February 22-29, 2024

Anomalous February Temperatures

Anomalous warmth gripped the Midwest to round out February. Average temperatures for the week were 10-14°F above normal for areas west of the Mississippi River, 7-11°F above normal across the Great Lakes, and 5-8°F above normal for the Ohio Valley (Figure 1). Iowa and Missouri both had an average temperature for the week that was 8.1°F above normal. This was followed by Illinois at 7.7°F above normal. In Kentucky, the average temperature was 5.3°F above normal for the week, the least anomalous in the region.

Minimum temperatures averaged roughly 4-8°F above normal (Figure 2). London, Ohio had a minimum temperature of 51°F on February 28, which was one of the top 10 warmest February minimum temperatures in London in 97 year of records. In Fremont, Ohio, the minimum temperature was 53°F on February 28, which was one of the top 5 warmest minimum temperatures on record for that station in over 100 years of records. By the end of the period, a sharp late winter cold front came through, and temperatures plummeted. On February 29, International Falls had a minimum temperature of -22°F, which was the second coldest on record for the day.

Maximum temperatures were very anomalous, with Iowa, western Illinois, and northern Missouri averaging 18-20°F above normal (Figure 3). Most of the rest of the region was 10-15°F above normal. Temperatures were already above normal to start the period, with 60s reaching southeast Minnesota on February 22. Temperatures were near or slightly above normal through February 25. On February 26, southerly flow entered the region. Temperatures were reaching the mid-upper 70s in Iowa. Des Moines, Iowa reached 78°F on February 26, which was not only 38°F above normal but also tied the all-time February high temperature record set back in 1930. Moline, Illinois rose to 76°F on February 26, setting the all-time February high temperature record, only to be eclipsed the next day, February 27, when the temperature reached 79°F and set the record again.

In total, there were over 400 daily high temperature records this week alone (Figure 4). Chicago, Illinois reached 71°F on February 26 and 74°F on February 27, which was the first time the temperature reached 70°F or above for consecutive days during February and meteorological winter. In St. Louis, Missouri, the temperature reached 80°F or higher two days in a row from February 26-27 for only the second time in February since 1873. The temperature rose to 86°F on February 27 in St. Louis, which was both the warmest February and wintertime temperature on record. Several spots recorded their first ever 70°F temperatures in February, including Alpena, Michigan; Traverse City, Michigan; Madison, Wisconsin; and Green Bay, Wisconsin. A few spots recorded their first ever 80°F temperature in February, including Springfield, Illinois; Quincy, Illinois; and St. Joseph, Missouri. When temperatures finally came back down, the drop was dramatic—in La Crosse, Wisconsin, the temperature dropped 58°F, the largest 24-hour temperature drop in La Crosse on record.

Precipitation Lacking, but Severe Weather Arrives

Areas west of the Mississippi River received little to no precipitation, with most spots at less than 10 percent of normal precipitation (Figure 5). Heading east, precipitation increased gradually, with Wisconsin, Illinois, and Michigan observing 10-50 percent of normal precipitation, while Indiana, Ohio and Kentucky saw 50-100+ percent of normal precipitation. Some parts of Kentucky received 1.5-2 inches of rain during the week. However, cold air on the back end of an earlier system pushed in fast enough to bring light snow of less than 2 inches to some of Ohio, Indiana and the Chicago area (Figure 6). Fort Wayne, Indiana received 1 inch of snow on February 24, which was more than all of February 2023 when 0.2 inches of snow fell. Even so, February 2024 still ended well below normal, with only 2.7 inches in Fort Wayne as opposed to the normal 5.1 inches.

Severe weather was abundant during the final week of the month. There were over 200 storm reports, 87 of which were hail alone (Figure 7). Preliminary data suggests Michigan may have seen its largest ever February hail report, with a 2.4-inch hailstone falling in the Lansing area. In DuPage County, Illinois, 2.5-inch hail was confirmed via social media.

There were also 33 preliminary tornado reports, most of which were confined to Chicagoland, central Ohio, and southeast Michigan. Several tornadoes reached EF-2 strength, including one in Clark County, Ohio, one in Frankly County, Ohio, and one in Grand Blanc, Michigan. The Grand Blanc tornado was Michigan’s 2nd ever EF-2 tornado in February. In Illinois, there were 11 tornadoes in the Chicagoland area, 6 of which were EF-1 tornadoes, which was the most tornadoes from one single event in February within the National Weather Service’s Chicago forecast area. Ironically, the last February tornadoes in the area were on February 27, 2023, when EF-0 tornadoes were reported in Joliet and Naperville. The strongest tornadoes from this week's system were in Ohio, where two EF-2 tornadoes were reported.

Drought Monitor

Drought slightly expanded, with D1 conditions now covering much of eastern Missouri, Wisconsin, and a third of the Midwest as a whole (Figure 8). Abnormally dry conditions were reintroduced to much of Illinois. D3 conditions persisted in much of Iowa.