Model output discussion 14/04/18

[matty007]

ECM has been the form horse for some time now and I would be trusting that outcome much more. Although still just outside reliable timeframe. 

GFS is a comedic run if you ask me, as is typically the way of being very dramatic and ‘worst case scenario’. 

That being said, there are signs that this weather pattern we’ve been so enjoying might just be losing its grip. 

However, I fully expect it to rebuild and don’t believe we’ve seen all of this great Summer yet. 

[Tamara]

2 hours ago, Man With Beard said:

What's really interesting about cluster 1 is that it has the negative heights anomaly precariously close to the UK at D11, but it actually withdraws it back into the Atlantic by D13/D14. That suggests something is pushing back at Atlantic troughing. Which would be the kind of scenario where a stable-ish plume can exist, where southerly winds can persist for a few days. The UK would then be precariously positioned, potentially either under a trough or under a plume.

Cluster 2 (not a small cluster at all) looks like a renewed push of heights across NW Europe - a much simpler continuation of our hot summer.

The good interpretation of these clusters, fits very conceivably with non-NWP assessment ahead 

Counter intuitive to see any progression to a long lasting UK trough though, based on where angular momentum is headed linked to shifting imprints in the Pacific that represent a new ENSO regime unfolding through the remainder of summer and into autumn - and just as seasonal wavelength changes are crucially starting to make this necessary to sustain a warm summer pattern.

To this end, and with the progression of last summer in mind, take a look at the differences in the Pacific base state to illustrate clearly how July 2018 is headed in a quite different direction to this time in July 2017.

 

With that comparison in mind, to a degree NWP is blind-sided by the counter action of short term -ve trade wind pattern in the Pacific and its representative death-throw Nina-ish synoptic reflection - but its clear enough that on-going adjustments are work in progress as the models risk overdoing the short term signal and then incrementally backtrack as they realise something quite, quite different is going on.

The post on Sunday suggested that the models would struggle with this evolution, further compounded by storm Chris (which in itself is a manifestation of the bigger picture c/o eastward moving kelvin wave having crossed the tropical Atlantic and leaving a window for tropical convectively linked cyclone development)

All demonstrating yet again (and without further copy and pasting of recent posts) to stress further that NWP is a snapshot in time assessment of the tropical and extra tropical signals. The models being led by the signals, not the signals being led by the models. Its true that the NOAA anomalies represent a best reliable guide to that NWP snapshot in time, but as numerical models do not always have the best handle on the atmospheric momentum budget, the anomaly charts will clearly be prone to changing/evolving just as much the rest of the modelling they represent.

I would be looking to a strong ocean/atmosphere imprint to be taking place through this month c/o robust MJO passage into the ever warming central Pacific - with repercussions for synoptic evolution ahead through the rest of this summer and into autumn

 

On that basis good credence to any extended ensemble guidance that suggests troughing backing west into the Atlantic with good downstream ridge response. Not surprised that ECM ensembles maybe will be dealing with this better than GEFS (the latter tends to have -ve tropical bias)

In the meantime, something a bit more disjointed, changeable and messy than we have been used to - to get through. But my little bit of advice, for what it is worth, would be to try to avoid failing to see the trees because of the suggested density of the wood they *appear* to reside in

Summer 2018 has plenty more to offer for sure - with south easterly vector interplay vs thundery troughs quite likely getting on in the act during Part II

 

 

 

Edited July 10, 2018 by Tamara

[shaky]

Well well already out to t111 hours and gfs has bumped that low further north and west!!ukmo looks hot and humid till the end and also splits that low before it enters the uk!!one part going into the continent and the other going above iceland!!

[northwestsnow]

2 minutes ago, shaky said:

Well well already out to t111 hours and gfs has bumped that low further north and west!!ukmo looks hot and humid till the end and also splits that low before it enters the uk!!one part going into the continent and the other going above iceland!!

Yes shaky- 850s on ukmo reveal a very warm run from 72-144

[Snowy L]

Think there is tentative agreement now that there will be a void left over the UK early next week with both high and low pressure seemingly backing away from the UK. This is now showing on all 3 main models. Does leave us very vulnerable to a flabby low to wander over towards us but there is also the ECM option of renewed Azores ridging.

[shaky]

Whilst gfs keeps pushing the low further north ans extending the heat expect further changes for next week!!at the moment its hot and humid for early part of next week BUT with thunderstorms around aswell!!but theres is also a very realistic possibility come the time there could well be a ridge over us and it will be hot humid and dry instead!!

[Frosty.]

34 minutes ago, northwestsnow said:

Yes shaky- 850s on ukmo reveal a very warm run from 72-144

Indeed and it's warmest at the end of the run

[northwestsnow]

3 minutes ago, Frosty. said:

Indeed and it's warmest at the end of the run

Yup- very warm across much of England and Wales- looks fairly slack so im thinking some thunderstorm potential

[SizzlingHeat]

Another awful GFS run from the mid to late frames. All FI of course and just as unlikely to verify as the 0z ECM! 

What's looking likely now however is a breakdown of sorts the beginning of next week with heavy showers and longer spells of rain for many. Although it is suggesting that 850s will remain relatively high so temps average if not above.

GEM most progressive of them all this evening and utterly vile from the end of the weekend. 

Lets see what ECM brings 

[mb018538]

Gfs and gem are a million miles from the ecm tonight....I’m thinking the ecm was also overly optimistic and may come back into line slightly later, though not as bad.

[Snowjokes92]

Am I only one who thinks gfs is an improvement towards the other models? The run as a whole has a lot more rain than we have been use to, but the midtern onwards wont be correct till the models have agreement on next week! The gfs rather mix and hot at times in fi, but usually at that stage the details change a great deal.we even pull a southerly up at 240 and the run is much dryer than previously suggested

[mb018538]

5 minutes ago, Snowjokes92 said:

Am I only one who thinks gfs is an improvement towards the other models? The run as a whole has a lot more rain than we have been use to, but the midtern onwards wont be correct till the models have agreement on next week! The gfs rather mix and hot at times in fi, but usually at that stage the details change a great deal.we even pull a southerly up at 240 and the run is much dryer than previously suggested

Much drier? There are plenty of places that receive over a months worth of rain in the next 10 days on that 12z GFS run! It’s awful if you like dry summer weather, great for the gardens and growers.

[Frosty.]

There's nothing vile about these Gfs 12z charts!..there's plenty of very summery weather shown with very warm surface conditions, plenty of sunshine and an increasing chance of heavy showers / thunderstorms with warm / very warm / hot sticky conditions deep into the run.

[Singularity]

Tamara’s excellent roundup highlights the fact that simply taking what the models show you is not an effective way to anticipate what will happen at more than a week’s range, sometimes even 4-5 days’ range.

Currently we see in the modelling evidence of a ‘spectrum of susceptibility’ with respect to responding too strongly to a trade wind burst that takes place against a contradictory larger-scale background state. At the most suspectible end lies GEM (shockingly so - just look at the NW-SE jet tendency it continues to advertise via trough movements!) and at the other lies ECM and UKMO (both similar; unclear which has the edge).

Even with this in mind though, GFS’ vast, slack Sceuro troughs are just plain weird - among the oddest formations I’ve ever seen in NWP modelling!

[Snowjokes92]

15 minutes ago, mb018538 said:

Much drier? There are plenty of places that receive over a months worth of rain in the next 10 days on that 12z GFS run! It’s awful if you like dry summer weather, great for the gardens and growers.

Like ive just said, the short term outlook is still up in air. None of the models are in agreement. Until the models have agreed with how craig and the atlantic will impact are weather in to next week, the models that further out can be taken with a pinch of salt. Theres a hint of a southerly on the 12z from around 240 hours. Again its no guarntee, but its the trends. Ecm and ukmo are much different to the gfs too. Ive more faith in them.And also on top of what tamara has mentioned recently about 2nd half of summer been more unstable and continental flow from the south/south east

 

Just one last thing, the gfs last week constistently had a low affecting the south of the uk. Gfs was last on board and are summer continued as we are all aware. Gfs is notorious for overplaying atlantic driven weather

Edited July 10, 2018 by Snowjokes92

[Mapantz]

I really don't see much to complain about if you're taking the GFS 12Z at face-value?! If you are taking it that way, then there's a fantastic chance of thunderstorms developing from falling heights and slack pressure.. that's probably why the GFS is showing some high rainfall totals, due to the model showing showers/thunderstorms breaking out, but not moving very fast.

Under normal British Summer standards, the outlook isn't that bad. 

[Snowjokes92]

5 minutes ago, Frosty. said:

There's nothing vile about these Gfs 12z charts!..there's plenty of very summery weather shown with very warm surface conditions, plenty of sunshine and an increasing chance of heavy showers / thunderstorms with warm / very warm / hot sticky conditions deep into the run.

The hints of a southerly plume around 240. Yes it gos pear shaped, but its all about the trends. The teleconnections for summer and also whay tamara has been talking about. This is the first gfs run in a few days thats shown a plume coming up from the south at that rough time slot

[StormChaseUK]

Looks likes a similar pattern  cools down  bit in the week then hot weekends.

[Snowjokes92]

4 minutes ago, Mapantz said:

I really don't see much to complain about if you're taking the GFS 12Z at face-value?! If you are taking it that way, then there's a fantastic chance of thunderstorms developing from falling heights and slack pressure.. that's probably why the GFS is showing some high rainfall totals, due to the model showing showers/thunderstorms breaking out, but not moving very fast.

Under normal British Summer standards, the outlook isn't that bad. 

Exactly and warm in the sunny spells. The showers will be hit and miss as well. They would be well scattered

[Methuselah]

14 minutes ago, Frosty. said:

There's nothing vile about these Gfs 12z charts!..there's plenty of very summery weather shown with very warm surface conditions, plenty of sunshine and an increasing chance of heavy showers / thunderstorms with warm / very warm / hot sticky conditions deep into the run.

Aye Karl - the 'vileness' escapes me too...What's unsummery about 22-28C with the chance of thunderstorms?

[Captain Shortwave]

15 minutes ago, beerandkebab said:

acc ppn charts out to and including T240 are about as much use as titties on fishes IMHO.....just an observation, not a pop 

There is one useful thing to look at, look how little rain falls in the north sea? This suggests that the rain will not be coming from frontal systems and as such any rain will come from showers forming over land. At that range the models will not be at all accurate and are often over-enthusiastic in terms of rainfall totals.

I think some kind of low will develop over western Europe but its position is very unclear at the moment, conditions still look warm though showers do look like breaking out on any day from the end of this week onwards. The further south and west this low forms then the drier and warmer the outlook will be (The UKMO looks pretty good and I must admit that if the Atlantic trough does sharpen up then a more westerly position f this low should be favoured).

[shaky]

Briliant ecm!!up to 168 hours!!hot and humid across england and a lot drier compared to gfs!pressure is higher aswell!!

[Mike Poole]

4 minutes ago, shaky said:

Briliant ecm!!up to 168 hours!!hot and humid across england and a lot drier compared to gfs!pressure is higher aswell!!

Yes it's an interesting run this one. Here more settled to T168, and an interesting evolution to T192, will be interested in the last two frames:

[Mike Poole]

ECM T240, ridges over the low cutting it off, heat encroaching from the south:

 summer 2018 rebooted!

[Dominic Carey]

I don’t see anything wrong with these charts tonight I know it’s not showing high high temperatures but at least it’s staying warm.