El Niño held at alert status as warmer conditions arrive

Australian Community Media

Below-average rainfall, with warmer, dryer conditions forecast for the remainder of year. Global sea temperatures have been high since May, breaking records each month.

Transcript

00:00 past month we've seen below average rainfall across much of Australia. It is

00:05 important though that it is still raining. We still have good water

00:08 storages across most of the country and some of our river systems have still got

00:12 reasonable flow, notably the Murray itself which has got good flows

00:17 downstream, even potential flooding should more rain occur. Having

00:23 said that, the long-range outlook out to October is for warmer and drier

00:27 conditions and that's been consistent now for a couple of months. We are seeing

00:32 things starting to warm up across Australia, so Tasmania just recorded its

00:36 warmest July on record and we're seeing generally above average temperatures

00:40 particularly in the southern capitals over the past four weeks. In terms of El

00:46 Nino, the Bureau continues to hold El Nino at alert status so we haven't

00:50 declared an event yet and that is largely due to the fact that the

00:54 atmosphere hasn't quite coupled or reinforced the pattern that we see in

00:58 the ocean that's typical of an El Nino event. So conditions are still neutral in

01:03 the atmosphere and we'll wait for those conditions to lock in before we declare

01:07 an event but it should be noted that when we go to an alert historically an

01:11 El Nino event does develop about 70% of the time. In terms of an event

01:17 declaration or not, it's important to kind of ask ourselves why we want to

01:20 know that. Largely the Bureau's dynamical model, so our forecast model, goes out for

01:25 three months so to the end of October and that's forecasting dry and

01:29 warmer conditions. Should an event lock in, an El Nino event, then that gives us a

01:33 bit more predictability over the summer for a dry and quite warm summer

01:39 period. So that's the reason that we're monitoring El Nino going forward. I'd

01:45 also just like to quickly note on some of the global conditions that we're

01:49 seeing. So obviously we've had a very warm July and there's been quite a lot

01:53 of press on that. July looks like it will be the hottest month recorded globally.

01:57 Sea surface temperatures, so the global oceans, have been warm now since May and

02:03 they've been setting records for each of those months. That very warm ocean

02:07 everywhere, including the tropical Atlantic and the tropical Pacific, is

02:11 possibly affecting the atmospheric response to El Nino. So normally we like

02:16 to see temperature gradients set up in the ocean. We're not seeing that at

02:20 this stage to the degree that we'd like. So historically we haven't seen

02:26 situation like this before where we're going into an El Nino event with record

02:29 global ocean temperatures. Following a typical El Nino cycle we would expect

02:34 those temperatures to keep warming now until the middle of next year. One of the

02:39 impacts of that warming has been a reduction in the growth of the Antarctic

02:42 sea ice. So sea ice is at its lowest extent for this time of year ever,

02:48 going from the satellite record back to the late 1970s. So it's still growing and

02:54 normally it grows up until mid-spring, the sea ice around Antarctica, but it's

02:59 growing at a much slower rate. So we're missing a chunk of ice about the size of

03:05 Western Australia at the moment. So it is quite a notable impact on the southern

03:10 hemisphere's climate system.

03:13 [BLANK_AUDIO]

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