Talking Winter 2012-2013

[easternsnowman]

That is only one of several clues we can use. The way the waters have warmed in recent years especially given the warm summers I don't think we can hold much credence to this idea.

[HM]

The early to mid 1950s have remained strong analogs since last summer (2011) and they accurately led to the right trends even since. If we do not see an improvement in our ozone levels this autumn with a weak BDC, then we could see a very similar AO and WPO state to last year. While it is still early, so far there are no signs of improvement.

[HM]

I think the odds probably favor a weak nino even with the cooling that has been taking place in the Pacific. Without a strong nino, I suspect that the pdo will stay negative. The ao and nao are always somewhat of a crap shoot. I'm worried that the ao and nao will again be more positive than negative but this early there is no real way to know. I'll be watching the snow cover and the stratosphere through the fall hoping they show me something that gets me excited. For DC, I'm not a fan of weak ninos. Since 1950 we have done less well than during moderate one and only about 1 in 3 ends up being above normal for snow plus when they do, they so far have not been mega-years in terms of snow.

I agree with these thoughts. If I don't see changes take place with the stratospheric system and ozone transport this autumn, then I may bias on the + side for the winter AO state.

So far this month, the radiative stage of the polar vortex growth is definitely strong again (cooling quickly) and the ozone remains below normal (still very early). This combined with the -PDO has shaped the North Pacific tropospheric anomalies perfectly and has continued the insane +WPO pattern.

[bluehens]

How bad was the 1952 winter in these parts?

[famartin]

How bad was the 1952 winter in these parts?

Snowfall:

16.8" in Philly, 17.9" in Allentown, 16.5" in Wilmington, 7.8" in Atlantic City, 12.9" in Trenton.

Average temp:

38.4 in Philly, 34.1 in Allentown, 37.7 in Wilmington, 40.3 in Atlantic City, 37.8 in Trenton.

[tombo82685]

Snowfall:

16.8" in Philly, 17.9" in Allentown, 16.5" in Wilmington, 7.8" in Atlantic City, 12.9" in Trenton.

Average temp:

38.4 in Philly, 34.1 in Allentown, 37.7 in Wilmington, 40.3 in Atlantic City, 37.8 in Trenton.

Thats not horrible at all, just a little below normal for philly. Seems like with that snowfall distribution their were a couple souther sliders where philly and ilg were just cold enough for snow and ac was to warm.

[tombo82685]

how long has this -pdo regime been in affect?

[am19psu]

how long has this -pdo regime been in affect?

Go ask SNE. They fight to the death about whether it started in 1998 or 200x. It's funny to watch.

[tombo82685]

Go ask SNE. They fight to the death about whether it started in 1998 or 200x. It's funny to watch.

regardless, it seems like it doesn't have a dominate role in whether or not the nao will be pos or negative, considering 09-10 and 10-11 had a -nao

[tombo82685]

Go ask SNE. They fight to the death about whether it started in 1998 or 200x. It's funny to watch.

does it play a role in mjo progressions?

[am19psu]

regardless, it seems like it doesn't have a dominate role in whether or not the nao will be pos or negative, considering 09-10 and 10-11 had a -nao

Nope. PDO can control the EPO/PNA regime, but not really the NAO. I mean, except for the fact the Ninos are more likely to have -NAOs and Ninos are more likely in +PDOs, but that's not really going to help you intraseasonally.

[WxMidwest]

Needless to say, the North Pacific needs some serious blocking coming into October for any real changes down the road in the upstream/downstream relationship with the AO/NAO into this winter. I ran the numbers on a specific September NAO Predictor, and the time series plot so far has a above/blazing NAO/AO into the Winter, that being said it's dependent on what transpires in months preceding winter as well (Oct/Nov). Too many mixed signals this year, I would take so many of these bullish forecasts with a grain of salt. The "El Nino" over the equator is still pretty juvenile, while the GWO has GSDM Stage 1 ( La Nina like pattern ) still active in the Global Pattern. If the GWO continues into these octants come late fall, we may be talking about a Winter that looks very Weak La Nina like vs these general ideas of a weak El Nino winter, this will especially be the case considering a handsome -PDO rules the the Pacific. A longer term Atlantic blocking predictor, yes I know this is a long shot, actually has a very strong signal for blocking over the Atlantic. This indicator is tied to the Kurushio current and an SST Dipole in the Northern Part of the WPAC. It's a 23-24 month precursor with a huge pearson correlation, the question is does it have causation?

Just some food for thought...

[Allsnow]

Snowfall:

16.8" in Philly, 17.9" in Allentown, 16.5" in Wilmington, 7.8" in Atlantic City, 12.9" in Trenton.

Average temp:

38.4 in Philly, 34.1 in Allentown, 37.7 in Wilmington, 40.3 in Atlantic City, 37.8 in Trenton.

After last year....i will sign for this

[famartin]

After last year....i will sign for this

Well it goes without saying, this would be a better winter for everyone. Not up to "normal" but almost anything would be an improvement over last winter.

[Rainshadow]

I agree with these thoughts. If I don't see changes take place with the stratospheric system and ozone transport this autumn, then I may bias on the + side for the winter AO state.

So far this month, the radiative stage of the polar vortex growth is definitely strong again (cooling quickly) and the ozone remains below normal (still very early). This combined with the -PDO has shaped the North Pacific tropospheric anomalies perfectly and has continued the insane +WPO pattern.

Ozone was pretty low last autumn too?

[Rainshadow]

1952 ftw

I would have gone with 2006, just lighter on the sleet please.

[tombo82685]

I would have gone with 2006, just lighter on the sleet please.

2006 wouldnt bother me either. Atleast that yr from jan 15 til april it felt like winter. Last winter was just brutal barely any cold at all. I was mowing greens in january, that i don't like.

[Voyager]

2006 wouldnt bother me either. Atleast that yr from jan 15 til april it felt like winter. Last winter was just brutal barely any cold at all. I was mowing greens in january, that i don't like.

We had tulips popping out of the ground in late February even up here.

[WxMidwest]

The 70 MB temps were also the Coldest on November since 1950...

[Allsnow]

The flip in the pattern after January 15th was rather awesome and we had a pretty extreme twelve week run after the flip...March and April were pretty whacked as well (St. Patrick's Sleet Storm and then the nor'easter on Tax Day that had snow mixed in across the Philly burbs).

How did you find departures that far back? Noaa only goes back to fall of 07. Unless im not looking in correct area....thanks

[phlwx]

Thats not horrible at all, just a little below normal for philly. Seems like with that snowfall distribution their were a couple souther sliders where philly and ilg were just cold enough for snow and ac was to warm.

52-53 is 15th warmest on record in Philly. Only two winters were 38F or warmer and had more snow than 52-53...32-33 (39.9 degree, 22") and 48-49 (38.8, 19.3").

the average snowfall in a winter where temps are between 38-39 F at PHL is 11.7"

52-53 had a 7" March snowfall, a 4.1" event in January, and a couple of minor ones spread around.

[phlwx]

How did you find departures that far back? Noaa only goes back to fall of 07. Unless im not looking in correct area....thanks

http://classic.wunde....html#calendar

for the daily data.

for the monthly, I have it on excel.

[Allsnow]

http://classic.wunde....html#calendar

for the daily data.

for the monthly, I have it on excel.

Thank you

[HM]

Ozone was pretty low last autumn too?

The ozone was generally increased 2009-2011 with a maximum in the early winter of 2010-11. It has since taken a huge hit (all started with the vortex replenishment late winter 2010-11 and cold early spring) and was very low last cold season. It has barely recovered so far this autumn but we've just begun. The good news is that a persistent tropospheric Aleutian Low will help build up stratospheric ozone at the North Pole (one key ingredient). But that doesn't always mean a -AO either.

[HM]

Needless to say, the North Pacific needs some serious blocking coming into October for any real changes down the road in the upstream/downstream relationship with the AO/NAO into this winter. I ran the numbers on a specific September NAO Predictor, and the time series plot so far has a above/blazing NAO/AO into the Winter, that being said it's dependent on what transpires in months preceding winter as well (Oct/Nov). Too many mixed signals this year, I would take so many of these bullish forecasts with a grain of salt. The "El Nino" over the equator is still pretty juvenile, while the GWO has GSDM Stage 1 ( La Nina like pattern ) still active in the Global Pattern. If the GWO continues into these octants come late fall, we may be talking about a Winter that looks very Weak La Nina like vs these general ideas of a weak El Nino winter, this will especially be the case considering a handsome -PDO rules the the Pacific. A longer term Atlantic blocking predictor, yes I know this is a long shot, actually has a very strong signal for blocking over the Atlantic. This indicator is tied to the Kurushio current and an SST Dipole in the Northern Part of the WPAC. It's a 23-24 month precursor with a huge pearson correlation, the question is does it have causation?

Just some food for thought...

Some of the El Niños of the 1960s and 1970s struggled to have much of an effect on the GLAAM. Most notably was the strong El Niño of 1972-73 and weak El Niño of 1976-77 with the following NDJFM GLAAM numbers:

-0.76 -0.46 -0.00 -0.17 -0.41

Here was 76-77:

-0.02 -0.60 -1.06 -1.41 -1.51

Even 1986-87 and 2009-10 were negative into December.

[Mitchell Gaines]

For what it's worth the CFS has once again has gone back to a cooler solution on the old seasaw for DJF.

[WxMidwest]

Here is something to Pay Attention Too, The NP SLP Box in October, only during El Nino Winters...

We need Low SLP's this October... I found this indicator in 2006, been pretty effective from past analogs and future prognostications. (06-07, 09-10)

[GaWx]

Here is something to Pay Attention Too, The NP SLP Box in October, only during El Nino Winters...

We need Low SLP's this October... I found this indicator in 2006, been pretty effective from past analogs and future prognostications. (06-07, 09-10)

1) Fwiw, I estimate that today's 12Z GFS has an avg. SLP at 45N, 150W, a point within the highest correlation area, for 10/1-14 way down at 1003 mb. Although I don't know the longterm avg. SLP for that spot for Oct. 1-14, I would think that it is a good bit higher than 1003 mb. Based on the persistent -EPO and attendant low SLP's in much of the NP box as well as this low SLP at 45N, 150W, I would educatedly guess that the box's avg. SLP is on the low side for 10/1-14 per the 12Z GFS. If so, we'd have a nice headstart toward getting a low SLP for the entire month of Oct. in the box, which apparently correlates partially with a DJFM -NAO. Any other opinion?

2) Weak Nino avg. DJFM NAO: -0.64 (seven winters)

Mod. to strong Nino DJFM NAO: +0.13 (twelve winters)

So, weak Ninos clearly favor a -NAO. An impressive 6 of the 7 weak Ninos since 1950 had a -NAO averaged over DJFM. The one that wasn't (2004-5) had only a modestly +NAO at +0.21 and had the highest Oct. SLP for the NP box of the 7 weak Ninos (1013.21 mb). In contrast, although the most -NAO winter was strong (2009-10), only 4 of the 12 moderate to strong Ninos since 1950 had a -NAO. The six most +NAO's of the 19 Ninos since 1950 were during mod. to strong Ninos. This is one of the reasons that weak Ninos are the coldest ENSO phase on average.

If we do have a fall/winter weak Nino peak, I'd think that the odds for a -NAO for DJFM would conservatively be 2 out of 3.

3) Avg. Oct. SLP for NP box for weak Ninos since 1950: 1012.3 mb

Avg. Oct. SLP for NP box for mod. to strong Ninos since 1950: 1013.3 mb

[tombo82685]

fwiw 12z euro shows the first possible frost for the burbs. Strong pna ridge and north atl ridge sending a cool shot right towards the eastern US.

[Rainshadow]

Here is something to Pay Attention Too, The NP SLP Box in October, only during El Nino Winters...

We need Low SLP's this October... I found this indicator in 2006, been pretty effective from past analogs and future prognostications. (06-07, 09-10)

The sampling you did was only for verified ninos?

Latest CFS2(s) continue to trend toward la nada.