestern Montana were made as 1.5-4 inches brought indices at or closer to normal. The rest of Montana remained unchanged as light snow and subnormal temperatures locked conditions in place for now.
Across the southern half of the West, the WYTD precipitation and SWC have been the opposite of the north, with nearly all basins below normal (drier as one heads southward) and SWC at half of normal or less. Basin average precipitation and SWC in Arizona, southern Utah and Colorado, and New Mexico lingered below 25%, with SWC in single digits in parts of Arizona and New Mexico. In western New Mexico, dry weather during the past 90-days brought indices in line with D1 conditions. In central and eastern New Mexico, however, wet weather during late September has kept this area out of D1, but as this time period falls out of the past 90-days, D1 expansion is possible as very little precipitation has fallen since then. For example, Albuquerque, NM, has recorded 81 consecutive days without measurable precipitation through Dec. 25 (but 2.10 inches during Sep. 27-30). Across the rest of the Four Corners states, future degradation is possible due to a poor WYTD, but recent light precipitation, lower temperatures, and waiting for final December numbers and impacts staved off downgrades this week. In southern California, the Thomas Fire continued to burn, with 272,600 acres consumed as of Dec. 22.