Evolution of Midwest Heat Projected Extended-range

Climate Impact Company U.S. Medium Range Report

Issued: Friday June 6, 2025

Highlight: Evolution of Midwest heat is projected in the extended range.

Chart of the day: Latest U.S. CDD forecast.

Discussion: Somewhat typical of the modern-day climate, the U.S. population weight CDD rides the 10-year normal during meteorological summer.

Medium-range 6-10 Day Forecast Valid June 11-15, 2025 (AI Graph Cast right)

Discussion: The ECM ENS is compared with the AI Graph Cast 6-10-day forecast. The AI GC is a little warmer from the Midwest into the Northeast across the important PJM region. In the West, the core of the anomalous heat shifts inland.

Medium-range 11-15 Day Forecast Valid June 16-20, 2025 (AI Graph Cast right)

Discussion: In the 11-15-day period, AI GC is notably warmer across the Midwest States. A key comparison that requires close monitoring into next week. Note that ECM ENS maintains hot weather in Southern California while AI GC is near normal. Both models agree on the core of U.S. heat shifting to the Central Continental Divide.

U.S. Medium-range Precipitation Forecast

Discussion: Heavy rains suppress anomalous heat risk in Texas and much of the Southeast U.S. in the 6-10-day period. Wet weather shifts into the East in the 11-15-day forecast, a likely favored area for wet weather during summer 2025. The Canadian Prairies gain a wet pattern.

Days 16-20 Extended range Temperature Forecast valid June 21-25, 2025

Discussion: Hot and dry weather is forecast by ECM as calendar summer arrives across Midwest U.S. while wet weather remains over the Gulf States.