Potential Excessive Rainfall Pattern for Mid-Atlantic into Early October

Climate Impact Company U.S. Medium Range Report

Issued: Thursday September 25, 2025

Highlight: Very warm forecast continues; Heavy rain suppresses warmth in the Mid-Atlantic States.

Chart of the day: ALERT…Dangerous flooding rainfall in the East!

Discussion: ECMWF forecasts heavy rain effects from Imelda early next week followed by a second event in the 11-15-day period. Each event combines for widespread flooding risk in the 15-day forecast.

Medium-range 6-10 Day Forecast Valid September 30-October 4, 2025 (ECM OP right)

Discussion: Becoming the primary focus of the 6-10-day period is the potential heavy rain in the Mid-Atlantic region which causes cooler changes. The ECM OP rainfall forecast is used in today’s outlook (below) therefore also used as the alternative temperature outlook.

Medium-range 11-15 Day Forecast Valid October 5-9, 2025 (ECM OP right)

Discussion: ECM OP indicates a potential second heavy rain event in the Mid-Atlantic region suppressing temperature in that region. Elsewhere, the broad extraordinary warm pattern continues during early October.

U.S. Medium-range Precipitation Forecast

Discussion: ECM OP indicates prohibitive rainfall in the Mid-Atlantic region centered on Virginia during the medium range. Western wet weather in the 6-10-day period shifts to the Central Rockies in the 11-15-day forecast.

Days 16-20 Extended range Temperature Forecast valid October 10-14, 2025

Discussion: The warm pattern continues in the extended range with new wet weather risk possibly associated with a tropical cyclone across the Southeast U.S. and Florida.