Lake Winnipeg melt-out and possible correlation with melting seasons

[bbr2315]

I think this thread (?) is the place for the below analysis, but correct me if I am wrong, Oren. I noticed Lake Winnipeg appears to be an epicenter for the impending cold across North America, and this caused me to go back through recent satellite data to report on melt date for the lake each year.

I used EOSDIS for the analysis. I consider 90%+ melt to be "melt date".

2019: 5/24
2018: 5/28
2017: 5/20
2016: 5/9
2015: 5/18
2014: 6/3
2013: 5/31
2012: 5/5
2011: 5/24
2010: 5/3
2009: 5/28
2008: 5/26
2007: 5/13
2006: 5/2
2005: 5/10
2004: 5/31
2003: 5/17
2002: 5/31
2001: 5/17
2000: 5/6

In the above group, the "early" stand-outs (before 5/10) are 2000, 2006, 2010, 2012, and 2016. The "late" stand-outs (5/25+) are 2002, 2004, 2008, 2009, 2013, 2014, and 2018.

Comparing the ensuing contrast between June, July, and August in those years, there are a few apparent differences that this indicator could be helpful in predicting.

1) In the late-melt years, the cold in Jun-August was focused in North America, with some spillage into Eurasia. In the early-melt years, cold was focused in the eastern Pacific, and it appears this resulted in much more advection / heat over North America.

2) Both early and late melt years featured hot Junes over Central / Northern Siberia. The late melt years featured more summertime heat focused over Scandinavia and the Barents, the early melt years featured more summertime heat over Western Russia.

3) June in early-melt years featured -500MB anomalies centered over the Arctic, with minor centers in the Barents and Hudson. June in late-melt years featured -500MB anomalies split between the Canadian Maritimes and Western Russia.

4) July-August in early-melt years feature a strong -500MB anomaly over the Kara / Barents, and strong +500MB anomalies over the Baffin / Greenland. July-August in late-melt years feature weak -500MB anomalies in the Okhotsk, CAA, North America, and the UK, with more tempered positive anomalies focused on the CAA, and stretching from Scandinavia into the Barents.

Thus, it appears that this metric has some predictive value for the ensuing summertime.

Current modeling portends the possibility of a very late melt-out of Lake Winnipeg. If past years are any indicator, this would signal a weak PV this summertime, with significant ridging extending from Scandinavia into the Barents and CAB come July-August. This would also be accompanied by continued relative cold into North America. Such a scenario could also portend warmth in June focused in the same region (Scandinavia -> Barents), with unseasonable cold centered in Western Russia.

I will keep an eye on Lake Winnipeg, but if this is of any value, it could be an early indicator favorable to a melt season that is especially impressive over the Eurasian sector, and somewhat muted across the CAA, with especially warm conditions possible from Scandinavia into Barents / CAB and also from Alaska into the Chukchi.

[oren]

Moved to a new thread to avoid cluttering the melting season thread. Personally I doubt the predictive value, but feel free to update this year's date and provide the prediction for the season.
What would have been the prediction for 2019?

[bbr2315]

2019 was close to a late melt-out. Would have been a bit tilted towards PV over CAA / strong Eurasian melt, AK / Chukchi heat, and Scandinavian + Barents + CAB +500MB anomalies.

It is interesting to note that all the early melt-outs since 2000 (2006, 2010, 2012, 2016) have all been blockbuster melt seasons. It is also notable that the three latest melt-outs (2004, 2013, 2014) were all lackluster overall (though 2014 did feature the NPole hole).

I think the significance of this indicator is that it shows the preponderance of heat over the leeside of the CAA / Baffin / Hudson Bay early in the season. When the heat is blunted across the Canadian Shield, it penetrates into the Arctic later into the season (CAA especially). When the heat is early over the Shield, the CAA is much more vulnerable, which gives the extra "oomph" to years like 2012 and 2016.

Paradoxically, that also results in a worse state of the CAB in years like 2013 and 2014 (i.e., the North Pole hole in 2014), with blocking spilling from Scandinavia into the Barents and CAB.

Given current model output, I would hedge that 2020 is going to fall into the "late-melt" (5/25+) grouping, and it could possibly enter the top three latest melt years in the recent satellite record.

[bbr2315]

We have now entered the "last" melt-out group as of today's EOSDIS data which confirms significant  extent remains on Lake Winnipeg.

The "twists" on the analogs (2002, 2004, 2008, 2009, 2013, 2014, 2018) is a drop in aerosols / contrails this year, warmer oceans, and lower albedo in Eurasia than any previous year. This should IMO "exacerbate" the mean map we see derived from those summers.

I think that will translate into a particularly potent cold bubble in North America, with snows beginning in August in the favored regions of the Yukon, Highest Rockies, and the mountains of Quebec and Labrador. Moreover, snows may continue falling in aforementioned regions well into June, and possibly into early July.

On the flipside, that will translate into BLAZING heat in northern Eurasia, expanding to encompass the entire Siberian shoreline by September. There is going to be a massive source of black carbon as the early spring = mass combustible material + WARMTH = major FIRES from Siberia this year, possibly worst ever.

While the conditions in North America are likely to be overall prohibitive towards severe fire seasons in the permafrost / conifer zones, I think the accelerated warming in Eurasia which will broil over into the Arctic is going to deal a near K/O to the CAB. We will still have the CAA and much of the Beaufort by the end of this melt season but the CAB could well be devastated and that could be sufficient to dip below 2012's area and extent #s.

[oren]

I hope you revisit these snow predictions in June and in August. I'll reserve my doubts until then.