April 1-9, 2006
Midwest Weekly Highlights - April 1-9, 2006
Stormy Start to April
The Midwest experienced two major severe weather outbreaks during the
first week of April, leaving residents wondering what's in store for
the rest of the spring.
On the positive side, rainfall was plentiful in the some areas of the
Midwest that have endured drought since last fall. The
rainfall
pattern this period was indicative of the general position of the
frontal systems during the week (Figure 1).
There were two notable areas of heavy rainfall. One
extended from the southern half of Minnesota through Iowa, and east
across southern Wisconsin and southern lower Michigan.
Another
band of heavier rainfall extended across central Illinois,
southern Indiana, and the eastern two-thirds of Kentucky.
The
driest areas were in west-central Missouri and northern Wisconsin into
the Michigan Upper Peninsula, where precipitation was 50 percent
or less of normal. The rain in Iowa and Illinois,
in
particular, fell in the core of the drought and has helped decrease the
intensity of the drought in those areas. The U.S Drought
Monitor
for April 4 (Figure 2)
indicated that extreme southwestern Missouri was in Extreme (D3)
drought, while a small portion of north-central Illinois was in Severe
(D2) drought. Since April 4, additional rain in
central
Illinois continued to chip away at the drought (Figure 3).
Temperatures the first nine days of April averaged near to above normal
across the entire region. with the coolest weather (0°F to
1°F
above normal) found from eastern Michigan to northeastern Ohio (Figure 4).
The warmest area extended from western Iowa through Missouri, where
temperatures averaged 4°F to 5°F above normal.
Major Severe
Weather Outbreak Brings Lots More than "April Showers"
On April 1 an area of low pressure moved off of the Pacific Ocean and
into the western U.S. By Sunday morning, April 2, the low was
intensifying over the central Kansas/Nebraska border, with a warm front
extending from the low across northern Missouri southeastward to
central Tennessee (Figure 5).
Some severe weather was reported in southwestern Missouri on April 1 as
storms developed along the warm as it lifted northward. The early
morning severe weather outlook on April from the Storm Prediction
Center indicated that the eastern half of Missouri and the southwestern
half of Illinois were in a moderate
risk for severe weather (Figure 6).
Storms began to fire across Missouri in the afternoon, and by
late afternoon tornado watches covered eastern Missouri, all of
Illinois, most of Indiana, and the western half of Kentucky.
As
the storms raced across Missouri, they spawned two tornadoes in
Missouri and four in the Metro East area of St. Louis, including one
that produced a fatality in Fairview Heights, IL when the tornado
struck a clothing store. Another man was killed in Ballwin,
MO (St. Louis County)
when high winds caused a tree to fall on him as he walked along a trail
in Castlewood State Park. Straight-line thunderstorm winds
were
measured at 74 mph in Chesterfield, MO and 70 mph at the St. Louis
Lambert International Airport. Power was reported out to over
200,000 customers in the metro area The storms also produced
pea
to baseball sized hail.
The line of storms crossed the Mississippi River into Illinois around
6:00 p.m. and continued to March steadily northeastward. The
storms produced 23 tornadoes in central Illinois, causing five
injuries, and widespread damage from straight-line winds.
Two tornadoes touched down in Springfield in the same general
area where a tornado produced significant damage and caused one
fatality on March 12. Wind gusts were measured at 74 mph at Champaign,
toppling high voltage power poles on the southwest side of town.
Power was out up to two days across parts of central Illinois
in
the wake of the storms.
As the storms pressed into Indiana the tornado threat lessened
somewhat, but there were numerous reports of high winds and hail.
The storms struck Indianapolis and sirens sounded as
thousands of
people were leaving a John Mellencamp concert being held as part of the
NCAA's Final Four weekend. Two tornadoes touched down in central
Indiana. One tornado touched down in near Greenwood in Johnson County and remained on the ground for 17 miles. The twister
damaged dozens of homes in Johnson and Shelby Counties.
A woman driving on I-74 in Shelby County was found walking
through a field introducing herself to no one in particular. Her
car "traveled" more than 50 yards across the interstate and a frontage
road before landing near a home. Authorities suspect she may
have
been sucked out of her car, perhaps through the sunroof. The
woman suffered only a mild concussion and some cuts and bruises.
The storms continued on into Kentucky and southwestern Ohio, with four
tornadoes reported in Kentucky. Authorities in Ohio reported that there
was some damage in every county in southwestern Ohio. A
tornado
in Van Wert, OH, damaged a number of buildings in its brief two-mile
stay on the ground. Van Wert was hit by an F-4 tornado during an outbreak
on November 10, 2002.
The latest
tally of storm reports for the April 2 outbreak from the
Storm Prediction Center as of April 9 totals 872 (Figure 7).
This will be updated as storm surveys are completed and new
information is included.
Round 2
High pressure building into the Midwest in the wake of the April system
kept the weather quiet for several days. By Thursday, April 6
another low was spinning up over the Central and Northern Plains. A
warm front once again bisected the region from northwestern Missouri to
eastern Tennessee (Figure 8).
Thunderstorms developed along and north of this front on April
6
and through the early morning hours of April 7. The training
nature of the storms (where storms repeatedly form and move over the
same area) resulted in extremely heavy rainfall in a band from
southeastern Iowa through central Illinois and into west-central and
southwestern Indiana (Figure 9, Figure 10). Heavy rain also fell in southern Minnesota (Figure 11)
. Minneapolis-St. Paul received 2.58 inches of rain, setting a new
daily record (old record of 1.50 inches in 2001) and a new record for
any day in April (old record 2.22 inches on April 27, 1975).
The
heavy rain closed roads in the Minneapolis area, and produced some
flash flooding in Iowa and Illinois. The early morning
storms,
constituting the first round of severe weather for April 7, also were
accompanied by some high winds and large hail (Figure 12).
After a brief lull during the morning and early afternoon of April 7,
the potential was again high for severe weather, although the highest
concentration of severe weather was expected across the southern
portions of the Midwest and northern Gulf region (Figure 13).
By mid-afternoon tornado watches covered the southern half
of
Illinois east through Ohio, and south through northern Mississippi and
Alabama (Figure 14) There were reports of tornadoes in Indiana and
Kentucky during the afternoon, but the most reports were of large hail (Figure 15).
A number of locations in Indiana reported hail 2.00 to 2.50
inches in diameter, and one inch hail was common.
Cooler weather spilled into the Midwest on April 8 behind the low as it
departed, but by April 9 temperatures were climbing back above normal
as high pressure settled in providing plenty of sunshine.
Red River Flooding
Melting snow and heavy rain across Minnesota and North Dakota combined
to push the Red
River above its banks this spring, and crests along the river this week fell
only two feet short of the record 1997 flood in Fargo, ND.
The Red River flows north along the Minnesota/North Dakota
border into Canada. Two
houses in Fargo and one in Moorhead, MN (east of Fargo) were destroyed
due to flooding. The flooding has also caused extensive
damage to
roads and bridges. The Red and Wild Rice Rivers in northwestern
Minnesota, about 30 miles north of Fargo, continued to climb and
workers were pumping out water that was leaking through a levee that
forms a square around the town of Hendrum, MN. The Wild Rice
River was expected to crest about four feet below the levee, which was
raised to 36.8 feet after the 1997 flood.
SDH