The Climate Prediction Center outlook is calling for a warmer, slightly wetter summer around Indiana, with the wetter signal in southern Indiana giving way to equal chances for above normal, normal, or below normal precipitation in northern Indiana. The cause for the outlook is mainly climate trends persisting into the season, as the El Niño Southern Oscillation (ENSO) begins the summer in a neutral pattern. Despite the slight signal for wetter conditions in southern Indiana, the possibility for flash droughts is high across Indiana based on patterns shown in the last few years.
The warmer outlook for Indiana is quantified at an anomaly of 0.25 degrees Fahrenheit. The odds of having the hottest summer on record is rather low, despite the tendency to sensationalize extreme model runs well before the season starts. Looking back across the seasonal outlook verification record, almost every season calls for warmer temperatures than the 30-year average, and this verifies frequently. We can anticipate this trend continuing in future seasons.
The ENSO signal drives a lot of climate outlooks when in the El Niño or La Niña phase of the cycle. The ENSO-neutral phase does not lend itself as a strong predictor in Indiana during the summer. We do anticipate a quick switch to the La Niña phase this summer, which may influence conditions by the end of summer. Particularly in August, the warm and wet signal may strengthen due to this ENSO phase.
Since 2021, the tendency during the growing season to see periods of drought bookended by intense, multi-inch precipitation events have increased. The likelihood of this to continue or intensify is high in this and future years. For that reason, coupled with the warmer than average prediction, the possibility for flash droughts still exists this year. “Flash drought” is a term that is often discouraged in some sectors of the climate science community; some prefer the phrase “rapid intensification of drought” instead. Truly, “rapid intensification of drought impacts” is more realistic, but the length of the phrase then lends itself to further expansion into “rapid intensification of drought impacts cumulatively understood to leverage overuse of unusual systems.” It’s an acronym.
The hurricane season is expected to be more active than normal this year, which increases possibilities for tropical depressions to drop more rain in Indiana. Meanwhile, the seasonal drought outlook is calling for development of drought in the Pacific Northwest and Southwest, which may be of little concern for Indiana unless that development is more widespread and blocks some synoptic events from bringing in the moisture needed for a summer rain.
For more information, please contact the Indiana State Climate Office at 765-494-8060 or hschmitz@purdue.edu.