As the north country endures another round of upper level low induced summer suckage you have to wonder exactly what that means for the upcoming winter.
First the answer is it has nothing to do with the upcoming winter. Any historical stat – espically with winter is just an expression of what happened in the past. As anybody knows – if you flip a coin 50 times and it lands on heads 50 times that doesn’t mean it will land on heads the 51st time. Now you say-well it should tell you that something is up with the coin and you can expect heads…and you might be right. Perhaps the coin is weighted funny. Perhaps you’re playing a cheater. Who knows. Well the same goes for the weather. Looking at historical data should only tell you that something is afoot. It should give you a guide for watching how things develop.
And so with that crap out of the way let me begin.
I noticed that the Artic Oscillation (AO) is extremely negative and has been so since early june.
In fact it’s been strongly negative. Since 1950 only seven other years have featured a june with such a strongly negative AO.
They were: 1951, 1957, 1958, 1982, 1987, 1997 and 1998.
So taking those years I figured lets look at what Mt. Mansfield shows as snowfall for the winter following those years.
Sadly examining this snow stake data is inconslusive. Early years showed a slightly below normal snow depth and the later years show a slightly above average snow depth. Clearly no conclusion can be drawn.
Perhaps we can draw some conclusions regarding what the weather might be based on comparing the years above with the AO in the corrseponding winters.
As you can see from the chart below, A negative AO generally leads to below average temperatures for the East and North east when the Negative AO occurs in J/F/M.
So what did these years have for the AO? (Numbers are D, J, F, M)
51/52: -1.9, -.85, -.4, -1.9
57/58: .8, -1.4, -2.2, -2.5
58/59: -1.67, -2.013, 2.5, 1.4
82/83: .967, 1.359, -1.806, -.567
87/88: -.534, .265, -1.066, -.197
97/98: -.071, -2.081, -.183, -.254
98/99: 1.353, .110, .482, -1.492
Looking at these numbers again is not conclusive BUT they do show that 75% of the time these winters exhibted a negative AO which is a good thing for our temperatures.
With a building “west based” el nino, which leads to cooler east coast temps the best guess at this time is that the signs point to a cool winter. Wish I could say all signs point to constant bombed out coastal lows but that’s reality!
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