August 1-10, 2005
Midwest Weekly Highlights - August 1-10, 2005
In the Grip of Drought
Much of the northern half of Illinois and northeastern Missouri
remained in the Extreme drought category at the end of the first 10
days of August. There was little significant precipitation
during the period outside of widely scattered showers and
thunderstorms (Figure 1). While a few locations did
receive significant rainfall they were few and far between. The August
9 edition of the U.S. Drought
Monitor (Figure 2) indicated that much of
northern Illinois and
northeastern Missouri were experiencing Extreme drought, the
area of Extreme drought was expanded into more of southeastern
Iowa. Moderate
to Severe drought covered much of Missouri, Illinois, Wisconsin, and
the Michigan UP. The first part of August was much
warmer than normal (Figure 3), with temperatures averaging
from 3oF
to 6oF
above normal over most of the region. The warmest
area was northeastern Wisconsin and the Michigan UP, where temperatures
were 7oF
to 8oF
degrees above normal.
Cold
Front Holds Promise, but
Doesn't Deliver
Early in the period a strong cold front made its way south through the
Midwest and held some promise for showers and thunderstorms along and
ahead of the front. On the morning of August 4 the front
extended
front central Lake Superior across eastern Iowa and into western
Missouri (Figure 4). The timing of the
frontal passage was
expected to be favorable for the drought areas of Illinois and
Missouri, coming near the maximum heating of the day and
instability. However, the strongest upper air support
remained to
the north and only scattered showers and thunderstorms developed.
Rainfall amounts averaged 0.30 to 0.50 inch in a band from
central and northeastern Missouri through central Illinois (Figure 5). The front stalled
out across southern Missouri and Illinois,
where it provided a focal point for more scattered shower and
thunderstorm development. Plenty of low level moisture,
combined
with slow movement of the storms produced heavy downpours in scattered
locations. The
cooperative weather observer at Round Spring Ranger Station near Eminence,
MO reported 5.65 inches of rain
in the 48-hour period ending
on the morning of August 7. West
Plains, MO set daily rainfall
records of 1.07 inches on August 5 (old record 0.67" in1961) and 1.49
inches on August 6 (old record 1.30" in 1993).
The front eventually washed out and high pressure dominated the region
again with hazy, warm, and humid weather. In general the high
pressure system provided a break from the extreme heat that had spread
over the region at the end of July, but highs were still generally
above normal in the upper 80s and low 90s. On August 8 the National
Weather Service office in Marquette, MI set a new high temperature
record of 91oF,
shattering the old record of
85oF
set in 2001. As the high moved east late in the period, southerly winds
began to transport warmer air into the Midwest. By August 10 high
temperatures
reached 100oF
again in central Missouri just south of a cold front extending east to
west across the region (Figure 6).
A second cold front pushed south through the northern Plains on August
8 (Figure 7), triggering strong storms
across Minnesota and Wisconsin on August 7-9. On August 8
softball-size
hail (4.25" in diameter) damaged cars and
buildings in Underwood,
MN,
east of Fergus Falls (Otter Tail County). This was the second week in a
row with hail in Otter Tail County.
A few severe storms also developed across Illinois and Indiana on
August 9 and 10 as widely scattered storms developed in response to a
weak upper level disturbance moving through the region.
High
and Dry
Although rain did fall in parts of the Midwest, much of the region saw
little or no water from the sky the first 10 days of August.
Crop conditions continued to worsen in the drought-stricken areas.
State crop reports from Illinois and Missouri showed continued decline
across the board. In Illinois, 61 percent of the corn crop
was reported in poor to very poor condition as of August 7, an increase
of 6 percent since July 31. 41 percent of the soybeans were
reported in poor to very poor condition, up from 34 percent the week
before. In addition to stress from the drought, soybeans are
being threatened by aphids and spider mites. In Illinois and
Missouri, the drought has hit pasture land extremely
hard. 82 percent of pasture in both states was reported in
poor to very poor condition as of August 7, an increase of 8 percent
from the week before in Illinois and 4 percent in Missouri.
Many farmers are feeding hay to supplement
pasture feed.
Good
News?
On August 10 the cold front that had been slowly moving through the
Midwest stalled over the central Midwest. Late on August 10 a
complex of thunderstorms had developed over central Iowa (Figure 8) and was headed for northern
Illinois. With the front expected to oscillate north and
south through the central Midwest for several days, the
chances for significant rain in the drought areas looked
better than they had been in some time.