Midwest Weekly Highlights - December 23-31, 2014

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Milder Temperatures Prevail

Average temperatures during the last week of December ranged from 30°F to 40°F across Missouri, Illinois, Indiana, Ohio and southern Michigan with Kentucky averaging temperatures above 40°F.  The northwest part of the region experienced temperatures below 30°F on average, with northern Minnesota averaging only in the low to middle teens (Figure 1). In relation to normal, these temperatures ranged from 2°F to 6°F above normal in the west and 6°F to 10°F degrees above normal in the east, with Ohio by far being the warmest (Figure 2). Maximum and minimum temperatures were both higher than normal. However, average maximum temperatures were highest over the eastern states (Figure 3), while average minimum temperatures were higher across more of the western states (Figure 4).  Records for the highest maximum temperature were broken December 23-26th, 2014 across southern Wisconsin, central Indiana, southern Michigan, and northwest Ohio and records for highest minimum temperature were set on December 23, 2014 across Minnesota and western Wisconsin.
 

Below Normal Snowfall

The fourth week of December passed with minimal precipitation impacts across the region with observed values ranging from 0.5” below normal to 0.5” above normal across much of the region (Figure 5). Those areas with above normal precipitation resulted from a winter system that traversed across northwest Iowa, southern Minnesota, and northern Wisconsin on December 26-27th (Figure 6). Snowfall amounts reached 6” across portions of southern Minnesota and northwest Wisconsin.  Despite this event, accumulated snowfall remained below normal across much of the region (Figure 7) and a rare climatological episode of more snowfall being observed across a vast majority of the 9-state Midwest Region during the month of November than during the month of December occurred.  Of all first-order stations in the region (46 stations), only 3 stations (International Falls, MN; Columbia, MO; and Kansas City, MO) recorded higher snowfall amounts during December than in November.

Severe Weather Event December 24, 2014

On Christmas Eve December 24, 2014 a weak linear convective system ahead of a cold front resulted in wind damage and a brief EF0 tornado in central Ohio (Figure 8). While December tornadoes are rare events, they can happen (Figure 9).
 

-OBK-