Welcome back to the Long Range Snow Center. We are finally going to work out the season using all the different factors. The last two outlooks I have posted for Australia have been from seasonal models, but this time we are going to look at it from a climate factors perspective.
Firstly the ten year average of the Spencer’s Creek maximum snow depth is 173cm. We are going to base our calculations off this number.
Climate ChangeI am going to shed off 1cm for every year in the 10 year average, so 173-10 = 163cm
SunspotsThere is a weak correlation between a higher amount of sunspots and more snow, as found by Francisco Sánchez-Bayo and Ken Green. We are heading towards a solar minimum, so I am going to cut off 2cm. 163-2 = 161cm
PDO There is a weak correlation between a positive PDO and low rainfall in our region. This reduces moisture for snowfall, supported by this graph created by Gerg. We are currently in a positive PDO phase, so I am going to shave off two more centimetres. 161-2 = 159cm
SAM There is a fairly strong correlation between negative SAM and more snowfall for the Alps. I talked about the seasonal prediction of SAM here. El Niño Modoki (the only seasonal prediction factor of SAM) is at a Neutral phase, so no effect on SAM, but it may go towards the warm phase during the season. Adding in climate change(that increases chance of positive SAM), I am going to cut off 5cm. 159-5 = 154cm.
IOD There is a strong correlation between the Australian snowfall and the IOD. There is a Positive IOD forecast for this winter. This is determental for our snow. I am going to shave off another 5cm. 154-5 = 149cm
ENSO There is a correlation between ENSO and Australian snowfall. The current model predictions show Borderline El Niño, but this chart indicates weakening El Niño conditions and the atmosphere doesn’t look very El Niño like, with strong trade winds. Given this, I predict roughly Neutral conditions for a Canonical ENSO, with limited potential for a El Niño Modoki warm Neutral event, as suggested by JMA modelling. This in turn may help a negative SAM. I won’t remove or add snow depth to the prediction, as ENSO should be Neutral this snow season. 149-0 = 149cm
MJO Australian snowfall and MJO have a very strong correlation. There’s been work done on the relationship between ENSO and OLR anomalies (related to MJO). An interesting article here. OLR anomaly forecasts are not usually given to the public. There is a 200hPa CHI anomaly forecast from CFS on Tropical Tidbits. It suggests negative anomalies (good for snow) above Australia in July and August. This would increase moisture for Australian snowfall. I am going to add on 5cm for this. 149+5 = 154cm.
SST anomalies in the Bight I assessed these SSTAs in this post. Based on current charts, the Bight is forecast to be cooler than normal this winter. Because of the strong correlation between SSTAs in the Bight and Australian snowfall, I will add 10cm on to the forecast. 154+10 = 164cm.
Volcanoes If a large stratospheric volcano explosion occurs, Australian snowfall substantially increases for that winter. None have occurred in the last year, so our forecast won’t be affected. 164-0 = 164cm
So my prediction for the Spencer’s Creek maximum snow depth for Season 2017 is 164cm. So it will be a roughly average year, based on current snow conditions. Thank you for reading this. Remember seasonal prediction isn’t an very accurate tool, so be careful when basing any major decision on any seasonal forecast, including my own.