RI (rapid intensification) is defined as a tropical cyclone gaining more than 35 mph in top wind speed within 24 hours. On the weekend, an upper-level high pressure builds east-northeast of Melissa forcing a discernable northwest steering current. During this time, upper-level shear eases. As Melissa moves northwest in an improving environment, the storm is better able to intensify rapidly moving across 30-31C surface water and the 3rd warmest upper ocean heat content on record for the Caribbean Sea.

One cold front has plowed into Northeast Brazil this week and another stronger front shifts across Argentina late week/early weekend. The second front delivers a widespread cool air mass for next week across Argentina. The supporting upper trough cuts off over central South America in early November to deliver wet weather to the Brazil drought zone.

The Madden Julian oscillation (MJO) remains active. The eastward shifting MJO in the tropical Indian Ocean (phase_3) to the Maritime Continent (phase_5) over the next 2 weeks will influence climate Australia and South America plus the West Pacific tropics to the U.S.

The NOAA/CPC meteorological winter 2025-26 forecast is cold and snowy across the northern states from Washington to Michigan while the Ohio Valley turns stormy likely favoring snow. The southern tier of the U.S. is dry and warm.