Winter 2022-23 early thoughts - general chat

[sebastiaan1973]

EC46 shows a La Nina setting for the second half of november and first week of december.

[northwestsnow]

1 hour ago, sebastiaan1973 said:

EC46 shows a La Nina setting for the second half of november and first week of december.

Yup ..

EC46 resolute in progging a seasonal pattern as we head through November ..

Fingers crossed  

Edited October 20, 2022 by northwestsnow

[CoxR]

I've been having a look at monthly England precipitation data from 1870 onwards to investigate which years are most analogous to 2022 and the results are very interesting.

In terms of patterns of precipiation observed from January through September 2022, the top analogues are 1887 and 1967 with 8 out of the 9 months' precipitation anomalies having the same 'sign'  (i.e. either negative or positive/ dry or warm) as Jan-Sep 2022.

Other good matches are 1870, 1874, 1876,1885, 1893, 1929, 1933, 1935, 1961, 1976, 1995, 1996, 2000, 2005 and 2010 with 7 out of the 9 months in these years sharing the same precipitation anomaly signs.

14 out of the 17 winters in this set of analogues had below average or cold Central England Temperatures with a median temperature anomaly of -0.85 degrees celsius. Decembers were particularly cold in this set of analogues with a median CET anomaly of -1.55 degC and Februaries were also cold with a median CET anomaly of -0.36 degC, whereas Januaries came out average (-0.05 degC). 

Plotting all years in the analogue set that are within NCEP's 1948-Sep2022 data timeframe, the average sea level pressure anomalies in December look like this: 

And for Jan: 

For Feb:

For these winters as a whole:

 

Assuming precipitation will turn out above average this month, I expanded the analysis through October and the top analogue was once again 1967 with 9 out of the 10 months sharing the same precipitation anomaly signs that have been observed from January to October 2022.

1870, 1874, 1885, 1887, 1929, 1933, 1935, 1961, 1976, 2000 and 2005 all had 8 out of their first 10 months sharing the same precipitation anomaly signs.

For this analogue set, 11 out of the 12 winters were below average or cold with a median CET anomaly of -0.89 deg C.

Again - Decembers were very cold on average with a median CET anomaly of -1.41 degC. 10 of the 12 Decembers were below average or cold, with 5 having CET anomalies below -2 degC, 2 of which were below -3 degC.

Februaries were colder on average in this analogue set compared to the Jan-Sep analogues, with a median anomaly of -1.08 deg C and 6 of the 12 having CET anomalies below -1.5 degC. Januaries remained a similarly mixed bag with a median CET anomaly of -0.04 degC.

Again, plotting sea level pressure anomalies for years in this analogue set within the 1948-2022 timeframe, you get these charts for the corresponding winter months.

December:

For Jan:

For Feb:

For winter as a whole:

 

I do think that this analogue set's winter SLP anomalies in the northern hemisphere bear quite a strong resemblance to the most recent seasonal output from JMA for the upcoming winter period, with the JMA's pattern generally shifted west relative to the anologue set and some discrepancies over Siberia. Here are the two side-by-side (sorry that they're not centered at the same longitude): 

 

Comparing average September SSTAs of the Jan-through September data analogues to the SSTAs observed at the mid-point of September this year: 

It's worth noting that the analogue SSTAs are biased negative because 4 of the 5 are earlier than the mid-point of the 1991-2020 reference period and that the observed SSTAs from last month are biased positive due to 2022 being a lot later than the mid-point of the reference period. 

Generally tropical SSTAs are very similar with the negative IOD and La Nina imprint present in both. I would say that north Atlantic SSTAs are fairly similar, with the warm Atlantic blob present last month centered further west relative to the analogue years, which could possibly partly explain the generally westward pattern shift of JMA's MSLP output for DJF relative to DJF in the analogue years but that's probably just conjecture. 

On the other hand, the north Pacific looks quite different, you would have to say.

 

This analysis was generally just out of curiosity and I certainly wouldn't want to make a forecast purely based on observed monthly precipitation prior to the target month, but it does beg the question of to what extent predictability of future weather patterns can be gained from looking at patterns of precipitation.

Whilst attempting to build my statistical model of CET and England Precipitation I have found statisically significant associations between precipitation in certain months and CET several months down the line. I would otherwise not have investigated these links were it not for several discussions I've seen on here (and YouTube) hypothesising a link between warm Septembers and warm winters and also dry Septembers and warm winters. The former has no connection statistically speaking with winter CET, but the latter does: there was a 99.6% confidence that a wet September was associated with colder Decembers if I recall correctly, but there was no statistically significant association between September and any other winter month.

I have to say, I went into that analysis very sceptical about there being any connection, and was intending to dispel the myth but needless to say I was proved wrong and I will now be incorporating patterns of precipitation into my model, so well done to whoever first suggested that link  

 

[Cheshire Freeze]

45 minutes ago, CoxR said:

I've been having a look at monthly England precipitation data from 1870 onwards to investigate which years are most analogous to 2022 and the results are very interesting.

In terms of patterns of precipiation observed from January through September 2022, the top analogues are 1887 and 1967 with 8 out of the 9 months' precipitation anomalies having the same 'sign'  (i.e. either negative or positive/ dry or warm) as Jan-Sep 2022.

Other good matches are 1870, 1874, 1876,1885, 1893, 1929, 1933, 1935, 1961, 1976, 1995, 1996, 2000, 2005 and 2010 with 7 out of the 9 months in these years sharing the same precipitation anomaly signs.

14 out of the 17 winters in this set of analogues had below average or cold Central England Temperatures with a median temperature anomaly of -0.85 degrees celsius. Decembers were particularly cold in this set of analogues with a median CET anomaly of -1.55 degC and Februaries were also cold with a median CET anomaly of -0.36 degC, whereas Januaries came out average (-0.05 degC). 

Plotting all years in the analogue set that are within NCEP's 1948-Sep2022 data timeframe, the average sea level pressure anomalies in December look like this: 

And for Jan: 

For Feb:

For these winters as a whole:

 

Assuming precipitation will turn out above average this month, I expanded the analysis through October and the top analogue was once again 1967 with 9 out of the 10 months sharing the same precipitation anomaly signs that have been observed from January to October 2022.

1870, 1874, 1885, 1887, 1929, 1933, 1935, 1961, 1976, 2000 and 2005 all had 8 out of their first 10 months sharing the same precipitation anomaly signs.

For this analogue set, 11 out of the 12 winters were below average or cold with a median CET anomaly of -0.89 deg C.

Again - Decembers were very cold on average with a median CET anomaly of -1.41 degC. 10 of the 12 Decembers were below average or cold, with 5 having CET anomalies below -2 degC, 2 of which were below -3 degC.

Februaries were colder on average in this analogue set compared to the Jan-Sep analogues, with a median anomaly of -1.08 deg C and 6 of the 12 having CET anomalies below -1.5 degC. Januaries remained a similarly mixed bag with a median CET anomaly of -0.04 degC.

Again, plotting sea level pressure anomalies for years in this analogue set within the 1948-2022 timeframe, you get these charts for the corresponding winter months.

December:

For Jan:

For Feb:

For winter as a whole:

 

I do think that this analogue set's winter SLP anomalies in the northern hemisphere bear quite a strong resemblance to the most recent seasonal output from JMA for the upcoming winter period, with the JMA's pattern generally shifted west relative to the anologue set and some discrepancies over Siberia. Here are the two side-by-side (sorry that they're not centered at the same longitude): 

 

Comparing average September SSTAs of the Jan-through September data analogues to the SSTAs observed at the mid-point of September this year: 

It's worth noting that the analogue SSTAs are biased negative because 4 of the 5 are earlier than the mid-point of the 1991-2020 reference period and that the observed SSTAs from last month are biased positive due to 2022 being a lot later than the mid-point of the reference period. 

Generally tropical SSTAs are very similar with the negative IOD and La Nina imprint present in both. I would say that north Atlantic SSTAs are fairly similar, with the warm Atlantic blob present last month centered further west relative to the analogue years, which could possibly partly explain the generally westward pattern shift of JMA's MSLP output for DJF relative to DJF in the analogue years but that's probably just conjecture. 

On the other hand, the north Pacific looks quite different, you would have to say.

 

This analysis was generally just out of curiosity and I certainly wouldn't want to make a forecast purely based on observed monthly precipitation prior to the target month, but it does beg the question of to what extent predictability of future weather patterns can be gained from looking at patterns of precipitation.

Whilst attempting to build my statistical model of CET and England Precipitation I have found statisically significant associations between precipitation in certain months and CET several months down the line. I would otherwise not have investigated these links were it not for several discussions I've seen on here (and YouTube) hypothesising a link between warm Septembers and warm winters and also dry Septembers and warm winters. The former has no connection statistically speaking with winter CET, but the latter does: there was a 99.6% confidence that a wet September was associated with colder Decembers if I recall correctly, but there was no statistically significant association between September and any other winter month.

I have to say, I went into that analysis very sceptical about there being any connection, and was intending to dispel the myth but needless to say I was proved wrong and I will now be incorporating patterns of precipitation into my model, so well done to whoever first suggested that link  

 

Great work mate

[sebastiaan1973]

An important new study

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JD037422

The Arctic stratospheric polar vortex is an important driver of winter weather and climate variability and predictability in North America and Eurasia, with a downward influence that on average projects onto the North Atlantic Oscillation (NAO). While tropospheric circulation anomalies accompanying anomalous vortex states display substantial case-by-case variability, understanding the full diversity of the surface signatures requires larger sample sizes than those available from reanalyses. Here, we first show that a large ensemble of seasonal hindcasts realistically reproduces the observed average surface signatures for weak and strong vortex winters and produces sufficient spread for single ensemble members to be considered as alternative realizations. We then use the ensemble to analyze the diversity of surface signatures during weak and strong vortex winters. Over Eurasia, relatively few weak vortex winters are associated with large-scale cold conditions, suggesting that the strength of the observed cold signature could be inflated due to insufficient sampling. For both weak and strong vortex winters, the canonical temperature pattern in Eurasia only clearly arises when North Atlantic sea surface temperatures are in phase with the NAO. Over North America, while the main driver of interannual winter temperature variability is the El Niño–Southern Oscillation (ENSO), the stratosphere can modulate ENSO teleconnections, affecting temperature and circulation anomalies over North America and downstream. These findings confirm that anomalous vortex states are associated with a broad spectrum of surface climate anomalies on the seasonal scale, which may not be fully captured by the small observational sample size.

Key Points

The broad spectrum of surface signatures of stratospheric polar vortex anomalies is obscured by the small observational sample size

A large ensemble indicates the observed magnitude of negative North Atlantic Oscillation and related surface anomalies during weak vortex winters may be inflated

Over North America the main driver of winter temperature variability is El Niño–Southern Oscillation (ENSO), but the stratosphere can modulate ENSO teleconnections

Plain Language Summary

The strength of the winds in the stratosphere over the Arctic provides useful information for seasonal forecasts of wintertime weather over Europe and North America. When we study these linkages, it is a challenge that we have few winters—only about 40—with reliable observations from the stratosphere. Here, we use data from a seasonal forecast model to generate a large collection of 3,000 possible winters, and we use these to examine different patterns of surface temperature and sea level pressure for winters with the strongest and weakest winds in the polar stratosphere. Some real-world episodes have attracted wide attention, including recent cold winters linked to weak stratospheric winds, and there seems to be an anticipation that weak winds in the stratosphere are synonymous with extremely cold weather in many regions. However, our results indicate that these expected surface signatures are in fact not particularly common. There are also scenarios when instead the opposite surface signature emerges. We find that it is not sufficient to know the state of the stratosphere; regional sea surface temperatures can either support or counteract the stratospheric influence on winter weather in any given year.

[Uncertainty]

On 21/10/2022 at 02:01, CoxR said:

I've been having a look at monthly England precipitation data from 1870 onwards to investigate which years are most analogous to 2022 and the results are very interesting.

In terms of patterns of precipiation observed from January through September 2022, the top analogues are 1887 and 1967 with 8 out of the 9 months' precipitation anomalies having the same 'sign'  (i.e. either negative or positive/ dry or warm) as Jan-Sep 2022.

Other good matches are 1870, 1874, 1876,1885, 1893, 1929, 1933, 1935, 1961, 1976, 1995, 1996, 2000, 2005 and 2010 with 7 out of the 9 months in these years sharing the same precipitation anomaly signs.

14 out of the 17 winters in this set of analogues had below average or cold Central England Temperatures with a median temperature anomaly of -0.85 degrees celsius. Decembers were particularly cold in this set of analogues with a median CET anomaly of -1.55 degC and Februaries were also cold with a median CET anomaly of -0.36 degC, whereas Januaries came out average (-0.05 degC). 

Plotting all years in the analogue set that are within NCEP's 1948-Sep2022 data timeframe, the average sea level pressure anomalies in December look like this: 

And for Jan: 

For Feb:

For these winters as a whole:

 

Assuming precipitation will turn out above average this month, I expanded the analysis through October and the top analogue was once again 1967 with 9 out of the 10 months sharing the same precipitation anomaly signs that have been observed from January to October 2022.

1870, 1874, 1885, 1887, 1929, 1933, 1935, 1961, 1976, 2000 and 2005 all had 8 out of their first 10 months sharing the same precipitation anomaly signs.

For this analogue set, 11 out of the 12 winters were below average or cold with a median CET anomaly of -0.89 deg C.

Again - Decembers were very cold on average with a median CET anomaly of -1.41 degC. 10 of the 12 Decembers were below average or cold, with 5 having CET anomalies below -2 degC, 2 of which were below -3 degC.

Februaries were colder on average in this analogue set compared to the Jan-Sep analogues, with a median anomaly of -1.08 deg C and 6 of the 12 having CET anomalies below -1.5 degC. Januaries remained a similarly mixed bag with a median CET anomaly of -0.04 degC.

Again, plotting sea level pressure anomalies for years in this analogue set within the 1948-2022 timeframe, you get these charts for the corresponding winter months.

December:

For Jan:

For Feb:

For winter as a whole:

 

I do think that this analogue set's winter SLP anomalies in the northern hemisphere bear quite a strong resemblance to the most recent seasonal output from JMA for the upcoming winter period, with the JMA's pattern generally shifted west relative to the anologue set and some discrepancies over Siberia. Here are the two side-by-side (sorry that they're not centered at the same longitude): 

 

Comparing average September SSTAs of the Jan-through September data analogues to the SSTAs observed at the mid-point of September this year: 

It's worth noting that the analogue SSTAs are biased negative because 4 of the 5 are earlier than the mid-point of the 1991-2020 reference period and that the observed SSTAs from last month are biased positive due to 2022 being a lot later than the mid-point of the reference period. 

Generally tropical SSTAs are very similar with the negative IOD and La Nina imprint present in both. I would say that north Atlantic SSTAs are fairly similar, with the warm Atlantic blob present last month centered further west relative to the analogue years, which could possibly partly explain the generally westward pattern shift of JMA's MSLP output for DJF relative to DJF in the analogue years but that's probably just conjecture. 

On the other hand, the north Pacific looks quite different, you would have to say.

 

This analysis was generally just out of curiosity and I certainly wouldn't want to make a forecast purely based on observed monthly precipitation prior to the target month, but it does beg the question of to what extent predictability of future weather patterns can be gained from looking at patterns of precipitation.

Whilst attempting to build my statistical model of CET and England Precipitation I have found statisically significant associations between precipitation in certain months and CET several months down the line. I would otherwise not have investigated these links were it not for several discussions I've seen on here (and YouTube) hypothesising a link between warm Septembers and warm winters and also dry Septembers and warm winters. The former has no connection statistically speaking with winter CET, but the latter does: there was a 99.6% confidence that a wet September was associated with colder Decembers if I recall correctly, but there was no statistically significant association between September and any other winter month.

I have to say, I went into that analysis very sceptical about there being any connection, and was intending to dispel the myth but needless to say I was proved wrong and I will now be incorporating patterns of precipitation into my model, so well done to whoever first suggested that link  

 

Thanks for this pal, Intriguing that these analogues are matched up with the anomalies progged by the Asian seasonal models (JMA/BCC). 
 

I think many on here are rightly sceptical of anything cold coming off this or any other winter due to so few -NAO winter months since 2013.  Though folks probably thought the same thing in 2008 and 1938 too. 
 

Nevertheless, most of the analogues and modelling I’ve seen does support the possibility of your analogue at least partially verifying. 
 

For coldies, That blasted SE euro high anomaly needs to do one though. Otherwise we could end up with a 2018/19 style anomaly with plenty of blocking but no real cold and snow. I think that’s more likely than a 19/20 style Pv of doom, at least till mid Jan. 

Personally I agree with @Singularity’s superb metswift analysis that mentions a 25% chance of very cold conditions. More than usual, but certainly not nailed on.

 

[Don]

5 hours ago, Uncertainy said:

For coldies, That blasted SE euro high anomaly needs to do one though. Otherwise we could end up with a 2018/19 style anomaly with plenty of blocking but no real cold and snow. I think that’s more likely than a 19/20 style Pv of doom, at least till mid Jan. 

My concern is what's going to move that SE Euro high?!

[Cheshire Freeze]

CFS nice and seasonal for December

[northwestsnow]

2 hours ago, CreweCold said:

CFS nice and seasonal for December

Fingers crossed  

I suspect we are all going to be sick of wind and rain in a few weeks time..

Anyway, 

Exeter flirting with snow in the NW as we head into the second half of November in their latest update..

2010 anyone

Edited October 23, 2022 by northwestsnow

[bluearmy]

7 hours ago, CreweCold said:

CFS nice and seasonal for December

Four pretty consistent runs with higher heights and slp to our northwest didn’t get to five 

[Don]

9 hours ago, CreweCold said:

CFS nice and seasonal for December

Yes not bad, if only we could rid that poxy high pressure over SE Europe!

6 hours ago, northwestsnow said:

Fingers crossed  

I suspect we are all going to be sick of wind and rain in a few weeks time..

Anyway, 

Exeter flirting with snow in the NW as we head into the second half of November in their latest update..

2010 anyone

Yes, that raised my eyebrow yesterday!

[BLAST FROM THE PAST]

This autumn and indeed summer ( more extreme of cse) has 1984 overtones to it.  I’m suspecting a generally mild Nov too.  No bad thing imo.  Very interesting posts above, great analysis and some eyebrow raising modelling

 

BFTP

Edited October 23, 2022 by BLAST FROM THE PAST

[Premiere Neige]

10 minutes ago, BLAST FROM THE PAST said:

This autumn and indeed summer ( more extreme of cse) has 1984 overtones to it.  I’m suspecting a generally mild Nov too.  No bad thing imo.  Very interesting posts above, great analysis and some eyebrow raising modelling

 

BFTP

No bad thing in terms of your heating bill or getting cold in later down the line? (Or both!)

[Don]

1 hour ago, Premier Neige said:

No bad thing in terms of your heating bill or getting cold in later down the line? (Or both!)

What will concern me is if we don't start seeing colder weather develop through November, given La Nina produces it's cold signal early winter and milder later.  I know there's more to it than ENSO, but I feel we need to see things changing soon.

[Gizzy]

6 minutes ago, Don said:

What will concern me is if we don't start seeing colder weather develop through November, given La Nina produces it's cold signal early winter and milder later.  I know there's more to it than ENSO, but I feel we need to see things changing soon.

I just read the snow word being mentioned in the met office outlook for the North end of November.

[SqueakheartLW]

40 minutes ago, Don said:

What will concern me is if we don't start seeing colder weather develop through November, given La Nina produces it's cold signal early winter and milder later.  I know there's more to it than ENSO, but I feel we need to see things changing soon.

Remember November and early December 2009 were mild and wet. Then we all know what happened after that. Same situation with November and the first 2/3's of December 2000 before a colder than average winter 2000/01 set in, admittedly not as cold as 2009/10 but mild autumn doesn't automatically mean mild winter to come.

Remember late October and then November 2005. We have very similar pattern now with persistent southerly winds and above average temps. Then a big flip mid November 2005 and snow was seen by late in the month.

Edited October 23, 2022 by SqueakheartLW

[damianslaw]

23 minutes ago, SqueakheartLW said:

Remember November and early December 2009 were mild and wet. Then we all know what happened after that. Same situation with November and the first 2/3's of December 2000 before a colder than average winter 2000/01 set in, admittedly not as cold as 2009/10 but mild autumn doesn't automatically mean mild winter to come.

Remember late October and then November 2005. We have very similar pattern now with persistent southerly winds and above average temps. Then a big flip mid November 2005 and snow was seen by late in the month.

Oddly I always think the chance of cold are much higher after a lengthy 'southerly very mild period as we are having now, all that heat heading north, comes back as cold heading south... warm air advection...

[Don]

1 hour ago, Gizzy said:

I just read the snow word being mentioned in the met office outlook for the North end of November.

Yep

[Don]

31 minutes ago, SqueakheartLW said:

Remember November and early December 2009 were mild and wet. Then we all know what happened after that. Same situation with November and the first 2/3's of December 2000 before a colder than average winter 2000/01 set in, admittedly not as cold as 2009/10 but mild autumn doesn't automatically mean mild winter to come.

Remember late October and then November 2005. We have very similar pattern now with persistent southerly winds and above average temps. Then a big flip mid November 2005 and snow was seen by late in the month.

Ref to 2009, there was a central based El Nino (Modiki) event, so I don't think this year is really comparable.  However, I do not know off hand what the ENSO state was in late 2005?  This October is similar to 2005 though which was the second warmest on record after 2001, I believe and rather wet, too.  We seemed to go from late summer to early winter that year, with little autumnal weather as September was also very warm!  

[damianslaw]

1 minute ago, Don said:

Ref to 2009, there was a central based El Nino (Modiki) event, so I don't think this year is really comparable.  However, I do not know off hand what the ENSO state was in late 2005?  This October is similar to 2005 though which was the second warmest on record after 2001, I believe and rather wet, too.  We seemed to go from late summer to early winter that year, with little autumnal weather as September was also very warm!  

November 2005 was interesting, a very mild first week, then high pressure took over by mid month, and the second half was notably cold with northerly winds... and snow for some.

[Don]

59 minutes ago, damianslaw said:

November 2005 was interesting, a very mild first week, then high pressure took over by mid month, and the second half was notably cold with northerly winds... and snow for some.

Do you know what the ENSO state was back then?

2005/06 was a little disappointing overall being a 'near miss' winter.

[North-Easterly Blast]

1 hour ago, SqueakheartLW said:

Remember November and early December 2009 were mild and wet. Then we all know what happened after that. Same situation with November and the first 2/3's of December 2000 before a colder than average winter 2000/01 set in, admittedly not as cold as 2009/10 but mild autumn doesn't automatically mean mild winter to come.

Remember late October and then November 2005. We have very similar pattern now with persistent southerly winds and above average temps. Then a big flip mid November 2005 and snow was seen by late in the month.

I would not call winter 2000-01 a particularly cold winter.  It was really fairly average overall for the south after the mild first half of December, although it was colder in the north as many colder spells that winter were more focused on the north.  I would put winter 2000-01 as a winter that was in some ways, a bit similar to 2020-21 more recently.  Admittedly winter 2000-01 was colder than many winters of the last 35 years, though in the grand scheme of things it was more of an average winter.

[summer blizzard]

05/06 was weak el Nino, -qbo, -pdo

[BLAST FROM THE PAST]

 October very wet and mild, Nov very mild with lots of southerly winds, December started mild but turned colder in south mid month.  1984 with La Nina

Jan 1985…..cet 0.8c…legend of a winter month.

no early winter.  ENSO only part of the picture so no panic in that regards.  I do think Scandinavia has to be watched though Nov/Dec, if it’s cold up there I much prefer that for cold chances.
 

BFTP

 

[jules216]

Sometimes my head just dont understand people. There is suddenly a large army of people hoping this obscure warmth in October and +10 days modeling lasts to remaining of cold season. Its crazy to want +3 anomally and thinking atmosphere wont find compensating month in spring, what is there to want if we start vegetation period 3-4 weeks early for frost to kill the crops in April? Or what if this +3 anomally will extend till summer? We had ,+2 May,+3 June and half the villages had their well waterfree by July. I just dont get this at All. They thing IT will be mild a la carte,how suits and then will moderate as they wish? I get the +1 winter OK bit of seasonality but why wanting this +3 to go on forewer?