Midwest Weekly Highlights - October 8-14, 2009
A Cold Week
The second week of October saw very cold temperatures (as much as 25°F below normal) settle into the northern plains and Rockies (Figure 1). The cold extended eastward into the Midwest with temperature departures of 18°F below normal in western Iowa and southwest Minnesota. More than half the Midwest averaged at least 10°F below normal for the week with the only extreme southeast Kentucky experiencing near normal temperatures (Figure 2).
Heavy Rains in Southern Midwest
Precipitation was way above normal in the southern half of the Midwest (Figure 3). Most of Missouri, Illinois, Indiana, and Kentucky along with parts of Ohio received more than twice the normal rainfall for the week. Rainfall exceeding 700% of normal extended from southwest Missouri, through southern Illinois, to the southwest tip of Indiana. The northwest half of the Midwest saw below normal precipitation with northern Minnesota getting less than 25% of normal. Drought in the northern Midwest continues but the abnormally dry conditions in Indiana and Ohio were removed from this week's US Drought Monitor.
Growing Season Ends Across Northern Half of Midwest
Cold Canadian air spilling into the Midwest produced temperatures in the mid 20s as far south as northern Illinois on the morning of October 10 (Figure 4), bringing an end to the growing season across the northwestern half of the region (Figure 5). Many locations through the Midwest set new record low minimum and maximum temperatures as this cold air mass settled in over the region.
The Midwest's only severe weather this week occurred in Kentucky on October 8th and 9th. An EF-0 tornado struck near Dyer, Kentucky (Breckinridge County) on October 8th. The damage included several mobile homes, barns, and trees along the path of the tornado. Thunderstorm winds on the 8th also caused damage to barns, other outbuildings, a carport, trees, and power poles.
October 9th brought more severe weather to the southeastern half of Kentucky. Tornadoes were reported in Monroe County (EF-2) with damage to homes, barns, and trees, Casey County (EF-2) with significant damage to homes and uprooted trees, and Estill County (2 EF-1 tornadoes) with reported damage limited to trees. Further damage to trees was reported across southeastern Kentucky due to thunderstorm winds.
Torrents of Rain in Southern Midwest
Waves of low pressure moving along a stalled front over the southern Midwest produced very heavy rain from southwestern Missouri through southern Illinois and Indiana. Flash flood and flood watches were issued for an area from southern Texas through central Indiana on October 8 (Figure 6). The heaviest rain fell in southwestern Missouri, where 24-hour rainfall totals exceeded five to six inches over a large area (Figure 7). Rainfall records were broken across the Ozarks. The rain caused flash flooding throughout southwestern Missouri, and the flooding resulted in four deaths. Three high school students were killed near Springfield, MO (Greene County) when the driver lost control of the car in extremely heavy rain and crossed into the opposite lane, hitting another vehicle. In Phillipsburg, MO (Laclede County) a 40-year-old farmer was struck by lightning and killed when he went out to check on cattle.
Five Missouri cooperative stations set records for all-time highest daily precipitation. The new records (old records in parentheses) were Neosho with 7.11" (7.00" on Dec 16, 1895), Marshfield with 6.17" (5.30" on Nov 25, 1987), Flemington with 5.35" (4.82" on Sep 14, 2008), Galena with 5.05" (4.87" on Dec 3, 1982), and Jerico Springs with 3.9" (3.75" on Sep 14, 2008).
More information of the heavy rain and its impacts in southwestern Missouri can be found on the NWS Springfield, MO web site.
To the east, the heaviest rain occurred in southeastern Illinois and southern Indiana, where numerous amounts from 3.50 to more than 4.50 inches of rain were measured.The largest amount was measured by a CoCoRaHS observer in Palmyra, IN (Harrison County) who reported 5.10 inches of rain for the 24 hour period ending at 8:00 a.m. EDT on October 9. Flash flooding around Henryville, Indiana (Clark County) closed or delayed schools when roads were closed by the rising waters which also flooded some homes.
Early Snow in Minnesota
An upper level wave moving through the northern Midwest October 11-12 resulted in an early fall snow over Minnesota and parts of northern Iowa. One to three inches of snow fell from Redwood Falls to Minneapolis/St. Paul with a few higher amounts reported. This was the first time since 1977 that a 1.0 inch or greater snowfall has been recorded this early or earlier in the month of October in the Twin Cities, when 2.5 inches fell on October 10, 1977. In a suburb of the Twin Cities, a woman was killed when a car lost control and struck her as she helped another motorist. In northern Minnesota a winter storm warning was issued for areas downwind of the Red Lakes (Beltrami County), where localized amounts of 6 to 10 inches of snow were expected. At the end of the week, snow was reported on the ground from northwest Iowa, across Minnesota and northern Wisconsin, to Upper Michigan (Figure 8).