Midwest Weekly Highlights - May 11-17, 2011
Hot Start, Cold End
Temperatures exhibited a wide swing this week, going from much above normal with some record highs, to much below normal weather more typical of March in the last four days of the week. Much of the week was dry, which allowed agricultural producers to make significant progress in spring planting.
At week's end temperatures across the Midwest ranged from 7°F below normal in western Minnesota to 3°F above normal in extreme eastern Ohio (Figure 1). However, the average over the week hardly tells the story. Temperatures May 11-13 were above normal over all but the northwestern half of Minnesota, reaching 9°F to 14°F above normal across much of Illinois, Indiana, Ohio, the southern half of lower Michigan, and Kentucky (Figure 2). Daily maximum temperatures reached 90°F as far north as southern Wisconsin on May 11th, and record highs in the mid to upper 90s in western and central Iowa. For the period May 14-17 the entire region was below normal, ranging from 2°F below normal in eastern Ohio to 12°F to 13°F below normal across Missouri and Illinois (Figure 3). Many record low maximum and record low miniimum temperatures were set or tied this period, especially across Missouri and Illinois.
This week was another case of feast or famine as far as rain was concerned. Precipitation was 200 percent of normal or more across southern Iowa, north central Illinois, northern Indiana, lower Michigan, and much of Ohio (Figure 4). The northern half of Minnesota received less than 25 percent of normal rainfall. Dry conditions continue to be depicted in the Arrowhead of Minnesota and small portions of the Michigan Upper Peninsula on the May 17th edition of the U.S. Drought Monitor (Figure 5). Rainfall was also much below normal this week across the lower Ohio Valley, good news for the flood-stricken communities along the Ohio River. River levels drooped considerable along the Ohio River in the past week, with most gaging stations reporting minor flooding. Moderate to major flooding was still ocurring from Paducah, KY to Cario, IL (Figure 6) Minor flooding was still occurring on the Mississippi River from Hannibal, MO to Chester, MO (Figure 7).
Scattered Severe Weather
Severe weather was reported in all states but Minnesota this week (Figure 8). The hot and humid weather May 11-13 combined with upper level disturbances moving through the Midwest provided the ingredients necessary for scattered severe thunderstorms during the period. Several tornadoes touched down in western Iowa on May 11th, including two tornadoes near Lenox, IA (Taylor County). The EF0 and EF1 tornadoes caused some building and tree damage. An 11-year old boy in Lenox took shelter from an approaching tornado in a clothes dryer in the windowless laundry room his home. The tornado demolished the second story of the house, but the boy was uninjured. More information on these tornadoes can be seen on the NWS Des Moines web site. Western Iowa and southwestern Missouri caught the brunt of the severe weather on May 12th. Baseball-size hail (2.75 inch) was reported in Woodbury County and Monona County, IA. Softball-size hail (4.25 inch) was reported in Camden County, MO. On May 13th a few severe storms were scattered from Missouri to Ohio. Two tornadoes were sighted in eastern Indiana and two in western Ohio on May 14th, none resulting in more than minor damage. There was no severe weather the remainder of the week.
Surge in Spring Planting
The mostly dry and unseasonably warm weather the first part of the week led to an increase in planting activities as soils dried to workable levels in many areas. Corn and soybean planting are well behind in all states except Missouri and Iowa, where planting is ahead of schedule. Ohio is in the worst shape, with only7 percent of the corn planted as of May 16, compared to a 5-year average of 70 percent. Soybean planting in Ohio was only 3 percent complete, compared to an average of 44 percent.
Slow Moving Low Brings More Rain
The transistion from summer-like warmth to March-like chill came as an upper level blocking pattern set up across the U.S. (Figure 9). Low pressure aloft over the Midwest brought rain and much colder weather to the region the last half of the week. The rain was most persistent and heaviest from north central Illinois eastward into northwestern Ohio (Figure 10). Heavy rain on May 14th resulted in flash flooding in portions of Indiana and Ohio. In Huntington County, IN three to five inches of rain fell in a short period of time, flooding 40 homes and affecting 60 structures. This low pressure system continued to affect the eastern half of the region through May 17th (Figure 11) further delaying spring planting in Ohio and Indiana.