Strong Madden Julian Oscillation Contributes to Inclement Weather in Australia (Credit: BOM and WA News)
DISCUSSION: The Madden Julian Oscillation (MJO) is an area of deep convection that forms along the equator and propagates eastward around the globe. The Australian region is currently experiencing an especially strong convectively-active westerly phase of the MJO. The active MJO phase is termed the westerly phase because a large-scale area of persistent anomalous westerly winds at the surface occur in association with the enhanced convection. The top figure above from the Bureau of Meteorology shows the forecast surface winds valid at 5 am AEDT 5 February 2018 showing westerly winds across and north of the northern part of Australia. The westerly winds help provide moisture to the convection and help drive storm systems and moisture into northwest Australia. One such storm (an ordinary tropical low, not a tropical cyclone) that occurred early last week dumped almost half a meter of rain in 24 hours on Broome, Western Australia. Broome is located near the black dot in the top figure, and the bottom picture from the WA News shows a flooded golf course that resulted from that much rain falling in such a short time. This storm system was also associated with severe winds. Dramatic storm systems like tropical cyclones and blizzards often grab our attention. But, it is important to remember that less dramatic or potentially less publicized weather events can also wreak havoc like this tropical low that was associated with a strong active MJO phase.
To learn more about other high-impact weather events occurring across the South Pacific Ocean and Australia, be sure to click here!
© 2018 Dr. Ken Leppert II