looking back at the last two winters with amazement

[TheTrials]

whats been great the past couple years is that the blocking hasnt been too severe to the point of supression. its been usually just enough about every time.

the AO has also been on our side the past two winters, esp. im beginning to think nothing can happen unless the arctic is in line.

IMHO, its not the strength of the block (speaking in terms of heights and anomalies) but the positioning of the block. For our area on north, you don’t want an east based –NAO. If you see those height anomalies on the 500mb maps centered to the east of Greenland, expect disappointment if you want a big storm. This was the case in January and the first week of February 2010 (see also January 2007). All those storms we saw pound DC and Southern Jersey in during snowmagedon where we were praying the sub pv would move out really had no shot regardless of how strong the southern vort was because the block was east based. The sub pv got trapped, and that was the end of the ballgame. Earthlight and I had a long disco on this and we realized after the fact that had we stepped back and looked at the positioning of the –nao leading up to those storms, it would have been easier to see much further out that those storms were not making it up to nyc in any meaningful way because of the block positioning.

The difference is easily seen when you look at December 2010 through January 2011. December started with a strong –NAO that was TOO east based (remember all that snow in England?) but towards the end of the month the block retrograded west towards the Davis Straight and when we had the first threat that barely missed the phase around the 20^th of the month and then the BAM we nailed the phase and got 12/26. The block then moved out and reformed and we got those smaller storms and norluns leading up to yet another big storm on 1/11. The block then retrograded again but we got saved with 1/27 by the combination of very very transient higher heights over Greenland and the short wave that sneaked in and brought in the subsidence which kept the vort from shooting inland and giving us rain.

So, long story short, dont fear the strength of the block in our area, fear its positioning.

[SnowGoose69]

I'm definitely thankful I became a weather enthusiaster more or less around 2000, just as the active winters were beginning to set in.

Actually the 80s weren't all that bad from CNJ southward through the mid atlantic. If I remember my numbers correctly, New Brunwick averaged about 27" during the 80s, contrast to a much lower NYC total. The 90s were much crappier for CNJ than the 80s.

But now that we've passed the height of the +PDO/+AMO regime, we should be safe in terms of long stretches (several consecutive years) with virtually nothing, like we had in the 1988-1993 period. PDO is now negative, and many longer term climate models indicate the AMO possibly going negative next year (at least temporarily). The AMO cycle change probably won't occur for another several years, and when that happens, expect global temperatures to take an even bigger tumble (in addition to the meager solar activity). I think we'll see global temps fall below normal by the start of 2012, as this second year Nina event kicks in.

The 1980s would not have seemed as bad in those regions simply because they average less snow to begin with. The problem in the 1980s was the NAO was positive so often. I think this was a bigger problem than the PDO issue, although it did seem that the pattern was always progressive, we never seemed able to get a ridge ON the West Coast and when we did it broke down within days. The Mid-Atlantic and South I think did better because the AO had a tendency to average negative often outside of the winter of 1988-89 and I think 1982-83....that caused severe cold outbreaks on occasion during the decade which caused suppression in the pattern when we did have a fresh and widespread cold air mass in place. 1987-88 was obviously a winter the south did extraordinarily well and the MA and even 1986-87, 1988-89, and 1983-84 were snowy winters in southern areas. Hell, even in 1989 DC had 2 winter storms in December when NYC had none. Whenever we did get a solid setup where suppression was not an issue the +NAO usually caused an inland track.

Here is my favorite illustration to show what a -NAO does...2 storms in 1991 and 1995, the pattern is ugly in most areas for a snow event in our area but in the 1995 event we get mainly snow because you can see the -NAO at work in SE Canada . Notice how the system cannot cut west in 1995.

http://www.meteo.psu.edu/~gadomski/NARR/1991/us0111.php

http://www.meteo.psu.edu/~gadomski/NARR/1995/us1219.php

[ORH_wxman]

IMHO, its not the strength of the block (speaking in terms of heights and anomalies) but the positioning of the block. For our area on north, you don’t want an east based –NAO. If you see those height anomalies on the 500mb maps centered to the east of Greenland, expect disappointment if you want a big storm. This was the case in January and the first week of February 2010 (see also January 2007). All those storms we saw pound DC and Southern Jersey in during snowmagedon where we were praying the sub pv would move out really had no shot regardless of how strong the southern vort was because the block was east based. The sub pv got trapped, and that was the end of the ballgame. Earthlight and I had a long disco on this and we realized after the fact that had we stepped back and looked at the positioning of the –nao leading up to those storms, it would have been easier to see much further out that those storms were not making it up to nyc in any meaningful way because of the block positioning.

The difference is easily seen when you look at December 2010 through January 2011. December started with a strong –NAO that was TOO east based (remember all that snow in England?) but towards the end of the month the block retrograded west towards the Davis Straight and when we had the first threat that barely missed the phase around the 20^th of the month and then the BAM we nailed the phase and got 12/26. The block then moved out and reformed and we got those smaller storms and norluns leading up to yet another big storm on 1/11. The block then retrograded again but we got saved with 1/27 by the combination of very very transient higher heights over Greenland and the short wave that sneaked in and brought in the subsidence which kept the vort from shooting inland and giving us rain.

So, long story short, dont fear the strength of the block in our area, fear its positioning.

I'm not sure what you are saying here. The extreme west based block causes more suppression than an east based block. The blocks in '09-'10 were all west based...but nuances within the blocks and their strength dictated how far north storms got or what path they took via retrograding.

Some east based blocks that occurred during past storms were Dec 5, 2003, PDII Feb 2003, Feb 5, 2001, Jan 25, 2000....and a lot of other storms that were pretty forgettable since they brought rain to a lot of the EC cities. The east based block (usually near Iceland) allows for further north tracks on the whole than those big west based blocks in the Davis straight and down into Baffin Island and Labrador.

I'm betting that the Boxing Day storm would have gone right up the Hudson River valley (or worse) if there had been an iceland block.

[SnowGoose69]

I'm not sure what you are saying here. The extreme west based block causes more suppression than an east based block. The blocks in '09-'10 were all west based...but nuances within the blocks and their strength dictated how far north storms got or what path they took via retrograding.

Some east based blocks that occurred during past storms were Dec 5, 2003, PDII Feb 2003, Feb 5, 2001, Jan 25, 2000....and a lot of other storms that were pretty forgettable since they brought rain to a lot of the EC cities. The east based block (usually near Iceland) allows for further north tracks on the whole than those big west based blocks in the Davis straight and down into Baffin Island and Labrador.

I'm betting that the Boxing Day storm would have gone right up the Hudson River valley (or worse) if there had been an iceland block.

You can add February 83 to that list as well.