June 22-30, 2004
Midwest Weekly Highlights - June 22-30, 2004
Cooler and Drier End of June
The last nine days of June were cool and dry in most of the Midwest. Precipitation exceeded one
inch only in a band from southwestern Wisconsin to central lower Michigan, and in eastern
Kentucky (Figure 1). These were also the only areas in the Midwest with above normal
precipitation for June 22-30, and large portions of the northern Ohio Valley, Minnesota, Iowa,
and Missouri received less than 50% of normal for the period (Figure 2). Temperature departures
for the period ranged from -10°F in the western Midwest to -3°F in the east (Figure 3).
Precipitation was suppressed by a series of Canadian high pressure centers moving into the
region from the Great Plains (Figure 4); they also brought the cooler than normal air masses and
some record temperature minima to the region. The last half of June proved to be a strong
departure from the wet pattern of May and early June in the Midwest, with the exception of a
severe weather outbreak along one of the cold fronts passing through Wisconsin on the 23rd.
A Wisconsin Tornado Outbreak
On the evening of June 23rd, more than 20 tornado sightings and dozens of severe hail and wind events were reported to the National Weather Service (Figure 5, SPC). Fifteen tornadoes were confirmed by NWS survey teams, making this the fourth largest one-day outbreak of tornadoes in Wisconsin history. A strong NW flow aloft with a jet exit over Wisconsin (Figure 6), College of DuPage) provided upper air support, and a surface cold front and low pressure center established a lifting mechanism in the area (Figure 7, COD). With such a classic set up, the Storm Prediction Center provided timely watches and warnings for the storms (Figure 8, SPC), which resulted in one death, two severe injuries, and a number of minor injuries. The tornadoes were spawned in two lines of convection in front of the cold front (Figure 9, COD). The northern line had a strong center of rotation easily visible in an image of storm relative motion, with bright green pixels indicating high wind toward the radar, and bright red couplet completing the counter-clockwise rotation about 60 miles northwest of Milwaukee (Figure 10, COD).
The death and one of the serious injuries occurred in Markeson, WI, where an F3 tornado flattened a wood house and swept the house and its occupants into an adjacent field. The other serious injury took place at Jellystone Campground in Warrens County, along with several moderate injuries as trees fell throughout the camp. Wind and large hail also accompanied the storms, with 1 inch hail reported in urban and suburban areas around Milwaukee and Racine. Tree damage was extensive and widespread, and 11,000 lost power due to the storms. Initial storm damage estimates include $5 M in the city of Madison and $6 M in Dodge County were several town took heavy damage. However, the total impact has not yet been calculated. The federal disaster declaration already in place for flooding in May and early June was expanded to include the tornado ravaged counties (Figure 11, FEMA). Officials estimated that up to 6,500 homes and businesses may have some loss from the storms and floods.
On the last day of the month, Michigan became the eighth state of the 9-state Midwest region to
receive a federal disaster declaration, for flooding due to heavy rain in May and June in the
southeastern part of the state (Figure 12, FEMA). The city of Dearborn Heights alone had more
than 1,000 reports of flooded basements, as sewer lines backed up due to three inches of rain that
fell in less than one hour. Of the Midwestern states, only Minneapolis has so far escaped weather
related federal disaster declarations in 2004. The remaining Midwestern states have received to
date more than $51 M in federal grants and low interest loans, but this does not make up for most
losses.
Record Cold Temperatures in the Midwest
The cold air started poking its way southward into the Midwest on the 22nd and 23rd, even before the major severe weather outbreak. International Falls, MN, set new temperature records on both days, while Springfield, Joplin, and Kansas City, MO, also set or tied cold records on the 23rd. The front continued southward on the 24th, triggering some severe storm reports in the Ohio Valley (Figure 13, SPC). Stark County in northern Ohio had a narrow band of damage about 12 miles long caused by 75-95 mph from a thunderstorm downburst on the evening of the 24th. By next morning, the cold air was in place, with widespread reports of record lows in the 40s in Iowa (12 locations), Wisconsin (2 places), and Missouri (1 location). The next morning, new record lows were set on the 26th further south and east in Missouri (4 locations), Illinois (2 locations), Indiana (1 location), and Ohio (2 locations). St. Joseph, MO, set or tied minimum temperature records on June 26, 28, 29, and 30. The week ended with two notable earthquakes in the region, a 4.1 Richter scale event 70 miles southwest of Chicago at 1:11 AM, June 28, and a 3.3 Richter scale event near Perry, in northeastern Ohio.