Model output discussion 9th April onwards

[Guest]

1 minute ago, Don said:

And that's exactly what I hope this summer will deliver.  Those insufferable Spanish plumes we had to endure during the last couple of summers can do one!

Must be hard to deal with it for all of a handful of days per year while most find it miserably cold for ~200-250 days per year,.,,

[Don]

2 minutes ago, Mike Poole said:

Well I disagree with @CreweCold

Well I hope Crewe is correct here, but that is down to personal preference of course!  As ever, time will tell 

[Cheshire Freeze]

4 minutes ago, Mike Poole said:

Well I disagree with @CreweCold, no surprise there as it is summer we’re talking about.  I think there is the prospect of quite a significant shift to heat, but not for a few weeks, I’m going on the GloSea5 outer quintiles plot, showing quite a few members developing favourable heights for that, ridging from the Azores there:

Meantime, the JMA T264 seems to be showing the way…

But I’m not seriously expecting many charts like this in the reliable for a couple of weeks yet, to be honest.

I'd look at the ensemble mean maps for GLOSEA rather than the probability charts. I find the probability charts none too useful.

For the core summer period it's showing benign conditions, with the wettest and coolest weather perhaps down towards the SE. It's in complete agreement with the EC seasonal.

Edited May 15, 2021 by CreweCold

[Don]

6 minutes ago, Alderc said:

Must be hard to deal with it for all of a handful of days per year while most find it miserably cold for ~200-250 days per year,.,,

For what it's worth, I would much rather have a summer 2018 over 2019/20 as although it was hot, it was never overly humid like you get with Spanish plumes!  That's the point I was making!

Edited May 15, 2021 by Don

[Mike Poole]

1 minute ago, CreweCold said:

I'd look at the ensemble mean maps for GLOSEA rather than the probability charts. I find the probability charts none too useful.

For the core summer period it's showing benign conditions, with the wettest and coolest weather perhaps down towards the SE

Yes, that might be the difference between you and me, Crewe, I live in a probabilistic world for my job, so I take a much higher than average probability of a scenario as more important than looking at the mean,  it suggests (to me) a signal.  We will, of course, find out as summer develops!  

[East_England_Stormchaser91]

1 minute ago, CreweCold said:

I'd look at the ensemble mean maps for GLOSEA rather than the probability charts. I find the probability charts none too useful.

For the core summer period it's showing benign conditions, with the wettest and coolest weather perhaps down towards the SE

Low pressure over Germany or the Low Countries is the absolute worst place to have it! All you will get is disgustingly cool northerlies regardless of the time of year! Whilst they potentially enjoy interesting, notable convection, just to rub it in! 

Them locations is exactly where you want high pressure to be! 

[Man With Beard]

24 minutes ago, CreweCold said:

I'd look at the ensemble mean maps for GLOSEA rather than the probability charts. I find the probability charts none too useful.

For the core summer period it's showing benign conditions, with the wettest and coolest weather perhaps down towards the SE. It's in complete agreement with the EC seasonal.

I interpret that chart not as showing high pressure to the NW, but as the positioning of the ridge pushing slightly NW compared with where it normally is. As the default position is often slightly SE of the UK, that's excellent news for a UK summer.

[Cheshire Freeze]

6 minutes ago, Man Without Beard said:

I interpret that chart not as showing high pressure to the NW, but as the positioning of the ridge pushing slightly NW compared with where it normally is. As the default position is often slightly SE of the UK, that's excellent news for a UK summer.

That's where interpretation comes in. I'm expecting mean HP to be situated slightly further NW at times owing to us being in the ascending from minimum phase of the solar cycle. We've already seen many examples of it this spring where a UK HP at day 10 has become a Greenland/Icelandic HP at closer timescales.

If we look at the geopotential height anomalies, it's a clear advocate of a potential Scandi trough dropping in from time to time

Edited May 15, 2021 by CreweCold

[Mike Poole]

16 minutes ago, CreweCold said:

That's where interpretation comes in. I'm expecting mean HP to be situated slightly further NW at times owing to us being in the ascending from minimum phase of the solar cycle. We've already seen many examples of it this spring where a UK HP at day 10 has become a Greenland/Icelandic HP at closer timescales.

If we look at the geopotential height anomalies, it's a clear advocate of a potential Scandi trough dropping in from time to time

I still think you are reading too much into a mean chart averaged over both 3 months and countless ensemble members.  Too much noise, not enough signal on these outputs unless you are careful at what you look at probabilistically.  I think summer is favourable (for heat lovers) once we’ve got rid of the current pattern, which will happen, it is a question of when.

Edited May 15, 2021 by Mike Poole

[Cheshire Freeze]

2 minutes ago, Mike Poole said:

I still think you are reading too much into a mean chart averaged over both 3 months and countless ensemble members.  Too much noise, not enough signal on these outputs unless you are careful at what you look at probabilistically.  I think summer is favourable (for heat lovers) once we’ve got rid of the current pattern, which will happen, it is a question of when.

I'm not basing my thoughts on any long range model. I've had some ideas since Feb/March with regards to the coming summer.

[NeilN]

So what are the long-rangers leaning to? Average, hot or poor? I'm still going to put my neck on the line for a poor summer. 

[Mike Poole]

Just now, CreweCold said:

I'm not basing my thoughts on any long range model. I've had some ideas since Feb/March with regards to the coming summer.

I’ve had some ideas since January, I posted them in here!  Some wobbles on those thoughts given the way spring has gone but still entirely plausible come June.  I’m still favouring the Azores ridge eventually pushing NE and delivering a sustained period of hot weather.  First week of June.  But let’s see, we are deviating from the models a bit here!

[Don]

7 minutes ago, Mike Poole said:

I’ve had some ideas since January, I posted them in here!  Some wobbles on those thoughts given the way spring has gone but still entirely plausible come June.  I’m still favouring the Azores ridge eventually pushing NE and delivering a sustained period of hot weather.  First week of June.  But let’s see, we are deviating from the models a bit here!

As long as it's not too humid if that's the case!

[Guest]

I’m sure when I went to bed last night it was the middle of May? Seem to have woken up in the middle of November, GFS has multiple deep lows barrelling across the UK from Friday onwards, cool wet and unsettled before it tees up the obligatory high pressure cell out west in about 12-13days time. At least we don’t have to worry about the return of the westerlies in June, there well and truly here now. 
 

Good to see GEM painting a much positive picture though, starts ringing in the Azores very nicely by day 9, it’s a much better run! 

[Methuselah]

Oh dear, the GEFS temperature ensembles continue to frustrate:

     

And there's little, even by Day 16 (barring perhaps the continued dwindling of the northern cold stuff?) to get one too excited!

     

Edited May 16, 2021 by Ed Stone

[minus 9]

Don't post much at all, but ecm looks better this morning after 168 With the high pushing in from the west. Something has to change soon I hope.

[Craig84]

Morning all.
 

Whilst I’m not too worried about the detail at this range, I’m pleased to see the ECM’s idea of low pressure winding up in Greenland area and the jet moving north in response  

 

 

[Guest]

32 minutes ago, Craig84 said:

Morning all.
 

Whilst I’m not too worried about the detail at this range, I’m pleased to see the ECM’s idea of low pressure winding up in Greenland area and the jet moving north in response  

 

 

Its been a while since we've seen an ECM run looking decent at D8, and then Bingo by D10!

[mushymanrob]

20 hours ago, Backtrack said:

Dropped a Tweet to Aidan McGivern earlier (Met forecaster). He tells me they are seeing signs of higher pressure dominance towards the beginning of June in the longer range models. 
 

 

feasible IF this evolution continues.... These charts have steadily and consistently developed high pressure ridging to our West and slowly building in towards us. Its not there yet, but IF this continues then a warmer drier more settled start to June is on the cards.
 

Edited May 16, 2021 by mushymanrob

[SqueakheartLW]

Which of these charts do you prefer then from yesterday's GEM 12z and Today's GEM 00z. It has to be said all of the 4 latest GFS runs had no hot day or spell in them and the highest temperature I could find in them was 23.5C in Scunthorpe

The GEM was much better for throwing in some hot members with thunderstorm potential too.

SCENARIO 1     12z GEM Member 12 +294 hours away     850hpa Temp 16.5C     2m temp max 30.3C

SCENARIO 2     00z GEM Member 19 +372 hours away     850hpa Temp 16.9C     2m temp max 30.0C

Which one of these do you prefer then?

[summer blizzard]

Interesting to see the GFS being the hold out this morning with the Euro and GEM building pressure from day 8/9.

Looking at the charts it looks to me as if the difference in outcome is generated by the pace of the low south of Greenland at day 6. The GFS/UKMO have a progressive feature, the Euro/GEM are much slower.

Note how the Euro being slower is much more phased with the upper low to the south west. The UKMO being progressive has no real link between the two. 

Although i'm not certain the long term signals really support ridging until early June i would suggest that normally the models do correct slower and weaker, both of which would support more phasing with the upper low. 

Edited May 16, 2021 by summer blizzard

[summer blizzard]

We can test out this theory right now it seems. The GFS6z is so progressive that our low south of Greenland is barely existent as an independent feature and thus it is my belief that without phasing with the upper trough behind it, the ridge will be pumped further west rather than east and we will see an outlook to day 10 supporting the status quo (pressure build in the Atlantic rather than into Europe).

[Frosty.]

I don’t know if anyone has posted the ECM 0z ensemble mean T+240 chart so forgive me if someone has already but to me it looks decent,  certainly compared to before that timeframe?..it gives the Azores high / ridge a chance to build in..on the cusp of the meteorological summer..I know for a fact that at least a few on here don’t think summer starts until the 21st June..longest day (solstice)....but I support the met office..1st June is the 1st day of summer!!!!!!!!!!!!! ...let’s hope it’s a good summer..let’s face it, most of spring has been crap..temperature wise at least  !!!!

 

 

Edited May 16, 2021 by Jon Snow

[Frosty.]

Yes it’s a trough dominated outlook in the short / medium term..that much is obvious when you look at the latest models...BUT..as I’ve said so many times I’ve lost count..the longer term outlook into late May / early June might become so much better?..as the GEFS 0z / 6z mean (combined) show!...I’m not making it up!..the mean improves!!!!!!  

[Man With Beard]

Looks increasingly likely that high pressure will become more dominant in the north Atlantic after next weekend, but the clusters below (D13) show how it's no guarantee of continuous good weather for the UK. All clusters show some sort of breakthrough by a trough, but the question is where?

Cluster 1 is the "sods law" where the small trough hits the UK like a magnet. Cluster 2 doesn't break the trough through but flattens the high slightly. Cluster 3 breaks the trough further south than cluster 1 and would probably bring hot days to the UK with the risk of thunder.

So, probably getting better before the month end, but not easily.