June 2001
Temperature and Precipitation Anomalies.
June 2001 was close to normal in both temperature and precipitation over much of the Midwest. For the region as a whole, it was the 40th wettest and 39th coldest June in the last 107 years. The central-western core of the region was 1-3°F below normal (Figure 1), but Kentucky ranked as having its 19th coldest June despite having a smaller negative departure of -1.1°F. The western portion of Missouri received more than 3 inches above normal rainfall for the month (Figure 2), reaching 8-10 inches (Figure 3) and causing Missouri to have its 22nd wettest June. The western Corn Belt through Iowa and Nebraska was quite dry, causing some concern in the grain markets.
The period June 1 to June 5 marked a return to heavy rain, after having a more normal amount in the previous week. Precipitation totals exceeded 2 inches in most of Missouri and parts of adjacent Iowa and Illinois (Figure 4). Even the drought areas near the southern tip of Illinois received above normal amounts of rain for the week (Figure 5). The region experienced another upper level low camping overhead, with Missouri, Iowa, Illinois, Indiana, Michigan and Ohio averaging only 2-3 field work days due to wet soils and precipitation. The state with the most short/very short topsoil moisture area is still Kentucky, but this is down to only 13% now. On the other hand, Iowa, Michigan, Minnesota, Missouri, and Ohio all have more than 40% of state farmlands with surplus topsoil moisture conditions. Therefore, there is no longer concern about short term drought in the area. Drought status has been eliminated in an agricultural sense in the Midwest, although some areas still are under hydrological drought due to a lack of subsoil moisture and groundwater (Figure 6). The main concern now is the lack of warmth and sunshine that is holding back the crops. Eastern Iowa, southern Wisconsin, and northern Illinois and Indiana were 10-12°F below normal for the period, and almost the entire Midwest was at least 5°F below normal (Figure 7).
The week of June 6 to June 12 displayed promising signs of a return to summer in the Midwest. Light precipitation was widespread (Figure 8), but the heaviest precipitation was focused into two corridors cutting from west to east and from northwest to east across the region (Figure 9). Temperatures for the week were still a few degrees Fahrenheit below normal in the eastern Midwest, but were at or slightly above normal in the western Midwest (Figure 10). The week started cool and wet, especially north of a frontal boundary running from northern Missouri due east to southern Ohio. A series of two mesoscale convective systems moved from Missouri through to Ohio on June 6 and 7, bringing flooding rains to the northern two-thirds of Missouri, central Illinois, and central Indiana. The heavy rains in Illinois and Indiana were tightly focused into two west-east bands affected by training thunderstorms, and so the more diffuse gridded precipitation map belies the impacts on crops and communities in the affected areas in Illinois (Figure 11) and Indiana (Figure 12) that can be seen in radar accumulation maps. The town of Divernon, IL, near the state capital suffered $500 K in damage, with 5 houses severely damaged and another 20 partially damaged. A trailer park was also evacuated as trailers were flooded. Flash flooding was common in the affected areas. The largest impacts, though, were in northern Missouri, which had experienced heavy rains in the days leading up to the 6th. Not only did flash flooding affect dozens of counties, but many major rivers rose beyond flood stage (Figure 13). Along the Blackwater River and Grand River, floods crested more than 10 feet above flood stage. Even the mighty Missouri River came dangerously close to over-topping the levees protecting the airport and businesses in the flood plain across the river from Jefferson City, the state capital. The river crested at 30.27 feet, which is within inches of the height of the levees in question (Figure 14), USGS). Airplanes and rental cars had been evacuated, and businesses were packed and ready to evacuate, but this was the only financial impact at that location. However, thousands of acres of farmland were flooded along rivers where levee protection was lacking or insufficient.
After a few more days of nearly normal temperature conditions, the warm air finally pushed northward and eastward to bring normal summer conditions to all of the Corn Belt. Summer heat arrived by the 10th, and on the 11th, new record high temperatures were recorded in Mason City and Waterloo, IA. However, with the advent of heat and humidity, a severe weather outbreak affected much of the northern Midwest at the end of the period. Copious rains in Minnesota and Wisconsin with this system did not aid farmers, either (Figure 15).
The week of June 13 to June 19 brought more disappointment to the saturated farms of the northwestern Midwest. All of Iowa, Minnesota, and Wisconsin received above normal amounts of rainfall (Figure 16). More importantly, central Iowa, eastern and southern Minnesota, and southern Wisconsin received rain from multiple mesoscale convective events traveling along either stationary or warm fronts draped across the area. Precipitation totals of 3-5 inches were commonplace in these already wet areas (Figure 17), more than 300% of normal in a wide swath through Minnesota (Figure 18). Heavy storms from the 12th to the 15th and on the 18th and 19th, brought not only field-flooding rains, but also severe hail and windstorms that further damaged crops that had emerged and progressed. Soil moisture ratings of surplus were found on more than 50% of the farmland in Iowa, Minnesota, and Wisconsin even without including the effects of the storms on the 18th. On the evening of the 19th, a tremendous mesoscale convective system dumped more than 10 inches of rain on places in northeastern Kansas, and then proceeded into northwestern Missouri, where 3-6 inches fell over an area still very wet from rains about a week earlier (Figure 19). Kansas City, MO, suffered significant urban street flooding, and flash flooding was widespread. In the rest of the region, precipitation was either near normal or drier than normal. Areas suffering from long term moisture deficits but that had received some relief earlier in the month started drying again, especially in the south-central Midwest. Short and very short soil moisture ratings increased greatly in south central and southeastern districts in Missouri, and increased generally in western Kentucky, southern Illinois, and southern Indiana. Most of the Midwest was above normal in temperature by 4-8°F (Figure 20), although it was nearer to normal in the persistently wet areas. The increased temperatures were very helpful to crop development and helped the corn and soybeans recover their normal green coloration in many areas this week.
Much of the northern Midwest enjoyed a reprieve from the wet weather that has plagued this area since the late spring during the last third of the month, June 20-30. Rainfall in Minnesota, the northern half of Iowa, and most of Wisconsin was less than 50 percent of normal for the period (Figure 21). The focus of the rainfall was in eastern Kansas and western Missouri, where training thunderstorms along a quasi-stationary frontal boundary dropped more than five inches of rain on already saturated ground (Figure 22). Kansas City reported 5.18 inches of rain for the week and Independence 4.91 inches. A number of other locations in western Missouri reported three to four inches of rain for the period. The heavy rain resulted in urban street flooding in Kansas City and widespread flash flooding.
The cold front finally pushed through the Midwest by the morning of Friday, June 22. High pressure built into the Midwest over the weekend, bringing dry and cooler than normal weather to the region. Late in the month, a slow, westward-moving upper level low pressure system brought scattered showers and thunderstorms to the western and southern portions of the Midwest. Most of this activity occurred in southern Missouri and southern Kentucky, and the storms produced copious amounts of rain in some areas. Showers and thunderstorms were widely scattered to isolated further north into Illinois and Indiana. Temperatures for the period June 20-30 averaged 2-4°F below normal across most of Illinois and Missouri, while they were 2 to 6°F above normal in Minnesota, Wisconsin, and the northern portions of Michigan (Figure 23).