Model output discussion - into the last third of January

[Battleground Snow]

Another solid mjo update today, should be crossing into western Pacific now, yesterday it was just about to,

I've also attached the ECM extended phase diagram.

It's looking more likely this forecast will now verify, perhaps the la Nina has just weakened enough?

Maybe 3 strat warmings, a weakening la Nina and the MJO crossing the favourable phase, will finally be enough to deliver the cold into Western Europe. Time will tell.

 

 

[Snipper]

I have the Windy App. When setting it up you can choose which weather forecast model to use. The options are AROME, NEMS, ICON, ECMWF, GFS. 

Which one to choose I ponder for my basic setup that is on average fairly accurate. Any suggestions which ones are good for what? Snow for instance. Been switching from one to another and they are all over the place. 

[Battleground Snow]

7 minutes ago, Snipper said:

I have the Windy App. When setting it up you can choose which weather forecast model to use. The options are AROME, NEMS, ICON, ECMWF, GFS. 

Which one to choose I ponder for my basic setup that is on average fairly accurate. Any suggestions which ones are good for what? Snow for instance. Been switching from one to another and they are all over the place. 

Arome has the the highest resolution, so in theory should be able to pick out the precipitation the best.

[IDO]

23 minutes ago, Battleground Snow said:

Another solid mjo update today, should be crossing into western Pacific now, yesterday it was just about to,

I've also attached the ECM extended phase diagram.

It's looking more likely this forecast will now verify, perhaps the la Nina has just weakened enough?

Maybe 3 strat warmings, a weakening la Nina and the MJO crossing the favourable phase, will finally be enough to deliver the cold into Western Europe. Time will tell.

 

 

Assuming this is correct and the composites are reflective, it still looks more like going into 6 rather than 7:

 source> https://twitter.com/bobbittweather5/status/1352388453607026688?s=20

I think 6 is a milder westerly phase though not sure with the enso factored in? The gefs mean at d16 suggesting nothing too cold and wintry or mild:

d16 mean>

The spread suggests the uncertainty as to where the severe cold and milder weather goes is not in our region:

So for me, I still would be non-committal post-d10, but low-confidence for>>> 

[Purga]

Another wind reversal at 10hPa being predicted by the latest ECM ensembles, for end of Jan

All gris to the mill.

[Griff]

2 minutes ago, Purga said:

Another wind reversal at 10hPa being predicted by the latest ECM ensembles, for end of Jan

All gris to the mill.

I think Biden might win the election too

I'm guessing you've been away from here and social media since last night? 

[Battleground Snow]

18 minutes ago, IDO said:

Assuming this is correct and the composites are reflective, it still looks more like going into 6 rather than 7:

 source> https://twitter.com/bobbittweather5/status/1352388453607026688?s=20

I think 6 is a milder westerly phase though not sure with the enso factored in? The gefs mean at d16 suggesting nothing too cold and wintry or mild:

d16 mean>

The spread suggests the uncertainty as to where the severe cold and milder weather goes is not in our region:

So for me, I still would be non-committal post-d10, but low-confidence for>>> 

Perhaps, but it's right on the line between 6 and 7, so maybe a hybrid composite would be most suitable? Also I notice that composite is marked in red for "low reliability. It looks to head into 7 eventually too.

I am not too sure that the composites are even going to be reflective this year, as this year seems to be a very unique one with a la Nina that atmospherically is acting  more like el Nino as @Daniel* has pointed out.

The positive I take from the MJO is it may at least allow blocking in our locale and the Atlantic, which may be able to link to the Arctic high which strat warmings are helping to maintain a long-term -AO

 

Edited January 22, 2021 by Battleground Snow

[mushymanrob]

Surely for February you need phase 8 not 6 or 7 (6 is similar to 7)

 

[Battleground Snow]

7 minutes ago, mushymanrob said:

Surely for February you need phase 8 not 6 or 7 (6 is similar to 7)

 

I really don't think these composites will be much use in this unique year, but strip ENSO out of the equation and this composite looks broadly similar to the ECM weeklies  even the 2m temps

[Frosty.]

Hey gang, whisper it..BUT..there is some snow in the forecast for the sarf / sarfeast during the next few days according too the Gfs 6z operational..Shirley that’s worth celebrating?...hmmmm..   ...ps.even though I’m from north of the wall.....My dads an eastender so I hope nobody takes offence when I say sarf east?

 

Edited January 22, 2021 by Jon Snow

[Battleground Snow]

Icon has adjusted south Sunday as per the fax chart, but another area of precipitation comes in later in the early hours of Monday morning and gets @sheikhys house... Probably just best to look out of the window this weekend tbh 

[nick sussex]

Both the GFS 06 hrs run and now the latest ICON at T96hrs have a stronger ridge extension from Greenland towards Iceland .

Interesting !

The second shortwave now trying to move in and this is a bit deeper but that also tries to eject east se .

A bit more forcing on that and things could get even more interesting .

 

Edited January 22, 2021 by nick sussex

[Biggin]

17 minutes ago, Jon Snow said:

Hey gang, whisper it..BUT..there is some snow in the forecast for the sarf / sarfeast during the next few days according too the Gfs 6z operational..Shirley that’s worth celebrating?...hmmmm..   ...ps.even though I’m from north of the wall.....My dads an eastender so I hope nobody takes offence when I say sarf east?

 

No offence taken Jon. As I see it  the signals / models are getting stronger for full blown snow here in the south next 4 days

[sebastiaan1973]

2 hours ago, Battleground Snow said:

Maybe 3 strat warmings, a weakening la Nina and the MJO crossing the favourable phase, will finally be enough to deliver the cold into Western Europe. Time will tell.

 

Haha. Totally true. Terrible, what is needed

[sebastiaan1973]

I think this is quite intresting with a cyclone stretched from Ireland, the UK to Poland.

Edited January 22, 2021 by sebastiaan1973

[mushymanrob]

This is why some of us use the NOAA 500mb charts as a guide to what the most likely synoptic pattern in the 6-14 day timeframe will be.

The anomaly chart was created on the 13th and covers the period 19th - 23rd. The GFS chart is todays 06z.

As you can see there is a very good agreement with only the centre of the Greenland High being slightly out, and the centre of the trough thats just Northeast of where it was predicted. They are not as close all the time, but are over a period of time pretty much there or thereabouts. Personally, i do think that based on this method we can get a good idea well beyond t144 and out to t240 or further.

 

[Matt H]

Whilst the ICON 12z has shifted the snow risk further south on Sunday, the GFS 12z is now more bullish about the system with a decent amount of snow across much of southern England and Wales. Looks like a very uncertain situation still.

[Singularity]

 

Broadly, there seems to be a trend for some reversal of the move toward more of a ridge from the south between the two troughs.

As a result, there's more westward cold air transport to the north of the UK. That cold air serves to keep the polar jet further south while also interfering with the shape of incoming lows - it has a flattening effect.

 

Incidentally, there's a handoff of control over proceedings from one jet stream to another during this period.

 

How quickly this happens has been giving the models a hard time and also affects how far north the cold/mild boundary gets positioned.

[nick sussex]

Lots of uncertainty regarding both snow potential re any breakdown from the Atlantic and whether the milder air will actually get to the far north .

 

[sheikhy]

3 minutes ago, nick sussex said:

Lots of uncertainty regarding both snow potential re any breakdown from the Atlantic and whether the milder air will actually get to the far north .

 

Can only be a good thing nick for midweek!!!milder air struggling to make it in as quick!!

[Matt H]

UKMO 12z develops a more notable feature on Sunday compared to the other models at t48. Would love to see the precipitation charts for this!

 

[sheikhy]

Just now, Frosty Winter said:

UKMO 12z develops a more notable feature on Sunday compared to the other models at t48. Would love to see the precipitation charts for this!

 

Similar to gfs maybe?!

[Singularity]

 

Some pretty drastic changes on this run by a week today in fact - will of course have to be weighed up against the ensembles & other model runs.

Speaking of which, UKMO just showed up fashionably late with a very similar +144 to the GFS 12z:

[Tim Bland]

2 minutes ago, Frosty Winter said:

UKMO 12z develops a more notable feature on Sunday compared to the other models at t48. Would love to see the precipitation charts for this!

 

Can’t believe there is this much uncertainty at 48hrs out I guess if it was just rain we wouldn’t even notice. Does that low zip north east? Goes south on other models

[sheikhy]

Lovely uncertainty between 96 and 144 hours today on the 12zs!!!yesterday it looked one way traffic with everything flatter and heading north east!!over to the ecm!