Great Rain…but now what?

Some great rain last night – at least enough to reduce the fire risk in the short term across our area. Much less rain inland however and numerous lightning strikes did start new fires. According to the RFS update on our local (Bees Nest) fire: “Storm cells moved across the fireground yesterday afternoon. Lightning strikes were detected across the area and a number of new fires have been reported. Make sure you report any unattended fires to Triple Zero (000) immediately. Although there was some rainfall across the fireground it has not been enough to extinguish the fire.”

Here’s the totals according to BoM gauges – you can see the (well forecast) good totals across our region:

One BIG reason why we’ve seen an increase in humidity and rain close to the coast is because the Southern Oscillation has gone positive. Here’s where it sits at the moment (with the forecast for the week ahead):

You can clearly see where it went negative in July – the start of the big dry for us near the coast – and remained that way until yesterday. Positive on this index means the high pressure cells are further south – letting onshore winds and higher humidity levels move in across our region. It’s forecast to stay positive for at least the next week, which means more likelyhood of onshore winds and the risk of showers. There has been a LOT of discussion about the Sudden Stratospheric Warming that took place at the south pole over the last month. The following chart shows the temperatures (top chart) and temperature anomolies (bottom chart) above the south pole – pretty dramatic:

We would usually expect to see one significant impact from this event – the development of a strongly negative Southern Oscillation – which means high pressure cells a lot further north and westerly winds blasting across our region. So far we’ve been blessed with that not eventuating – but these events last over months rather than days, so there is still the potential for that to happen over the next couple of months. If it does we will quickly see a return of fire weather…so something I’ll keep a close eye on over the next couple of months. Meanwhile for the inland – they’ll likely need to wait for the Indian Ocean patterns to change before they see much rain – and that is likely some time away.

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