October Pattern Suggests Stronger Winter 13-14 EPO Blocking Than NAO and AO

[Sundog]

The fact that the -NAO has been so persistant over the past several months has me concerned that it'll break down at the worst time. Blocking this month is nice and all - finally a normal autumn progression - but it doesn't get me excited for winter. We'll see what the N Hemisphere looks like 3-4 weeks from now.

Don't we want a warm November? Someone posted the Novembers prior to our best winters and the composite was quite a bit above normal.

[NEG NAO]

snow cover is starting to build up north

http://www.natice.noaa.gov/ims/loop/nhem-1mo-loop.html

[MJO812]

Snow cover has ramped up nicely. Good to see.

[WXeastern]

One of my concern as others have also stated is that the -NAO and -AO, after persisting for so long, fall apart at the wrong time.

A negative AO hasn't persisted..its been mostly positive since last winter!

The October negative AO is HIGHLY suggestive of a -NAO/AO blocky winter..as the OP alluded to!

[blizzardof09]

Im reallg eager to see how our -NAO/AO can carry itself into the winter with some strength and not weaken as we deeper into it. Also i dont think its been discussed as much here as i feel it should but the pacific MUST cooperate as well. I know this is a nao/ao thread but its a tidbit that i personally keep track of as it is pretty important when forecasting during the winter months

[bluewave]

I made some composites to show the November variability after an October with blocking before a winter with blocking.

The first group of composites shows years when October blocking continued into November and the winter.

The second batch of composites show the years that the October blocking faded in November and returned for winter.

[blizzardof09]

Great composite bluewave! We really gotta hope that the NAO can stay consistently negative or predominantely negative as we head through november. Im cautiously optimistic about the -NAO in that there really isnt anything atleast in the near future that may make it go into a +NAO regime, so thats a good sign. If the blocking does get weaker in the past months its always came back into negative territory shortly thereafter.

[WXeastern]

All Winters since 1950 with October AO values of at least -1.00

If you add the month of March this anomaly is a little colder

Precip

[uncle W]

here are the top ten coldest Novembers since 1950...seasonal snowfall that followed and winter temperatures...

year...temp...seasonal snowfall...

1976...41.7....24.5"

1967...42.5....19.5"

1996...43.0....10.0"

1962...43.2....16.3"

1951...43.5....19.7"

1995...43.6....75.6"

1955...44.3....33.5"

1972...44.4......2.8"

1980...44.6....19.4"

1997...44.5......5.5"

maps of all ten...There were four mild and six cold winters that followed...

[NYCSuburbs]

A negative AO hasn't persisted..its been mostly positive since last winter!

The October negative AO is HIGHLY suggestive of a -NAO/AO blocky winter..as the OP alluded to!

I know that... I missed that part when typing my post although I did reference to the NAO in the first part of the post. It'll be interesting to see where we go from here, I'm encouraged by the -NAO and periods of blocking as well as the current pattern, although after last year's disaster I'd rather wait to see how the rest of the month and the pattern unfold before making my outlook.

[JBG]

My early guess right now is that we'll have blocking patterns to work with at some point this winter.

But it's tough to tell this soon if it will turn out like a 06-07 blocking pattern with little snow or the other

years that did better. So as always, we'll have to take a wait and see approach on the snowfall potential.

2006-7 did OK with two storms, VD and a similar, though snowier, mid-March storm.

[uncle W]

October 2012 AO is averaging quite low so far...Here are the nine lowest October AO index years...

year...AO index...

2009...-1.540.....el nino...snowy winter...

2002...-1.489.....el nino...snowy winter...

1979...-1.243.....neutral/weak positive...snow was lacking...

1960...-1.187.....neutral...snowy winter...

1981...-1.167.....neutral...average winter...

1966...-1.077.....neutral/weak negative...snowy winter...

2006...-1.029.....el nino...mild start...cold ending...snow was lacking...

1974...-1.024.....la nina...mild...snow was lacking...

1968...-1.013.....el nino...snowy winter...

five snowy winters...

one average...

three below average snow years...

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index.html

[bluewave]

October 2012 AO is averaging quite low so far...Here are the nine lowest October AO index years...

year...AO index...

2009...-1.540.....el nino...snowy winter...

2002...-1.489.....el nino...snowy winter...

1979...-1.243.....neutral/weak positive...snow was lacking...

1960...-1.187.....neutral...snowy winter...

1981...-1.167.....neutral...average winter...

1966...-1.077.....neutral/weak negative...snowy winter...

2006...-1.029.....el nino...mild start...cold ending...snow was lacking...

1974...-1.024.....la nina...mild...snow was lacking...

1968...-1.013.....el nino...snowy winter...

five snowy winters...

one average...

three below average snow years...

http://www.cpc.ncep....x/ao_index.html

It's interesting that 8 out of the following 9 winters featured at least one winter month with an AO below -1.000.

[uncle W]

It's interesting that 8 out of the following 9 winters featured at least one winter month with an AO below -1.00.

yea 1974-75...a la nina year...it had no real cold period...2006-07 atarted out even warmer but February was one of the coldest in years...only 79-80 had lousey February snowfall...2006-07 had the Feb. sleet storm that was not bad...

[bluewave]

This October followed the pattern of the years that featured winter blocking. Both the NAO and AO came in

with very negative values for October.

[bluewave]

AO

2002 1.381 1.304 0.902 0.748 0.401 0.573 0.328 -0.229 -0.043 -1.489 -1.425 -1.592

2003 -0.472 0.128 0.933 -0.178 1.017 -0.102 0.075 -0.280 0.467 -0.670 0.642 0.265

2004 -1.686 -1.528 0.318 -0.409 -0.094 -0.236 -0.201 -0.720 0.855 -0.515 0.678 1.230

2005 0.356 -1.271 -1.348 -0.046 -0.763 -0.383 -0.030 0.026 0.802 0.030 0.228 -2.104

2006 -0.170 -0.156 -1.604 0.138 0.156 1.071 0.103 -0.265 0.606 -1.029 0.521 2.282

2007 2.034 -1.307 1.182 0.544 0.894 -0.555 -0.397 -0.034 0.179 0.383 -0.519 0.821

2008 0.819 0.938 0.586 -0.455 -1.205 -0.090 -0.480 -0.080 -0.327 1.676 0.092 0.648

2009 0.800 -0.672 0.121 0.973 1.194 -1.351 -1.356 -0.054 0.875 -1.540 0.459 -3.413

2010 -2.587 -4.266 -0.432 -0.275 -0.919 -0.013 0.435 -0.117 -0.865 -0.467 -0.376 -2.631

2011 -1.683 1.575 1.424 2.275 -0.035 -0.858 -0.472 -1.063 0.665 0.800 1.459 2.221

2012 -0.220 -0.036 1.037 -0.035 0.168 -0.672 0.168 0.014 0.772 -1.514**************

NAO

2002 0.44 1.10 0.69 1.18 -0.22 0.38 0.62 0.38 -0.70 -2.28 -0.18 -0.94

2003 0.16 0.62 0.32 -0.18 0.01 -0.07 0.13 -0.07 0.01 -1.26 0.86 0.64

2004 -0.29 -0.14 1.02 1.15 0.19 -0.89 1.13 -0.48 0.38 -1.10 0.73 1.21

2005 1.52 -0.06 -1.83 -0.30 -1.25 -0.05 -0.51 0.37 0.63 -0.98 -0.31 -0.44

2006 1.27 -0.51 -1.28 1.24 -1.14 0.84 0.90 -1.73 -1.62 -2.24 0.44 1.34

2007 0.22 -0.47 1.44 0.17 0.66 -1.31 -0.58 -0.14 0.72 0.45 0.58 0.34

2008 0.89 0.73 0.08 -1.07 -1.73 -1.39 -1.27 -1.16 1.02 -0.04 -0.32 -0.28

2009 -0.01 0.06 0.57 -0.20 1.68 -1.21 -2.15 -0.19 1.51 -1.03 -0.02 -1.93

2010 -1.11 -1.98 -0.88 -0.72 -1.49 -0.82 -0.42 -1.22 -0.79 -0.93 -1.62 -1.85

2011 -0.88 0.70 0.61 2.48 -0.06 -1.28 -1.51 -1.35 0.54 0.39 1.36 2.52

2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06

[uncle W]

October 2012 AO is averaging quite low so far...Here are the nine lowest October AO index years...

year...AO index...

2009...-1.540.....el nino...snowy winter...

2012...-1.514.....???

2002...-1.489.....el nino...snowy winter...

1979...-1.243.....neutral/weak positive...snow was lacking...

1960...-1.187.....neutral...snowy winter...

1981...-1.167.....neutral...average winter...

1966...-1.077.....neutral/weak negative...snowy winter...

2006...-1.029.....el nino...mild start...cold ending...snow was lacking...

1974...-1.024.....la nina...mild...snow was lacking...

1968...-1.013.....el nino...snowy winter...

five snowy winters...

one average...

three below average snow years...

http://www.cpc.ncep....x/ao_index.html

October 2012 had the second lowest AO reading for that month on record...

[dbc]

AO

2002 1.381 1.304 0.902 0.748 0.401 0.573 0.328 -0.229 -0.043 -1.489 -1.425 -1.592

2003 -0.472 0.128 0.933 -0.178 1.017 -0.102 0.075 -0.280 0.467 -0.670 0.642 0.265

2004 -1.686 -1.528 0.318 -0.409 -0.094 -0.236 -0.201 -0.720 0.855 -0.515 0.678 1.230

2005 0.356 -1.271 -1.348 -0.046 -0.763 -0.383 -0.030 0.026 0.802 0.030 0.228 -2.104

2006 -0.170 -0.156 -1.604 0.138 0.156 1.071 0.103 -0.265 0.606 -1.029 0.521 2.282

2007 2.034 -1.307 1.182 0.544 0.894 -0.555 -0.397 -0.034 0.179 0.383 -0.519 0.821

2008 0.819 0.938 0.586 -0.455 -1.205 -0.090 -0.480 -0.080 -0.327 1.676 0.092 0.648

2009 0.800 -0.672 0.121 0.973 1.194 -1.351 -1.356 -0.054 0.875 -1.540 0.459 -3.413

2010 -2.587 -4.266 -0.432 -0.275 -0.919 -0.013 0.435 -0.117 -0.865 -0.467 -0.376 -2.631

2011 -1.683 1.575 1.424 2.275 -0.035 -0.858 -0.472 -1.063 0.665 0.800 1.459 2.221

2012 -0.220 -0.036 1.037 -0.035 0.168 -0.672 0.168 0.014 0.772 -1.514**************

NAO

2002 0.44 1.10 0.69 1.18 -0.22 0.38 0.62 0.38 -0.70 -2.28 -0.18 -0.94

2003 0.16 0.62 0.32 -0.18 0.01 -0.07 0.13 -0.07 0.01 -1.26 0.86 0.64

2004 -0.29 -0.14 1.02 1.15 0.19 -0.89 1.13 -0.48 0.38 -1.10 0.73 1.21

2005 1.52 -0.06 -1.83 -0.30 -1.25 -0.05 -0.51 0.37 0.63 -0.98 -0.31 -0.44

2006 1.27 -0.51 -1.28 1.24 -1.14 0.84 0.90 -1.73 -1.62 -2.24 0.44 1.34

2007 0.22 -0.47 1.44 0.17 0.66 -1.31 -0.58 -0.14 0.72 0.45 0.58 0.34

2008 0.89 0.73 0.08 -1.07 -1.73 -1.39 -1.27 -1.16 1.02 -0.04 -0.32 -0.28

2009 -0.01 0.06 0.57 -0.20 1.68 -1.21 -2.15 -0.19 1.51 -1.03 -0.02 -1.93

2010 -1.11 -1.98 -0.88 -0.72 -1.49 -0.82 -0.42 -1.22 -0.79 -0.93 -1.62 -1.85

2011 -0.88 0.70 0.61 2.48 -0.06 -1.28 -1.51 -1.35 0.54 0.39 1.36 2.52

2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06

Wow, so 2006 vs 2002 NAO when it comes to being closest to 2012. Two very different winters. We shall see if any mimicking occurs.

[uncle W]

looking at the October NAO is interesting...2006 is the only year the nao was negative and the winter was a dud...

year Oct Nao snowfall

2002...-2.28...49.3"

2003...-1.26...42.6"

2004...-1.10...41.0"

2005...-0.98...40.0"

2006...-2.24...12.4"

2007..+0.45...11.9"

2008...-0.04...27.6"

2009...-1.03...51.4"

2010...-0.93...61.9"

2011..+0.39.....7.4"

[bluewave]

Wow, so 2006 vs 2002 NAO when it comes to being closest to 2012. Two very different winters. We shall see if any mimicking occurs.

looking at the October NAO is interesting...2006 is the only year the nao was negative and the winter was a dud...

year Oct Nao snowfall

2002...-2.28...49.3"

2003...-1.26...42.6"

2004...-1.10...41.0"

2005...-0.98...40.0"

2006...-2.24...12.4"

2007..+0.45...11.9"

2008...-0.04...27.6"

2009...-1.03...51.4"

2010...-0.93...61.9"

2011..+0.39.....7.4"

The interesting thing about 2006- 2007 is the strong blocking waited for February to arrive. Valentine's day would

have been a great snowstorm if it wasn't sleet and freezing rain. February was also the coldest for average

temperature in many years.

[thunderbolt]

The interesting thing about 2006- 2007 is the strong blocking waited for February to arrive. Valentine's day would

have been a great snowstorm if it wasn't sleet and freezing rain. February was also the coldest for average

temperature in many years.

nice work bluewave and uncle w

[IntenseBlizzard2014]

If it weren't for the slight East Based -NAO, then that storm would've been legendary for the I-95.

[uncle W]

The March sleet storm was good also...If both storms were snow it would have been above average too...Other years shared the same faith...1973-74 comes to mind...

[Isotherm]

I don't believe we can say that it was simply bad luck that Feb 14 07 ended up being a sleet/ice event for our region. The pattern was not necessarily even close to ideal for a major I-95 snowstorm.

If we take a look at the H5 pattern on the daily reanalysis - let's compare Feb 14 2007 to Dec 26 2010 at 500mb.

Feb 14 2007 :

Dec 26 2010 :

Note how anomalously strong the blocking feature was on Dec 26th 2010 - that pattern was extremely favorable to pop a significant bombing low near the mid atl coast. The Feb 2007 map is wishy-washy; there's some blocking to the north but not strong enough to prevent a coastal hugger / "near miss" (as Kocin's book would have it) for I-95.

[Isotherm]

Actually the Feb 13th 2007 H5 map looks good w/ a 50-50 low, but the blocking seems to weaken quite a bit as the storm gets going, and that was the problem w/ it.

[Snow_Miser]

Thought I'd bump this thread. There's a signal on the long range Ensembles for High latitude ridging to return in early October.

 

[bluewave]

Thought I'd bump this thread. There's a signal on the long range Ensembles for High latitude ridging to return in early October.

 

12z gefs blocky.gif

 

Thanks, for bumping it. The blocking pattern last October was a great hint to the blocking pattern

that we got last winter. It was just unfortunate that the Pacific was stuck in a -PDO/La Nina mode.

 

 

 

 

 

Updated October to winter composites to include 2012-13:

 

October to winter blocking composites since 2002

 

 

 

 

 

October to winter no blocking composites since 2002

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[uncle W]

 October AO/NAO index before our snowiest winters...

season........AO......NAO

1955-56..+0.099....-1.47

1957-58...-0.903...+1.32

1959-60...-0.249...+0.89

1960-61...-1.187....-1.73

1963-64..+1.069...+0.94

1966-67...-1.077....-0.68

1968-69...-1.013....-2.30

1977-78...-0.009...+0.52

1978-79..+0.895...+1.93

1982-83...-0.211....-0.74

1992-93...-0.366....-1.76

1993-94...-0.565....-0.71

1995-96..+0.183...+0.19

2000-01..+0.317...+0.92

2002-03...-1.489....-2.28

2003-04...-0.670....-1.26

2004-05...-0.515....-1.10

2005-06..+0.030....-0.98

2009-10...-1.540....-1.03

2010-11...-0.467....-0.93

2012-13...-1.514....-2.06

 

1964-65..+0.342...+0.74

1981-82...-1.167....-1.35

A negative ao/nao in October isn't a bad thing...

[Snow_Miser]

 October AO/NAO index before our snowiest winters...

season........AO......NAO

1955-56..+0.099....-1.47

1957-58...-0.903...+1.32

1959-60...-0.249...+0.89

1960-61...-1.187....-1.73

1963-64..+1.069...+0.94

1966-67...-1.077....-0.68

1968-69...-1.013....-2.30

1977-78...-0.009...+0.52

1978-79..+0.895...+1.93

1982-83...-0.211....-0.74

1992-93...-0.366....-1.76

1993-94...-0.565....-0.71

1995-96..+0.183...+0.19

2000-01..+0.317...+0.92

2002-03...-1.489....-2.28

2003-04...-0.670....-1.26

2004-05...-0.515....-1.10

2005-06..+0.030....-0.98

2009-10...-1.540....-1.03

2010-11...-0.467....-0.93

2012-13...-1.514....-2.06

 

1964-65..+0.342...+0.74

1981-82...-1.167....-1.35

A negative ao/nao in October isn't a bad thing...

 

Looks like 18 out of the 23 years listed there either had a -NAO or a -AO or both. Good stuff Uncle.

[WEATHER53]

Let's get ready to block!