March 15-23, 2006
Midwest Weekly Highlights - March 15-23, 2006
The third week of March was quieter than the second week, but still had its round of interesting weather conditions and climate anomalies. Headlines this week revolved around several snow events, below normal temperatures, and a blizzard! The average daily temperature departures across the Midwest indicate that much of the region was significantly below average for this time of year, with a gradient from west to east (Figure 1). Average daily mean temperatures for the third week of March ranged from 4-8°F below normal across Kentucky, Indiana, Illinois, and Ohio, to 3-5°F below normal across Missouri, Wisconsin, and Michigan. The coolest part of the Midwest this week was across Minnesota and northwestern Iowa, synonymous with deep snow cover, where temperatures were some 10 to 14°F below average! No record temperatures were set this week across the Midwest.
Precipitation for the
week was relatively infrequent and light, thus many locations
received below
normal amounts of precipitation. This week, Wisconsin,
Minnesota, the Upper Peninsula
of Michigan, and Ohio
experienced precipitation deficits ranging from 0 to 25% of normal,
while much of Indiana, Missouri, Iowa, Kentucky, and Illinois, saw
between
25 and 75% of the normal
precipitation (Figure 2).
The lack of significant precipitation resulted in little change
in the drought status. However, long-term drought still exists,
and a region of "abnormally dry" was added to western Minnesota where
they have missed a number of weather systems during the past 90 days (Figure 3).
In addition, burn bans remained in effect for six counties in
southern Iowa, and a few locations in central Illinois.
Streamflows across Illinois, Indiana, and Missouri, while peaking
during last week's heavy precipitation events, have dropped back to
previous low levels....a good indicator of long-term dryness.
Snow was abundant this week, and virtually the only precipitation
type, with many Minnesota, Wisconsin, Iowa, Missouri, Illinois,
Indiana, and Ohio residents finding themselves digging out after two
main
events tracked across the Midwest. The snow
cover
map from March 22 (just prior to significant snow melt) illustrates how
expansive and deep the snow
depth remains across the region (Figure 4).
Winter Refuses to Let Spring Arrive
During the third week of March, the weather was largely dominated by sprawling high pressure centers that sank southward out of Canada. The North Atlantic Oscillation turned negative this week (Figure 5), which signaled a pattern change from last week's stormy weather, to a generally drier and cooler pattern for this week. A few systems dropped southward out of Canada this week, and one system slid through the southern portions of the Midwest. On March 16, a snow event in the greater Minneapolis, MN area resulted in a FedEx cargo plane sliding off a runway at the Minneapolis-St.Paul International Airport. The plane was trying to land at around 8:20am when it slid of the runway in snowy conditions. This resulted in the closure of a runway for about three hours while crews worked to free the plane. As much as 8.6 inches of snow fell in the Minneapolis area, and surrounding locales saw between 2 and 5 inches of snow (Figure 6). The system continued southeastward into the Chicago, IL area, causing delays at O'Hare International Airport of between 60 and 90 minutes, and resulted in 80 departure cancellations.The biggest story of the week, however, centered on one large storm system that barreled through the Midwest on March 20-21, bringing heavy snow to parts of Missouri, Iowa, Illinois, Indiana, and Ohio. Numerous winter storm warnings, and even a blizzard warning (across central Illinois) were issued for this event (Figure 7). When all was said and done, snow totals ranged from as little as one inch, to as much as ten inches across this region (Figure 8, Midwestern Regional Climate Center). Several National Weather Service Offices have assembled snow fall maps for this event, including St. Louis, MO (Figure 9); Indianapolis, IN (Figure 10); and Lincoln, IL (Figure 11).
The storm resulted in several new daily snow fall records for the 21st, including Des Moines, IA (5.0 inches), St. Louis, MO (2.6 inches), Galesburg, IL (2.6 inches), Decatur, IL (4.0 inches), Windsor, IL (7.0 inches), Flora, IL (3.0 inches), Springfield, IL (4.0 inches), and Peoria, IL (3.8 inches). Many of these amounts exceed the normal total monthly snowfall for March! The snow was easily seen in the visible satellite imagery for March 22, courtesy of the National Weather Service in Lincoln, IL (Figure 12). Despite the heavy snow, very few impacts were felt across the Midwest, aside from a few car accidents across Iowa and Illinois into Ohio, and a number of school closings in this same area. The snow was quick to melt in the following days, allowing school operations to return to normal.
The remainder of the week featured another area of high pressure settling down from Canada, resulting in significantly cooler than normal temperatures for this time of year, and little in the way of precipitation. A quick southeastward moving "Alberta Clipper" dove through the region on March 23, resulting in a few snow showers across Wisconsin, Minnesota, and eventually into Illinois, Indiana, and lower Michigan, but no significant accumulations were reported.
Going into the final week of March, will temperatures remain below average, or will spring fight off Old Man Winter? Find out in next week's edition of the Midwest Climate Watch.
Kruk