Last week southern oscillation index returned to weak positive phase and trade winds off the northwest coast of South America also returned. As a result, the increased trade winds up-welled cool waters to cause all Nino SSTA regions to fall to within La Nina thresholds. However, the subsurface at 75+ meters continue to warm and subsurface cool water supply to sustain La Nina is steadily losing amplitude.

A titanic blocking high-pressure ridge south-southeast of Australia during the past 5+ days forced a deep upper trough to form along the southern Australia Coast this past weekend and into this week. Tropical moisture entrained into the upper trough from a warmer-than-normal water surface north and northeast of the continent lead to the 60-year flooding episode in Sydney and surrounding areas.

Heavy rains have caused widespread flooding across New South Wales this weekend due to a moist onshore tropical flow into a low-pressure trough made more intense by a blocking high-pressure area to the south. A low-pressure area has formed along the low-pressure trough in far northwest New South Wales.

NOAA/CPC is indicating a fairly robust stratospheric warming event centered on the U.S. East Coast at the end of March. Although not in the ideal polar location, the event would be enough to cause the troposphere below to cool.