Model output discussion 24/01/21

[winterof79]

15 minutes ago, sebastiaan1973 said:

i guess you mean this area. So, what do we need? It must move? Disappear? I fear that EC is right, it repeats itself. Not a good sign.

Have a look on the up side for once its great. Stalling front this week ....yes this week

[MATTWOLVES 3]

Seriously guys the models can't even work out the evolution for later this week, so I reckon next week is beyond redemption. Pretty amazing NH profile for that Vortex from GEM and UKMO... They both look like a rabbit thats expecting triplets... Baby vortices in other words. Are bless... Not so sure about the insistence to place some of that Vortex over North Greenland though next week.. With further warming likely in the next week or so, we could have yet more displacement if not a split event.. Again the models are asking more questions rather than giving out answers. FI starts on Wednesday if you ask me. 

[Tim Bland]

2 minutes ago, winterof79 said:

Have a look on the up side for once its great. Stalling front this week ....yes this week

I think everyone needs to accept there is an element of IMBYism happening with posts, which is entirely natural. If I was in Huddersfield 162m asl I would be quite upbeat about the end of this week. As my earlier post states it could be very snowy in the far north. For those north of midlands there could be some transient snowfall Thursday, but for everyone else there is little hope as it would be a monumental turnaround to see anything white this week. If I was in the far south I’d be keeping a close eye on the weekend for that Channel low though !

[tight isobar]

Love this evening ecm-marvels with convert and progression..this weekend "COULD" take me bk to my 80s childhood...keep watching!!!.✌

Edited January 25, 2021 by tight isobar

[swebby]

2 hours ago, claret047 said:

To the more learned on here is there a way to calculate the temperature at ground level, should we ever be fortunate enough to have -24 @ 850 as currently shown on the charts to our northeast well into FI? I like to dream!

Many thanks

Kind Regards

Dave

 

You timed that question well, just as an Easterly appears and distracts everyone!

In theory you could make a crude estimate based on a standard lapse rate.

Look at the emagram on this wiki page and you can trace along the lines from a starting temperature for one altitude/pressure to another based on it being a moist or dry air mass.

Lapse rate - Wikipedia

EN.WIKIPEDIA.ORG

 

I've linked also to John's page on skew T's that was archived that explains lapse rates.

 

Of course, you need to know if it is a dry or moist air mass.

John will be able to better advise if you drop him a PM.  If memory serves, the likes of Steve Murr and @bluearmy were good at advising on lapse rates depending on the source of air shown on a chart.

[MAF]

2 minutes ago, tight isobar said:

Love this evening ecm-marvels with convert and progression..this weekend "COULD" take me bk to my 80s childhood...keep watching!!!.✌

i prefer other comics to Marvel

[weathermadbarnsleylad]

7 minutes ago, MATTWOLVES said:

Seriously guys the models can't even work out the evolution for later this week, so I reckon next week is beyond redemption. Pretty amazing NH profile for that Vortex from GEM and UKMO... They both look like a rabbit thats expecting triplets... Baby vortices in other words. Are bless... Not so sure about the insistence to place some of that Vortex over North Greenland though next week.. With further warming likely in the next week or so, we could have yet more displacement if not a split event.. Again the models are asking more questions rather than giving out answers. FI starts on Wednesday if you ask me. 

Couldn't be more spot on with FI 72hrs at MOST. 

[tight isobar]

2 minutes ago, MAF said:

i prefer other comics to Marvel

The evolutionary=prog coming into scope via certain outs is crazy...obviously a world away in meteorological time lapse....but without doubt..nicking a big one ☝ this weekend...is as close as a Turkish shave!!!✌

Edited January 25, 2021 by tight isobar

[winterof79]

7 minutes ago, Tim Bland said:

I think everyone needs to accept there is an element of IMBYism happening with posts, which is entirely natural. If I was in Huddersfield 162m asl I would be quite upbeat about the end of this week. As my earlier post states it could be very snowy in the far north. For those north of midlands there could be some transient snowfall Thursday, but for everyone else there is little hope as it would be a monumental turnaround to see anything white this week. If I was in the far south I’d be keeping a close eye on the weekend for that Channel low though !

Only response from me is I was talking about a stalling front and showed mild air retreating. Good for all UK. We're not all on here to discuss regional weather. Regionals do that

[Cavehill Snow]

1 hour ago, Daniel* said:

To not hear about marginal conditions again would be music to my ears. That really is an exceptionally rare deep freeze pattern on GFS 12z spanning all of northern Eurasia it has a February 1956 look to it. 

Typical - misses imby and goes into N Africa. Looks very impressive, but in reality you would expect some short waves to disrupt the flow somewhere along the track.

[tight isobar]

Also retract for the time being imo from the larger scales @mjo forcing \bullets of ssw crumbs and note basical raws it's in chaos ..and ocean ramifications to boot....layers @atmosphere are in mobile as @GWO..Feb looks the dapper man...to me!!!!!!!!

 

 

[ItNeverSnowsInWindsor]

Time to start taking snapshots of the output and comparing with the following days output to see how progressive models tend to be with these cold blocking scenarios. Already someone posted the FAX chart differences for this Thursday!

[Lord Grogon]

6 minutes ago, tight isobar said:

Also retract for the time being imo from the larger scales @mjo forcing \bullets of ssw crumbs and note basical raws it's in chaos ..and ocean ramifications to boot....layers @atmosphere are in mobile as @GWO..Feb looks the dapper man...to me!!!!!!!!

 

 

I love your posts. They vie with Tamara’s for being the most confusing, albeit in a slightly different way. 

[ItNeverSnowsInWindsor]

There’s a cluster already showing colder options for this weekend and a few hinting on less mild options during this week on the 12z Gefs.
 

Momentum is with the colder solutions...

Edited January 25, 2021 by prolongedSnowLover

[East_England_Stormchaser91]

23 minutes ago, swebby said:

You timed that question well, just as an Easterly appears and distracts everyone!

In theory you could make a crude estimate based on a standard lapse rate.

Look at the emagram on this wiki page and you can trace along the lines from a starting temperature for one altitude/pressure to another based on it being a moist or dry air mass.

Lapse rate - Wikipedia

EN.WIKIPEDIA.ORG

 

I've linked also to John's page on skew T's that was archived that explains lapse rates.

 

Of course, you need to know if it is a dry or moist air mass.

John will be able to better advise if you drop him a PM.  If memory serves, the likes of Steve Murr and @bluearmy were good at advising on lapse rates depending on the source of air shown on a chart.

For snow or any form of convective precipitation, they are a key player. For snow, on the 500Hpa chart, you ideally need the greens/blues over the source of convection for better cloud height and development (lower pressure), and of course the colder 850hpa temps, the better (in storm terms it would be like more CAPE). That’s a basic take on it. 

[Tim Bland]

14 minutes ago, winterof79 said:

Only response from me is I was talking about a stalling front and showed mild air retreating. Good for all UK. We're not all on here to discuss regional weather. Regionals do that

So you think all of the Uk is in with a shout of snow at the end of this week ? By ‘good’ I assume you mean cold and snow?  And you describe the fax as ‘good for all the Uk’ You don’t have to go into the regionals to refer to areas of the UK when describing what a chart shows, and no chart I have seen today shows snow (other than an hour of sleet) for over half the UK?

[winterof79]

Just now, Tim Bland said:

So you think all of the Uk is in with a shout of snow at the end of this week ? By ‘good’ I assume you mean cold and snow?  And you describe the fax as ‘good for all the Uk’ You don’t have to go into the regionals to refer to areas of the UK when describing what a chart shows, and no chart I have seen today shows snow (other than an hour of sleet) for over half the UK?

Oh give it up I'm not arguing. Wwarm air retreating has to be good. I couldn't give a chuff who gets snow. 

[tight isobar]

3 minutes ago, Tim Bland said:

So you think all of the Uk is in with a shout of snow at the end of this week ? By ‘good’ I assume you mean cold and snow?  And you describe the fax as ‘good for all the Uk’ You don’t have to go into the regionals to refer to areas of the UK when describing what a chart shows, and no chart I have seen today shows snow (other than an hour of sleet) for over half the UK?

And so it shouldn't \wouldn't..especially with the vast impactual

human input ;faxes:....on we watch !✌

Edited January 25, 2021 by tight isobar

[Tim Bland]

4 minutes ago, prolongedSnowLover said:

There’s a cluster already showing colder options for this weekend and a few hinting on colder during this week on the 12z Gefs.
 

Momentum is with the colder solutions...

Yes, the weekend dip is a consistent signal now, here is the 06z set...

[Mike Poole]

I’m not sure but I may be about to say in many paragraphs what @tight isobar has just said above in two lines, but hey ho!

I think it is pretty clear that FI is T96 or maybe even earlier and that the models are struggling with this situation.  

Let’s start with the strat, here NAM plot based on the GFS 0z:

The downwelling from the SSW seemed to hit a block and will continue to do so as forecast, but not for long, with the -NAM taking hold at the surface at the end of the run.  This must be linked to the MJO story - others have posted the MJO phase diagram, but I expect MJO into phase 7 at reasonable amplitude is a big part of the uptick in AAM as per CFS forecast, and it isn’t coming from a low base now:

This would discount any idea of a La Niña end to winter.  

As the op runs are struggling, the ensembles are a better guide at day 10, ECM T240:

So with the mean plot, Azores displaced, UK trough into Europe, so potential for sliders there if even slightly higher heights can hold over or near Iceland.  

Spread plot, uncertainty near the tip of Greenland is relevant, and SE of us in Europe, suggests there might be a signal for more southerly tracking lows on some members. 

All of which says, cold February to me.

All the best,

Mike

[tight isobar]

8 minutes ago, Mike Poole said:

I’m not sure but I may be about to say in many paragraphs what @tight isobar has just said above in two lines, but hey ho!

I think it is pretty clear that FI is T96 or maybe even earlier and that the models are struggling with this situation.  

Let’s start with the strat, here NAM plot based on the GFS 0z:

The downwelling from the SSW seemed to hit a block and will continue to do so as forecast, but not for long, with the -NAM taking hold at the surface at the end of the run.  This must be linked to the MJO story - others have posted the MJO phase diagram, but I expect MJO into phase 7 at reasonable amplitude is a big part of the uptick in AAM as per CFS forecast, and it isn’t coming from a low base now:

This would discount any idea of a La Niña end to winter.  

As the op runs are struggling, the ensembles are a better guide at day 10, ECM T240:

So with the mean plot, Azores displaced, UK trough into Europe, so potential for sliders there if even slightly higher heights can hold over or near Iceland.  

Spread plot, uncertainty near the tip of Greenland is relevant, and SE of us in Europe, suggests there might be a signal for more southerly tracking lows on some members. 

All of which says, cold February to me.

All the best,

Mike

Nice summed mike..the Eurasian quarter is clearly @miss modeled atm as the layer impact wiped it's brow!....yet the impacts are of shy for our part...get ready for some inter timeframe synoptic madness ..then likely fruition overhead......@momentum in ept!!!..even our inscribed ens are refuse of meanline gain......as we ...gain..the fruit tree nearly ready for picking!!.✌✌

Edited January 25, 2021 by tight isobar

[Downburst]

59 minutes ago, Lord Grogon said:

I love your posts. They vie with Tamara’s for being the most confusing, albeit in a slightly different way. 

Very Joycean, so like reading tight isobars posts.

Edited January 25, 2021 by Paul

[Griff]

Ecm zonal latest just in... More questions than answers perhaps? 

(I have a reminder to check) 

I've included the previous for comparison. 

Edited January 25, 2021 by Griff

[Griff]

1 minute ago, Griff said:

Ecm zonal latest just in... More questions than answers perhaps? 

(I have a reminder to check) 

I've included the previous for comparison. 

FYI on 2nd thoughts scale is confusing, and look at below average longevity on latest

[tight isobar]

4 minutes ago, Griff said:

FYI on 2nd thoughts scale is confusing, and look at below average longevity on latest

Classic layer *want of align*   @10hp a worth watching=as dysfunction...reverse then ....??@dissaray..and it's nw Euro time to roll in jam !...we'll have a look at the layers and 500 pots later...so I can hopefully...make my point!!!✌

Edited January 25, 2021 by tight isobar