After a challenging start to the 2019 growing season, September precipitation patterns split the state with repeated heavy rainfall in northern Illinois, while south of I-72 saw less than half of normal rainfall. Temperatures were above average allowing for the crucial accumulation of growing day units late in the season before the first frost. Cold weather is coming behind a powerful winter storm on Oct. 10-13 that will likely bring frost to the northern parts of Illinois, but the biggest challenge through October might be frequent rainfall.
Keep a close eye on the Pacific Ocean this fall as a “Modoki” EL Niño sets up with cool water off South America, but warm water in the central Pacific. This, combined with a warm north Pacific Ocean and the strongest positive Indian Ocean Dipole in recent years will likely produce a strong subtropical jet stream. If these features dominate the flow of the atmosphere, expect a very active and potentially wet start to winter for Illinois farms in November and December.