Model Output Discussion - Mid Summer Onwards

[Mark wheeler]

36 minutes ago, WeatherEnthusiast said:

Really want a Spanish plume but it never quite makes it. 

I am sure it would be hot enough on those charts especially after what we have endured .

JMA also has a brief attempt at the plume before being pushed east . It is great to see at least we look like getting a couple of decent days of decent weather. Lots of variations across the models of where we go after the initial push from the south . Very fascinating viewing at the moment .

 

Navgem

Edited August 3, 2023 by Mark wheeler
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[LetItSnow!]

With warm seas already a feature I wouldn’t be surprised to see models experimenting with lows blowing up and (at least attempting a) pushing away hot air rather quickly. Humid and moist air will only intensify any systems so perhaps a rather volatile pattern of weather coming, though switching to a warmer side than the cool side we’re on right now. Props to the comment mentioning the soil moisture, that will inhibit temperatures to what they usually would be under normal circumstances. Any pushes of very hot air won’t have the same potency as last year, though very hot upper air temperatures could still lift temperatures very high. 

In short, expect a warm up next week but a switch to a warm and dry pattern throughout the rest of August I would remain sceptical of at this time. 

[Faronstream]

Lol now even the long range models have lost the high pressure rising from the south for the 3rd and last week of august, maybe we are getting a clear improvement in september when no one really wants it, a little too late.

[Nick2373]

59 minutes ago, WeatherEnthusiast said:

I'm Interested to hear a technical analysis as to why the jet has suddenly started to show signs of fragmenting?

Jet streams are typically continuous over long distances, but discontinuities are also common. The path of the jet typically has a meandering shape, and these meanders themselves propagate eastward, at lower speeds than that of the actual wind within the flow. Each large meander, or wave, within the jet stream is known as a Rossby wave. Rossby waves are caused by changes in the Coriolis effect with latitude. Shortwave troughs, are smaller scale waves superimposed on the Rossby waves, with a scale of 1,000 to 4,000 kilometres (600–2,500 mi) long, that move along through the flow pattern around large scale, or longwave, "ridges" and "troughs" within Rossby waves. Jet streams can split into two or fragment  when they encounter an upper-level low, that diverts a portion of the jet stream under its base

[CoventryWeather]

Surprised no one has mentioned the ICON this morning - to me, that is the pick of the bunch if you want a few days of warmth. 

Charts at 180

Low doesn't intensify, but stays well to the SW, high builds to the NE - probably a huge outlier but I feel this model did pick up the heat for next week rather well, would like to see if any start following this. 

[Mark wheeler]

11 minutes ago, CoventryWeather said:

Surprised no one has mentioned the ICON this morning - to me, that is the pick of the bunch if you want a few days of warmth. 

Charts at 180

Low doesn't intensify, but stays well to the SW, high builds to the NE - probably a huge outlier but I feel this model did pick up the heat for next week rather well, would like to see if any start following this. 

Blimey , Yes I totally forgot to check the Icon . That's a hot run .

 

Edited August 3, 2023 by Mark wheeler

[johnholmes]

Thur 3 August; update with NOAA 500 mb anoalies and ECMWF output

Certainly a change in the long wave pattern showing on the 6-10 with more of a s of west flow into the UK, still quite a strong flow though. A moderate –ve anomaly about 40W in the Atlantic seems to be the cause of this? The +ve heights across the far north remain. As this is the first such chart it is best to see if this is a consistent pattern over the next couple of issues. At least the 8-14 issue looks very similar perhaps suggesting this is a pattern of 3-4 days at least.

Looking at the ECMW set of charts for the period 8-13 August, so from about day 5 from now. The trough gets replaced by a ridge edging up from southern Spain/N Africa, temporarily before a trough swings back in from the west by the 12 th. So no long lasting settled weather being suggested.

At least with the EC we should get a break from the current procession of weather systems, warmer too, possibly middle 20’s C for southern areas and mainly dry with some sunshine. With the NOAA outputs not looking much like EC at 500 mb then it does make it look like a short break only. What happens 10-12 days from now is certainly not clear to me.

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

[Man With Beard]

ECM ensemble support for the warm up, at least temporarily, now very high. Looks nationwide:

Personally, 16C mean uppers are consistent with 30C being reached or exceeded in the south, either on the day shown or the day after.

Edited August 3, 2023 by Man With Beard

[Mike Poole]

1 hour ago, Mark wheeler said:

Blimey , Yes I totally forgot to check the Icon . That's a hot run .

 

Yes, I mentioned yesterday, the potential for a hot burst (if short lived) is there within the model output.

57 minutes ago, Man With Beard said:

ECM ensemble support for the warm up, at least temporarily, now very high. Looks nationwide:

Personally, 16C mean uppers are consistent with 30C being reached or exceeded in the south, either on the day shown or the day after.

It is a question of how much of a southerly draw we get.  ECM clusters T192-T240:

Cluster 3 with 10 members looks like it could include some hot ones, but the warmer spell is there on all of them, short  lived on cluster 1.  T264+:

While cluster 1 looks mobile westerly, cluster 2 flirts with the atlantic trough scandi high option, while a ridge from the Azores maintains some influence for the south on cluster 3.  So different options in play at this timeframe, but all an improvement on July!

[Downburst]

UKV in range for Saturday and it's certainly suggesting turning the heating on to the north of England, although not too warm anywhere else thats for sure

Upstream and pressure falls over next week in north america, so changes afoot to the general picture. Although heights seem to hang around over Greenland at the end of the ECM, so who knows, my guess is never settled for next two weeks

 

Today Pressure Pattern, look over north america

A lot of change by next Tuesday upstream from here, but not enough to the north of here

At the end of the run 10 days out the Greenland High is back and steering the trough, to our north west, but not far enough north west, so we need heights to drop in Greenland area really.

[Snowy L]

2 hours ago, Faronstream said:

Lol now even the long range models have lost the high pressure rising from the south for the 3rd and last week of august, maybe we are getting a clear improvement in september when no one really wants it, a little too late.

 

I'm not too fussed about charts like that, on a local scale something like is possible

 

When we had a similar set up in June it was a lot of fun. Warm and sunny during the day then thunderstorms in late afternoon.

[Alderc 2.0]

5 minutes ago, Snowy L said:

I'm not too fussed about charts like that, on a local scale something like is possible

 

When we had a similar set up in June it was a lot of fun. Warm and sunny during the day then thunderstorms in late afternoon.

Unfortunately it’s all too brief, the heat is quickly cleared away though Saturday and could be very similar to the July one day wonder spell which for many resulted in a poor weekend despite mild uppers. 

[chapmanslade]

5 minutes ago, Alderc 2.0 said:

Unfortunately it’s all too brief, the heat is quickly cleared away though Saturday and could be very similar to the July one day wonder spell which for many resulted in a poor weekend despite mild uppers. 

Amazing certainty from you for 10 days away!

The reality is the heat is never far away by then compared to recent weeks so very small changes in the low position to the west make a huge difference to what happens in the UK. Mid to high 30's over France later next week.

So perhaps 'it MAY be brief, but then it may not'.

[Alderc 2.0]

Just now, chapmanslade said:

Amazing certainty from you for 10 days away!

The reality is the heat is never far away by then compared to recent weeks so very small changes in the low position to the west make a huge difference to what happens in the UK. Mid to high 30's over France later next week.

So perhaps 'it MAY be brief, but then it may not'.

But that’s what the model shows does not? A brief one, or two day spell, given momentum of the low pressure would be a minor miracle to the warmth to hang around any longer. 

[CoventryWeather]

10 minutes ago, Alderc 2.0 said:

Unfortunately it’s all too brief, the heat is quickly cleared away though Saturday and could be very similar to the July one day wonder spell which for many resulted in a poor weekend despite mild uppers. 

The GFS has been wobbly on its outputs recently - the ICON has been much more consistent on a pattern that looks something more prolonged as posted by me above. I doubt it would clear that quickly, I suspect it to be a few days longer than currently being shown

[Man With Beard]

52 minutes ago, Alderc 2.0 said:

But that’s what the model shows does not? A brief one, or two day spell, given momentum of the low pressure would be a minor miracle to the warmth to hang around any longer. 

Agreed, but the shape of developments doesn't preclude a potential extension of the warmth, I think.

[Alderc 2.0]

Just now, Man With Beard said:

Agreed, but the shape of developments doesn't preclude a potential extension of the warmth, I think.

Oh absolutely, but the Ops is way above the mean and by 00Z on the 13th the majority of ensembles are back below the LTM indicating the heat may go even quickly - actually that looks more likely than an extension of any warmth.

[Addicks Fan 1981]

According to this it does look like we will have  WWB activity which should enhance better weather and I have seen a potential standing wave on the cards.   

Time-longitudes diagram - Extended range forecast

CHARTS-TEST.ECMWF.INT

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This diagram is a time/longitude diagram (Hovmöller diagram) of the 500 hPa or 1000 hPa height mean anomaly (contours) and spread (shading) of the ECMWF extended range ensemble...

Am with @mushymanroband trust these hovmoller charts more than i do with the ones I see on the site owned by Mike ventrice.    

 

[Mark wheeler]

Navgem is being uncharacteristically quite consistent the last few runs . This the 6z .

[Rain All Night]

The GEFS 6z ensemble mean looks different, in a bad way, to other recent runs of the three 15-day ensemble models; the ridge next week doesn't come nearly as far north... watch the animation here: https://www.tropicaltidbits.com/analysis/models/?model=gfs-ens&region=eu&pkg=z500aMean&runtime=2023080306

Edited August 3, 2023 by RainAllNight

[Nick2373]

06z continues with its up's and downs of no prolonged warmth just few warmer days followed by cooler with showers chucked in. never know such a stubborn pattern.  

[Nick2373]

3 minutes ago, RainAllNight said:

The GEFS 6z ensemble mean looks different, in a bad way, to other recent runs of the three 15-day ensemble models, the ridge doesn't come nearly as far north... watch the animation here: https://www.tropicaltidbits.com/analysis/models/?model=gfs-ens&region=eu&pkg=z500aMean&runtime=2023080306

Briefly visit's then as quickly vacates backwards to Spain, Greece France etc.  

[Cloud 10]

8 hours ago, Alderc 2.0 said:

Those verification numbers across the board look lower than they usually are? Also which is the Indian model? 

Indian model is the IMD.

 

The verification numbers in my post were for day 6,so a bit lower than the day 5 numbers which are normally posted.

https://www.emc.ncep.noaa.gov/users/verification/headlines/acc_archive/

 

 

[WeatherEnthusiast]

56 minutes ago, Nick2373 said:

Briefly visit's then as quickly vacates backwards to Spain, Greece France etc.  

I give up on sunny weather in Summer 2023 with this short lived sunny spell. I'm off to Tenerife instead. In fact I may emigrate! 

[seb]

Why are we still comparing the 6z GFS run with the 0z? There have always been and will always be periods where the 6z is wildly different to the other runs (many reasons for that) and if that also happens to be a period where other models are close to what GFS is showing on its 12, 18 and 0 runs then that is the time to ignore the 6z.

Or, to be super safe: compare 12z with 0z and the other models’ runs at those times.