Model Output Discussion - New Year and Beyond

[alexisj9]

16 minutes ago, mushymanrob said:

Hi
to answer your  points, yes they are anomalies, but you can determine where the mean surface troughs and highs are, the flow contours illustrate that in conjunction with the surface pressure anomalies. And the Anomalies are only useful when consistent, and the EPS very often arent as you pointed out. But overall, they are saying the same thing. This is supported by the NOAA charts which i prefer, others have said they expect a period of Westerlies, a +ive NAO for this period.

So these charts may vary a little, but broadly they are on the same page and with NOAA support id suggest this pattern has some merit, with the usual caveat that nothing is certain until it happens!

We all have our "go to" preferred suite to determine what might lie ahead, its all part of the fun. Obviously im a fan of Anomaly charts, because i have never made the MJO work! I see a strong orbit an a phase, check the composite for that phase in that month...and it never seems to become reality! Ok others might argue against that, fair enough . The MJO doesnt "work" for me like the Anomalies dont "work" for others ... theres no right or wrong here, just differences in preferences and understandings.

If these predictive charts change, then so be it, but for now a +ive NAO looks likely to start February.. imho.

These charts lag behind the EPS, but are heading the same way, dropping heights to our North they showed just the other day.
 

Was it temp or high anomalies, as it looked like hight anomalies to me, which might not be as warm as they look, although the one over us, it does depend on whether it's centered over us or below, it looked quite mid, alother also at the Azores and Europe, so might have it's center over us, which would actually be cold, as apposed to what some models were showing yesterday which would be warm

[MATTWOLVES 3]

Tell you what gang if Marco p is talking up the chances of an SSW event we are looking good...as our Marco loves nothing more than some milder conditions  

Let's make February a little more spicy hey chaps and lasses.

Have a large Weekend and have a cheeky topple for ya old mate Matt  

[mushymanrob]

14 minutes ago, alexisj9 said:

Was it temp or high anomalies, as it looked like hight anomalies to me, which might not be as warm as they look, although the one over us, it does depend on whether it's centered over us or below, it looked quite mid, alother also at the Azores and Europe, so might have it's center over us, which would actually be cold, as apposed to what some models were showing yesterday which would be warm

Height..... also use the contour lines, they represent the DAM... they flow West - East or left - right and suggest a mean Southwesterly over us. A Southwesterly in February isnt usually cold!

[bluearmy]

1 hour ago, Catacol said:

2 things on EPS anomaly charts. Firstly - they are anomaly charts and not synoptic charts. I have been caught out more than once before in reading an anomaly as a likely guide to flow...but it doesn't always happen that way.

Secondly they vary wildly though, like many, I enjoy using them to try and pick patterns. Take the chart for a week ago on EPS for the 29 Jan at 360 given you are using very long range charts:

 

And now the EPS from last night for the same day:

Just a tad different in the atlantic.

I think EPS up to 240h is useful. Beyond that - cannon fodder. I'd rather interpret based on likely drivers and at the moment there is a fading MJO phase 7/8 signal that we are still benefitting from plus an impending SPV slowdown and stressed pattern that may impact things into February. This suggests pathways are still open for blocking, and if the MJO does manage to get back around to phase 7 on its 30-60 day cycle which currently looks to be moving on the swift side, then another blocking pathway will be open for the second half of February also.

Cold has been extended, models have not performed well this winter overall imo. Much gravy still in the pot.

I would never ignore week 2 eps output BUT ahead of a very quick reversal of flow above 70N, I’ll make an exception 

[TSNWK]

1 hour ago, mushymanrob said:

Hi
to answer your  points, yes they are anomalies, but you can determine where the mean surface troughs and highs are, the flow contours illustrate that in conjunction with the surface pressure anomalies. And the Anomalies are only useful when consistent, and the EPS very often arent as you pointed out. But overall, they are saying the same thing. This is supported by the NOAA charts which i prefer, others have said they expect a period of Westerlies, a +ive NAO for this period.

So these charts may vary a little, but broadly they are on the same page and with NOAA support id suggest this pattern has some merit, with the usual caveat that nothing is certain until it happens!

We all have our "go to" preferred suite to determine what might lie ahead, its all part of the fun. Obviously im a fan of Anomaly charts, because i have never made the MJO work! I see a strong orbit an a phase, check the composite for that phase in that month...and it never seems to become reality! Ok others might argue against that, fair enough . The MJO doesnt "work" for me like the Anomalies dont "work" for others ... theres no right or wrong here, just differences in preferences and understandings.

If these predictive charts change, then so be it, but for now a +ive NAO looks likely to start February.. imho.

These charts lag behind the EPS, but are heading the same way, dropping heights to our North they showed just the other day.
 

Big test of the theory of anomoly or gfs  op runs today.. be interesting to see outcome in 10 days.

[nick sussex]

The ICON remains least interested in some colder air around the southern and eastern flank of the high between day 5 and 6 .

This comes after a slightly more amplified ECM op 06 hrs run to T90 hrs.

 

[Mike Poole]

2 hours ago, mushymanrob said:

Hi
to answer your  points, yes they are anomalies, but you can determine where the mean surface troughs and highs are, the flow contours illustrate that in conjunction with the surface pressure anomalies. And the Anomalies are only useful when consistent, and the EPS very often arent as you pointed out. But overall, they are saying the same thing. This is supported by the NOAA charts which i prefer, others have said they expect a period of Westerlies, a +ive NAO for this period.

So these charts may vary a little, but broadly they are on the same page and with NOAA support id suggest this pattern has some merit, with the usual caveat that nothing is certain until it happens!

We all have our "go to" preferred suite to determine what might lie ahead, its all part of the fun. Obviously im a fan of Anomaly charts, because i have never made the MJO work! I see a strong orbit an a phase, check the composite for that phase in that month...and it never seems to become reality! Ok others might argue against that, fair enough . The MJO doesnt "work" for me like the Anomalies dont "work" for others ... theres no right or wrong here, just differences in preferences and understandings.

If these predictive charts change, then so be it, but for now a +ive NAO looks likely to start February.. imho.

These charts lag behind the EPS, but are heading the same way, dropping heights to our North they showed just the other day.
 

As you say, we all have our go to products to gaze into the future.  I know that the anomaly charts have been shown to work well in some circumstances.  My take is that they work well when the ensemble members are broadly in agreement about the direction of travel, but maybe disagree about the time to get there - the fact they are averaged over time as well as ensemble members gives some protection against that, when compared to the ensemble mean at one particular time.  

They are not my preferred tool, though, for two reasons.  First, I don’t really like averaged pressure/heights or anomaly charts.  At 10 days out, an average chart is like no actual weather would actually be, so it can be difficult to interpret the highs and lows and flows.  

The second reason relates more to the 10-15 day period, which we are often looking at in winter, it seems.  This is that they really don’t work when there are big divergences in model predictions, which can be completely masked by the averaging.  It’s like trying to shoehorn the fact that multiple possibilities exist, into a single prediction, which for me, often doesn’t respect the uncertainty that exists on that timescale. 

Which is why I much prefer the cluster analysis on this timescale - if there are multiple, different options, they are shown.  And they are each illustrated not by an average, but by a single representative member, so the pressure field makes sense.  The downside is they often don’t really illuminate just one most likely path…

 

Edited January 21, 2023 by Mike Poole

[mushymanrob]

5 minutes ago, Mike Poole said:

As you say, we all have our go to products to gaze into the future.  I know that the anomaly charts have been shown to work well in some circumstances.  My take is that they work well when the models are broadly in agreement about the direction of travel, but maybe disagree about the time to get there - the fact they are averaged over time as well as ensemble members gives some protection against that, when compared to the ensemble mean at one particular time.  

They are not my preferred tool, though, for two reasons.  First, I don’t really like averaged pressure/heights or anomaly charts.  At 10 days out, an average chart is like no actual weather would actually be, so it can be difficult to interpret the highs and lows and flows.  

The second reason relates more to the 10-15 day period, which we are often looking at in winter, it seems.  This is that they really don’t work when there are big divergences in model predictions, which can be completely masked by the averaging.  It’s like trying to shoehorn the fact that multiple possibilities exist, into a single prediction, which for me, often doesn’t respect the uncertainty that exists on that timescale. 

Which is why I much prefer the cluster analysis on this timescale - if there are multiple, different options, they are shown.  And they are each illustrated not by an average, but by a single representative member, so the pressure field makes sense.  The downside is they don’t really illuminate just one most likely path…

 

Hi Mike...

To pick up on your second point, yes, they can miss the emerging correct pattern at first, so might not always be "first" to spot the emerging trend. But for me theres strong point is the opposite .. they also cancel out false "garden path" developments. So for me, "average" is good, because if theres a new emerging pattern, the anomalies will pick it up (unless its too near) , even if they arent first - they seldom lead us up the garden path... well, not as much as the ops! And being a blend of the GFS, ECM, and Canadian suites to create an average , are their strength imho.

Anyway, lets just move on now, February is a long way off and im not as confident with the EPS suite as i am the NOAA, so the EPS charts i used earlier may well not be proven accurate. Ill be happier when/if the NOAA fully support them.

[Bristawl Si]

1 hour ago, MATT TATTOO said:

Tell you what gang if Marco p is talking up the chances of an SSW event we are looking good...as our Marco loves nothing more than some milder conditions  

Let's make February a little more spicy hey chaps and lasses.

Have a large Weekend and have a cheeky topple for ya old mate Matt  

MetO update mentions nowt nor any hints.

Huge disconnect there.

MP is a MetO employee. Very strange.

No reputable company would allow a senior bod to tweet stuff, totally at odds with official comms.

[syed2878]

2 hours ago, January Snowstorm said:

From years of watching and trying to interpet charts I get a feeling we are on the cusp of something special next 48hours!! Upgrades can arrive very quickly and at a short timeframe +150 hrs etc.

As teits commented the gfs control looks good, indeed it's not far off spectacular 

 A very optimistic post. I would love to think this would be the case even the Met office. Don’t think we will be affected by an SSW. In fact they are going for temperatures average to slightly above for February in their extended outlook. By no means I am calling winter over because it’s not we have quite a bit of time to go but it’s not looking very good.

[feb1991blizzard]

40 minutes ago, nick sussex said:

The ICON remains least interested in some colder air around the southern and eastern flank of the high between day 5 and 6 .

This comes after a slightly more amplified ECM op 06 hrs run to T90 hrs.

 

The GFS 6z is best in this regard, was going to ask if your ignoring it and only using reliable models but its a rhetorical question really.

[Ali1977]

10 minutes ago, Bristle Si said:

MetO update mentions nowt nor any hints.

Huge disconnect there.

MP is a MetO employee. Very strange.

No reputable company would allow a senior bod to tweet stuff, totally at odds with official comms.

Any SSW ramifications would be after mid feb, their long range only just gets towards mid feb. I imagine we may see some wording change referencing the chance of colder conditions by early next week - if they think there’s a decent chance of an SSW that is. 
 

They do mention poss colder chances 1st week of February, short ones, so poss topplers 

Edited January 21, 2023 by Ali1977

[January Snowstorm]

Poor gfs run anyway, that's for sure!! You couldn't draw charts any worse tbh. Here's hoping the ukmo and ecm can produce something even a small bit better!

[Mike Poole]

GFS and GEM at T240:

GFS seemingly not following the 6z but not the ECM 12z of yesterday’s horror solution.  GEM maintains the high stronger west of the UK, and makes more of the trough into Eastern Europe, which, in the absence of any high lat blocking available, remains a positive sign, so GEM the pick of the two.

Edited January 21, 2023 by Mike Poole

[Ali1977]

Different strat at day 12, but pretty impressive still!! 

[minus10]

While the strat maybe heating up, once again the gfs finding a massive vortex ....

Edited January 21, 2023 by minus10

[Mike Poole]

Just now, Ali1977 said:

Different strat at day 12, but pretty impressive still!! 

It looks much better than the 6z to me.  The 6z ended up with the vortex rump in a horrible place!  We don’t want it there:

[Mike Poole]

How’s this for a vortex of doom, T306?  Looks like a constipated cat!

Edited January 21, 2023 by Mike Poole

[January Snowstorm]

You can't help but think the Strat charts are going to bear fruit at some point in February. The warmings are showing up almost daily

[Ali1977]

4 minutes ago, Mike Poole said:

How’s this for a vortex of doom, T306?  Looks like a constipated cat!

Building it up ready to be smashed to pieces in 3 weeks

[minus10]

929 mb ???

[Iceman2606]

Someone please sedate the PV on today's GFS 12z lol

[minus10]

Used to seeing the high black hole but the low??

 

[LightningLover]

This low does a pretty good job at challenging the all-time North Atlantic minimum pressure record (916mb in January 1993)!

[lassie23]

The models spew out constantly changing weather scenarios daily as it is, with nobody any the wiser as to what will happen a week away. The spewing will be on another level if an SSW occurs. I think we should let the spewing continue without taking what the models show currently as gospel.