Model Output Discussion - The Start Of Summer

[knocker]

9 minutes ago, johnholmes said:

And the EC 500 mb anomaly flips again

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

stick with the NOAA version and its 8-14 chart for the most likely upper air pattern for the next 1 to 2 weeks in my view

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

So mostly a changeable outlook, that does not exclude one day here and there with dry and somewhat more summery weather for many!

 

And the funny thing is John the ext EPS is not a million miles from the NOAA chart

[northwestsnow]

GEM is beautiful this morning with the azores high dominating proceedings by day 8/9..

 

Unfortunately the model seems isolated, the others going with the pronounced Greenland block.

[mountain shadow]

1 minute ago, northwestsnow said:

GEM is beautiful this morning with the azores high dominating proceedings by day 8/9..

 

Unfortunately the model seems isolated, the others going with the pronounced Greenland block.

At least it gives us something good to look at. 

[northwestsnow]

14 minutes ago, mountain shadow said:

At least it gives us something good to look at. 

TBH  this is the kind of progression i was hoping for towards mid month, unfortunately , as of yet, this has not materialized on EC/GFS..

In my experience it would be very rare for GEM to Donald all the others but it has happened once or twice. Im hoping this is one of them hens teeth moments but confidence is low.

Edited June 5, 2019 by northwestsnow

[Badgers01]

Interestingly Matt Hugo in his tweet mentions 2012 pattern similarity with current model output - he’s a pro and a level headed guy so certainly something to note ...!!?

[northwestsnow]

13 minutes ago, Badgers01 said:

Interestingly Matt Hugo in his tweet mentions 2012 pattern similarity with current model output - he’s a pro and a level headed guy so certainly something to note ...!!?

Too early to be making those sorf of comparisons but we really need to see this persistant blocking to the NW 'do one'..

[Guest]

GFS 06Z appear to be heading down a slightly more settled route however the cold pool left over takes an age to erode and warm. Seem these sorted of runs too often recently only to be back up 6/12hrs later by a pile a cac!

[mb018538]

Basically what I’ve been worried about for weeks now. Northern blocking sets in and just doesn’t budge.

Unfortunately the clusters have all locked in to another substantial Greenland block forming by day 10, those dark reds in completely the wrong place again. Don’t expect anything decent now before the last third of the month at a bare minimum, just a continuation of suppressed temperatures. Grim viewing if you like warm and settled weather in the summer.

[weathermadbarnsleylad]

     Azores ridging next Thursday. Is this a trend. Did it also show on the gem earlier? @NorthWest_Snow

[weathermadbarnsleylad]

Just now, weathermadbarnsleylad said:

     Azores ridging next Thursday. Is this a trend. Did it also show on the gem earlier? @NorthWest_Snow

Just looked at gem same timescale. We have some agreement I think. 

[Guest]

1 minute ago, weathermadbarnsleylad said:

Just looked at gem same timescale. We have some agreement I think. 

It all hangs on the Greeny high eroding as it does on this specific run - will need many subsequent runs to back this up! The evolution beyond T168 in the GFS 06Z isn't amazing but its a million times better than the current synoptic setup thats for sure! 

[Methuselah]

I don't think the 06Z was that bad, over all: certainly nowhere near as bad as 2012 was!

 

I also think that HLBs are given far too much credit (or blame) and the clusters spent the whole of last winter 'progging' immensely high SLP anomalies, from Greenland to Scandinavia...Even the experts (not just us armchair enthusiasts!) are unable to make reliable forecasts, for the next three-months...Que sera?

Edited June 5, 2019 by Ed Stone

[northwestsnow]

29 minutes ago, mb018538 said:

Basically what I’ve been worried about for weeks now. Northern blocking sets in and just doesn’t budge.

⁸

Unfortunately the clusters have all locked in to another substantial Greenland block forming by day 10, those dark reds in completely the wrong place again. Don’t expect anything decent now before the last third of the month at a bare minimum, just a continuation of suppressed temperatures. Grim viewing if you like warm and settled weather in the summer.

Cluster 1 is the best option ...

Fingers and toes crossed..

[Methuselah]

And this is what the FV3 comes up with: the snot's still there, but Greenland HP isn't?

 

[StormChaseUK]

If the high pressure can get established and erode that cold pool we might be in business.  The pattern shows that whenever the cold pool dies out another injection beefs it up again from the north/north west.   

Holland eastwards look like the best place to be for a summer this year.

[StormChaseUK]

Also France unusually are having pretty crappy cool weather too. 

[Methuselah]

Time for the 06Z ensembles, which don't suggest a heatwave is imminent:

 

The only positive, I can see (imagine?) is that scatter increases rapidly post Day 6...So perhaps a pattern-change is coming. Then again, perhaps a pattern-change isn't coming!

[mb018538]

I'd say the scatter isn't from a pattern change - northern blocking to persist etc - but with flabby lows and high pressure to the north you can get a whole raft of outcomes, hence all the noise.

You need to get really lucky in this sort of set up to not end up with rubbish weather. Best bet is probably a little stalling low to the west to scoop up some continental heat and send it our way. Certainly no strong anticyclone and home grown warmth like 2018, that's for sure.

[Tamara]

So much going on right now that renders over scrutiny of NWP, especially each and every operational output, even less sensible than is usually the case.

Yet another occasion therefore to attempt to supply some analysis of drivers, for those who at least might be interested in reading between the lines a bit and looking at some causes and effects, rather than simply wading through a diet of a cacophony of intra day spasmodic gloomy reactions.

First of all, if we take a strong westerly phase of the Quasi Biennial Oscillation (QBO) aligned with solar minimum conditions  - plus added to that a stratosphere > troposphere profile that has a lot in common with years like 1995 and 2013, then the summer in terms of broadscale  height anomaly pattern *should* be on destination to something like this during this summer :

If a weak El Nino atmospheric circulation forcing is added to the melting pot which engages extra tropical propagation of planetary waves from tropical convection located within an Pacific standing wave, then something akin to this becomes the framework destination as summer wavelengths really start to engage the closer we head towards July: 

The former anomaly chart to the one just posted has some similarities at face value to those we have become accustomed to. One highly crucial stark difference is that the emphasis has been for the longwave trough wrapped within that arc of height anomalies to be displaced towards the UK and locked in over us rather than westward placing in the Atlantic and which would make a massive change to warm air advection adjusted our way rather than stuck to our east.

Some post analysis, from those that read them, discussed a week or so back, why the trough was displaced in our vicinity, and what it would take to displace it westwards to more closely the blue print composite anomaly that reflects what some will coin/overdub the "background signals" as identified above.

The cause, for another further reminder is a combination of persistent override from a dynamic element to the final stratospheric warming, later than usual in Spring - sustained further by a "destructively acting" phase of the tropical cycle on the El Nino standing wave (suppression in the Pacific) which skews the blueprint of the above expected anomaly towards a greater emphasis of Atlantic/Greenland ridge, rather than Scandinavian and European. Furthermore, and most crucially it places the trough further east towards us than the suggested composite.

This is redolent of an a-typical La Nina type adaptation of the template pattern that has the crucial effect of making a vast difference between sharing the heat over the nearby continent, and instead being stuck in a cool and unsettled envelope.

That struggle clearly evident within NWP - with heat locked in to the east, and despite hints from some NWP ensemble suites,  unable to advect far northwards or westwards due to the propensity of ridging to the west and northwest. Hence the upper trough has nowhere to go, but stay in situ, with more and more surface troughs being bred at its base and being pulled northwards within the upper cold pool created.

Frustration with the deadlock is understandable, but objectively it is more rewarding, ay least in my opinion, to identify causation though diagnostic approach and probability assessment, look at what is required to change the rossby wavelength, and then once again through the use of diagnostics (beyond the face value identification of the upper air and surface patterns), the probabilities of change occurring to what remains actually a finely poised pattern based on the drivers in play than the computer models might appear to suggest moving forward

Its worth looking at that height anomaly cross section and where we at vs the most recent of the years mentioned above -  2013.

As we know, putting aside the anomalously much colder first half of Spring than 2019, nevertheless the profiles of the atmosphere this year share some noteworthy similarities in terms of slow speed of strong downwelling into the troposphere - and which continued to scramble the pattern of late Spring and first part of summer in 2013.

Now lets take a look at the representative QBO values for both years: Both firmly westerly by this time, and to very similar strength.

2013 -6.07 -1.23  2.85   8.39  12.64 13.38 14.27 14.66 13.12 11.69 12.45 12.55

2019  9.02   9.25  11.82 13.36 14.59 (May to date)

QBO Calculated at NOAA/ESRL PSD 30mb zonal wind at the equator, zonal average For info https://www.esrl.noaa.gov/psd/data/climateindices/list/ units=ms-1

Next up lets look at that -ve disconnect to the tropical cycle to the El Nino standing wave and latest EC weekly forecast of propagation timing of the MJO back to the Pacific - returning a more constructively acting relationship to the Nino standing wave and hence re-configuring the downstream pattern to more of an Atlantic rather than UK trough

 

The risk to persistence of the Atlantic and Greenland pattern becoming the default remains failure of the propagation of this MJO wave and what difference it would make not just to any June improvement but how it might alter the progress to a more mid latitude pattern deeper into summer as the template Nino/wQBO low solar combination suggest.

But the present forecast from a much more reliable velocity potential component forecast to tropical forcing than RMM modelling, continues to suggest eastward propagation into the Pacific, albeit on a slow time envelope for realistic timing being from third week of June. I'm not sure the MJO RMM deterministic forecasts are especially helpful here, and which underestimate eastward progression - especially around the Maritime Continent and where models tend to try to "stall" the topical wave and interpret loss of signal.

This bias tendency will also skew NWP perceptions - hence another reason to treat models with caution who, as is well known, have a capacity for apparent consensus to extrapolate a signal for indeterminate periods of time, and then catch on what is happening and head into reverse.

With all of the above analysis in mind, there is good reason to discount the upcoming period as unlikely to change until that disconnect tropical phase is complete - but a lot of evidence and added research to show, that as 2013 suggested into July, it is baseless to extrapolate an apparent persistence factor out across weeks of a whole season, let alone a whole season.

Evidence base reasoning is always a more constructive (and enjoyable) method and pastime, and which can always be sensibly monitored for progress and revision according to any further departures from the template - than just pessimistic frustration which offers no objectivity other than based on previous worst case scenarios.

 

 

[MATTWOLVES 3]

1 hour ago, Ed Stone said:

Time for the 06Z ensembles, which don't suggest a heatwave is imminent:

 

The only positive, I can see (imagine?) is that scatter increases rapidly post Day 6...So perhaps a pattern-change is coming. Then again, perhaps a pattern-change isn't coming!

These ensembles from GFS are not great again Pete. I've noticed how the FV3 is going from 10+c uppers some days, and back down to 0c the next, simply put, it has not got a clue. The ECM ensembles really do need to improve. The operational was again on the cold side, with the mean being a tad higher, but overall +7c uppers is still relatively disappointing for the time of year.. Big improvements required... I've just noticed Tamara has posted as I complete this, so hopefully she will bring a bit of joy. 

Edited June 5, 2019 by Mattwolves

[Methuselah]

58 minutes ago, mb018538 said:

I'd say the scatter isn't from a pattern change[...]

Indeed it's not, mb: it's 'simply' down to information/signals being swamped by noise...Which is why I cannae help but imagine meteorology being in a similar (though FI will hopefully start a tad later?) position, 20-years' down the line, to where it is today.

Is there any single part of weather-forecasting that doesn't rely upon numerical modelling? I mean, a model's a model whether its numbers are crunched by computers, or by thousands of people armed with slide rules?

And, at the end of the day, a forecast is a forecast. It's not a guarantee!

[knocker]

Earlier today there were some hefty Cu/Cbs around in these parts accompanied by some nasty showers During the morning these tended to become less developed as a layer of high Sc appeared to put the cap on them, and the showers died out. The midday sounding illustrates this.

Anyway enough of that twaddle and on to later today

The heavy showers over Scotland and N. Ireland will tend to die out this evening although the rain will linger a while over the latte, courtesy of the stray occlusion. But away to the south east there is a lot of convective activity moving north into the North sea from Germany, associated with the waving front, and that will just brush along the east coast Elsewhere a clear night and temps may well get down to near freezing in some spots in the south west

 

Edited June 5, 2019 by knocker

[mushymanrob]

4 hours ago, mb018538 said:

Basically what I’ve been worried about for weeks now. Northern blocking sets in and just doesn’t budge.

Unfortunately the clusters have all locked in to another substantial Greenland block forming by day 10, those dark reds in completely the wrong place again. Don’t expect anything decent now before the last third of the month at a bare minimum, just a continuation of suppressed temperatures. Grim viewing if you like warm and settled weather in the summer.

northern blocking isnt a problem per se, its there most of the time over greenland anyway. its only a problem for heat lovers if it is combined with troughing over scandinavia (like in 07, 08, 12) . if theres a ridge into europe, then we are likely to get a southeasterly flow... perhaps not dry, but its still warm.

[MATTWOLVES 3]

A slightly better evolution from icon, still the signs of ridging approaching by day 7...im pretty sure if this ran just a few more days things would be looking a little more peachy... 

[Yarmy]

1 hour ago, knocker said:

The heavy showers over Scotland and N. Ireland will tend to die out this evening although the rain will linger a while over the latte,

Has it smelled the coffee?