Eastern Cornbelt:
Dry weather was reported across Illinois and Indiana during the week, with temperatures reaching the 40s and 50s. Widespread showers were possible over the Christmas weekend, though temperatures were expected to remain well above normal.
A cold front pushed through the Great Lakes region early in the week, dropping significant lake-effect snow in parts of northern Ohio, along with 40-50 mph winds. The heaviest accumulation ranged from 8-11 inches, but temperatures were expected to warm to the 40s as the week advanced.
Parts of Michigan were also under winter storm warnings early in the week, with 4-6 inches reported in southwestern areas of the state and 1-2 inches inland.
Western Cornbelt:
Mild temperatures and spotty showers were reported across Iowa and northern Missouri during the week, with an increased chance of rain over the Christmas weekend.
Central and eastern Nebraska were also bracing for an increased chance of rain showers and thunderstorms over the weekend, with some snow accumulation possible in western areas of the state on Christmas Eve.
California:
A powerful Pacific storm brought torrential rain to much of California during the week, triggering flooding and debris flows in some areas.
After drenching Northern and Central California at midweek, the system was expected to push southward and inland over Southern California, delivering what several forecasters said would be a month’s worth of rain in just 24 hours.
Forecasts warned of 1-4 inches of rainfall in coastal areas from Los Angeles to San Diego, while 6-8 inches was expected in the mountains from Santa Barbara County to Ventura and Los Angeles counties, with some areas potentially getting much more.
Pacific Northwest:
Dry, mild weather conditions were reported across the inland Pacific Northwest during the week, while coastal areas of Washington were under a flood advisory at midweek after heavy rains hit the region.
The latest round of moisture follows a powerful atmospheric river that swept the Pacific Northwest in early December, resulting in Seattle and several other Washington cities posting daily record rainfall totals that pushed the Stillaguamish River to 21 feet above flood stage, flooding portions of Granite Falls, Wash.
Western Canada:
Western Canada continued to experience unseasonably mild temperatures and a lack of snowfall in December. Average highs across much of the region have been 5-10 degrees above normal for the month, while December snowfall in Winnipeg, Man., has totaled only 2.2 cm so far, well below the 23 cm average for the month.
The dry end to the year capped a heavy fall fertilizer season across much of the region, with the weather providing ideal conditions for fall fieldwork.