Negative Indian Ocean dipole (-IOD) contributes to Central and East Australia rainfall during winter and spring while La Nina biases eastern continent wet. Both climate signals emphasize a wet bias to Australia climate and diminish dry risk. The -IOD regime is well established while borderline weak La Nina is present but without a clear atmospheric response. Consequently, the anticipated wet climate for early spring is patchy, based on September rainfall terciles. Note the dryness in key Australia crop areas in Victoria and eastward.

Since last month, it’s getting more difficult to make the case for significant cold this winter season. The November forecast edges warmer, and DEC/JAN is already warm. FEB cold risk remains but confidence is lower. MAR chill remains in the forecast. Forecast models are warm. Mid-latitude oceans are warm. The orientation of mid-latitude SSTA supporting cold weather in North America this winter season showed potential one month ago but are eroding since that time.

Major Hurricane Humberto disrupts steering currents associated with the North Atlantic subtropical ridge tomorrow enabling westerly flow aloft to turn both Humberto and Imelda northeastward away from the U.S. East Coast. Tropical storm force winds affect Bermuda from outer bands of Humberto tomorrow and again later this week as Imelda passes.

The late summer season drought in the Midwest States is strengthening. Dry-to-drought conditions have also developed and are intensifying in the Gulf Coast and Northeast regions. The late summer new drought generation has caused a shift in U.S. regions observing drought from 45% in mid-August to nearly 70% during late September.