AWF Climate Outlook - Spring 2012

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flyfisher
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Joined: Wed Jul 18, 2012 1:39 pm
Location: Belgrave

Re: AWF Climate Outlook - Spring 2012

Post by flyfisher » Fri Jan 18, 2013 8:39 pm

Well - we could not have been more wrong in our predications of how this summer would turn out. The rains and flooding did not occur - quite the opposite.

I have been pouring over the information and charts to determine where it all went wrong. This is my theory....

In spring we had a +IOD and a weak El Nino. Waters NW and NE of Australia were cooler than normal. This allowed significant heating to occur over central Australia with low humidity and little cloud cover. The NW waters did heat up fast, but not enough to effect the atmosphere which lags the ocean by months. The same applies to the Coral sea, which still is slightly cool.

The massive heat low over Australia in turn has an upper level high pressure component - this effected steering of systems around Australia. The anti cyclonic winds in the uppers, which were incredible warm, pushed and is still pushing cyclone and monsoon activity away from the continent. A bit of a feedback loop as it allowed full summer sun to roast the centre. Cyclones sitting in the coral sea, block pacific moisture and continue to cool sea surface temps. Cyclones forming near Australia and moving off into the pacific are never good for our rainfall. The Jet stream is no where to be seen.

As the same time I think the SAM has been contributing to high pressure systems in the Tasman to be at a much higher latitude for summer than we like. So instead of moist SE/NE winds we were getting NW and SW winds. The NW winds dragging the extreme heat down south.

Going forward? It is all starting to break down into a normal summer pattern. The monsoon trough is finally over Australia, cloud is building over the centre. The oceans are mighty warm even with monsoon activity over them. I am not sure about the SAM but the next high pressure system is moving through a much more south latitude giving us easterlies - hopefully turning some fires back on them self and providing higher DP's.

So the potential is there for good rains and the extreme range models keep hinting at such. So we could still get our wet end to summer. The amount of dead plants around we surely need it. I still think we are looking at least weak La Nina conditions this year. For our winter that will mean good rain.

Fingers crossed!

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