ECM projects the Greenland Block to continue and finally produce cool troughs into the Ohio Valley/Mid-Atlantic States and Northwest Eurasia late this month into early November. Expect a cooler U.S. pattern especially in the East, as November approaches.

So far, the Caribbean Sea has not observed a tropical cyclone in 2025 while only 1 tropical cyclone formed in the Gulf of Mexico. The last time each basin was inactive to this extreme were during strong El Nino years (1997, no activity in The Caribbean and 2015, 1 tropical cyclone in the Gulf of Mexico). Part of the explanation is the mid-troposphere anomalous dry air strongly identified in the Caribbean Sea since June.

The convection phase of the Madden Julian oscillation (MJO) is alive shifting eastward across the East Pacific tropics to tropical Africa and eventually western tropical Indian Ocean during the next 2 weeks. Intensity is marginal although ECM indicates weak-to-moderate intensity. Usually, an MJO shift through phase_1/phase_2 increases risk of hot and dry weather in Australia and a wetter regime for South America.

The ECM/ECM ENS continue a wet forecast bias across northwest South America, much of Brazil, and Uruguay during the past 30 days for all 15-day forecasts. This wet bias increases during the medium (6-10-day) and extended (11-15-day) range. The GFS/GFS ENS has a dry bias for West Brazil and Paraguay/Southeast Brazil.