it’s the beginning of the month and that’s the time when models issue their longer term outlook. For us that means we’re looking under the Pacific – and right now we can see a warm tongue starting to move east:
When it reaches South America it will likely surface and the start to move west at the surface. This is how models see it happening between now and June 2023:
This matches the GFS model fairly closely, so there is decent confidence in the event playing out as forecast:
That has all the finger prints of an incoming El Nino – and that can make for a big change in rainfalls across our region. Warm wet air rises – so where it’s warm on the ocean right now (close to Aus) the air will rise, and where it is cooler (closer to South America) it will sink…so we see increased rain, and they see much drier conditions. By June that pattern has swapped around with the warmer ocean close to South America…which greatly increases the chances of drier conditions for us. This is how the models see the change in rainfall across the Pacific over the same period:
On a local scale you can see the higher chances of wet early on before it switches to drier as we head into winter:
Note that the change from one pattern to another doesn’t guarantee wet or dry – it simply increases the chances of it ending up one way or the other. It’s possible to get flooding rains in El Nino and dry spells through La Nina – and we have the fly in the ointment that is the Tongan volcano eruption and how the ongoing effects will play out…but for now it’s worth being aware of the larger pattern changes that are likely to take place.
Thanks as always to Kombu and Snapfrozen for sponsoring this site, and to Meteologix and NOAA for the images.