Have you ever heard of the song by Glenn Frey, “The Heat Is On”? No pun intended, but the heat is certainly on! Heat index values over 110F have made things sticky and oppressive across the state. As I drove into work on Thursday morning, the humidity was so high that I had to defrost my windows repeatedly. Fortunately, this heat and humidity will be short-lived as temperatures and humidity levels return to near normal by Saturday. Over the last 30 days (July 24 to August 23), temperatures have been normal, or more precisely, 0.2F above normal (Figure 1). The cool start to August and the current warm temperatures have balanced average temperatures out a bit for the last 30 days. Modified Growing Degree Days (MGDDs) have accumulated between 1600 and 2900 units across the state, which are near to slightly below normal (Figure 2).
Figure 1. Climate Division data by state, between July 24 and August 23, 2023, which includes observed temperature and precipitation, normal temperature and precipitation, temperature deviation from normal and percent of normal precipitation.
Figure 2. Total Accumulated Indiana Modified Growing Degree Days (MGDDs) April 1-August 23, 2023 (left) and Total Accumulated MGDDs represented as the departure from the 1991-2020 climatological normal (right).
The state average precipitation total was 4.79 inches (July 24 to August 23), which was 0.98 inches above normal, or 126 percent of normal. The uptick in precipitation has greened up the landscape, and drought conditions have dramatically improved across the state. Actually, I have had to mow my lawn a couple times a week for the last few weeks, and I’m kind of tired of mowing at this point. Usually, things begin to dry out in August, and weekly mowing suffices. The August 22 US Drought Monitor continued with a no-drought status but does have three areas of abnormally dry (D0) conditions in the state (Figure 3). The heaviest precipitation fell in northwestern Indiana as local amounts reached up to 7 inches, which was between 150 and 175 percent of normal (Figure 4). Southwestern Indiana also had precipitation measuring between 5 and 6 inches.
Figure 3. August 22, 2023, US Drought Monitor. The US Drought Monitor is released every Thursday morning by 8:30 AM.
Figure 4. Observed precipitation (left) and percent of mean precipitation (right) for July 24-August 23, 2023.
Shifting to the climate outlooks, the Climate Prediction Center (CPC) has elevated chances of below-normal temperatures between August 29 and September 2 (Figure 5). Higher confidence in below-normal precipitation is also noted in the 6–10-day outlook. The 8-14-day outlook has elevated chances for above-normal temperatures and below-normal precipitation, so there is hope for slowed lawn growth over the coming weeks. Hooray to mowing the lawn less frequently, and this shift should help begin the dry-down process for corn and soybeans. The new seasonal outlooks do not have a firm grasp on what will happen with temperature and precipitation this fall, as the CPC has equal chances of above-normal and below-normal precipitation. Only time will tell!
Figure 5. CPC 6-10 day temperature and precipitation outlooks for the United States, valid August 29-September 2, 2023 (top). CPC 8-14 day temperature and precipitation outlooks for the United States, valid August 31-September 6, 2023 (bottom).