*shrug* If you think the winter maximum is a good predictor of the course of the melt season, you're welcome to demonstrate the correlation directly - e.g. by showing a strong correlation between (detrended) winter max and (detrended) summer minimum - rather than reading the tealeaves of day-by-day wiggles near the maximum.
[... snip...]
We can reasonably assume a very low maximum is mainly an anomaly rather than trend, however even then a large anomaly may persist long enough to get the season off to a fast start and that could be important - certainly I have seen musings to that effect. IOW rather than testing detrended max and min for correlation, testing 1 May and minimum for correlation may be more relevant?
Perhaps also use PIOMAS rather than area might help to find correlation?
Flawed as I believe PIOMAS to be for thin/melting ice, for trends I would have guessed that adding the extra dimension might filter out some of the noise from variations in here-today, gone-tomorrow start/end of season weather conditions. Others have suggested that these effects make area/extent on it's own useless as a predictor of what's going to happen later on in the season - and I'd generally agree.
But eyeballing those PIOMAS monthly trends it seems to me that there's been something very odd going over the past year... either with the model, or with the real world, or both... Viz:
1. The trends for March and May crossed in 2009. Before then, there was consistently more ice in May than in March, since then there has consistently been less ice in May than there was in March - including last year, which was well above the trend for both months.
2. According to PIOMAS there has since 2009 been a consistent 1M km3 volume gain Mar-Apr , and it has always been lost Apr-May, again regardless of trend.
3. Backing up to January , and roughly eyeballing the graph, PIOMAS has never come up with a Jan-Feb volume increase of less than ~2.5 Mkm3, or a Feb-Mar increase less than ~2Mkm3
So if PIOMAS stays true to form, the Feb number will be >= 21M, and under better-than-existing worst case conditions the the March number will be >= 23M and the April number will be >= 24M
In other words, the January number is high enough to guarantee that the April number will be more than a million km3 *higher* than it was in 2014, absent worse than existing worst-case behavior in February and March.
So we just lived through Feb - and to my eyes at least it looked as though it might indeed have have been the worst ever. Assume that PIOMAS cuts it's previous worst-case Feb growth in half (i.e. from ~2.5 to ~1.25m). If it did that the Feb number would be the same as it was last year.
Looking at the actual area today it is essentially the same as it was this time last year - so If PIOMAS does come up with a 50% cut in Feb volume growth over 2014 (which itself was very low), it might be a plausible number - albeit an unprecedentedly bad February for the arctic - but only if the avg. thickness is also now the same as this time last year. This seems a stretch given the weak winter and the low thickness estimates. If the ice is actually thinner, then PIOMAS would need essentially zero Feb growth to avoid coming up with an incredible number for Apr/May.
If, OTOH, PIOMAS comes in with the same (already low) Feb & Mar growth that it did in 2014, it can only end with a modeled March-May volume >1m km3 higher than it was last year, which would IMO be astonishing if true, because it would imply faster Feb growth than 2014, on top of thicker ice than 2014, in the presence of higher temperatures than 2014.
So all in all, I'm wondering if this might be the year when PIOMAS last-meter uncertainties finally cause it to part company with directly observable reality.
Interesting times indeed.