Model output discussion 14/04/18

[Tamara]

1 hour ago, Alderc said:

, the cold front racing south on Wednesday continues to accelerate forward in the model output to the extent that tomorrow is now likely to the be the warmest day of the week. Also the cold pool behind is quite potent for the time of year and takes around 4days to mix out before the ridge once again regresses westwards. 

Given how this week's brief ridge has panned out I have little confidence in any scenario beyond about Saturday (despite the good ensemble agreement), definitely more runs required but certainly a lot of dryness about. 

Based on non-NWP data, I have been cautious about the retrogression signal c/o falling atmospheric angular momentum this week, so do understand any caution also expressed in NWP terms - as whole suites can, on occasion, flip when upstream signals are not clear

However, though you do describe pleasant weather in the offing, I also think your choice of terminology rather detracts from that by over dramatizing and over emphasising the downsides of the synoptic response to the slightly retrogressive signal this week. One might for forgiven for almost thinking a wintry squally mix was being ushered in by this weeks cold front reading your description  When in fact bar a few (rain) showers in the east on Thursday, there looks to be increasing amounts of sunshine and temperatures on the rise once again. This is taking NWP as an overview and not unnecessary face value dissection of individual operational intra day output.

Previous posts spoke of the hope that this "lull" atmospheric angular momentum phase would continue the theme of being shallower than the last. This is proving to be the case, and based on continuing favourable upstream support in the Pacific, the Global Wind Oscillation represents a very weak, almost indeterminate, Phase 1/2 signal currently - which endorses the watered down east Atlantic ridge/downstream trough scenario of this week

 

The coolest air advection associated with the synoptic response to this looks set to be steered into the nearby continent to our east. I think that the ensemble members for The Netherlands, but more especially further east in Berlin and Warsaw illustrate this drop clearly. The extent of the cooler interlude is put into good perspective in London - with daytime temperatures for the latter part of the week close to normal and feeing warm in sunshine. So nothing especially "potent" suggested

In any case, all localities reflect the transitory nature of the cooler interlude with considerable warm-ups thereafter. These represent very encouraging ensemble sets and as others have demonstrated well through use of the clusters, once the usual eccentric members are taken out of the equation, very good agreement for the extended period that most should be only very happy with as summer gathers her momentum

 

No further commentary to be added on previous recent analysis here - based on the tropical signal, the considerable changes happening in the Pacific clearly representing a shift in regime, there is good support for continued ridging and any retrogressive/lowering of the jet signal restricted to temporary incursions furthest north and west. In any event, Bournemouth is probably set very fair and warm, as are many British cities, and unlikely that contingency energy supplies are going to have to be drawn up with the National Grid just yet 

 

[mb018538]

Belting UKMO run tonight - high pressure really in control at 144

Edited June 18, 2018 by mb018538

[Captain Shortwave]

GFS/UKMO and GEM at day 6

      

Solid UK based high on both here, the UKMO starting to dig cold air towards that low west of Iberia which would be a classic precursor to some serious heat spreading north into northern Europe as we went further. The GFS looks better than the 06z run and crucially both are starting to drift towards a solution by the ECM suite this morning. The end of the week still looks quite cool for the time of year but temperatures should recover by the weekend and into the following week.

Edited June 18, 2018 by Captain Shortwave

[Singularity]

These plots have their limitations, but at least I can show you that ECMF has moved toward the enthusiastic output from CANM with respect to the MJO propagation during the next week.

Still much more adjustment needed before it starts to look properly promising, but it's a start .

Overall, today has brought a bit of good news with respect to longer-term prospects. Long may that continue .

[mb018538]

On ‎16‎/‎06‎/‎2018 at 11:10, johnholmes said:

Looking at the latest 6-10 day 500 mb anomaly output suggests that any upper ridging is a short lived affair with a mainly westerly pattern showing. You can see this, albeit certainly not cast in stone, on this morning's ECMWF if you play the previous chart from yesterday. This has a marked +ve ehight anomaly this morning no sign. NOAA also shows this over the past 2 days or so. I generally take NOAA as the most reliable with EC following and GFS some way behind unless it is similar to the other two. No GFS either yesterday or today on the link I have. The 8-14 NOAA similar to the 6-10. To me it remains looking like a NW-SE split on average through the next 2 weeks. Obviously they are 'mean' charts and some divergence on occasasional days will occur but no major difference over the period as a whole.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

Just digging this up from Saturday - not to have a go at @johnholmes at all or anything like that, more to illustrate the fact that the anomaly charts are only as good as the current data that is being fed into them. Only 3 days ago there was no suggestion of any sort of strong anticyclone building.....and that has quickly changed. So while these charts are useful a lot of the time, sometimes they aren't!

[Mike Poole]

Add into the mix the ICON at T180, and I'm starting to think that on the back of the 0z ECM and ensembles we may see a settled full house in the 12s at least out to day 10, or as far as the models go, here's hoping:

[Summer Sun]

Absolutely brilliant from UKMO 12z great times ahead potentially

[Djdazzle]

ECM 12z is showing heatwave conditions.

[SizzlingHeat]

Absolutely stunning 12z ECM once again. Words alone cannot describe how good this run is again! Builds the high in very quickly after a slightly cooler Interlude on Thursday with temps well into twenties again by the Sunday. The latter stages of the run once again dominated by high pressure across the entire of the UK with 850s up at 15c over England from Monday. Temps likely to be above 30 for some if this run comes off. Fantastic stuff. 

[mb018538]

Yes, ecm is a dream if you like heat....we’re looking at a fair stretch of days above 80f if that verifies. If you don’t like the heat, look away now. Great for me!

[Fourty Point Three Degrees]

2 hours ago, Mike Poole said:

Add into the mix the ICON at T180, and I'm starting to think that on the back of the 0z ECM and ensembles we may see a settled full house in the 12s at least out to day 10, or as far as the models go, here's hoping:

I think you can add ECM 12z into that and make a full house. Whats the prize?

[Ice Man 85]

1 minute ago, 38.5*C said:

I think you can add ECM 12z into that and make a full house. Whats the prize?

A stay in broadmoor.

Edited June 18, 2018 by Ice Man 85

[Djdazzle]

ECM will prob see temps into the low 90s.

[Singularity]

Amazing how only a slightly flatter high sees ECM wafting the 10*C 850 hPa isotherm across central parts midday Sunday while GFS is still in the process of ditching the 5*C is isotherm.

Then the ECM’s flatter high drifts more east and the differences grow increasingly pronounced. ECM 12z looks ripe for 30s across quite a few places by Tuesday. Wednesday potentially even hotter depending on whether any thunderstorms break out. Impressive.

GFS while less dramatic is very pleasant with mid 20s shown and - correcting for bias - high 20s probable on a good few places by Wednesday.

 

Right, back to the VAR debate ... I mean England game

[Frosty.]

Stunningly Beautiful Ecm 12z..who wants boring average summer conditions when you could have this?..really exciting times for summer heat lovers!

[CheesepuffScott]

16/17C uppers widely at +240 on ECM.

[Summer Sun]

What a sensational run 12z ECM is

The best could be yet to come

[Matthew.]

The best summers do see the trademark of high pressure in the last third of June with dry the dominant feature of the month

[Gordon Webb]

39 minutes ago, Singularity said:

Amazing how only a slightly flatter high sees ECM wafting the 10*C 850 hPa isotherm across central parts midday Sunday while GFS is still in the process of ditching the 5*C is isotherm.

Then the ECM’s flatter high drifts more east and the differences grow increasingly pronounced. ECM 12z looks ripe for 30s across quite a few places by Tuesday. Wednesday potentially even hotter depending on whether any thunderstorms break out. Impressive.

GFS while less dramatic is very pleasant with mid 20s shown and - correcting for bias - high 20s probable on a good few places by Wednesday.

 

Right, back to the VAR debate ... I mean England game

prefer the GFS myself and as for VAR involved in every penalty except one

[damianslaw]

Whilst both UKMO and ECM are showing the evolution of a UK based high as we approach the weekend, GFS is still less than convincing in this regard - though moving towards such a scenario.

Always best to remain cautious, I'd say the balance in favour of the high migrating west or east is 50/50 at this point. This is often a pivotal time.. the northern hemisphere settles into its summer base state, and high pressure ruling the roost, is generally usually a very positive sign. This summer certainly has potential to be the best overall since 2006 - which is a high benchmark.

Edited June 18, 2018 by damianslaw

[Daniel*]

Hot stuff from ECM tonight may see a string of 30C+ days if this come to fruition. That low W of Iberia may pull up some spectacular thundery weather too, up from south, not far off a classic.   

[Frosty.]

England win and the models, especially the Ecm 12z op showing a potential heatwave on the way...life is good!

Fantastic Ecm 12z ensemble mean!

Edited June 18, 2018 by Frosty.

[Singularity]

If one model is to be more west with the high, it’s usually encouraging if it’s GFS and you want the high more east, due to the model’s low AAM bias (albeit this less pronounced when AAM is low in the first place).

ECM 12z evolved into a proper 76-style toaster for the S in particular what with the dry run of weather lately. That’s not to say it will be anything like as prolonged as that, though! (Well.. almost certainly?).

[SizzlingHeat]

Cracking mean at 216 from ECM. The op has significant support now for a significant warm/hot spell. If the op was anywhere near correct, we would have days of temps above 30 degrees and approaching if not close to the mid thirties by midweek. I would even go to say a touch higher if the ECM showed a 256 frame. Best ECM mean and op in many years. Fantastic stuff. Lovely to see the support across models as well. Fantastic spell of summer weather enroute. Long may it continue. Summer has only just begun!

[Captain Shortwave]

      

I guess the best thing about this is the position of the high pretty much gives light winds and lots of sunshine to pretty much the whole of the UK. Maybe a little cloud building up inland during the middle of the day whilst coastal areas remain sunny and a little cooler as onshore breezes develop.

Looking at the 850s, good agreement on that shallow low persisting west of Iberia and this should help to allow the heat building over Spain and France to slowly move northwards, add to that the temperatures at the surface should rise too under light winds and prolonged sunny spells. The ECM op for example should get close to 32C/90F by day 10 and I guess moving forward would likely to increase further as the surface high begins to drift east of the UK again. The ens probably keeping a mix of solutions in week two though in general keeping the high close to the UK, if it ends up over Ireland temperatures will proably settle in the high twenties, but if it can set up over the vicinity of Germany then it will allow a southerly wind to push northwards and this has the potential to be hot or even very hot. One to watch but overall the outlook is very settled with temperatures above or well above average after a cooler couple of days to end this week.