Model Output Discussion - 3rd May Onwards 00z--->

[Biggin]

The GEFS 6z mean is perfect, high pressure building in and becoming warm / very warm. The MO outlook is superb with high temperatures and lots of sunshine and a growing chance of thundery weather at times in the south where it becomes very warm / hot and humid. Once the pattern change arrives, it looks set to become entrenched and is unlikely to be displaced until sometime in July, who knows, it may last longer. I hope it does

Frosty, I was wondering, come June 15th ish  isnt that gonna be one dirty polluted High ??

Edited May 30, 2015 by Biggin

[Captain Shortwave]

eh? when did one day make a summer? or a heatwave?

The GFS 6z shows just that... a one day hot event. no spell! far from it.

We tend to get carried away, and it continues....

obviously more runs needed, but plumes are always projected in this way, then as time progresses are considerably watered down. 

The GFS 6z is more inline with its own ensemble mean, while the 0Z and others were complete outliers. Just as the ecm op has been shown to be an outlier.

 

the mean for the chart you flag, keeps reality afloat. 

As others have discussed above your post, the validity of the mean surface temperatures seems to be highly questionable.

Wind generally off the continent

Mean 850s in the warm to very warm category

 

It would be highly unlikely that we would be experiencing near normal temperatures under the synoptics shown above.

Given the the ECM suite is even warmer than the GFS suite I am still going to confident of very warm conditions effecting most of the UK.

 

Also not a single post in the last few pages which mentions the words "heat wave", as I said there is widespread warmth even on the run you quoted.

Edited May 30, 2015 by Captain shortwave

[Frosty.]

Frosty, I was wondering, come June 15th ish  isnt that gonna be one dirty polluted High ??

Yes, if there are no brief incursions of fresher atlantic air, it will be hot, humid and hazy across the south of the UK. What a great outlook though. May has been disappointingly cool and unsettled, especially in the north / northwest of the UK but we are now on the cusp of a prolonged spell of increasingly summery weather.

[knocker]

I don't see how you can say that when any change is still yet to happen, indeed if it all goes **** up from here history will show them to have done an abysmal job, so best not get too far ahead of ourselves even now. Up until yesterday UKMO were not fully onboard at 144hrs re the pressure rise and 24hrs before that they were positively against it, hence my increased optimism this morning.

 

The highlighted area is precisely the point, and obviously failing, I was trying to make.

 

Digressing. I Have seen a few comments vis the ECM undercooking surface temps. Is this still the case since the upgrade?

Edited May 30, 2015 by knocker

[Tamara]

NWP has for some time consistently followed the guidance offered by longer term Global Atmospheric tools in advertising quite a marked pattern change to commence this coming week. Say 'adieu' to the cool changeable theme of recent weeks and instead the arrival of a very summer-like, much warmer regime, which will be fully in place by the close of the coming week for all parts

 

I think the differences will be especially marked and noticeable with the overnight temperatures which have often been significantly below average at times in certain parts of the UK during May.

 

With high pressure becoming established to give northern and especially northern western parts a well overdue spell of summer-like weather with deep blues skies and a lot of wall to wall sunshine close to the High pressure, a cut-off low aspect to the S & SW looks set to play its own role in the other high temperature summer weather variant, taking on a typically tropical aspect for southern and south western UK - as thundery activity ebbs and flows, as it moves up from Biscay and continental Europe periodically

 

GWO forecasts continue to emphasise an orbit drift through to Phase 3/4 with possible rebound thereafter to Phase 2.  As suspected, amplitude of the GWO orbit low AAM 8/1/2 phases has been rather over-played by these forecasts, even though it still is supplying distinctly cool and unsettled conditions in the very short term

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

So support is there for the robust upper ridge building to our NE and the slack pressure drop to our SW. Should the GWO rebound (very briefly probably if it does happen) to Phase 2, as currently suggested, then this would encourage renewed ridge amplification to our west across the NE Atlantic, and further high pressure re-enforcement to follow immediately from the initial plume

 

Under such a scenario arriving from the Atlantic (if it happens) subsequent return to any mobile westerly is very unlikely as the problematic upper trough over northern Canada that has engaged the stronger jet stream is set to vaporise in association with the pattern change. The current and upcoming troughing of the next few days is its farewell salvo.

 

I think that extended GEFS members are showing support with this possible immediate reload theme - with the next ridging arriving and holding across northern UK into week 2. Therefore there is no requirement for any intra output hiatus over differences in GFS output pressure, CAPE and precipitation parameters - the model (like all the global synoptic models) is dealing with complex and real Atmospheric processes which are underpinned by Science, and not to try to give emotionally induced palpitations to heat seekers or those who want storms over their house each afternoon and evening after the BBQ has been lit 

 

Away from chasing such fine details, which is futile several days away, in broad UK synoptic terms the larger scale pattern translates to, maybe, one peak in convective thundery activity for especially the south and/or south west of the UK, and then the new ridging re-setting the pattern back to a further heating up from the continent thereafter as pressure across the north of the UK continues to consolidate itself.

 

Although its too early to be certain that this will play out exactly as described, this type of extended pattern evolution is also given some evidence in the newly updated London ECM ensembles - with one spike in temperatures through next weekend, followed by a relatively small cooling (but still above average).

 

http://www.weathercast.co.uk/meteo/eps/ensemble-tt6-london.gif

 

This might suggest (at face value) that the ECM operational (and corresponding overnight GFS 0z as denoted by the blue line) is slightly overdoing the longevity of the amplification of the initial upper ridge and hence it is at the very top end of the ensemble temperature spike.

 

In this regard, those ensemble temperature indicators in summer are often a few degrees below reality - so the consistent ensemble average 20C line currently indicated might suggest peak daily averages closer to 25C. On that basis, temperatures next weekend in that initial hot spike period fully support the 30C mark being breached

 

The weakly low uppers to the SW and S look embedded to stick around for some time to come - much as bluearmy suggested earlier, and this will prop up the pattern and keep the very warm/hot humid air masses close to or over the south of the UK, whilst northern and especially north western most parts generally experience and enjoy lower humidity levels under stable high pressure. So there is no downplaying of the marked change which is set to occur later this week in any way, and quite a heating up process is going to occur in a very short space of time.

 

Based on longer term signals, it is reasonable at this stage to expect further spike(s) to appear in  extended ECM and other model ensembles with generally above, or, at times, well above temperatures likely throughout these processes.

Edited May 30, 2015 by Tamara

[Polar Maritime]

A few off topic posts have been moved, If yours is missing it's here https://forum.netweather.tv/topic/82655-model-banter-moans-and-ramps-springsummer-2015/page-16

Edited May 30, 2015 by Polar Maritime

[049balt]

With high pressure becoming established to give northern and especially northern western parts a well overdue spell of summer-like weather with deep blues skies and a lot of wall to wall sunshine close to the High pressure, a cut-off low aspect to the S & SW looks set to play its own role in the other high temperature summer weather variant, taking on a typically tropical aspect for southern and south western UK - as thundery activity ebbs and flows, as it moves up from Biscay and continental Europe periodically

 

 

Music to my ears

[Summer Sun]

The low between Iceland and northern Scotland is worth keeping an eye on later next week, UKMO has it closer by on this run and could introduce some rain for the far north

 

 

GFS has it further north though some thundery showers could be breaking out for western parts of England and Wales

 

 

Temperatures again back to 30c for next Saturday on this run in the south, could be rather hot at the Epsom Derby if this comes off

 

[Scorcher]

That run from the GFS is garbage for everyone outside the south and east when you consider what has gone before. The GFS really is all over the place at the moment from run to run. At least Friday looks considerably warmer than on previous runs, but it seems to want to push a front through much quicker this time and that low over the Bay of Biscay has all but disappeared.

Edited May 30, 2015 by Scorcher

[Cheshire Freeze]

Nice to see the ecm and gfs mean charts being identical and both agreeing a big high pressure over us:

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

Which means broadly speaking settled conditions and very warm early summer weather particularly for the South east.

Kudos for cfs v2 for picking up on what could be a potentially hot June coming up.

 

For my money there's just too much pressure knocking around at the high latitudes for June as a whole to be anything of note in terms of sustained heat. I said this last week and still stand by my assertions now. The latter stages of FI of the 12z GFS highlights this with increasingly cool and unsettled weather courtesy of retrogressing HP and associated Scandi troughing.

 

Still, it does look like we'll see some pleasantly warm and settled weather for a time and perhaps even a storm or two

[Man With Beard]

Well this is rather interesting. The models have been hinting at a warmer spell for a while, and it has not disappeared as T0 approaches. Only a fool predicts a UK heatwave more than 6 days in advance - too many ways to go wrong at any time - but the ingredients are now in the pot for a prolonged hot spell, particularly in the south - the ingredients just need mixing in the right way. 30C by the end of the week looking likely - that will be a shock after a below average May - but chances for many days above 80F if that second high builds over the top of the cut-off low, as some models show.

[Milhouse]

16c 850 hpa temps into the south by next Friday. Sure is looking very warm, becoming hot for a time.

 

[Milhouse]

Hot and sultry with storms breaking out best describes next weekend on the ECM. Some very impressive temperatures would result from this. 30c quite widely i would say.

 

 

[Captain Shortwave]

Fair to say I wasn't expecting the ECM to crack this run out. Considering the trends from the. Other models the last thing you expect is for the warmest model this morning to churn out something even hotter!!! The ECM remains consistent in the general longwave pattern. But is it consistently wrong?

Edited May 30, 2015 by Captain shortwave

[knocker]

Tonight's GEFS anomalies look fine but they don't point to excessive heat as the HP is either to the east or over the UK although of course minor adjustments could occur. Friday the upper trouigh Iceland could just impact the NW of Scotland.

http://www.tropicaltidbits.com/

[Milhouse]

There is considerable support for high pressure to dominate going by the GEFS mean.

 

[Winter Cold]

Im still not seeing this supposed long hot spell some are talking about....GFS and ECM are basicaly 48 hour blink and youll miss it and then back down to average. Here you go:

 

 

Note that once again, the op run is almost outlier next weekend. 850 graph is also the same. Temps then back down to 15-20 up to mid June..

Edited May 30, 2015 by Winter Cold

[knocker]

Fair to say I wasn't expecting the ECM to crack this run out. Considering the trends from the. Other models the last thing you expect is for the warmest model this morning to churn out something even hotter!!! The ECM remains consistent in the general longwave pattern. But is it consistently wrong?

 

It seems to be down to the fact that it's pushing the LP to the SW up into Biscay and the HP just s bit further east thus maintaining a slack SE flow. Which the GFS ops is also doing with highs in the high 80s on Saturday. A delicate analysis one might say.

 

I love the ECM 850mb temp anomaly. A work of art.

http://www.tropicaltidbits.com/

Edited May 30, 2015 by knocker

[Frosty.]

Next weekend looks a scorcher, loving these Ecm 12z charts, I think low 30's celsius next weekend across southern uk and a risk of T-Storms breaking out, then the Azores high set to build in again. After weeks of cool unsettled dross, I'm really excited by the potential later next week onwards

[Lincstim]

Would the outcome of this heat just create speradic thunderstorms or are they likely to to follow some sort of structure / pattern

I can not believe what the weather could be possibly like next Saturday for the festival I'm involved

Extremely excited

[049balt]

Would the outcome of this heat just create speradic thunderstorms or are they likely to to follow some sort of structure / pattern

I can not believe what the weather could be possibly like next Saturday for the festival I'm involved

Extremely excited

Dramatic changes do happen as we move into Summer and the continent heats up, looks like we have conditions for  the "perfect storm".

[stodge]

Evening all
 
Some people starting to get a bit excited about the upcoming weather:
 
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

The NAO continuing to trend negative to neutral as the forecasts have been suggesting for several days. That would suggest higher pressure to the north and east and lower pressure to the south and west and a degree of northern blocking in evidence though not as much as at the beginning of the month  

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015053012/gfs-0-276.png?12

 

This is a good example of that development as the HP withdraws west to the area normally associated with LP creating the pressure anomaly but the negative NAO often means HP to the north of the British Isles.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

The AO also trending negative in the short term before recovering (according to some members):

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015053012/gfsnh-0-240.png?12

 

The AO suggests nothing too much happening over the Pole so not a huge amount to read into that at this stage. The evolution to something more settled is illustrated by the weakening NAO but strangely I don't think that translates to a long period of heat and indeed as the HP retreats the door is open to colder air coming back from the north for the middle of the month.

[Milhouse]

The ECM mean does look good. Lots of very warm/humid/thundery conditions on offer with these sort of charts.

 

[William of Walworth]

stodge : lets see shall we?

 

Not all models support the suggested downgrade (beyond next weekend) that shows in those links you posted.

[mountain shadow]

No comments on the GFS 6z Op? No wonder. Terrible for the warm/dry spell being projected by some models. Lets hope its just the usual GFS inter run chaos.

 

Will we actually get a firm indication for next weekend in the 0z's?

 

It has a cold front pushing through over the weekend, the UK back into cooler Atlantic air by Sunday after about a day and a half of warmer air.

 

http://max.nwstatic.co.uk/gfsimages/gfs.20150530/18/174/h850t850eu.png

Edited May 30, 2015 by mountain shadow