An eastward shift of the convection phase of the Madden Julian oscillation (MJO) is forecast by all operational models. The MJO was semi-permanent in the tropical Indian Ocean to Maritime Continent since early August. The eastern shift is across the tropical East Pacific and Atlantic to West Africa through the next 2-3 weeks activating tropical cyclone activity in each ocean basin.

AIFS indicates potential for a developing tropical cyclone late in the 1-5-day period in the west-central Caribbean Sea. In the 6-10-day period, there is the likelihood of a hurricane developing in the Gulf of Mexico. The hurricane is likely to turn northeastward into the northeastern Gulf of Mexico and the Southeast U.S. early in the 11-15-day period.

The Climate Impact Company initial U.S. gas population weight heating degree day forecast for the 2024-25 cold season is issued. Most striking is the warm mid-winter forecast as national HDD falls well below the 30-year and 10-year climatology. The DEC-24 and FEB-25 forecasts are each close to the (warm) 10-year normal.

The Nino34 SSTA is trending toward the La Nina threshold and subsurface waters of the central/eastern equatorial Pacific are cooling foreshadowing a stronger La Nina ahead as agreed upon by most dynamic ENSO forecast models and Climate Impact Company constructed analog forecasts.

A historic early-to-mid September heavy rain episode across East and Southeast Europe continues. The focus of this week's rain shifts to the west coast of Southeast Europe. Later this month more widespread rains are likely across the northern half of Europe.

Small but potent upper trough brings an unusually chilly air mass to Southeast Australia on Sunday producing exceptional cold mornings on Sunday and Monday. GFS indicates <32F/0C risk into North-central New South Wales Sunday morning with -5C across the interior southeast including northeastern Victoria. On Monday morning, the cold regenerates and extends northward to near the Queensland/New South Wales border just inland from the coast.