The graphics and statistical information on this page fill gradually as they become available, with some not available until the next day.
The page is updated every 30 minutes at about 20 and 50 minutes past the hour.
For weather news as it breaks that is tagged and organised, use the links on the Weather and Climate Media Reports page.
What's in store for the 2017 snow season?
Forecasting what the snow season will be like over the next three or four months is like forecasting fairly precisely how much rain will fall in the NSW Snowy Mountains and VIC Alps next summer. Snow is, after all, just a frozen version of rain and behaves in exactly the same way. To get a handle on what the probabilities are, however, is something we can tackle.
Ben Domensino wrote a useful piece in Weatherzone News on Will we have a good snow season this year? He gave a good rundown on influencing drivers and statistical chances without either giving a forecast or probability expectations, but it was very good as a broad primer.
On Tuesday, Gerg of Gerg's Net put his neck on the line, crunched the probabilities and came up with an estimated peak of 163 ± 44cm at Spencers Creek. He did this using a scientifically valid model he has been developing for over a decade. It is based on applying various weightings to forecasts of the winter means of all medium to long term climatic influences that drive the local atmosphere. These are the Antarctic Oscillation, Southern Oscillation Index, Indian Ocean Dipole, Pacific Decadal Oscillation, sea surface temperatures and a measure of volcanic aerosols. He explains it and his rational for the 2017 forecast here, and about a week ago he did an analysis of the 2016 season and how well his forecast for that performed here. Details of his current Spencers Creek maximum snow depth prediction model are here.
If you're not familiar with his site, the posts are usually accompanied by a profusion of well-explained graphs. It helps if you have some basic knowledge of statistics to fully understand these, but they are quite meaningful even if your stats is rusty or non-existent. This is, however, the most detailed information on Snowy Mountain snow depth available, with an occasional reference to the VIC Alps which, unfortunately, do not have the length of record of snow depths that the Snowies has.
Australian weather briefs
- While April was a month of very mixed rainfall across the country, some of the record-breaking April rain fell where it was needed. Victoria in particular benefited, with farmers in the west delighted with the timing of the break [Wimmera Mail-Times]. The month was the wettest April on record around Castlemaine and Daylesford [Bendigo Advertiser] and close to the highest across much of southwestern VIC [The Standard].
- With the Wet Season ending on 30 April, pastoralists in the Northern Territory are describing as "magnificent" the rain that produced the third-wettest "Wet" on record in the NT [ABC News]. One producer, Tom Stockwell from Sunday Creek station near Daly Waters, said "It has been a wonderful season for cattle production. It hasn't been overly wet so the cattle have kept going all wet season really, so it should be a bumper year in terms of productivity." The BoM put this handy map of NT rainfall percentage of average for the season up on Twitter.
- A cold change on Tuesday morning that was widely tipped to bring snow to lower levels in TAS failed to deliver. Some small hail was reported on the Central Highlands, while both Kunanyi (Mount Wellington) and Cradle Mountain had a light dusting at their higher levels. Nothing remotely like snow reached the mainland Alps.
"The Arctic is unravelling" before our very eyes
The accelerating break-up of Arctic ice bodes ill for all Arctic ecosystems, including the indigenous ones there, but is also a grim portent of much more at stake.
Yet another month has passed with record low ice cover [Climate Central], April 2017 tying with April 2016 for the lowest on record by far. Temperatures in parts of the Arctic averaged 8°C above normal for the month, though had been up to 27°C above normal at times during the winter. Through April, the Arctic had just over one million square kilometres of ice less than normal.
Perhaps even more important, of the remaining ice, only 5% is now made up of thicker ice more than five years old compared to 30% in 1984. Younger ice is more susceptible to melting in warmer air or sea currents, and has more chance of being broken up by storms. The less ice there is, and the younger it is, the faster it goes.
The consequences of the warming of the Arctic more than twice as fast as the rest of the planet are detailed in a report compiled by over 90 scientists, Snow, Water, Ice and Permafrost. Summary for Policy-makers, reported in Scientific American. From 2011 to 2015, the Arctic was warmer than at any time since records began around 1900. Not only is sea ice melting rapidly, but snow cover in June across Arctic land areas of North America and Eurasia is half that of observations before 2000. It is boosting sea level rise through hastening the melting of glaciers, in addition to shifting ecosystems and weather patterns. Warming of the Arctic tundras releases huge amounts of methane, a more potent greenhouse gas than carbon dioxide. Feedback loops are set up accelerating, not only the loss of sea ice, but melting of tundra and glaciers.
Morten Skovgård Olsen, who coordinated the assessment and leads the Danish Ministry of Energy, Utilities and Climate’s Arctic programme, says "The Arctic that you will have by mid-century will be very different from the Arctic that we see today." Rafe Pomerance, who chairs a network of conservation groups called Arctic 21, adds "The take-home message is that the Arctic is unravelling. The fate of the Arctic has to be moved out of the world of scientific observation and into the world of government policy."