October 11-17, 2004
Midwest Weekly Highlights - October 11-17, 2004
Dry Weather Ends in Southern Half of Region
After six weeks of very dry weather across much of the Midwest,
significant rain finally fell across the southern half of the
region. Precipitation for the period October 11-17 was more than
twice
normal across the southeastern two-thirds of Missouri, the southern
halves of Illinois and Indiana, and most of Kentucky (Figure 1).
Rainfall was more than 300 percent of normal across extreme southern
Missouri, extreme southern Illinois, and a small adjacent portion
of Kentucky. Western Iowa was the driest portion of the region
this week, with little rainfall reported. Precipitation across
the northwestern half of the region was generally less than 50 percent
of normal. October precipitation through October 17 is
still below normal across most of the region with the exception of
Missouri, western Illinois, Kentucky, and northern Michigan (Figure 2). Cool weather continued across the Midwest again this
week,
with below average temperatures across the region (Figure 3). Temperatures
in Missouri , Iowa, and the southern half of Minnesota averaged 6 to 8F degrees
below normal, while in the eastern portion of
the region temperatures were 4 to 6F below normal.
Matthew Breaks Dry Weather
Pattern, and First Snow Falls in the North
The remnants of Tropical Storm Matthew entered the Midwest on October
11, bringing with it much needed rain. It was the first
significant rain for the central portion of the Midwest in almost four
weeks. The low pressure system moved from the Arkansas-Louisiana
border on the morning of the 11th to near the Missouri boot heel by the
morning of October 12 (Figure 4). The
storm pushed rain northward in a wide arc from Ohio westward into eastern Iowa
(Figure 5,
UCAR/RAP). Rainfall from this system was heaviest across
Missouri, Illinois, Indiana, and Ohio as the low slowly moved through
the Ohio Valley the first three days of the period. As what
remained of T.S. Matthew departed the region, a strong upper level low
began digging into the central U.S. on October 13, and by October 14
was entering western Missouri (Figure 6). A wide
band of rain developed ahead of the upper low and more rain fell from Missouri
through Illinois and Indiana, as well as in northern Michigan (Figure 7, Unisys). The surface low rapidly intensified on October
14-15
as it moved northeast into the Great Lakes, generating strong
northwesterly winds and pulling down much colder air into the
Midwest. On October 14, International Falls, MN tied their record
low temperature with a reading of 21F. Embarrass, MN reported
18F, the coldest reading in the contiguous 48
states on October 14.
High temperatures on October 16 reached only the upper 40s to low 50s
as far south and east as southern Ohio (Figure 8, Unisys & MRCC),
and maximum temperatures were 16 to 20 F below normal in a band from northwestern
Minnesota to the Ohio River (Figure 9).
The first snow of
the season was recorded in parts of Wisconsin and Michigan on October
16. Heavy snow fell in the western
Michigan UP in the Keweenaw Peninsula, with 14.0 inches reported at
Phoenix and 6.0 inches at Wakefield. One to four inches fell over
much of the area. In lower Michigan, Gaylord received 3.0 inches of
snow, with other locations
in northwest lower Michigan reporting an inch of new snow. A few
tenths of an inch of snow accumulated in the lake effect areas of
northern Wisconsin. Green Bay and Rhinelander, WI reported a
trace of snow, and flurries were reported in a few other locations in
central and east-central Wisconsin. Ice pellets were reported at
Madison, WI and other counties in south-central and southeastern
Wisconsin.