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Looks like the long winter is about to set in along the Brooks Range in northern Alaska:

Zone Forecast: Northwestern Brooks Range Mobile Weather Information

Last Update: 442 AM AKDT WED SEP 18 2013

Today: Occasional snow. Areas of fog. Snow accumulation around 2 inches...highest amounts in the brooks range. Highs in the lower 30s. North winds 15 to 20 mph.

Tonight: Occasional snow. Areas of fog. Snow accumulation up to 2 inches. Lows in the mid 20s. North winds around 15 mph.

Thursday: Snow likely. Areas of fog. Snow accumulation up to 2 inches. Highs in the lower 30s. Variable winds less than 15 mph.

Thursday Night: Snow likely. Areas of fog. Lows in the upper 20s. Variable winds less than 15 mph.

Friday: Snow likely. Highs in the lower 30s. Northwest winds around 15 mph.

Friday Night: Cloudy with a chance of snow. Lows in the mid 20s.

Saturday And Saturday Night: Cloudy with a chance of snow. Highs around 30. Lows in the mid 20s.

Sunday: Cloudy with a chance of snow. Highs around 30.

Sunday Night: Cloudy. Lows around 20.

Monday Through Tuesday: Mostly cloudy. Highs around 30. Lows in the mid teens to lower 20s

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You have to go back to 2002 to find a year with as much snow on September 22nd as we have this year. The last few years have been particularly dead around this time. Naturally, this is all transient snow, but it's still good, I suppose, to see it showing up even in September.

Also encouraging is that central and northern Hudson's Bay is so darn cold

I went through the Unysis ssta archive and none of the years going back through 1999 had Hudson's Bay so below normal in mid-September

1999 and 2007 it was cold, but it was the southern region very likely due to ice melt

current map shows what I'm talking about

http://weather.unisys.com/surface/sst_anom.gif

and I don't believe this year is due to ice melt as evidenced by the map below from Aug. 4 showing well above temps

the below normal temps this year are from colder than normal temps which apparently have outdone anything this early in the season for the past 14 years

http://weather.unisys.com/archive/sst/sst_anom-130804.gif

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You have to go back to 2002 to find a year with as much snow on September 22nd as we have this year. The last few years have been particularly dead around this time. Naturally, this is all transient snow, but it's still good, I suppose, to see it showing up even in September.

 

No, it's definitely not good to see it yet, at least from a -AO winter standpoint. Statistically speaking, we want low anomalies over Eurasia at the beginning of October, and high anomalies at the end. Hopefully the stuff over Siberia melts before October.

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You have to go back to 2002 to find a year with as much snow on September 22nd as we have this year. The last few years have been particularly dead around this time. Naturally, this is all transient snow, but it's still good, I suppose, to see it showing up even in September.

No, it's definitely not good to see it yet, at least from a -AO winter standpoint. Statistically speaking, we want low anomalies over Eurasia at the beginning of October, and high anomalies at the end. Hopefully the stuff over Siberia melts before October.

I'm not sure if that statement verbatim is correct. Eg: Huge ramp up on October is correlated with neg ao but if you start above and then go way above is it bad? It really doesn't make sense. Did Cohen specify that specifically?

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I'm not sure if that statement verbatim is correct. Eg: Huge ramp up on October is correlated with neg ao but if you start above and then go way above is it bad? It really doesn't make sense. Did Cohen specify that specifically?

 

In his original paper, it was just about the average snow extent in October over Eurasia. But Cohen published another paper which shows that the increase in snowcover during the month is actually the better measure. Correlations are very high.

 

This actually worked beautifully last October. Snowcover started the month below normal, and was significantly above by the end of the month. And as the index suggested, we had a very -AO winter.

 

It's called the "snow advance index"

http://dosbat.blogspot.com/2011/12/cold-winters-snow-advance-index.html

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In his original paper, it was just about the average snow extent in October over Eurasia. But Cohen published another paper which shows that the increase in snowcover during the month is actually the better measure. Correlations are very high.

 

This actually worked beautifully last October. Snowcover started the month below normal, and was significantly above by the end of the month. And as the index suggested, we had a very -AO winter.

 

It's called the "snow advance index"

http://dosbat.blogspot.com/2011/12/cold-winters-snow-advance-index.html

So we just never had -AOs back when we had a lot more sea ice and snow coverage in the early-season Arctic? I have to wonder if this model is only relevant for years with generally low snow and ice cover which end up recovering.

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It also had an October explosion. Perhaps it's not so much above vs. below normal as massive rate of increase over the month.

 

 

That's exactly what it is about. Its just that if you start the month way above normal, it might be a bit tougher to have an even higher anomaly at the end of the month. In his paper though, they didn't make the distinction of "starting below normal and finishing above" as any better than "starting above normal and finishing way above normal"...the index is just using a rate increase.

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I would love to see those satellite images of that pre-1979 snow cover data... I have to wonder how accurate they are, the anomaly suddenly changed as if a switch got flipped. Then again, we aren't talking much snow to begin with in August.

 

Actually you'll note 3 of the 6 highest years were post 1979 (1979-1981). 

 

Here's the analysis from week 32 1980. As you can see there was snow on much of the canadian archipelago. I don't believe there is any sign of snow over most of the archipelago week 32 any year for the last decade. 

 

198032.png

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So we just never had -AOs back when we had a lot more sea ice and snow coverage in the early-season Arctic? I have to wonder if this model is only relevant for years with generally low snow and ice cover which end up recovering.

 

October snowcover over Eurasia hasn't changed THAT much in the past 50 years or so. Sea ice may have, but that's not part of the correlation. Besides, it's about the INCREASE in snowcover, not the actual amount, so in the past it could have just been shifted up uniformly throughout the month. Throw a constant on that b**ch! :P

 

 

That's exactly what it is about. Its just that if you start the month way above normal, it might be a bit tougher to have an even higher anomaly at the end of the month. In his paper though, they didn't make the distinction of "starting below normal and finishing above" as any better than "starting above normal and finishing way above normal"...the index is just using a rate increase.

 

This.

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I'm not sure if that statement verbatim is correct. Eg: Huge ramp up on October is correlated with neg ao but if you start above and then go way above is it bad? It really doesn't make sense. Did Cohen specify that specifically?

 

Yeah I'm not sure either if it is correct, trying to think of it from a physical standpoint... Regardless, cohen's index is based off snow cover advancement "equator-ward of 60N"..that's where it has the highest correlation..  If it already exists in bulk across the far north going into October, I guess its true it limits the over all advancement possibilities, but im not thinking it hurts things. 

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Yeah I'm not sure either if it is correct, trying to think of it from a physical standpoint... Regardless, cohen's index is based off snow cover advancement "equator-ward of 60N"..that's where it has the highest correlation..  If it already exists in bulk across the far north going into October, I guess its true it limits the over all advancement possibilities, but im not thinking it hurts things. 

 

That's a good point, and I had forgotten about that. We can (and should) build as much snow north of 60N as possible. It's south of 60N that we want it bare at the beginning of October! (Makes it easier to have a large increase during the month if you start low.)

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