Model Output Discussion - Autumn arrives

[Cheshire Freeze]

Baltic HP looks like an embedded feature to me. Same as the Atlantic HP. Parts of S/C/E Europe look to be in a feedback loop of heat. Could get very uncomfortable in places like Italy and into the Balkans. A continuous heat pump.

In between the Atlantic and Baltic HP it looks like there will be a weak trough. Nothing overly inclement but unsettled at times for the UK.

Thank the heavens we're not stuck under that heat dome...it would be unbearable.

Edited June 22, 2022 by CreweCold

[northwestsnow]

EC not great .far too much high lat blocking for my liking .

Could end up very wet as troughing gets stuck in our locale.

Edited June 22, 2022 by northwestsnow

[mb018538]

43 minutes ago, CreweCold said:

Really depends on spot totals, even in the east. At this time of year it's pretty much impossible to rule out torrential downpours with pressure sub-1020mb. I've seen many 'mainly dry' days with the cap punctured and localised 50mm falling.

Happened in August 2007 here. Fairly benign day but with a cell that developed in isolated fashion and dropped a couple of inches of hail in an hour period.

This was the the chart that day

Equally though - today pressure has been around 1013mb and it’s been dry, sunny all day and very warm at 26-28c. Difference is that chart has an upper trough over the UK which just forces showers very easily and today has a ridge. Surface pressure is only one ingredient of the days weather. No forcing today and a lovely day.

[Cheshire Freeze]

14 minutes ago, mb018538 said:

Equally though - today pressure has been around 1013mb and it’s been dry, sunny all day and very warm at 26-28c. Difference is that chart has an upper trough over the UK which just forces showers very easily and today has a ridge. Surface pressure is only one ingredient of the days weather. No forcing today and a lovely day.

Of course but my point was that we’re in a broad trough into next week. The ridge is situated well to the E, even if pressure isn’t desperately low.

20 minutes ago, northwestsnow said:

EC not great .far too much high lat blocking for my liking .

Could end up very wet as troughing gets stuck in our locale.

EC is very wet to end yes. However it’s 9-10 days away. 

[sunnijim]

With the trough anchored some way West of the UK in a week from now and pressure High to the East,no reason why 25c+ is  not feasible again in the SE with winds from the SW and dry too.

Edited June 22, 2022 by sunnijim

[Nigelapplewhit4]

7 hours ago, richie3846 said:

It's interesting to look further ahead, though there's hardly any talk about the situation that is developing over the weekend. I'm at a loss to why there is so much talk about fantasy models for 12 days ahead, when there is a lot of interest coming up which seems to be void here? 

 

I'm trying to make sense of it through the met office interpretation currently, they seemed to have toned down the impact of the change of air for the south, with temps looking slightly up for Friday to Tuesday, and some pleasant sunshine in-between the showers, temps now only a margin below average.

 

If any model watchers have anything to add about the weekend/early next week period, that would be amazing. 

Saturday is very unsettled according to the latest models here is an example for Saturday and Sunday  : 

[Nigelapplewhit4]

1 minute ago, Nigelapplewhit4 said:

Saturday is very unsettled according to the latest models here is an example for Saturday and Sunday  : 

The latest GFS model is predicting it will take over a week for the low pressure to slow fill and be replaced by very weak high pressure ridging into S and SE England. By this stage the Jetstream is weak over the UK  

Just now, Nigelapplewhit4 said:

The latest GFS model is predicting it will take over a week for the low pressure to slow fill and be replaced by very weak high pressure ridging into S and SE England. By this stage the Jetstream is weak over the UK  

According to the FL forecast we may see some ridging by July 5th. 

[Frosty.]

The longer term GEM 12z mean offers hope for summer fans in early July from the Azores sector and even before then might not be so bad with the trough a smidgen to the west with heights further east so at least it could be on the warm side with winds from more of a southerly direction?…anyway, it may not be as bad as some think? ️  

 

Edited June 22, 2022 by jon snow

[tight isobar]

The 12z ens stumps! @ gem/@ecm @gfs.. @ London ones note a slump in overall temperatures.. but then a recovery of above.. perhaps going into well above territory as we creep into the new month @ July.. the precipitation spikes note the uncertainty as to ... indeed precipitation!.. however as again The modelled limpit trough “ I’m not buying “.. as the angular momentum stakes don’t exactly align.. still think July will start.. and continue as an improving picture.. for most.. but yeah undeniably the further south/east the higher the temperatures.. and arid conditions- in compare. There’s a lot to play for if you’re a summer fan for sure!!.. roll on winter

Edited June 22, 2022 by tight isobar

[Don]

7 hours ago, Ed Stone said:

And here's this week's Met Office Ten-Day Trend. And it's hardly a washout! Doom-mongers wrong again? We'll see!

Looks pretty similar to this week and not ever getting particularly cool at all!

[clark3r]

Hints of a heatwave FI on gfs this morning towards the end of the run

[slater]

1 hour ago, clark3r said:

Hints of a heatwave FI on gfs this morning towards the end of the run

Sure is, and here in the East weather is looking rather nice for next week, I know its not looking to great for most of the UK but Norfolk seems to be in doing well so far this Summer,

[mb018538]

Not the most enthralling set of charts for the 7-10 day period. Low pressure hanging around for the duration - still more focussed out to the west, so western areas taking the lions share of the rain. Western parts of Ireland look exceptionally wet! Best of the conditions towards the E/SE.

[mountain shadow]

1 hour ago, clark3r said:

Hints of a heatwave FI on gfs this morning towards the end of the run

Only one run in the suite of course.

Out to day 10 and low pressure remains anchored near the UK with wetter windier to the North West and drier to the South East. No heat wave in this time frame. 

[mb018538]

28 minutes ago, mountain shadow said:

Only one run in the suite of course.

Out to day 10 and low pressure remains anchored near the UK with wetter windier to the North West and drier to the South East. No heat wave in this time frame. 

Yep - I wonder which one it could be....90% of the runs tightly clustered between the 5-10c range, which is bang on the average for July. Sunshine and showers.

[Methuselah]

I'd prefer seeing charts like these a lot closer than T+384!

    

[mb018538]

All eyes still on the tropics as we head into July - MJO still forecast to traverse phases 4/5 through the first week. With a bit of lag time for the effects to filter through....perhaps an improving picture after the first week of July, as the more unsettled NW European pattern starts to flush out towards the end of this period?

[Earthshine]

There has been a signal for some time that July could be a significantly better month than June (not that June has been bad mind you, not often we see 30°C here pre-solstice and yesterday was the best summers day I can remember for a long time).

[Neil Harris]

29 minutes ago, Earthshine said:

There has been a signal for some time that July could be a significantly better month than June (not that June has been bad mind you, not often we see 30°C here pre-solstice and yesterday was the best summers day I can remember for a long time).

I hope July is better than June, but yes as you say can't really moan about June. Only switch some of the heat to the weekends!

Today is a proper cracker, I'm a novice on models. What is todays model looking like, and where is todays heat coming from.
It's a nicer heat than late last week.

[mushymanrob]

2 hours ago, mb018538 said:

Yep - I wonder which one it could be....90% of the runs tightly clustered between the 5-10c range, which is bang on the average for July. Sunshine and showers.

Indeed... average for July isnt bad at all...

 

1 hour ago, mb018538 said:

All eyes still on the tropics as we head into July - MJO still forecast to traverse phases 4/5 through the first week. With a bit of lag time for the effects to filter through....perhaps an improving picture after the first week of July, as the more unsettled NW European pattern starts to flush out towards the end of this period?

(this isnt aimat you, im just using your MJO post to comment about the MJO)
I have to say it ..... i dont "get" the MJO at all.... oh i get the theory that a phase here leads to a certain weather pattern here. But how often has that verified? Unlike the NOAA charts that i can "get" and do think they work, i cannot make the MJO be of any use.
On my Facebook timeline a couple of weeks ago, memories, i reported that hot settled weather was on its way because "the experts at netweather (forum) had said the MJO was going to orbit through phase 8 and 1 which in June brings high pressure " ............. that was from June 2012 !!!!

[mb018538]

4 minutes ago, mushymanrob said:

Indeed... average for July isnt bad at all...

 

(this isnt aimat you, im just using your MJO post to comment about the MJO)
I have to say it ..... i dont "get" the MJO at all.... oh i get the theory that a phase here leads to a certain weather pattern here. But how often has that verified? Unlike the NOAA charts that i can "get" and do think they work, i cannot make the MJO be of any use.
On my Facebook timeline a couple of weeks ago, memories, i reported that hot settled weather was on its way because "the experts at netweather (forum) had said the MJO was going to orbit through phase 8 and 1 which in June brings high pressure " ............. that was from June 2012 !!!!

It's obviously not a fool proof way of making a forecast, otherwise it would go like clockwork and be very predictable. It's just a forecasting tool like any other teleconnection. The mechanisms of why an MJO passage through phase 4/5 would help promote settled weather in NW Europe in early July make sense - but the weather makes mugs of us all repeatedly, so it's no guarantee! Just one to watch, hence the 'perhaps' and question mark in my post!

[Tamara]

On 22/06/2022 at 14:49, JayAlmeida said:

Wasn't AAM predicted to rapidly fall throughout the second half of June and thus the weather would be unsettled as a result? 

Apart from a few days here and there it has turned out to be the complete opposite (regional differences aside).

The background drivers seem very accurate at explaining weather after the fact rather than predicting it in advance.

Either that or the models themselves aren't very good at predicting the trajectories of the background drivers.

 

If a diagnostic is not attempted to gauge the turning forces (angular momentum) exerting within the global atmospheric circulation (which is a key determiner of the where the jet stream ebbs and flows around the globe) then that is one vital key missing that inevitably guarantees error - however difficult and complex it still remains to predict weather patterns even for the most experienced. Such an approach though is anything but retrospective.

Low angular momentum has indeed predominated this month and the signature Atlantic ridge has advertised that very accurately and clearly - and within keeping of stated expectations.. The effects of eastward propagating tropical convection within the MJO "mini ENSO cycle" can be seen on this chart in respect of the temporary rise in momentum during May - according to a convectively coupled kelvin wave passing through the tropical Pacific ocean and briefly interrupting the domination of of the La Nina standing wave throughout the bulk of the Spring season,

 

This dominating Nina forcing continuing into the new season, and according to early summer wavelengths in tandem with a summer arctic profile which has not been exerting any particular sustained suppression at mid latitudes amidst a generally wavy and quite weak jet stream, and so has still allowed some ridge extension of the main height anomaly, fixed to the west, eastwards towards Europe with trough disruption dropping southwards towards Iberia around the perimeter of the main anticyclone. Quite typical for La Nina June/ early summer - and a pattern that often allows (usually fairly brief) warm air advection around the eastern flanks of such southward disruption

The equation changes heading through July,  with the switch to peak summer wavelengths. If the atmospheric circulation remains as it is now with easterly trade winds (shaded blue up to the dateline) perpetuating both Pacific and downstream responding Atlantic amplified sub tropical ridges...

 

.....then there will become a tendency for cooler more unsettled conditions to be longer lasting and harder to move on as the Atlantic ridging becomes increasingly further retracted and suppressed and less inclination for trough disruption just west of Europe, but making greater inroads instead through NW Europe and Scandinavia.

On the other hand, should eastward moving tropical convection re-configure the upstream pattern with westerly wind additions to the atmospheric circulation across the tropics (which would be red shading towards the dateline on the Hovmollers plot above) - then rising frictional and mountain torques will help de-amplify the upstream amplification and replace the Atlantic ridge with increased troughing and in turn the greater high pressure anomaly will be adjusted as downstream ridging cross Europe. This set-up  increases the chance of more sustained heat build advected northwards from Africa and southern Europe adjusted further westwards towards NW Europe - rather than under a La Nina displaced Azores ridge regime in mid Atlantic where heat advection favours more central and eastern parts of Europe (and Russia) downstream of a NW European trough

So there are some broad indicators to watch for heading into July as to which way the pattern may evolve. Nothing is black or white, and some kind of pattern half way house may develop depending on what extent rally in momentum may occur. NB: Tropical convection patterns need to be viewed within the context of how wind eddies propagate further to the extra tropics. Changing wavelengths within seasons and indeed from one month to another make subtle differences to how the macro pattern evolves according to tropical>extra tropical wind-flow signals. But that said,  as is the case in winter, there tends to be a closer relationship at these peak opposite seasons of the Annular Mode (AO and NAO in this relevant part of the hemisphere) than during the transitional parts of the year.

On that basis there is a decently observed correlation year on year that  La Nina-esque July's to be less forgiving than in June. So with this in mind in it is important to return to Paragraph 1 and keep attempting these diagnostic inspections. That is clearly pro active and not reactive to events.

 

Edited June 23, 2022 by Tamara

[bluearmy]

eps over the past two suites have the upper trough a bit further east next week which is less good for the country as a while (moreso as you head nw) 

some signs that later week 2 sees an improvement as the Azores ridges in and the sceuro ridge is actually reduced.

[clark3r]

12z showing some warmth Wednesday and Thursday in the east next week 

[Captain Shortwave]

It isn’t much of a shift, but it is enough to bring sunnier and warmer conditions into more southern and eastern areas

UKMO and GFS

   
 

A battleground develops for midweek with a front running through the country, to the east the temperatures are back into the mid to high twenties. Both models also want to collapse the Atlantic ridge eastwards, this will weaken the trough near the UK.

The GEM rolling out now and is better still and the high to the east gets the upper hand.

Edited June 23, 2022 by Captain Shortwave