Midwest Weekly Highlights - June 1-9, 2009
The first week of June was cooler than normal, particularly in the north. Temperatures for the week ranged from near normal in Missouri to as much as 10°F to 12°F below normal in Minnesota (Figure 1). June 7-9 had especially cool daytime highs that set scores of records across the northern states. The three-day average of maximum temperature was more than 10°F below normal across the northern third of the region with the largest departures, between Minneapolis and Duluth, approaching 25°F below normal (Figure 2). Minneapolis had three consecutive June days with highs below 60°F. A similar string of cool June days only happened four other times, most recently in 1951.
Rainfall across the region mostly fell between 0.5 inch and 2.5 inches (Figure 3). Along the Missouri-Iowa border rainfall was slightly higher with peak values exceeding 3.5 inches and southwest Missouri was a dry spot but received rain after the morning observations on June 9 (Figure 4). In the moderate and severe drought areas of Minnesota and Wisconsin there was not enough rain to improve the status in the most recent Drought Monitor (Figure 5). Soybean planting in Missouri, Illinois, Indiana, and Kentucky was running behind the 5-year average due to wet soils and the delayed corn planting in those states.
River flooding was limited to northern Missouri (Figure 6) and west central Illinois (Figure 7) this week. The river flooding in Missouri is recent while the Illinois River is a long-term situation with Havana and Beardstown above flood stage for more than 100 days and counting.
Two periods of severe weather affected the southern two-thirds of the region this week. The first was June 1-3 and the second was June 7-9. The days between were mostly quiet but there were a few reports of large hail. Every state in the region except Minnesota experienced severe weather during the week.
June 1-3 began with a stationary front extending from west to east across the middle of the region. Severe weather was confined to a narrow swath along the front on June 1, then on June 2 and 3 the front moved south and east spreading the severe weather around (Figure 8). Tornadoes were reported in Illinois (Vermilion, Stephenson, Adams, Brown, and Pike counties) and Ohio (Fairfield County). Hail and wind damage was reported across Missouri, Illinois, Indiana, Ohio, and Kentucky. The largest hail fell in Harrison County, Missouri (2.75") on June 1, Hamilton County, Indiana (2.75") on June 2, and Breckinridge County, Kentucky (1.75") on June 3. Other June 2 reports of 2" or greater hail occurred in Ohio (Madison, Pickaway, Montgomery, Warren, and Preble counties).
June 4-6 was relatively quiet in the Midwest as the plains took the brunt of the severe weather (Figure 9). There were no severe weather reports in the Midwest on June 4. Iowa (Sac County) had a single report of 1" hail on June 5. With only two reports of hail on June 6, it was again fairly quiet but both reports were significant. 1.75" hail was reported in Missouri (Lewis County) and 2.00" hail was reported in Iowa (Cass County).
June 7-9 saw a return of widespread severe weather that affected eight of the nine states in the region (Figure 10). Tornadoes occurred June 7 in Missouri (Dekalb, Caldwell, and Davies counties) and Iowa (Cass, Dallas, and Polk counties); June 8 in Illinois (St. Clair, Calhoun, and Perry counties) and Wisconsin (Racine and Waukesha counties); and June 9 again in Missouri (Hickory County). The Illinois tornadoes damaged more than 100 homes, mostly in O'Fallon and Shiloh, and knocked out power to 12,000 Ameren customers. Massive hail stones, reported at over 4.00" in diameter, fell in Missouri (Holt and Davies counties) on June 7. Several other Missouri counties (Dekalb, Grundy, Livingston, and Lafayette) reported hail of at least 2.00". St. Clair County, Illinois was hit with 2.00" hail on June 8. Large hail returned to Missouri on June 9 with 2.75" hail in Laclede County and 2.50" hail in Cass County topping the list. Ohio also received hail on June 9 with the largest reported hail stones in Pike County (1.50"). National Weather Service Offices in Kansas City and St. Louis, Missouri and Des Moines, Iowa provided detailed coverage of the storms in their warning areas.