April 15-21, 2008
Midwest Weekly Highlights - April 15-21, 2008
Spring Has Sprung - Finally!
This was a relatively quiet week across the Midwest, with the first 70°F temperatures appearing in many areas. The temperature pattern was somewhat unusual this week with the northeast quarter much warmer than normal, and the southwest being cooler. Temperatures ranged from 8°F to 10°F above normal in northern lower Michigan to 2 °F to 4 °F below normal in southeastern Missouri through southwestern Kentucky (Figure 1).
Precipitation this week was confined to a relatively narrow band extending from northern Missouri into central Wisconsin (Figure 2). Rainfall in this band was as much as two times normal for the week. Over the reminder of the Midwest there were only light amounts of rain. The drier weather was welcomed by agricultural producers, as corn planting is behind schedule in many areas due to the wet, cool weather.
The warmer weather resulted in a significant reduction in snow cover across the upper Midwest. However, as of April 21 more than a foot of snow was still on the ground in the Arrowhead of Minnesota and on Michigan's Keweenaw Peninsula (Figure 3).
Sunshine and 70s
The week started out cool, but with plenty of sunshine as high pressure moved over the Midwest. Warmer weather started its return on April 16 as strong southwest winds set up over the Midwest. Wind advisories were in effect on April 16 from Missouri northeast through Wisconsin (Figure 4), although the strongest wind gusts ended up being observed only in a few areas (Figure 5). Janesville, WI (Rock County) reported a wind gust of 53 mph during the afternoon on April 16, and a few other locations reported wind gusts to 47 mph. The strong winds transported the warmer air well to the north, and high temperatures reached the mid 70s as far north as Traverse City, MI (Figure 6).
The only significant rain this week occurred as a wave of low pressure developed along a cold front moving through the Midwest on April 17. This low intensified and moved to just northeast of Kansas City by the morning of April 18 (Figure 7). There were a few severe storms producing hail from 1.00 to 1.75 inches near Kansas City on April 17. The heaviest rain with this system fell along and behind the cold front, and was confined to a band of one to two inches of rain from northwestern Missouri into central Wisconsin. Clouds persisted behind the departure of the surface low and cold front as a large upper low moved southeast through the Midwest (Figure 8). Sunshine and warmer weather returned on April 20-21.
Flooding Persists
While the weather was much quieter this week, flooding still persisted in many areas in the wake of the recent weeks of wet weather. Moderate flooding was occurring along the Rock River in Wisconsin and in Illinois (Figure 9). In addition, moderate flooding was occurring on the Mississippi River from Rock Island, IL south to Hannibal , MO. Some minor flooding was occurring south of Hannibal (Figure 10). Moderate flooding was occurring on the Illinois River south of Havana, IL, and minor flooding along the Wabash in Illinois and Indiana.
SDH