Model output discussion - 20th Feb onwards

[Evening thunder]

51 minutes ago, CreweCold said:

Liklihood we'll be in Nina territory by July....it's a toss up as to whether the atmosphere engages a full Nina base state as soon as June IMO. Doesn't look good but the weather will always surprise us. 

But even if it does, surely summer wouldn't necessarily be poor, even if it is a bit more likely? After all ENSO is said to have a less clear influence in summer than winter, and it looks relatively weak for Summer at least. Also from what I can tell looking at past ENSO graphs, 1975, possibly 76 and also 89 occurred in or around La Nina conditions?

[Singularity]

Let's not forget - the atmosphere does not respond instantaneously to the SSTs changing. The change in state and in particular downstream impacts for the UK could take a couple of months to fully emerge. The likes of CFSv2 and GloSea5 aren't hinting at a decent summer from nothing.

I actually have a feeling that the post-Nino, pre-Nina state of affairs is quite good for the UK's summer prospects. Alas, as far as I'm aware, this is unproven - but in the list are 1994/5, 2002/3 and 2005/6. These were however weaker events that faded sooner in the year. 1982/83 and 1997/8 are better fits, but offer contrasting signals (decent, at times glorious v. uninspiring, at times poor).

Still, I have a sense that we may at least do okay this year (i.e. a typical summer, with a few hot spells and thundery breakdowns). Fingers crossed.

[Cheshire Freeze]

2 minutes ago, Evening thunder said:

But even if it does, surely summer wouldn't necessarily be poor, even if it is a bit more likely? After all ENSO is said to have a less clear influence in summer than winter, and it looks relatively weak for Summer at least. Also from what I can tell looking at past ENSO graphs, 1975, possibly 76 and also 89 occurred in or around La Nina conditions?

The evidence is pretty compelling if you look at the past 100 years or so....it's less about the Nina as such, more about the atmospheric response when seeing a dramatic switch from extremely strong Nino to a Nina. 

But you are correct in as much as the weather surprises us from time to time....hence my disclaimers. 

[Cheshire Freeze]

1 minute ago, Singularity said:

Let's not forget - the atmosphere does not respond instantaneously to the SSTs changing. The change in state and in particular downstream impacts for the UK could take a couple of months to fully emerge. The likes of CFSv2 and GloSea5 aren't hinting at a decent summer from nothing.

I actually have a feeling that the post-Nino, pre-Nina state of affairs is quite good for the UK's summer prospects. Alas, as far as I'm aware, this is unproven - but in the list are 1994/5, 2002/3 and 2005/6. These were however weaker events that faded sooner in the year. 1982/83 and 1997/8 are better fits, but offer contrasting signals (decent, at times glorious v. uninspiring, at times poor).

Still, I have a sense that we may at least do okay this year (i.e. a typical summer, with a few hot spells and thundery breakdowns). Fingers crossed.

BUT the modelling you mention was demonstrating a pretty dire summer prior to the last update. I suspect that their cheerier outlook was influenced by the fact Nina looked as though it may hold off until September a few weeks back. We seem to have reverted to the possibility of an earlier Nina lately and so I wouldn't be surprised to see the likes of the Glosea revert to a more unsettled picture in a week or so when it next updates.

[Evening thunder]

13 minutes ago, CreweCold said:

The evidence is pretty compelling if you look at the past 100 years or so....it's less about the Nina as such, more about the atmospheric response when seeing a dramatic switch from extremely strong Nino to a Nina. 

But you are correct in as much as the weather surprises us from time to time....hence my disclaimers. 

Well fair enough that's interesting, but how many occasions has such a switch occurred, let alone during summer? 1983 had a July locally better than 2006 here, yet had a big switch from El Nino to La Nina during the year at least, I guess it may have been a bit later than is likely this year, not sure without me finding detailed data sets to look.  Very different from 1998 though.

From what I've heard and seen the modelling isn't that bad for summer at the moment, even though/if there's also a consensus about La Nina

Anyway, not saying you don't have decent reason for these thoughts, I'm just not really concerned about it, there's other factors and I think our ENSO dataset is often too small. I'd have wasted a lot of worry if I had been too bothered by forecasts or modelling for recent summers. Though summer could of course be poor due to La Nina or other factors.

Edited April 29, 2016 by Evening thunder

[Nouska]

According to Meteo France three month outlook, the switch in ENSO state is causing a chaotic response in seasonal models - to such an extent - that no scenario is envisaged. The quote below which I've put through Google translate.

Forecast for the quarter May, June and July 2016 on Europe and mainland France

For several months, the presence of a strong El Niño phenomenon has probably improved the performance of seasonal forecasts to our latitudes. With the disappearance of this constraint, forecasts are more chaotic. Thus no majority option emerges from the analysis of models for seasonal forecasting centers around the world over most of Europe.

http://www.meteofrance.com/accueil/previsions-saisonnieres

The cooler prospects for western coasts are probably still tied to the negative SST anomaly.

Edit to add a table of historic seasonal ENSO conditions - there are very few years where such a switch, as forecasted, takes place over the high summer period.

http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml

 

Edited April 29, 2016 by Nouska

[mb018538]

Cracking output this morning, ecm and ukmo show 21c plus for sure, with the southerly draw lasting a good few days. Al kicks off on Thursday, be sure to have your tickets ready!! Summer is finally arriving!

[knocker]

21 minutes ago, mb018538 said:

Cracking output this morning, ecm and ukmo show 21c plus for sure, with the southerly draw lasting a good few days. Al kicks off on Thursday, be sure to have your tickets ready!! Summer is finally arriving!

Yes indeed the ecm from the end of the week until the end of the run. Perhaps even 24C

Off to give Sidney the news. Oops seems he has already heard.

[Frosty.]

Very pleasing 00z output, especially the Ecm 00z which eventually bathes the uk in much warmer conditions sourced from southern europe from towards the end of next week onwards..low to mid 20's celsius could be ours! might soon be time for the first BBQ..BANK!

[William Grimsley]

Ooo, yes please! At least 21°C showing here with the potential of widespread thunderstorms! Come on guys!

[Nouska]

The cold is departing with a sting in its tail!....

Another good job of forecasting from the ARPEGE model.

      

 

[knocker]

The ens 850mb 6-10 temp and anomaly. Dare I say it but things are not looking too bad out to the 15th. Temps dropping a little as the winds veer to the SW.

Mind Canada is really expecting a sizzle.

Edited April 30, 2016 by knocker

[Frosty.]

Well what can I say about the Gfs 6z operational in low res except...BANK A lovely plume of continental warmth extending northwards across the UK with temps soaring into the 20's celsius with very warm sunshine and a risk of thundery rain / showers but then high pressure settles things down nicely towards the end of the run..very summer like charts, hopefully it's the way forward through late spring!

[andymusic]

5 minutes ago, Frosty. said:

Well what can I say about the Gfs 6z operational in low res except...BANK A lovely plume of continental warmth extending northwards across the UK with temps soaring into the 20's celsius with very warm sunshine and a risk of thundery rain / showers but then high pressure settles things down nicely towards the end of the run..very summer like charts, hopefully it's the way forward through late spring!

what you on about - we ain't had a spring - we're going straight to summer now lol

[Scorcher]

Although those charts that you've posted look great Frosty, in the short to medium term that run is actually quite poor compared to the ECM 00Z- I imagine we would have a fair bit of rain next week if that run came off. Yes after that it does look great but the good stuff is mostly well into FI on this GFS run. 

There is no real ridging of the high pressure on this run as on the ECM 00Z from midweek next week. Plus it shows a direct hit from that low next weekend which would make Sunday a washout for most of us. I am as always more inclined to trust a run from the ECM than a GFS 06Z run so let's hope it backtracks on this.

Nevertheless, whatever happens we are going to be cutting off that northerly flow and it will certainly be feeling a lot warmer for all from the middle of next week onwards.

[Frosty.]

8 minutes ago, andymusic said:

what you on about - we ain't had a spring - we're going straight to summer now lol

Lol what you on about, I was just commenting on the Gfs 6z in low res which looks summery, I didn't say anything about the spring, or lack of so far..I just hope the last third of spring will bring an early taste of summer.

P.S..I agree Scorcher but I just thought those 6z FI charts were worth posting since they show a warm plume. 

[Gael_Force]

14 hours ago, Evening thunder said:

Well fair enough that's interesting, but how many occasions has such a switch occurred, let alone during summer? 1983 had a July locally better than 2006 here, yet had a big switch from El Nino to La Nina during the year at least, I guess it may have been a bit later than is likely this year, not sure without me finding detailed data sets to look.  Very different from 1998 though.

From what I've heard and seen the modelling isn't that bad for summer at the moment, even though/if there's also a consensus about La Nina

Anyway, not saying you don't have decent reason for these thoughts, I'm just not really concerned about it, there's other factors and I think our ENSO dataset is often too small. I'd have wasted a lot of worry if I had been too bothered by forecasts or modelling for recent summers. Though summer could of course be poor due to La Nina or other factors.

Not really. In 1998 spring quarter was plus 1 and summer (JAS) was minus 1. Looks to be something similar in the forecast graphs.

[William Grimsley]

To be honest, sorry to burst everyone's bubble in the east, but most thundery weather will be confined to south western parts of the UK where it may be slightly colder with more drier and warmer air to the east.

[Frosty.]

It really does sound like it's going to become much warmer, especially across the south of the uk with temps rising well above average at times so a marked pattern change is on the way I'm pleased to say and it appears charts similar to the recent Ecm output in particular, could well be quite realistic...Bring it on!

[I remember Atlantic 252]

3 hours ago, William Grimsley said:

To be honest, sorry to burst everyone's bubble in the east, but most thundery weather will be confined to south western parts of the UK where it may be slightly colder with more drier and warmer air to the east.

miles deep FI, who knows where yet! I generally favour eastern areas for storms, just hope the warm air happens, far from certain

[William Grimsley]

I tell you, if that GFS run pulls off, we are in for a supercell on the 13th of May!

[Evening thunder]

5 hours ago, Gael_Force said:

Not really. In 1998 spring quarter was plus 1 and summer (JAS) was minus 1. Looks to be something similar in the forecast graphs.

Oops - I meant the weather experienced here was very different in 1998 compared to 1983. Probably should have been clearer and properly re-read my post before adding that snippet on the end

Edited April 30, 2016 by Evening thunder

[Frosty.]

Spring truly springs on the Gfs 12z op, especially through low res with even an early taste of summer as temperatures soar well into the 20's celsius which I'm sure most of us are hoping for!...Yes I'm a coldie but it's May 1st tomorrow and I hope we have plenty of continental plumes to look forward to between May and september.

 

 

Edited April 30, 2016 by Frosty.

[cheese]

Wow, that first chart shows quite the north-south divide. I hope that doesn't happen.

[knocker]

The Gefs 9-14 still looking good with trough running down into Iberia maintaining the SSW flow. and temps well above average.

Edited April 30, 2016 by knocker