Model Output Discussion - Early Summer and Beyond

[kold weather]

Tuesday looking very interesting in terms of temperatures, possibly Wednesday depending on how much cloud cover is left behind from any convection moving NE overnight on Tuesday.

Could well get well into the mid 20s on Tuesday probably quite widely in the south, could well see a 27-28c at somewhere like Heathrow, etc. Wednesday has potential to be even higher locally I suspect towards 29c IF the cloud cover co-operates enough. If its cloudy probably more likely in the 22-24c range for the SE.

Does anyone know the date records for the 17th and 18th May, fair chance we will get close based on tonights model.

[damianslaw]

1 hour ago, kold weather said:

Tuesday looking very interesting in terms of temperatures, possibly Wednesday depending on how much cloud cover is left behind from any convection moving NE overnight on Tuesday.

Could well get well into the mid 20s on Tuesday probably quite widely in the south, could well see a 27-28c at somewhere like Heathrow, etc. Wednesday has potential to be even higher locally I suspect towards 29c IF the cloud cover co-operates enough. If its cloudy probably more likely in the 22-24c range for the SE.

Does anyone know the date records for the 17th and 18th May, fair chance we will get close based on tonights model.

Really, can't see any date records falling. Highs for London possibly just nudging 25 degrees. Not enough homegrown warmth or warm uppers from the continent.

Outlook broadly a warm one but quite unsettled. Hefty downpours in places as the upper trough forces down on relatively weak heights.

[Kentspur]

2 hours ago, damianslaw said:

Really, can't see any date records falling. Highs for London possibly just nudging 25 degrees. Not enough homegrown warmth or warm uppers from the continent.

Outlook broadly a warm one but quite unsettled. Hefty downpours in places as the upper trough forces down on relatively weak heights.

Higher than 25c according to Met who knows

[Earthshine]

Outlook looks pretty warm.  A few cooler members but also a few exceptionally warm too.  I would say a 14°C CET month isn't outside of the question especially if we continue to see some very mild nights.

[jamesthemonkeh]

11 hours ago, kold weather said:

Does anyone know the date records for the 17th and 18th May, fair chance we will get close based on tonights model.

This is what I use for date records - 

The Tornado and Storm Research Organisation (TORRO)

WWW.TORRO.ORG.UK

---

TORRO is a privately-supported research body specialising in severe convective weather in Britain and Ireland

 

[Man With Beard]

32 minutes ago, Earthshine said:

Outlook looks pretty warm.  A few cooler members but also a few exceptionally warm too.  I would say a 14°C CET month isn't outside of the question especially if we continue to see some very mild nights.

Iberia is going exceptionally hot this weekend (over 40C), heat down there often has a way of working its way close to our shores so you couldn't rule out a hot end to the month in spite of the current ops.

For the coming week, it was very typical how the models performed in the past 5 days:

- ECM was correct to pick very warm weather from some way out 

- GFS was correct to limit the extent of hot/dry weather

- ECM overdid amplification at the D7-D10 stage 

- GFS overdid the Atlantic incursion at the D5-D7 stage 

- UKMO ... I don't really know how to read this model anymore, it can swing either way 

The general picture was right though - the UK would sit on a dividing line between settled and unsettled with a warm feed. An interesting and unpredictable week lies ahead!

 

 

 

[ANYWEATHER]

Potential for a good soaking this week for some especially for southern Britain, although any precipitation forecasts as to exactly how much rainfall and exactly where will be largely inaccurate as to the nature of the upcoming weather this week. Certainly warmest in the southeast of England 25c/ 77f possible . Looks like the warm ,moist feed from the south will be cut off by about Friday as winds switch round to a more westerly flow bringing cooler fresher air in from the Atlantic ...

[Summer8906]

13 hours ago, Singularity said:

As I said before, this isn't what -AAM directly corresponds to in late spring and early summer. An unsettled UK outcome with -AAM depends on there being at least a weakly negative NAO setup in play. Without that, the Azores High tends to extend at least a little way across the UK.

While I tend not to take its predictions very seriously, GFS actually predicts slightly +AAM through to 20th.

http://www.atmos.albany.edu/student/ventrice/real_time/AAM.png

AAM has indeed climbed impressively in recent times, taking us out of what had been a well entrenched -AAM regime so far this spring. This change is evident in the Azores High being greatly diminished in the week ahead. Instead there's a broad low to our west that reaches quite far south, which is more of a Nino-like setup under a neutral or positive NAO.

With the oceanic La Nina going from strength to strength, AAM is bound to tumble away again sooner or later. Then, the sNAO (summer NAO) state will be crucial for what happens in June. Most seasonal models are banking on ocean-atmosphere feedbacks over the N. Atlantic sustaining a +sNAO and forcing the re-inflated Azores High to extend well to the ENE or NE, resulting in an anomalously warm/hot and dry June for a large part of Europe, including southern UK. That's what happened in 2018 when AAM cascaded during the 2nd half of June.

Should the feedback cycle instead break down, the Azores High will be more inclined to focus further west (which as demonstrated in June 2010, can be half decent in early summer, albeit mainly for southern parts of the UK, if you can tolerate chilly starts to the day) or, if the sNAO flips negative, northwest (June  2007 style). We've seen GFS display its usual enthusiasm for such a switch-flip in the later stages of a few recent runs but given how often we've seen a +sNAO self-reinforce in recent years, it seems the lowest likelihood outcome at this stage (versus neutral or positive sNAO).

As the summer goes on, a +sNAO tends to force the Azores high to extend more E than ENE or NE, making a changeable westerly pattern more likely by August. In 2018 that shift occurred unusually late, during the 2nd half of Aug, perhaps owing to the exceptional strength of the +sNAO setup that season.

This is why, very broadly, La Nina summers tend to slide gradually downhill (or climb uphill if you like it cool & unsettled) over time.

Were, say, 1988, 1992, 1993, 2015 and 2017 La Nina summers? They are obvious ones which started relatively well and generally got progressively worse (though in 1988 and 1993, July rather than August was the poorest month).

Edited May 15, 2022 by Summer8906

[summer blizzard]

42 minutes ago, Summer8906 said:

Were, say, 1988, 1992, 1993, 2015 and 2017 La Nina summers? They are obvious ones which started relatively well and generally got progressively worse (though in 1988 and 1993, July rather than August was the poorest month).

88 - Nino to Nina flip

92 - Nino to Neutral

93 - Neutral-Positive

15 - Super Nino

17 - Neutral to Nina

93 and 15 probably underperformed, the others all saw tendancy going the wrong way.

[Guest]

Outlook beyond Thursday / Friday becomes increasingly poor. Low pressure firmly in control and pretty cold too. Can see that locking in for the long bank holiday. 

[Earthshine]

49 minutes ago, Alderc said:

Outlook beyond Thursday / Friday becomes increasingly poor. Low pressure firmly in control and pretty cold too. Can see that locking in for the long bank holiday. 

Really?  I'd say worst case scenario is around mid- to high-teens which is roughly average for mid May.

[Guest]

9 minutes ago, Earthshine said:

Really?  I'd say worst case scenario is around mid- to high-teens which is roughly average for mid May.

Yes really, we looked primed for a tough to get stuck near or over the Uk during the last tercile of May. 
 

These are not average charts and usually at a 10day are pretty well modelled. 

 

[mushymanrob]

24 minutes ago, Alderc said:

Yes really, we looked primed for a tough to get stuck near or over the Uk during the last tercile of May. 
 

These are not average charts and usually at a 10day are pretty well modelled. 

 

But thats assuming these days 9 charts are accurate!.... the chances of them changing are around 90%... cherry picking poor charts to support a pov is not how it works, and the Anomalies do not support low pressure domination (other than a 24-48 hours blip at the very most) for that timeframe.

[Cambrian]

The UKMO fax charts suggest that the cold front becomes detached from the centre of the Atlantic low and makes only very slow eastward progress during the middle part of the week.

 

Pulses of more persistent and heavy rain run northwards along the front as it trundles through, some heavy rain for Ireland on Tuesday shown on the 6z GFS operational run, as some warmth builds before the front over England…

 

then Wednesday evening into Thursday a slow moving area of heavy rain brings 15-30mm to much of southeast England…

 

leaving us all in a fresher air mass under a ridge of high pressure on Thursday as the front departs.
 

[Guest]

2 hours ago, mushymanrob said:

But thats assuming these days 9 charts are accurate!.... the chances of them changing are around 90%... cherry picking poor charts to support a pov is not how it works, and the Anomalies do not support low pressure domination (other than a 24-48 hours blip at the very most) for that timeframe.

Funny how you spin everything back to the anomalies not supporting something. Last week they didn’t support low pressure near the uk, yet here we are…..

[Earthshine]

3 minutes ago, Alderc said:

Funny how you spin everything back to the anomalies not supporting something. Last week they didn’t support low pressure near the uk, yet here we are…..

That doesn't mean that the outcome shown by a few charts is more likely!  We can only really go by what the trends show at the moment (particularly with how uncertain things are at the moment).  9 days away is anyone's guess

[Summer8906]

2 hours ago, Cambrian said:

The UKMO fax charts suggest that the cold front becomes detached from the centre of the Atlantic low and makes only very slow eastward progress during the middle part of the week.

 

Pulses of more persistent and heavy rain run northwards along the front as it trundles through, some heavy rain for Ireland on Tuesday shown on the 6z GFS operational run, as some warmth builds before the front over England…

 

then Wednesday evening into Thursday a slow moving area of heavy rain brings 15-30mm to much of southeast England…

 

leaving us all in a fresher air mass under a ridge of high pressure on Thursday as the front departs.
 

Knowing our luck you can just bet that the front arrives earlier and coincides with daylight hours on Wednesday, and then that frontal wave over Biscay will extend northwards and give us a dull, wet day on Thursday!

Edited May 15, 2022 by Summer8906

[mushymanrob]

41 minutes ago, Alderc said:

Funny how you spin everything back to the anomalies not supporting something. Last week they didn’t support low pressure near the uk, yet here we are…..

You really should do some research before making unfounded inaccurate claims.
 

On 10/05/2022 at 13:08, mushymanrob said:

 

 

On 10/05/2022 at 11:53, mushymanrob said:

Interestingly the Anomalies have shifted the centre of the high over to the Eastern side of the North Sea... this would make a plume or lengthier hot/very warm spell more likely. Humid and thundery is likely..

 

[Guest]

On 06/05/2022 at 12:01, mushymanrob said:

I wouldnt worry too much about any hiccup next week, these charts have slowly been building high pressure to our near Southeast/East which at least could allow for a plume. And even IF we dont get a full blown hot spell temperatures will be very pleasant/warm and with a high pressure anomaly over us - not much in the way of rain either... some damn good pleasant warm weather is firmly on the cards.
 

Not what you were saying a little bit further back when the outlook was already starting to look dodgy…..absolutely didn’t happen…

Edited May 15, 2022 by Alderc

[mushymanrob]

42 minutes ago, Alderc said:

Not what you were saying a little bit further back when the outlook was already starting to look dodgy…..absolutely didn’t happen…

Youve proven my point, that chart is pretty much bang on the general synoptic pattern we have now. It shows the anomalies are accurate... The only thing that they cannot pick up on is the shallow trough we have now thats bringing some showery conditions. It was very nice on Friday, yesterday, tuesday and most of wednesday isnt expected to be too bad. And temperatures are certainly well up. So the only thing i got "wrong" was the thundery activity, until the anomaly charts changed to suggest it... Thats what forecasting is all bout, updating constantly as new data emerges.

[Frosty.]

Looking at the next two or three days, the Gfs 12z operational indicates above average temperatures, indeed feeling more like summer than spring! ….some fine sunny weather punctuated by bands of heavy showers and thunderstorms moving from southwest to northeast..plus some homegrown storms being sparked by the warmth / humidity…nothing to moan about in my opinion… can’t speak for longer term as the run hasn’t got that far.. yet!.. should just add, pretty cold in parts of Scotland tomorrow under the heavy rain..if you’re wearing a kilt??  ! ️ ⛈ 

 

Edited May 15, 2022 by jon snow

[Cambrian]

The gradual trend over the next week for a straightening of the Atlantic jet stream and easing of mid-Atlantic cyclogenesis is in evidence on the 12z GFS operational run, the jet stream weakening too over the UK and Ireland by day 6

Day 3 / Day 6

 
 

 

- encouraging a bit more confidence that in the fullness of time higher pressure will build from the south bringing some spells of generally dry and warm weather, a high already emerging over the UK and Ireland by day 10, as the mid latitude jet stream fragments, developing a nicely positioned block by day 12. 

  

The pressure never builds that high though so no doubt prone at times to thundery breakdowns from the southwest. Still, I’ll take this coming towards the end of May, with three full months of summer ahead.

[E17boy]

Hi peeps,

I thought earlier that tonight might be quite a lively night here in the south with thunderstorms. I have been watching the radar all evening and there were some intense downpours just on the other side of the channel which have been moving up. However in the last hour the intensity seems to have died down a bit and so have the lightening strikes. So some places may still get something tonight whilst others may just have a quite night. 

[Earthshine]

Just a smidgen of cherry picking  but not half bad for day 10 (here's where it's 10°C and raining instead)!

[Uncertainty]

3rd time lucky?

ECM day 9

GEM day 10

GFS day 11

 

All 3 models build HP to the NW of Ireland, as the models generally have for about 11 months now. It has often materialised too, but the last few times it’s been modelled it’s trended S and E hence the frustration on here.

NOAA has it too, as do the EPS

But it’s not a strong signal. And recent history tells you not to book the bbq just yet.