On April 30, 2020, the national Climate Prediction Center released its monthly outlook for May (Figure 1). There is slight confidence that temperatures will be below normal and the northern half of Indiana will be drier than normal. The probabilities are only slightly significant, so there could be a lot of variability throughout the month. The 8-to-14-day outlook (representing May 7 – 13, 2020) indicates a very strong probability of below normal temperatures, so after a brief warming over the next week, expect temperatures to become unseasonably cooler. With each day that passes, the climatological risk of freezing temperatures decreases so hopefully cooler temperatures will only result is reduced evapotranspiration rates and accumulated growing degree days. Speaking of growing degree days, the modified growing degree days (50F/86F) are running about 30 to 70 units below normal across the state with the greatest departures to the south (Figure 2 and 3).
Figure 1. Climate outlooks of temperature (left) and precipitation (right) for May in the probabilistic confidence of having above- or below-normal conditions over the month.
Figure 2. Modified growing degree day accumulations from April 1-29, 2020.
Figure 3. Modified growing degree day accumulation for April 1-29 by year for 2016 through 2020.
