Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Early run up to Winter 2020/2021 discussion


Mapantz

Recommended Posts

Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
7 hours ago, damianslaw said:

Shouldn't the stratosphere be warming rather than cooling due to greenhouse gas emissions, perhaps my logic is all wrong.. 

No. See what Pete said. CC = cooling stratosphere.

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: Prague
  • Location: Prague
On 18/11/2020 at 10:52, jules216 said:

The atmosphere was fully coupled with La Nina this year if we take in to account summer weather in Europe. This was the wettest summer here since 1998 and 2010 - those were also forming Ninas in spring those years. I have made a very good summer forecast locally based on this as monthly blends were exactly how the regime behaved in May,June and July, things have started to be complicated exactly in August where there was a heatwave in central Europe that lasted for nearly 3 weeks - not seen in analog blend which suggested euro trough. This is probably because of +AAM spike. This AAM spike in autumn also put La Nina off track so no early season cold shot in Europe but Euro high instead. This will be 1st La Nina that will not feature any snow here in November(Slovakia)  out of last 10! crazy if you thing this will be 1st no November snow La Nina - all 2017,2016,2011,2010,2008,2007,2005,1998,1998,1995 featured at least one if not multiple cold shots in to continental Europe in November yet this one is such an exception.

If you want to know my opinion I either dont understand AAM/GSDM at all or think its overrated, why? Because there were a good few of those last 10 La ninas that had similar MJO progress in autumn yet produced Europe cold shots, so presuming +AAM is not an exception this year and also featured in some past 10 autumn Ninas but didn't stand in the way of cold shots in November.

What I do think its more relevant is - Haddley Cell poleward expansion and cooling upper levels of atmosphere to balance out record warm troposphere. Already if you look at polar profile this autumn its nearly a continuation of last winter while we keep breaking global temperature records at surface level. These two Haddley Cell + stratosphere are easily outweighing what would you call typical atmosphere behavior driven by Pacific Ocean - ENSO. Unfortunately these effects are enhanced in boreal winter which is even worse for those of cold persuasion. 

Hey Jules,

is there any source where to gain a deeper understanding of the impact of AAM on Europe? Thanks!

Link to comment
Share on other sites

Posted
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
4 hours ago, BREZEEK said:

Hey Jules,

is there any source where to gain a deeper understanding of the impact of AAM on Europe? Thanks!

You need to read the whole GSDM synoptical conundrum. As a general rule to get cold weather in to Europe in winter from AAM perspective we need a robust MJO convection to travel eastwards from Indian Ocean to Maritime continent and Western/Eastern Pacific - phases 4-8. Initially there is a rise of frictional torque followed by mountain torque events that slow that general westerlies in mid latitudes. The Rossby wave train associated with strong MJO pulses initially effect the Pacific jet stream and initially force a equatorward momentum flow at 35N which help promoting ridges to the north. It is a very complex diagnostics very much dependant on the base state of the atmosphere plus seasonal wave lengths. So AAM response in winter may be different to the summer one. We have some experts here in the forum like @Tamara or @Blessed Weather who can explain this in greater detail then me for sure

 

cfsv2_aam_fcst_current.png

GWO_members_current.png

image.png.b7ca17078035440d92fd88ebd4e8538d.png

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Prague
  • Location: Prague
43 minutes ago, jules216 said:

You need to read the whole GSDM synoptical conundrum. As a general rule to get cold weather in to Europe in winter from AAM perspective we need a robust MJO convection to travel eastwards from Indian Ocean to Maritime continent and Western/Eastern Pacific - phases 4-8. Initially there is a rise of frictional torque followed by mountain torque events that slow that general westerlies in mid latitudes. The Rossby wave train associated with strong MJO pulses initially effect the Pacific jet stream and initially force a equatorward momentum flow at 35N which help promoting ridges to the north. It is a very complex diagnostics very much dependant on the base state of the atmosphere plus seasonal wave lengths. So AAM response in winter may be different to the summer one. We have some experts here in the forum like @Tamara or @Blessed Weather who can explain this in greater detail then me for sure

 

cfsv2_aam_fcst_current.png

GWO_members_current.png

image.png.b7ca17078035440d92fd88ebd4e8538d.png

Thanks a lot!!! I know how the MJO modulates the mid-latitude circulation, but I am missing the connection to AAM. I will go through the article you recommend. Hezký den!

Link to comment
Share on other sites

Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset
On 22/11/2020 at 11:01, SqueakheartLW said:

Here's a nice little run for those who hate the Atlantic dominating during December to February in particular, the latest 12z CFS

 

Love it. I'm sure a winter like that would please the majority on here.

I've also always though the first half of March is a near perfect time to have a spell of Atlantic storminess - the best of winter has passed but spring proper is still a few weeks away, but Pm airmasses pack more of a punch than in December. 2015, 2019 and 2020 (and a to a lesser extent 2017) were all great in that respect.

Link to comment
Share on other sites

Posted
  • Location: manchester
  • Weather Preferences: Summer
  • Location: manchester

There seems to be a trend within the CFS model for a Scandi High build and an easter'ly coming off it around the mid December to Xmas period. Gav Partridge has also been highlighting it in his Christmas updates. 

 

  • Like 4
Link to comment
Share on other sites

10 minutes ago, 38.7°C said:

There seems to be a trend within the CFS model for a Scandi High build and an easter'ly coming off it around the mid December to Xmas period. Gav Partridge has also been highlighting it in his Christmas updates. 

 

Yeah I think it will come off! These Cfs charts won’t drop the idea, it’s been a trend on there models! I’m so excited!! 

Link to comment
Share on other sites

Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Storm, drizzle
  • Location: Woodchurch, Kent.
5 hours ago, SqueakheartLW said:

Right near that green patch across E England on the first chart. Shame the snow level numbers aren't at 0 as that will be a no show event otherwise

Knowing the luck of the South that's true

Link to comment
Share on other sites

Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

My sixth CFS Christmas update here for you all to read today containing the next 10 days worth of analysis from the CFS 9 monthly runs from meteociel

My first to fifth updates came in with the following figures

Update 1

26/09/2020 to 05/10/2020 Data

Temps            0z          6z       12z          18z     TOTALS          Precip            0z           6z         12z      18z      TOTALS

V Mild                                                                    0                   V Dry                                                                     0

Mild                 2                        1              2          5                   Dry                  2             4          3           7           16

Average          4            6          5              3         18                  Average          4             2          4           2           12

Cold                 4           3          4              3         14                  Wet                 4             4          3           1           12

V Cold                           1                          2          3                   V Wet                                                                    0

LEADER        AV/CD    AV    AV/CD    AV/CD    AV                  LEADER     AV/WET     AV       AV       DRY       DRY

AVERAGE TO COLDER THAN AVERAGE CHRISTMAS PREDICTED IN FIRST UPDATE

DRIER THAN AVERAGE CHRISTMAS PREDICTED IN FIRST UPDATE

Update 2

06/10/2020 to 15/10/2020 Data

Temps           0z           6z         12z       18z     TOTALS          Precip           0z           6z           12z       18z     TOTALS

V Mild                                                                   0                   V Dry                                                                     0

Mild                1                                                    1                   Dry                 2             2              2           1         7

Average         7             7             6            3       23                 Average         6             4             7            6        23

Cold               1             3             2            5       11                 Wet                2             3             1            3         9

V Cold            1                            2            2        5                  V Wet                            1                                      1

LEADER        AV          AV           AV         CD      AV                LEADER        AV           AV          AV          AV      AV

AVERAGE TEMPERATURES PREDICTED FOR CHRISTMAS. COLDER THAN AVERAGE MOST LIKELY ALTERNATIVE

AVERAGE PRECIPITATION EXPECTED FOR CHRISTMAS

Update 3

16/10/2020 to 25/10/2020 Data

Temps          0z           6z           12z         18z         TOTALS          Precip           0z           6z           12z          18z       TOTALS

V Mild                                                                        0                     V Dry                                                                         0

Mild                                                              2           2                     Dry                1             3              3               3         10

Average        5             4              5              3          17                   Average        6             7              4               5         22

Cold              5             3              5              4           17                  Wet               3                             3                2         8

V Cold                          3                              1            4                   V Wet                                                                        0

LEADER     AV/CD     COLD     AV/CD      COLD    AV/CD           LEADER       AV           AV           AV              AV       AV

AVERAGE TO COLDER THAN AVERAGE CHRISTMAS PREDICTED

AVERAGE PRECIPITATION PREDICTED FOR CHRISTMAS

Update 4

26/10/2020 to 04/11/2020 Data

Temps          0z           6z           12z         18z         TOTALS          Precip           0z           6z           12z          18z       TOTALS

V Mild                                                                             0                V Dry                                                             1                1

Mild                1             2             1             1                 5               Dry                 4            6              4               5               19

Average          6            6             7              3               22              Average         4            4              5               3               16

Cold                3                            2              5               10             Wet                2                             1               1                5

V Cold                            2                             1                3              V Wet                                                                               0

LEADER         AV           AV          AV           CD             AV             LEADER    AV/DRY    DRY      AV/DRY       DRY          DRY

AVERAGE TEMPS PREDICTED FOR CHRISTMAS

DRIER THAN AVERAGE CHRISTMAS PREDICTED

Update 5

05/11/2020 to 14/11/2020 Data

Temps          0z           6z           12z         18z         TOTALS          Precip           0z           6z           12z          18z       TOTALS

V Mild                                                                             0 (0)          V Dry                                                                             0 (-1)

Mild               1             1              2             1                5 (0)          Dry                                 1              1              1             3 (-16)

Average        4             4              4             5               17 (-5)        Average          9            5              6              6             26 (+10)

Cold              5             5              3             4                17 (+7)      Wet                  1            4              3              3             11 (+6)

V Cold                                          1                                1 (-2)        V Wet                                                                             0 (0)

LEADER    AV/CD    AV/CD    AV/CD     AV/CD         AV/CD        LEADER          AV     AV/WET       AV            AV           AV

LATEST UPDATE - UPDATE 6

Now it is time to reveal the latest 10 days of analysis from the 9 monthly CFS runs for Christmas 2020. The change from the previous update is shown in brackets next to the figures in the totals column.

15/11/2020 to 24/11/2020 Data

Temps          0z           6z           12z         18z         TOTALS          Precip           0z           6z           12z          18z       TOTALS

V Mild                                                                             0 (0)          V Dry                                                                             0 (-1)

Mild               2             1                             1                4 (-1)         Dry                  1            2              3              3             9 (+6)

Average        1             7              2             5               15 (-2)        Average          6            7              3              6             22 (-4)

Cold              6             2              7             4                19 (+2)      Wet                  3            1              4              1             9 (-2)

V Cold           1                              1                               2 (+1)        V Wet                                                                             0 (0)

LEADER       CD          AV            CD          AV              AV/CD        LEADER         AV          AV          AV             AV            AV

Temperatures - Between update 5 and the latest update 6 we have seen a small shift back towards colder than average again which is good news if you are looking for a cold Christmas anyway. The most important factor is to have the day cold first so that if we do get any precipitation it has a higher chance of ending up wintry or snow

Precipitation - Between update 5 and the latest update 6 we have shifted back towards really bang on average this time compared with the wetter update last time. 22 for average with 9 each for dry and wet really confirms the average signal in the last 10 days. Still a chance of a white Christmas then with the colder signal too

ECWEF CHARTS

Here are the latest 500mb anomaly charts for the week that includes Christmas Day since my last update

Untitled500a.thumb.png.f9667580caced327e56d1ad5453ad77a.pngUntitled500b.thumb.png.3f99d4c9714d7152d14cc51bea8f0ba1.pngUntitled500c.thumb.png.2ccb50255c3917aecf7d09b2b6158fb3.png

Here are the 2m temperature anomaly charts that go with the above

Untitled2a.thumb.png.298bce819bc7b8f50c1098ff4ca6ef0d.pngUntitled2b.thumb.png.11397ee3df43b97b6719a880ef9f28a1.pngUntitled2c.thumb.png.e008c0b063c3b6a792272ffe10b823dd.png

All in all ECWEF are going for below average precipitation with the high pressure signal on 2 of 3 of the latest runs but not looking good for cold based on the 2m temp anomaly charts as 1 is average and the other 2 have us just above average overall so no white Christmas if ECWEF have it nailed on that is

GFS Extended

Another recently discovered thing now is the extended GFS charts and I have dug out todays 12z extended control run chart just to show you and on each update until the final one I shall just throw in this chart as a bonus extra at the end of the update

The latest 500mb chart from this run is below with the 850mb chart with it

image.thumb.png.b7385c3f2a3d61be959f00542724664b.pngimage.thumb.png.2d451fa3dcb88e99e670032cfe4383ad.png

That looks good for Christmas Day with that nice Arctic northerly, no doubt bringing a risk of snow for some, especially in the north. At least one cold option showing up but is this part of a trend or a one off?

My next update will be on 04/12/2020

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
13 hours ago, Turnedoutniceagain said:

Has Madden dropped his usual "12metres of SNOW, Arctic KILLER BLAST" on the Daily Express yet?

Watch it... I recently questioned the veracity of the 'LIA Footprint' (I think?) But, hey, posts do have an ever-increasing habit of 'disappearing' these days?

Link to comment
Share on other sites

Posted
  • Location: Netherlands
  • Location: Netherlands

Previous studies have revealed the relationship between the Madden–Julian oscillation (MJO) and the Arctic Oscillation (AO). The MJO phase 2/3 is followed by the positive AO phase, and the MJO phase 6/7 is followed by the negative AO phase. This study reveals that the MJO phase 6/7–AO connection is modulated by the Quasi-Biennial Oscillation (QBO) through both tropospheric and stratospheric pathways during boreal winter. The MJO 2/3 phase and AO relationship is favored in both QBO easterly (QBOE) and westerly (QBOW) years because of the MJO-triggered tropospheric Rossby wave train from the tropics toward the polar region. The AO following the MJO 6/7 phase shifts to negative in QBOW years, but the MJOAO connection diminishes in QBOE years. In QBOW years, the Asian-Pacific jet is enhanced, leading to more evident poleward propagation of tropospheric Rossby wave train, which contributes to the tropospheric pathway of the AOMJO 6/7 connection. Besides, the enhanced Asian-Pacific jet in QBOW years is favorable for vertical propagation of planetary waves into the stratosphere in MJO phase 6/7, leading to negative AO, which indicates the stratospheric pathway of the AOMJO 6/7 connection.

atmosphere-11-00175-g001-550.jpg
WWW.MDPI.COM

Previous studies have revealed the relationship between the Madden–Julian oscillation (MJO) and the Arctic Oscillation...

 

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

Anyone hoping for a cold December may wish to be more patient. The CFS monthly charts on weather outlook are favouring a back loaded winter with quite a strong signal for this. Take today's set of charts as an example

December 2020

12_2020_00z_500.thumb.png.1d73f660f96d4aa796a051cfa29e31bb.png12_2020_00z_850temp.thumb.png.a3ba1be7dd8d4f3dc0660e6243d3f5e0.png

January 2021

01_2021_00z_500.thumb.png.7e65f6529397c4990caa79e5bb83beca.png01_2021_00z_850temp.thumb.png.d4db4f33c8f600f123e4996311d7566a.png

December and January charts have this sort of flavour a lot with low pressure either over us or to our N or NW bringing Atlantic domination and no doubt average temperature when averaging out the alternating Pm and Tm airmasses between systems

December looks slightly cooler than January here on the above charts with more of a W wind on average with December compared with a more SW - NE axis on January

However the fun begins in February

February 2021

02_2021_00z_500.thumb.png.b796fc95e55f46bc43081d8dc51e9876.png02_2021_00z_850temp.thumb.png.57165cffe3b4bb88e18167b2a52d8b6d.png

Look at that big pattern flip for February 2021. Have been seeing this trend a lot in the last few weeks with very much boring mundane conditions for earlier in the winter then the fun starting later on. With that low pressure parked over the UK and all that blocking to our W and N that looks game on for a cold February and some snow at least with that low pressure near to us.

March 2021

03_2021_00z_500.thumb.png.166bbcc5d4ed74f8c94006b6fca937e4.png03_2021_00z_850temp.thumb.png.51a7ed022489b5dad171d6075da96e05.png

This March chart today looks quite extreme for the blocking and how long fetch those NE winds are. The winds originate all the way from eastern Siberia and blow right across Russia and into Europe. This is a real snow maker March if this average monthly anomaly came off

Link to comment
Share on other sites

Posted
  • Location: Aviemore
  • Location: Aviemore

Since the weather has been doing irony pretty well this year (wall-to-wall sunshine throughout the spring lockdown as an example), I'm wondering if we ought to prepare for the mother of all snowstorms to arrive on the 23rd so we're all snowed in for Christmas?

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl

We are heading into a strong +PNA phase according to forecasts in a moderate/strong Nina background state. Not common. There is much about the global climate setup at the moment that is uncommon. i'm going to say again - historical analogues are looking increasingly suspect. I believe that the amplification that is approaching will not last long - but who knows..... the source of any blocking coming up in the next 10 days is not an artefact of a Nina ridge - it is much more the product of a Nino style wave breaking setup across both atlantic and pacific. I wish I had more long term knowledge and the time to delve into archives to work out just how "uncommon" this all is - but what I am feeling is that we are heading into a winter that might hold a surprise. Strong signal for that Sceuro High, Aleutian Low combo I keep referring to. The head tells me we are moving towards a pretty non descript and generally mild winter - but my heart is not so sure.....and certainly there is some head scratching going on! Weather predictions are never simple...

Edited by Catacol
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Scunthorpe
  • Location: Scunthorpe

I have posted the general version of this post in the ENSO thread but I wanted to post a more specific to this winter version here.

I have crunched all of the data on the websites containing all of the NINO region anomalies on the websites at the top of my latest thread on the ENSO thread, refer to this if you want to see the links

In this thread however I shall specifically concentrate on what is more relevant for this winter, La Nina

First I will post the La Nina years as well as the La Nina stats I have shown on the other thread

La Nina Years

1831601824_LaNinaYears.thumb.jpg.3a3ae1e2d5388a15de2487bb9d92afa3.jpg

La Nina Stats

1304471575_LaNinaStats.thumb.jpg.08ca6fed4f064e80182851890111863d.jpg

The years are arranged in order of highest overall Dec-Mar CET to lowest so as you can see the daddy of all La Nina winters is 1916/17 and by far the most boring mild fest is 1956/57

When looking at the La Nina Stats image there is a clear difference between La Nina strengths and types. It is clear the stronger the event the milder the anomaly becomes overall.

Central Pacific La Nina's came out as mildest overall with East Pacific coldest with mixed events somewhere in the middle. One event somehow achieved Super Nina status using my measure even if this isn't an officially recognised super event but no doubt 1988/89 was a very strong La Nina otherwise

Now I wish to show another piece of recent data and this is simply looking on tropical tidbits and at each NINO chart and taking down the daily NINO anomaly for each region. I only started this a couple of days ago but can't find any daily data anywhere so I can add to my figures

390682917_NinoStatus.thumb.jpg.93625ea428838e0d1fd2584a160bffae.jpg

Using official calculations this La Nina easily fits the moderate status at present based on daily anomalies and using certain calculations it is currently classed as an EP La Nina although no doubt a few weeks ago we would have easily got a mixed event.

Calculation Nino 4 - Nino 3

Nino 4 - Nino 3 is the official calculation used to decide where the biggest anomalies are based with El Nino and La Nina.

El Nino - The more negative this figure the more east based the positive anomalies. The more positive the more centrally based the El Nino is

La Nina - The opposite rule applies for La Nina, positive means more east based, negative more centrally based

Calculation Nino 3.4 - Nino 1+2

This is a calculation I have added myself and is to show how east or centrally based the event is.

El Nino - More negative numbers mean very east based, Positive Numbers mean more centrally based

La Nina - Opposite rule applies to La Nina

Calculation Nino 3.4 - Nino 3

Another custom calculation and this one is more to decide how mixed the ENSO event is. The closer the number is to 0 the more mixed the ENSO event is regardless of type

El Nino - The more positive this number the more the warm anomaly is based nearer NINO 3.4 than 3. Negative numbers mean more NINO 3 based

La Nina - As with other calculations the opposite rule applies to La Nina

Summary

Using my calculations on the latest daily figures we score EP La Nina in NINO 4 - NINO 3 quite easily

NINO 3.4 - NINO 1+2 also scores EP La Nina but only by a small margin. If figure was between -0.09 and +0.09 then it would score mixed

NINO 3.4 - NINO 3 did score mixed on this calculation

The majority score counts here and as EP was 2 to mixed 1 then overall assessment for recent days is EP La Nina

WINTER PROSPECTS IF WE KEEP THIS SETUP

1304471575_LaNinaStats.thumb.jpg.08ca6fed4f064e80182851890111863d.jpg390682917_NinoStatus.thumb.jpg.93625ea428838e0d1fd2584a160bffae.jpg

Referring back to both of these images for the stats we can narrow down straight away to Moderate La Nina. Also we can rule out CP La Nina since it scored 0/3 in the calculations.

EP La Nina is at 2/3 so we can use these figures most but since Mixed got 1/3 then we can look at this as well just in case mixed ends up the end result La Nina over the winter

December Anomaly Moderate EP La Nina = -0.27C          December Anomaly Moderate Mixed La Nina = +0.01C

January Anomaly Moderate EP La Nina = -0.56C               January Anomaly Moderate Mixed La Nina = +0.26C

February Anomaly Moderate EP La Nina = -0.54C            February Anomaly Moderate Mixed La Nina = -0.69C

March Anomaly Moderate EP La Nina = +0.05C                March Anomaly Moderate Mixed La Nina = +0.17C

Overall Anomaly Moderate EP La Nina = -0.33C          Overall Anomaly Moderate Mixed La Nina = -0.06C

 

Using the above and accounting for EP La Nina scoring 2/3 we can calculate an average for all months using this fact combined so EP figures twice along with mixed figures once to produce a predicted anomaly list based on that

Overall December Anomaly Moderate La Nina = -0.18C

Overall January Anomaly Moderate La Nina = -0.29C

Overall February Anomaly Moderate La Nina = -0.59C

Overall March Anomaly Moderate La Nina = +0.09C

Overall Anomaly Moderate La Nina = -0.24C

Overall currently looking good for a colder winter overall, especially in February which is tying in perfectly with the CFS predictions of a cold February in particular but if we can increase the signal for an EP La Nina and iron out the mixed event risk we will be in an even better place overall

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Wath upon Dearne, Rotherham
  • Weather Preferences: Snow, severe frost, freezing fog and summer sunshine
  • Location: Wath upon Dearne, Rotherham
On 24/11/2020 at 07:17, Turnedoutniceagain said:

Has Madden dropped his usual "12metres of SNOW, Arctic KILLER BLAST" on the Daily Express yet?

Haven't seen anything yet. Maybe Nathan Rao of the Express has been on annual leave....

Link to comment
Share on other sites

Posted
  • Location: Scunthorpe
  • Location: Scunthorpe
23 hours ago, sebastiaan1973 said:

Previous studies have revealed the relationship between the Madden–Julian oscillation (MJO) and the Arctic Oscillation (AO). The MJO phase 2/3 is followed by the positive AO phase, and the MJO phase 6/7 is followed by the negative AO phase. This study reveals that the MJO phase 6/7–AO connection is modulated by the Quasi-Biennial Oscillation (QBO) through both tropospheric and stratospheric pathways during boreal winter. The MJO 2/3 phase and AO relationship is favored in both QBO easterly (QBOE) and westerly (QBOW) years because of the MJO-triggered tropospheric Rossby wave train from the tropics toward the polar region. The AO following the MJO 6/7 phase shifts to negative in QBOW years, but the MJOAO connection diminishes in QBOE years. In QBOW years, the Asian-Pacific jet is enhanced, leading to more evident poleward propagation of tropospheric Rossby wave train, which contributes to the tropospheric pathway of the AOMJO 6/7 connection. Besides, the enhanced Asian-Pacific jet in QBOW years is favorable for vertical propagation of planetary waves into the stratosphere in MJO phase 6/7, leading to negative AO, which indicates the stratospheric pathway of the AOMJO 6/7 connection.

atmosphere-11-00175-g001-550.jpg
WWW.MDPI.COM

Previous studies have revealed the relationship between the Madden–Julian oscillation (MJO) and the Arctic Oscillation...

 

Makes me wonder why so many want an EQBO for winter if the WQBO is better at creating a negative AO during phases 6 and 7 compared with an EQBO

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-29 07:13:16 Valid: 29/03/2024 0600 - 30/03/2024 0600 THUNDERSTORM WATCH - FRI 29 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather

    Difficult travel conditions as the Easter break begins

    Low Nelson is throwing wind and rain at the UK before it impacts mainland Spain at Easter. Wild condtions in the English Channel, and more rain and lightning here on Thursday. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-28 09:16:06 Valid: 28/03/2024 0800 - 29/03/2024 0600 SEVERE THUNDERSTORM WATCH - THURS 28 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather
×
×
  • Create New...