June 1-9, 2007
Midwest Weekly Highlights - June 1-9, 2007
Wet and Cool West, Warm and Dry East
The month of June began with more rain in the western portions of the region, and a continued lack of rain in the east. Precipitation the first nine days of June ranged from twice normal in an area from southwestern Missouri through northern Illinois, southern Wisconsin, and lower Michigan (Figure 1). Rainfall was also two to three times normal across the northwestern two-thirds of Minnesota, and resulted in continued flooding along the Red River. South and east of a line from Springfield, MO to Chicago, IL to Detroit, MI rainfall ranged from less than 50 percent of normal in the Ohio River Valley to around 75 percent of normal. While areas in the northern Midwest received more relief from the extended drought there, Moderate drought has spread through Kentucky and into southern Ohio, with Abnormally Dry conditions into southern Indiana and Illinois on the U.S. Drought Monitor (Figure 2).
For most of the region, temperatures averaged close to normal, ranging from 1.5°F below normal in the far western portions of the region to about 1°F above in Illinois and eastern Indiana (Figure 3). Temperatures ranged from 3°F to 4°F above normal from western Kentucky through the Ohio Valley, eastern Indiana, and Ohio.
Upper Low Spins Slowly Over Upper Midwest
As the month of June began a slow-moving upper low was approaching the Midwest from the Dakotas (Figure 4). This low took four days to move to southern lower Michigan, when it was absorbed by another trough and then swept east. The cold air aloft associated with the low created very unstable atmospheric conditions ripe for severe thunderstorms, and the path of the low across the region could be tracked by the occurrence of severe weather the first four days of the month.
Tornadoes Slam Eastern Iowa
Severe thunderstorms rapidly developed in the late morning of June 1, and tornado watches were issued from eastern Iowa across northern Illinois and southern Wisconsin. Shortly after noon CDT the first tornado touched down one mile south of Granview, IA (Louisa County), and struck the town of Grandview eight minutes later, causing severe damage to homes. This tornado continued on the ground for 16 miles, hitting the towns of Fruitland and Muscatine, IA (Muscatine County). Damage was extensive to homes and trees (rated EF2 on the Enhanced Fujita scale). A total damage estimate was not yet available but will likely be in the tens of millions of dollars. A trucking company on the north side of Muscatine alone suffered between $4.5 and $5 million in damages when it took a direct hit from the twister.
Another tornado touched down near Bellevue, IA (Jackson County) causing EF2 damage to numerous farm outbuildings and to trees. The tornado crossed the Mississippi River into Jo Daviess County, IL where it dissipated
Storms continued to move into Illinois during the afternoon and produced several hail and high winds, with numerous reports of large tree limbs and power lines brought down by the storms. Other severe weather reports came from Wisconsin, Missouri, Indiana, and Ohio.
More Severe Weather
The upper low produced severe weather again on June 2, with most severe reports received from lower Michigan and eastern Ohio. Most severe weather reported was large hail and damaging winds, although there was an unconfirmed report of a brief tornado touchdown in Ionia, MI (Ionia County). Hail from the thunderstorms in western Michigan damaged some apple and cherry crops, and for some the damage was significant. Damaged apples may be used for juice or applesauce, but the price difference between what a grower received for fresh picked versus sauce is significant.
Scattered severe storms also occurred across the Midwest on June 3 and June 4 but was much less concentrated than the first two days of the month. Brief tornado touchdowns occurred in Illinois and Wisconsin on June 3, and a brief touchdown occurred in eastern Indiana on June 4 causing some minor damage.
Upper Low Shifts to the East
By the June 5 the upper low had been absorbed by a strong trough of low pressure over the Great Lakes, and a cold front was pushing south through the Midwest (Figure 5). More severe weather developed ahead of the cold front from southern Indiana through northern and eastern Kentucky. Baseball-size (2.75 inch) hail was reported near Versailles, KY (Woodford County), and there were a number of reports of golf ball-size (1.75 inch) hail.
Another Low Spins Up Over Rockies
An unseasonably strong low pressure system developed over the Rockies on June 6, setting the stage for the next round of severe weather. Severe storms on June 6 were largely confined to Minnesota, where an advancing warm front caused a number of storms that produced hail up to 1.75 inch. Back in the Central Plains, surface winds gusted to in excess of 55 mph as the low intensified and began to move east. By the morning of June 7 the intense surface low pressure system was located over western Minnesota (Figure 6), with a warm front arcing across northern Wisconsin into western Ohio and a cold front trailing south. While surface winds were not quite as strong as they were in the Central Plains the day before, southerly winds were sustained at 20 to 30 mph with gusts in excess of 40 mph across much of the region. The strong surface winds affected air travel, and by noon delays for arriving flights at Chicago's O'Hare airport were exceeding two hours. In addition, the western half of the region was placed in a Moderate to High Risk for severe weather (Figure 7). By early afternoon tornado watches were in effect from Oklahoma to northern Minnesota and Wisconsin. Thunderstorms developed in the early afternoon over western Minnesota and central Iowa. Individual storms moved rapidly to the northeast, while the area of thunderstorms progressed slowly eastward. A number of tornadoes were reported, most numerous in central Wisconsin during mid to late afternoon and early evening. The most significant tornado reported touched down east of Mattoon in Shawano County, WI , and then traveled east-northeast through Menominee, Langlade, and Oconto Counties in northeastern Wisconsin. This tornado has been given a preliminary rating of EF-3 on the Enhanced Fujita scale, with estimated winds of 140 to 160 mph. The tornado was on the ground for about 40 miles, and was at least 1/2 mile wide at times. The tornado heavily damaged a resort in Langlade County and flattened thousands of trees in the Nicolet National Forest in Oconto County. In addition to the tornadoes and straight-line wind damage, there were also several reports of hail ranging in size from 3.00 to 4.25 inches in central and northwestern Wisconsin. There were 214 severe weather reports for the day, most of them in the Midwest.
Storms Continue the March Eastward
Storms continued to fire ahead of the cold front on June 8. While the tornado threat had diminished, the potential for straight-line damaging winds continued. Lines of thunderstorms swept ahead of the front (Figure 8), and by early afternoon severe thunderstorms watches extended from Arkansas through Ohio and into New York (Figure 9). While there were a few reports of very large hail, including 2.75 inch hail in Summit County, OH, most of the severe weather reports were from straight-line winds.
The period ended with high pressure settling over the central Midwest, bringing fair weather to most of the region. A few thunderstorms erupted in northwestern Minnesota ahead of a cold front pushing south out of Canada, some of which produced severe hail (>= 0.75"). 1.75" hail was reported east of Thief River Falls, MN (Pennington County).
SDH