The latest United States Drought Monitor map has been released.
A westerly flow dominated the upper-level circulation across the contiguous U.S. (CONUS) during this U.S. Drought Monitor (USDM) week. The week began with a frontal system exiting the eastern CONUS, and ended with another Pacific system moving across the country. The systems brought an inch to more than locally 5 inches of precipitation to the coasts and Cascades of northern California to Washington; 1 to 2 inches of precipitation to parts of the northern Rockies and in swaths from eastern Nebraska to the Great Lakes and from southeastern Oklahoma to the Mid-Mississippi Valley; and a few reports of 1 inch or more across parts of the South and Southeast. These amounts translated to above normal for the central Plains to western Great Lakes, parts of the Pacific Northwest, the swath from southeastern Oklahoma to the Mid-Mississippi Valley, and a few areas in the South and Southeast. But for large parts of the country, the week was drier than normal, with little to no precipitation falling across large parts of the Southwest and Southern Plains. The westerly flow brought above-normal temperatures to most of the West and across the northern states, especially the Northern Plains to western Great Lakes where weekly temperature departures were 9 to 15 degrees above normal. Weekly temperatures averaged below normal across the southern states from eastern Arizona to North Carolina, where the effects of earlier cold air masses still lingered. Contraction of drought and abnormal dryness occurred with the large winter storm that dumped on eastern Nebraska to the Great Lakes, and contraction occurred in a few other areas in the southern Plains and Northeast. But the continued dry conditions in the Southwest to Southern Plains and Southeast intensified and expanded drought and abnormal dryness in these areas.
An inch or more of precipitation was reported at stations in eastern Nebraska and a few stations in western Wyoming and the Colorado Rockies. Amounts dropped off to the north and south, with many stations in the Dakotas and Kansas measuring no precipitation for the week. D0 contracted in eastern Nebraska and southeastern South Dakota, and D2 was trimmed in western South Dakota, but D0 expanded in northeastern South Dakota and eastern North Dakota, D1 from Oklahoma crept into southeastern Kansas, and D2 from New Mexico pushed into southern Colorado. As relayed by the NDMC, agricultural impacts from the drought are being felt in Utah, Kansas, and Oklahoma and include decreasing hay and soybean yields, deteriorating wheat and grazing conditions, and decreasing water supplies — ponds and wells going dry. Some of these effects started from moisture deficits dating back to summer 2017.
In the 2 days since the Tuesday morning cutoff time of this week’s USDM, one storm system moved across the Northeast and exited the CONUS while another Pacific low and frontal system was moving into the Northwest. The Pacific system will dry out as it crosses the Rockies, then pick up Gulf of Mexico moisture when it moves across the eastern half of the country. For January 23-30, 5+ inches of precipitation is forecast for the coastal regions from northern California to Washington and up to 5 inches for northern Idaho, with lesser amounts from central California to Montana. When the system crosses the Plains, another region of precipitation will develop with amounts ranging from half an inch to locally over an inch along a line from eastern Texas to the eastern Great Lakes, then eastward from that line to the East Coast. Little to no precipitation is forecast for southern California and the Southwest, much of the Plains, and most of the Upper Midwest. Temperatures are predicted to be above normal across most of the CONUS. For January 30-February 7, precipitation is expected to be below normal for Alaska and much of the West to southern Plains, but above normal from Montana to the Great Lakes and from the Mississippi Valley to the East Coast. Odds favor above-normal temperatures across the Southwest and along the East Coast, and below-normal temperatures in southeastern Alaska and from Washington State to the northern Plains. Projections suggest that the central Plains will begin the period warmer than normal, but that colder-than-normal air masses will plunge south and east into the southern Plains and Great Lakes by the end of the period.