July 2019
Monthly Overview - July 2019
Summer Heat
Widespread heat and an intense heat wave led to above normal temperatures for almost all the Midwest in July despite cooler temperatures to end the month
(Figure 1). Regionwide, temperatures were 74.4 °F which was 1.7°F above normal. Some of the warmest areas were across Ohio, northern Illinois and southern Wisconsin. Minimum temperatures were very warm across the region (Figure 2). Parts of Wisconsin, northern Illinois and Ohio had minimum temperatures 3-5°F above normal for the month. Of the more than 400 daily high temperature records broken or tied in the region, more than 370 were for high minimum temperatures
(Figure 3).
Wetter and Drier Areas
Precipitation followed two main storm tracks across Minnesota and Wisconsin and across the southern Midwest during July (Figure 4). Regionwide precipitation was 4.07 inches (103.3 mm) which was near the normal of 4.06 inches (103.1 mm). Heavy rain from storms during the middle of the month in central Wisconsin and southern Minnesota led to 125-150 percent of the normal amount of rainfall for the month
(Figure 5). A few areas in the Missouri Bootheel and southwestern Minnesota had more than twice the normal amount for the month. Heavy precipitation was common when it fell across the region. More than 300 daily precipitation records were broken in July (Figure 6), with more than 40 records in Minnesota, Wisconsin and Missouri each. Drier areas evened out regionwide precipitation across the central Midwest. Portions of Iowa and Illinois had less than half the normal amount for July.
July 18-21 Heat Wave
A heat wave from July 18-21 led the National Weather Service to issue Excessive Heat Warnings across a large portion of the Midwest. Heat index values of 115 °F and higher were reported in Illinois, Iowa, Minnesota and Wisconsin, with widespread values over 100 °F
(Figure 7). Several of the locations with a heat index at or above 115 °F included Minneapolis, MN, La Crosse, WI and Joliet, IL. Two deaths were reported in Chicago, IL related to the heat.
Drought-Free Period Reaches 7 Months
As of the July 30th U.S. Drought Monitor, the Midwest reached its 31st consecutive week without drought (Figure 8). The streak of drought-free conditions began on January 1, 2019. This more than doubled the previous record streak of 14-week weeks from January 5-April 5, 2016 since the inception of the U.S. Drought Monitor in January 2000. However, a dry month of July aided in the development of abnormally dry conditions across southeastern Iowa, northwestern Illinois and several other areas in the Midwest. Soil moisture in these areas decreased significantly from the heat and lack of rainfall in these areas
(Figure 9). The effects of the dryness on agriculture were being felt from previous impacts of a wet spring. Soil compaction led to poorer root systems for corn and soybeans and increased their susceptibility to dryness and drought.
Active Severe Weather
Severe weather was active across the Midwest in July as more than 1,100 reports of wind, hail and tornadoes were recorded (Figure 10). More than 900 of these storm reports were for thunderstorm wind gusts. Gusts of 75-85 miles per hour were reports at several locations. The strongest gust reported near Plover, WI was 86 miles per hour on July 20. Two people were also injured near Galesville, WI from severe winds. Of the reported tornadoes across the region, most were weak EF-0 or EF-1 tornadoes.
-BJP-