December 2010
Midwest Overview - December 2010
Precipitation
Precipitation varied across the Midwest and across Iowa in particular. Percent of normal precipitation ranged from less than 25% of normal in southern Missouri to nearly 500% of normal in west central Minnesota (Figure 1). In Iowa the numbers ranged from less than 50% of normal in the south to more than 200% of normal in the north. Above normal totals occurred in the northwest quarter of the Midwest and in the extreme southeast reaches of the region. Between the wet areas totals were less than half of normal from Missouri to Lake Huron.
Snowfall for the month was heaviest in southern Minnesota and Upper Michigan (Figure 2). Totals of three to four feet were recorded at 20 Minnesota stations, five Michigan stations, and three Ohio stations with another six Michigan stations, one Wisconsin station, and one Ohio station above four feet. The snowiest December on record occurred in Minneapolis, Minnesota with 33.6", Urbana, Illinois with 20.4", and Jackson, Kentucky with 18.5". Rochester, Minnesota recorded its wettest and snowiest December on record with 3.68" of precipitation and 41.3" of snow. Snow depth reached two feet at four Iowa, four Wisconsin, and 18 Minnesota weather stations. More than 1000 daily snowfall records were set in December with at least 50 in each Midwest state and over 75 records on seven different dates.
Cold Temperatures
December temperatures ranged from 10°F below normal in eastern Kentucky to near normal in the upper Midwest
(Figure 3). Maximum temperatures were slightly cooler relative to normal with departures ranging from -14°F to -1°F (Figure 4). Kentucky recorded a colder than normal month for the first time in nine months. Jackson, Kentucky was spared its coldest December by two warm days to end the month.
Tornado Outbreak
Severe weather was absent for the first 29 days of the month in the Midwest. On the 31st, however, a cold front pushed across the region triggering thunderstorms including tornadic storms. Three of the tornadoes were rated EF3 on the Enhanced Fujita Scale indicating winds of . NWS investigation teams verified 17 tornadoes in Missouri and two more in Illinois. There were two fatalities near Lecoma, Missouri
(Dent County) and two more near Rolla, Missouri
(Phelps County) and four people died across the border in Arkansas. Structural damage was significant with nearly 300 structures damaged and 50 destroyed by the storms. Included in the total were 60 homes at the Fort Leonard Wood military base (Pulaski County). The 17 tornadoes in Missouri set a state record for the most tornadoes on a single December day.
December Snow Storms and Blizzards
Numerous snow storms hit the Midwest but three dropped a narrow swath of snow from Minnesota to Kentucky along roughly the same path. The first of these occurred on the 4th
(Figure 5), again on the 16th (Figure 6), and finally on the 21st
(Figure 7). Two more widespread snowfalls events occurred around the 11th and Christmas. A blizzard on the 11th and 12th affected about half of the region. Heavy snow fell and strong winds whipped up blizzard conditions even further south. Interstate highways were closed in several states as the conditions swamped attempts to keep roads clear and open. The Christmas storm was not as windy and brought a white Christmas to much of the Midwest. Most of the region reported snow on the ground Christmas morning (Figure 8). Blizzard conditions also returned to Minnesota on the 31st associated with the same system that brought the severe weather further to the south.
Drought
Drought conditions in the Midwest remained largely unchanged during the month
(Figure 9). The hardest hit area was the Missouri bootheel where Extreme Drought conditions continued. Severe Drought extended to parts of southeast Missouri and western Kentucky with pockets of Moderate Drought in Indiana and Minnesota.
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The Indiana State Climate Office also contributed to this report.
The Iowa Climatology Bureau also contributed to this report.
The Kentucky Climate Center also contributed to this report.
The Minnesota State Climatology Office also contributed to this report.
The Missouri Climate Center also contributed to this report.