Above-Normal Temperatures Dominate

Strong upper-level ridging dominated the Midwest through most of the week, which contributed to above-normal temperatures across the region (Figure 1). The greatest temperature departures occurred in Minnesota and Wisconsin, as these areas recorded temperatures between 9-15°F above normal. Statewide, Minnesota and Wisconsin averaged 10.6°F and 8.7°F above normal, respectively. Warren WSD, located in Marshall County, Minnesota, averaged 16.1°F above normal and topped the chart for temperature departures this week. Maximum (Figure 2) and minimum (Figure 3) temperatures followed similar patterns, but portions of the eastern Midwest saw minimum temperatures that were 1-3°F below normal. As the week progressed, an upper-level trough began to build and allowed a lower-level cold front to develop and pass through the eastern Midwest between June 5-7. As a result, eastern Midwest temperatures averaged 1-5°F below normal to round out the week. There were 406 preliminary daily high maximum and minimum temperature records broken or tied across the Midwest this week (Figure 4).

Below-Normal Precipitation Continues

Rain was hyper-localized as limited forcing and moisture was available for widespread precipitation events. The highest rain totals occurred in the western Midwest (Figure 5), but nearly the entire region saw precipitation that was 0.5-1.2 inches below normal (Figure 6) or 0-75 percent of normal (Figure 7) for the week. Only central Iowa and northwestern Minnesota saw precipitation greater than 100 percent of normal. Madison County, Iowa measured 3.38 inches for the week (3.19 inches fell on June 1). Roseau County, Minnesota recorded 4.59 inches this week (2.98 inches on June 5). Meanwhile, stations in Illinois, Indiana, Ohio, and Kentucky have not received precipitation in more than 15 days and in some cases more than 20 days. As of June 7, Galesburg and Knoxville, Illinois went 24 consecutive days without rain.

Rapidly Drying Conditions

The lack of precipitation, combined with above-normal temperatures, abundant sunshine, and low humidity, has contributed to rapid drying across the Midwest. The June 6 US Drought Monitor had nearly 85 percent of the Midwest rated in D0 (Abnormally Dry), D1 (Moderate Drought), D2 (Severe Drought), or D3 (Extreme Drought), which was almost a 20 percent increase from the previous week (Figure 8). Expansion of D0 and D1 categories occurred in most of the Midwestern states. D2 was introduced in northeast Iowa this week. Impacts ranged from pond water levels dropping, dormant grass, reduced hay quality, and stressed crops. Streamflows were also dramatically reduced across the Midwest as many gauges reported low, much-below-normal, and below-normal conditions (Figure 9).

Sporadic Storm Reports

Accompanied with the hyper-localized precipitation, there were preliminary storm reports every day this week. There was 1 tornado, 12 hail, and 40 wind preliminary storm reports this week (Figure 10). There was a brief landspout reported on June 1 in Walworth, Wisconsin. A 64-mph gust occurred at the Kirksville Regional Airport on June 2. Henderson, IL reported crop damage as a result of hail on June 4.

Poor Air Quality

Canadian wildfires continued this week resulting in widespread air quality alerts. The US Air Quality Index exceeded 101, which impacts sensitive groups, in Midwest locations nearly every day this week. Smoke was visible at times, but did not look as ominous as the pictures out of New York City on June 7. At times, the Air Quality Index exceeded unhealthy levels. The Air Quality Index for June 7 was worst in the eastern Midwest extending to the east coast (Figure 11).