February 15-21, 2008
Midwest Weekly Highlights - February 15-21, 2008
Another Active Week
A series of cold fronts brought reinforcing shots of Arctic air to the Midwest this week. The northwest to southeast temperature gradient prevalent the past several weeks was evident again. Average daily temperatures ranged from 14°F below normal over Iowa and southern Minnesota to 4°F above normal across southeastern Kentucky (Figure 1). Precipitation was well above normal across the central third of the Midwest from southwestern Missouri northeastward through Michigan from two major storms, one early in the week and one at the end of the week (Figure 2). Snowfall was also well above normal in this same band (Figure 3), and the additional snowfall has pushed seasonal totals in a number of locations in Wisconsin into the top ten list of snowiest winters.
The U.S. Drought Monitor changed only slightly this week in the Midwest, with improvement in northern Wisconsin and the eastern Michigan U. P. (Figure 4).
Major Storm #1
Midwest residents braced themselves for another major storm as the week began. The low pressure system began taking shape in the Desert Southwest on February 15 and moved eastward into Texas on February 16. This storm began to intensify rapidly as the upper level low lifted northeastward, spreading heavy rain from southwestern Missouri through central Illinois (Figure 5). By the morning of February 17 the storm was centered over north-central Missouri (Figure 6). In contrast to the last storm, much of the precipitation was in the form of rain as the strong circulation funneled warm air northward. Rainfall from this system was heaviest from Missouri into west-central Illinois, where amounts topped one inch over a large area (Figure 7). The rain caused flooding once again in northern Illinois and Indiana, where the rain combined with melting snow to push some rivers and stream above their banks. Record daily rainfall amounts were set at a number of locations in Missouri, Illinois, and Indiana on February 16 and 17. Muskegon, MI tied their record high temperature on February 17 with a reading of 50°F. As the low pressure system continued to deepen on February 17, winds intensified and wind gusts to more than 55 mph hour were reported in Missouri, Illinois, Indiana, and Kentucky. The winds either blew over or uprooted a dozen trees in Magoffin County, KY and also damaged some roofs of houses. Funnel clouds were reported with thunderstorms in Clark County and Champaign County, OH. The winds added to power outages in southeastern Missouri in areas still trying to recover from the ice storm the week before.
To the north of the storm track, heavy snow fell in a band from northwestern Missouri through eastern Iowa, the southeastern half of Wisconsin, and the Michigan U. P. (Figure 8). Winter storm warnings covered much of Wisconsin and blizzard warnings were in effect for portions of central Wisconsin. Snowfall in this band ranged from 3.0 to more than 8.0 inches. Many locations in Iowa, Wisconsin, and Michigan established new daily snowfall and new daily precipitation records during this storm. The severe winter weather canceled town hall meetings scheduled in northeastern Wisconsin by presidential candidates Senator Barack Obama and Senator Hillary Rodham Clinton.
Lake-Effect Snow, Frigid Cold
Another surge of Arctic air plunged through the Midwest following the departure of this storm. On February 20 the high was pushing into the northern Midwest, with and a low was moving through the Ohio Valley (Figure 9). Strong northwest winds on the east side of the high streamed across Lake Michigan, producing heavy snow in northern Indiana and southwestern Michigan, while most of the region to the west had sunny but frigid weather. The heavy snow combined with strong winds caused whiteout conditions at times and brought traffic to a standstill across northern Porter County, IN. The heavy lake-effect snow caused a chain reaction crash on Interstate 94 west of Michigan City, IN during the early morning hours (Figure 10). The crash involved 13 semi-trailer trucks and 14 other vehicles, and forced authorities to close all westbound lanes for almost 8 hours. The pileup resulted in only four minor injuries. Up to 10 inches of snow accumulated during this lake-effect event.
This latest push of Arctic air brought some of the coldest temperatures of the season to much of the northern Midwest. Minimum temperatures the morning of February 20 were below zero across the northern half of the region, with lows down to -33°F in northwestern Minnesota (Figure 11). Temperatures remained well below zero during the day in northwestern Minnesota, and struggled to reach the single digits across the remainder of the state (Figure 12). Rockford, IL (Winnebago County) set a new record low maximum temperature for the day if 14°F, breaking the old record of 16°F set in 1966.
Next Storm Takes Aim on Southern Midwest
On February 21 a wave of low pressure was developing along the Arctic boundary in Texas (Figure 13). In anticipation of more winter weather a variety of winter weather advisories and warnings were issues in a band from the Texas panhandle to the mid-Atlantic coast (Figure 14). Ice storm warnings extended from southeastern Missouri across southern Illinois and through southern Indiana and the northern half of Kentucky. Sleet and freeing rain fell across much of this region during the day. Up to 2.5 inches of sleet fell in southeastern Missouri, southern Illinois, and southwestern Indiana, with lighter amounts of freezing rain. Some of the heavier precipitation was accompanied by thunder and lightning. The storm brought travel to a halt in many areas and led officials to cancel classes at Southern Illinois University in Carbondale, IL (Jackson County) for the second time this winter because of severe winter weather.
SDH