Midwest Weekly Highlights - April 10-16, 2011

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Warm Temperatures Continue

Warm temperatures continued in the second week of April across most of the Midwest. Minimum temperatures averaged above normal across the region (Figure 1) and maximum temperatures were also above normal in all areas except in the far northwest reaches of the region (Figure 2). Minimum temperatures ranged from near normal in the upper Midwest up to 8°F above normal in east central Missouri. Maximum temperatures were below normal, as much as 7°F, in a good part of Minnesota and a small part of northwest Iowa. The rest of the region experienced warm maximum temperatures ranging up to 6°F above normal in parts of Missouri and Ohio. Daily temperature records were dominated by more than 200 record highs early in the week as temperatures reached the 80s across most of the region (Figure 3).
 

Hit or Miss Precipitation

Precipitation totals for the second week of April varied from less than 50% of normal to several times normal across the Midwest (Figure 4). Kentucky and the southern extremes of Indiana and Ohio picked up more than 3" during the week, three to five times normal for the area (Figure 5). Below normal totals extended from northeast Missouri and eastern Iowa to the thumb of Michigan and the Lake Erie area. A swath from western Iowa, across southern Minnesota, central Wisconsin, and into northern Michigan picked up more than twice the normal precipitation. Additional pockets of below normal precipitation were recorded in central Minnesota and northwest Wisconsin while northwest Minnesota picked up three to seven times their normal totals. Many daily precipitation records were set during the week.

Snow fell in the northwest parts of the Midwest, extending into parts of Iowa, Minnesota, Wisconsin, and Upper Michigan (Figure 6). The highest amounts were in northern Minnesota with 2" to 8". The winter snow pack had melted off in all but a few locations prior to this new snow (Figure 7).
 

Two More Severe Weather Outbreaks

Severe weather reports continued to pour in across the country during April. More than three dozen deaths occurred in the south and southeast US as tornado outbreaks moved from the Great Plains (14th) to the Gulf Coast (15th) to the Mid-Atlantic (16th). Two outbreaks of severe weather affected the Midwest, the first on the 10th and the second on the 15th.

On April 10th, the system that caused tornadoes the previous day in Iowa moved into Wisconsin (Figure 8). Thunderstorms spawned 12 tornadoes in Wisconsin, the strongest an EF3 in Marathon County, causing widespread damage across the middle of the state. Other tornado reports came from Adams, Eau Claire, Forest, Juneau, Lincoln, Outagamie, Waushara, and Winnebago coutnies. In addition to the tornadoes, large hail pelted the state as more than 50 reports of 1" or greater hail came in to the NWS. Hail up to 3.00" in diameter was reported in Ashland County, up to 2.75" in Winnebago County, and up to 2.50" in both LaCrosse and Monroe Counties. Nearly 100 reports of severe thunderstorm winds were recorded including a 78 mph gust near Augusta, Wisconsin (Eau Claire County). Trailing to the south was a cold front that triggered storms all the way to Texas (Figure 9). Hail, up to 3" in diameter, covered the ground in Houston County, Minnesota. Golf ball size hail (1.75") also fell in Itasca County, Minnesota. Webster County, Missouri was also hard hit with a tornado report, hail to 2.75", and a 68 mph wind report.

On April 15th, severe weather in the Midwest hit hardest in eastern Missouri, central and southern Illinois, and western Kentucky (Figure 10). A handful of wind reports came from further east in Kentucky, Indiana, and Ohio. One person was injured in a home struck by a tornado near Poplar City, Illinois (Mason County). Other tornado reports came from Menard and Montgomery Counties in Illinois, Pike and Scott Counties in Missouri, and Trigg County, Kentucky. Hail, 1.75" to 2.00" in diameter, was reported in Morgan, Franklin, and Sangamon Counties in Illinois, Franklin, Scott, and Cape Girardeau Counties in Missouri, and Ballard County in Kentucky.
 

River Flooding on Many Midwest Rivers

Major flooding continued for the Red River on the Minnesota western border. Flood crests continued to move north along the river remaining a few feet shy of the records. Cresting waters moved north from near Fargo early in the week to near Canada by the end of the week. The river was reported to be 10 miles wide in some places and widespread overland flooding was also hampering travel. I-29 was under shallow water but remained passable as the water was not flowing rapidly.

Moderate to major flooding was also reported on many Minnesota and Wisconsin rivers and along the Mississippi River to St. Louis. Numerous roads and bridges in Minnesota, Wisconsin, and Iowa were closed due to high waters. Minor flooding also occurred on the Ohio River during the week.
 

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