The early speculation on winter 2013-14

[blizzardof96]

You should try to filter out years to include only ENSO neutral years.

Only two years in the data set but H5 pattern looks like this:

[weathafella]

You should try to filter out years to include only ENSO neutral years.

Only two years in the data set but H5 pattern looks like this:

I'll take it!

[CoastalWx]

Ugh, 91.

 

Anyways, hopefully the models are correct with the Pacific.

[weathafella]

Ugh, 91.

Anyways, hopefully the models are correct with the Pacific.

I thought that was a potentially very snowy look.

[weathafella]

And wasn't 1991-2 a robust niño?

[blizzardof96]

And wasn't 1991-2 a robust niño?

Years used were 1985-86 and 1990-91.

[CoastalWx]

I thought that was a potentially very snowy look.

 

If that pattern verbatim happened, probably thanks to a nice gradient.

[mitchnick]

he used the 30mb monthly anomaly number in picking his years

is the actual qbo number or the anomaly more important and why?

although I've looked at the anomaly I've never read any of the mets base their discussion/research on the anomaly

 

 

p.s. this year's +21.36 anomaly is the highest + monthly anomaly number going back to 1979 at this link

http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index

(fwiw, 8/97 was the second highest + anomaly qbo number since 1979 at 21.30)

[J.Spin]

LoL, you will have snow cover from Dec until late March whether its 8 inches thick or 30.

 

Actually, you raise an interesting point.  It’s true that there’s not going to be much difference between those two scenarios from a visual standpoint, but functionally, there’s a big difference.  With only 8 inches of snow cover, all the ski descents/routes to/in the lower valleys are off the table, lower elevation Nordic areas are struggling to open, many valley bottom snowmobile trails are closed, etc.  Last season was actually a great example of that, with less than half the normal snowpack here as measured by snow depth days (729 SDD).  And amazingly, the way last season’s snowpack played out actually conspired to make it worse than the lowly 2011-2012 season, which even had slightly less overall snowpack (688 SDD).  In 2012-2013, substantial periods were even spent below 5 inches of snowpack, such as that period from mid January to mid February, and that stretch in mid March.  That’s a depth at which the snow is pretty unusable, during periods when there’s typically a good deal more snow that has settled into a dense base:

 

 

Despite being slightly lower in SDD, the 2011-2012 season was deficient early, but finally rose during mid January and maintained at a better level for the duration of the season.  While the mountains have generally been fine these past two seasons, valley snowpack has been by far the worst since I started keeping records, so something closer to normal would be much appreciated.

[cny rider]

Thanks, that's great data.

I came up to ski the Bolton back country trails in the middle of January last year.

No dice.

[ORH_wxman]

Building up big snow cover already in Siberia...we may have our first above average September snow cover anomaly since 2002. This probably means the SAI won't call for a hugely negative AO, but we could be susceptible to more impressive cold with a good source region...assuming the pattern cooperates. We'll have to see how it looks in another week. But I think its going to continue to build.

 

 

 

[forkyfork]

if we have a strong enough ak vortex the cold will never make it here a la 11/12

[ORH_wxman]

 

if we have a strong enough ak vortex the cold will never make it here a la 11/12

 

That is always the case...AK vortex = mild winter pattern.

[WxUSAF]

Building up big snow cover already in Siberia...we may have our first above average September snow cover anomaly since 2002. This probably means the SAI won't call for a hugely negative AO, but we could be susceptible to more impressive cold with a good source region...assuming the pattern cooperates. We'll have to see how it looks in another week. But I think its going to continue to build.

 

 

 

Looks like a piece of the PV is progged to stay near eastern Siberia, so that snowcover should keep building.  But, yeah, AK vortex is a concern going forward into the winter.  

[Ginx snewx]

Actually, you raise an interesting point. It’s true that there’s not going to be much difference between those two scenarios from a visual standpoint, but functionally, there’s a big difference. With only 8 inches of snow cover, all the ski descents/routes to/in the lower valleys are off the table, lower elevation Nordic areas are struggling to open, many valley bottom snowmobile trails are closed, etc. Last season was actually a great example of that, with less than half the normal snowpack here as measured by snow depth days (729 SDD). And amazingly, the way last season’s snowpack played out actually conspired to make it worse than the lowly 2011-2012 season, which even had slightly less overall snowpack (688 SDD). In 2012-2013, substantial periods were even spent below 5 inches of snowpack, such as that period from mid January to mid February, and that stretch in mid March. That’s a depth at which the snow is pretty unusable, during periods when there’s typically a good deal more snow that has settled into a dense base:

Despite being slightly lower in SDD, the 2011-2012 season was deficient early, but finally rose during mid January and maintained at a better level for the duration of the season. While the mountains have generally been fine these past two seasons, valley snowpack has been by far the worst since I started keeping records, so something closer to normal would be much appreciated.

The point I was making was a winter which features very little thawing like 60/61 will be great regardless if you have 8 or 30 inches on the ground in the valley. Snowmobiling and CC are highly dependent on cold.

[heavy_wx]

Is there any dynamical reason why snow cover increases earlier in the fall don't produce the same effect on the AO? Maybe the climatological wave pattern of the stratospheric vortex in October is more conducive to interference from momentum fluxes over Eurasia?

[Ginx snewx]

That is always the case...AK vortex = mild winter pattern.

70/71?

[ORH_wxman]

 

70/71?

 

Nah, that was a big western Canada vortex with a very poleward Aleutian ridge...combine with a -NAO and that is a classic cold La Nina pattern for much of the northern 2/3rds of the CONUS:

The key is the cross polar flow to make Canada very cold...with the vortex further west over AK or EPO/WPO region, the source region is no longer the arctic for Canadaian airmasses, it becomes the Pacific. The '70-'71 pattern above supports a flow right off the arctic down into western Canada...and then it can spread eastward with little Pacific taint.

[weathafella]

There is really no guidance indicating a stable and entrenched AK vortex. Can it happen? Of course. Are there signs it will now? No.

[ORH_wxman]

 

Is there any dynamical reason why snow cover increases earlier in the fall don't produce the same effect on the AO? Maybe the climatological wave pattern of the stratospheric vortex in October is more conducive to interference from momentum fluxes over Eurasia?

 

I believe the lowering of the summer insolation leads to October being the month where the Siberian high strengthens the fastest...so when snow cover is present, it enhances that formation through surface cooling. This then in turn, enhances the strength of the polar jet leading to better transport of heat to the north which disturbs the PV. That is the very quick and crude explanation anyway.

[forkyfork]

There is really no guidance indicating a stable and entrenched AK vortex. Can it happen? Of course. Are there signs it will now? No.

it's on the euro ens mean and gfes mean through day 15

[Ginx snewx]

it's on the euro ens mean and gfes mean through day 15

yeah important in September should stay there right through March.

[tamarack]

People here would have been screaming bloody murder in the autumn of 1960. While Donna gave a big blow to the entire east coast, the overall trend was rather mild right up to the big blizzard of 12/11-12 or a few days before. October and November were mild and rather dry. Thanksgiving was in the 40s but the rest of the weekend was well into the 50s. My 14th bday was chilly on 12/1 but it milded up quickly and the first week of December was unpleasantly mild. There must hve been a boundary 12/4 as that was the day I went to the Giants- Dallas game with temperatures approaching 70. Our dads were remarking on the warmth but I was disgusted. Boston was in the 40s that day but the mild air made it in and a few days later we saw temperatures here in the 50s. Then we had a mundane step down until right before the December 1960 blizzard at which time the bottom dropped out. My mother made me sweep the oak leaves blowing into the garage whch was left open. I dutifully ....gleefully complied as I was sweeping into a north wind with temps down in the low 20s and warnings up for snow. What a storm that was! Heavy snow, heavy winds, single number temperatures during the storm.... Oustanding!

The next 2 months were among the best wintry periods of my lifetime. Coming of age in the 60s got off to a wintery bang! But some here would have lamented losing the winter months of October and November. Keep hope alive...it's coming and coming hard!

 

NYC temps for Oct were close to their (then) average, but Nov was mild, +2 or so, and they had several days of mid-60s in early Dec.  Easy to agree that the period 12/11 thru 2/4 was as good as it gets for the NYC area and into SNE - sustained cold, three huge storms, record snowpack.  (Not so much farther north due to suppression.)  At my NNJ home we also had the surprise tree-bender on 3/23 and several slushy April events ended by about 3" on 4/18, and a few ice pellets in 5/27's cold rain.

[forkyfork]

yeah important in September should stay there right through March.

it did two years ago

[easternsnowman]

We don't have many analogs pointing 2011-2012, not too much in common with that year.

[Damage In Tolland]

it did two years ago

Are any 2 years the same? Please post examples. Thanks

[Damage In Tolland]

it did two years ago

Are any 2 years the same? Please post examples. Thanks

[weathafella]

There is really no guidance indicating a stable and entrenched AK vortex. Can it happen? Of course. Are there signs it will now? No.it's on the euro ens mean and gfes mean through day 15

No. It is not in the same position and in fact it's far enough west vs 2 years ago to have a different outcome. Is your forecast that this vortex will ruin winter?

[forkyfork]

 

 

 

[weathafella]

Loop the 12z GEFS and the transient nature and instability is clear. A lot less robust vortex vs 6z