Midwest Weekly Highlights - March 11-17, 2004

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Winter hangs on in the Midwest.

A stormy weather pattern continued on through the middle of March, producing record-setting snow in Iowa and keeping spring-like weather at bay.

Temperatures averaged from 3 to 8°F below average during the week (Figure 1), with the largest departures in a band from northern Minnesota to northern Illinois to Ohio, reflecting the mean position of the jet stream during the week.  A series of storms was swept along by the strong northwesterly flow, but for the most part these did not produce a great deal of precipitation. Precipitation for the week was well below normal except for the southern two-thirds of Iowa, northern Missouri, northern Wisconsin, and the Michigan Upper Peninsula (Figure 2). Precipitation in these areas reached almost twice normal for the week, largely as the results of heavy snow.  Snowfall was much above normal in Iowa, northern Wisconsin, and the Michigan U.P. (Figure 3).

The period began with two cold fronts sweeping through the Midwest (Figure 4, Unisys).  Strong low pressure generated strong winds throughout much of the region, but only light rain and snow showers. The heaviest snow fell in some lake effect areas in Ohio, with more than 5 inches reported at Pierpoint in Ashtabula County.  Another strong cold front followed late on March 13 and on March 14, producing more high winds (Figure 5, Unisys).  Winds gusted to more than 50 mph in Wisconsin and Michigan, and gusts near 40 mph were reported as far south as Illinois.  This system also brought some heavy snow to northern Wisconsin, with 5 to 7 inches in northern central Wisconsin into the Michigan UP.  Lighter amounts fell in adjacent portions of Minnesota and lower Michigan.

By the evening of March 14 yet another storm system was winding up over the Central Plains, and by the morning of March 15 snow was falling from eastern Nebraska through the western two-thirds of Iowa.  The low pressure system moved southeastward through Missouri and across southern Illinois early on March 16.  In its wake the storm left more than a foot of snow on the ground in central and western Iowa, 3 to 6 inches from northern Missouri to western Illinois, and 1 to 2 inches from central Illinois into western Indiana (Figure 6).  Snowfall became heavier from eastern Indiana into Ohio. In Iowa, numerous snowfall records were set for this storm as heavy snow blanketed the western and central portions of the state (Figure 7). Sioux City, IA set a number of records including:

Record daily precipitation	1.66 inches, old record 0.87 in 1983
Record daily snowfall for the day	18.4 inches, old record 2.7 inches in 1990
Record March daily snowfall	18.4 inches, old record 16.0 inches on 3/28/1890
Second greatest 24 hr snowfall	18.4 inches, old record 20.0 inches

      
Des Moines set a new record snowfall of 15.6 inches for March 15, setting a new record for the day and the month. The previous record for the day was 6.5 inches in 1923. The previous March record snowfall was 11.1 inches in 1999.  This was the third snowiest day on record for Des Moines.  The storm closed schools, hampered travel, and resulted in one death in Iowa.  A motorist was struck and killed after walking into the path a semitrailer truck after his car slid of the highway. Officials reported that most weather-related accidents were minor.

Even as this storm departed the region, another weaker storm was dropping into the northern Plains.  Late on March 16 and early on March 17 another 1 to 2 inches of snow fell in a band from Minnesota to Indiana (Figure 8).

Temperatures near or above freezing on March 16 and March 17 combined with limited sunshine to eat at the snowcover across much of the region. Snow that fell across Illinois and Indiana had disappeared by the end of the day, and there were significant reductions t the snowcover across Iowa (Figure 9). At the end of the period the greatest snowcover was in the Michigan Upper Peninsula where 2 to 4 feet of snow still blanketed the region (Figure 10, NWS Marquette).