In the West, freeze warnings are in effect this morning in portions of California’s San Joaquin Valley, where some producers are taking measures to protect citrus and other temperature-sensitive crops. However, valley temperatures are not low enough to cause significant freeze-injury concern. Elsewhere, a new storm is maintaining showery conditions in the Pacific Northwest, while precipitation lingers in the Four Corners States.

On the Plains, a developing storm centered near the Texas-New Mexico border is producing increasingly windy conditions across the southern half of the region. Markedly colder air is overspreading the northern and central High Plains, while warmth lingers across the southeastern Plains.

In the Corn Belt, mild, dry weather prevails in advance of an approaching storm system. A generally shallow snow cover blankets portions of the northern Corn Belt; current depths include an inch in Madison, Wisconsin, and Minneapolis-St. Paul, Minnesota.

In the South, mild, dry weather favors fieldwork, including late-season harvest activities.

Outlook: For today and Thursday, winter storm warnings are in effect from central portions of the Rockies and Plains northeastward into parts of Wisconsin and Michigan. Blizzard conditions can be expected in some areas on December 19-20, mainly on the central High Plains and across parts of Iowa and southern Wisconsin. Storm-total snowfall may exceed a foot from Iowa to northern Michigan. Meanwhile, December 20-21 rainfall totals of 1 to 3 inches will be common in the Northeast. Farther west, late-week temperatures will quickly rebound to above-normal levels across the south-central U.S. By early next week, however, a new storm will cause temperatures to plunge across the western and central U.S. Significant precipitation will accompany the storminess; 5-day precipitation totals through early Monday, December 24, will reach 4 to 10 inches in parts of northern California and the Pacific Northwest. The NWS 6- to 10-day outlook for December 24-28 calls for near- to below-normal temperatures and near- to above-normal precipitation nearly nationwide. Warmer-than-normal weather will be confined to areas from the Great Lakes region into northern New England, while drier-than-normal conditions will be limited to the southern Rockies.