January 18-24, 2010
Midwest Weekly Highlights - January 18-24, 2010
Warm Temperatures
Temperatures were well above normal in the third week of January. Departures above normal were 6°F to 10°F across the central parts of the Midwest, exceeded 10°F across southern Missouri and most of Kentucky, and ranged from 10°F to nearly 20°F in upper Michigan, northern Wisconsin, and northern and central Minnesota (Figure 1). The warm temperatures pushed the Midwest snow cover further north this week (Figure 2). Numerous record high daily temperatures were set, mostly record high minimum temperatures during the latter half of the week.
Varied Precipitation
Midwest precipitation varied widely with northeast Michigan receiving less than 25% of normal while parts of Missouri, Iowa, and Minnesota exceeded 500% of normal (Figure 3). Most of the western and southern halves of the region were above normal for the week. Precipitation type varied as well with rain, thunderstorms, freezing rain, and snow in various locations. More than 300 daily precipitation records were set during the week with 177 records on the 24th alone. The heaviest precipitation missed the persistent drought region centered on northwest Wisconsin (Figure 4).
Ice Storm Glazes Iowa
On January 20th a low pressure system moved into northwest Missouri (Figure 5). The system pulled moisture from the south and it overran the cold air at the surface. This led to widespread precipitation, and in a swath from Iowa to Ohio, ice storm warnings and freezing rain advisories (Figure 6). The largest ice accumulations were in Iowa which recorded between a quarter and three-quarters of an inch of ice over a large portion of the state (Figure 7).
Power was disrupted to 20,000 customers of MidAmerican Energy in west central and central parts of the state. Thousands more Alliant Energy and Iowa Association of Electric Cooperatives customers were also without power. Carroll, Iowa schools (Caroll County) were closed for three days due to the power outage in the area. School cancellations across Iowa brought concerns about make-up days as the numbers mount. Ice accumulations were lighter to the east but there were scores of accidents blamed on the icy roads from Minnesota to Ohio.
Weekend System Brings Thunderstorms, Heavy Rain, Snow, and More Ice
The next storm system moved across the Midwest at the end of the week. A surface low moved across the upper Midwest with an occluded front extending to the south and a cold front trailing to the southwest (Figure 8). The southern part of the region received a shot of warmth (Figure 9) and thunderstorms with heavy rain (Figure 10). Northern Minnesota and Wisconsin received a mix of freezing rain, sleet, and finally snow (Figure 11). Strong north to northwest winds behind the low, 30 to 40 miles per hour with gusts up to 50, caused blowing snow from Iowa to Wisconsin. The winds caused blizzard conditions in Minnesota and Iowa.
Flooding Develops
Heavy rains (Figure 12) and melting snow (Figure 13) from the weekend system pushed river levels higher. Many river and streams went above flood stage over the weekend and many more were close and rising (Figure 14). In northeast Missouri, eastern Iowa, and northwest Illinois flooding was further aggravated by ice jams which caused rivers levels to fluctuate rapidly.
Severe Thunderstorms in Southern Kentucky
Severe thunderstorms pushed across the lower Mississippi Valley on January 20th and 21st. Most of the severe weather remained south of the Midwest but a few storms reached severe levels in Kentucky on the 21st (Figure 15). One inch hail fell in Albany, Kentucky (Clinton County). Reports from Glasgow, Kentucky (Barren County) reported wind damage such as downed trees, shingles torn off roofs, and a carport that was blown off a house. In Franklin, Kentucky (Simpson County), thunderstorm winds blew part of a house roof off.
-MST-