Model Output Discussion 12z 30/06/13

[Cecil Hogmanay Melchett]

Hmm ECM and UKMO seem to be moving to the GFS scenario.. shame the better two models do that rather than the GFS move when the ECM showed something I kind of wanted to occur.

gfs loooks better in fi than ecm to my eyes

[Frosty.]

The Gem 00z is my pick of the 00z output up to T+240 hours but then beyond that, the Gfs 00z is sensational with the azores anticyclone building strongly northeastwards again and again. This week, all the models show high pressure in control with lots of warm, very warm and hot weather with plenty of strong sunshine, there is a bit of a blip towards midweek across the northeast with briefly more cloud and lower temperatures but most of the uk remains fine and very warm throughout. Then looking further ahead the gem keeps the very warm and settled spell intact across southern britain whereas the gfs and ecm bring unsettled and windier weather across northern uk but the south holds on to the warmer 850's with temperatures never worse than the low to mid 20's celsius but generally mid to high 20's and occasionally touching 30 celsius or possibly higher.

[Cecil Hogmanay Melchett]

ecm brings in huge northern blocking in Fi we dont want that trend continuing!

gem looks great and gfs is actually better than ecm imo,ecm looks terrible going inrto the 2nd half of july with that greeny blocking

[Tamara]

I think that the model evolution with this fine spell and the trends to follow (eventually) have been very consistent to this time. That is taken on a basis of measuring from day to day, and over a few days, rather picking out individual outputs in isolation that may have been less consistent with this.

 

There is really very good agreement between the main models for High pressure to adjust slightly westwards with time and allow weather fronts to brush and influence the weather in Northern UK from time to time. With winds coming around the High from a more atlantic source, this could also have the effect of reducing sunshine amounts further south as well, although the generally settled and fine pattern looks reasonably assured here.

With the upper ridge holding quite strongly over Southern and Central UK, and the PFJ held to the north of us, then the upper warm pool of air that is giving our present hot spell of weather looks set to remain over the nation, so even where conditions might become rather more changeable, with time, for more northern parts - it still looks to remain warm or very warm for most parts.

 

South Western parts looks to stay sunniest of all with the very highest temperatues seen here for the longest

 

However before then, this week holds good for plenty more warm/hot sunshine - with just regional subtlties day to day in terms of, f.e, east coastal areas seeing some cloud and slightly cooler temperatures midweek - but this phase of weather looks less accentuated than it did leading up to the weekend

 

There have been a lot of comparisons recently with 2006.  I think in terms of the general pattern there are clear differences to then with High pressure more UK and eastern atlantic based - rather than European and with heat sourced from southerlies as High pressre ridges move from west to east in sequence, plus there was also a weak low pressure anomaly over the Azores that time which assisted the plumes of air from the south and gave temporary thundery breakdowns.

 

We saw the hot spells ebb and flow in this way through much of June and July that year wheras the fine hot spell we are experiencing this time started from an Azores ridge which took the jet stream north, but it has developed as a UK based High and looks to be showing impressive longevity in terms of staying close by to us, and, unlike 2006, the eventual trend as already discussed is to take this to the west of us - and not the east

Edited July 8, 2013 by Tamara Road

[johnholmes]

A look at the anomaly charts this morning gives a much more realistic view of what upper pattern and thus the surface weather may be in 7-10 days time from now. Over the past 4-5 days all of the 3 major anomaly charts have shown a similar progression. That is from an upper ridge over/close by the UK to a flatter type with +ve heights less obvious over the country and upper trough or even cut off upper lows showing more than the last week or so on the charts.

Yes a good week to come for many although eastern districts, as today, less so thanks to N Sea cloud at times, and on Wednesday from the decaying front moving around the NE edge of the surface high, but less settled for many for the northern half 6-10 days down the line. Beyond 12-15 days is not clear yet which pattern will be dominant.

noaa charts

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

ECMWF_GFS charts

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

compare the above with those showing seom days ago, see a post I did a week ago or thereabouts in the slower thread for comparison. I'll drop some charts in during today, not got time at the moment.

Edited July 8, 2013 by johnholmes

[shedhead]

Not a lot to add to the above posts from JH and Tamara, which both highlight the likely trend as we move across the next week to 10 days. I think we have probably now seen the peak of the heat for E and SE'ern areas, but the SW and Wales may well get a degree or two hotter still during the next few days, especially if there is sufficient E gradient to keep the sea breezes at bay. Next week is now showing consistent signs of cooling off and turning rather more cloudy as the air becomes increasingly Atlantic sourced, but as has been said consistently this summer it's all relative, with most of us likely to have been delighted 12 months ago with what the models are showing for next week. Time for changes yet, but I just do not see the HP drifting east and bringing hotter conditions at this stage.... as ever tho time will tell.

Edited July 8, 2013 by shedhead

[snowmadchrisuk]

I think IMBY will come into play here , if your taking into account day to day conditions , for example if you look at where I live in Weston-Super-Mare, We have at least another 7 days of Mid to High 20's with the exception of a little sea mist in the mornings , blue sky's light winds and Sunshine . Where as if You lived in Skegness , you could be looking at low 20's and cloud for 3 days. I think the High will win in the SW out until at least day 10 , and if next weekend turns out to be 29-32 deg then the Models will have done a wonderful job , as by then that would have been showing for over 7 days . By law of average we are due a good Summer , and the rinse and repeat of the Azores high would be a very possible outcome at the moment . The NW will always be more likely to receive attempted pushes from low pressure , but even here should see some high 20's before this is all done . 

[johnholmes]

If you go to the in depth thread I am putting a comparison of the 500mb charts in there. Not technical all in simply English.

[Frosty.]

The Ecm 00z ensemble mean shows the very warm weather persisting across southern britain until later next week with temperatures of 25 celsius or higher, much higher at times this week, nearer to 30 celsius, the overall trend is for a strong ridge to be maintained across the southern half of the uk until next week with mainly dry, sunny and very warm weather but for scotland & n.ireland a slow erosion of the fine spell with more of an atlantic westerly influence over time but still with occasional fine and warmer days too, there are a lot of reasons to be optimistic about longer term prospects and to enjoy the current summery weather across the southern half of the BI as it looks set to last for many days to come.

Edited July 8, 2013 by Frosty039

[bluearmy]

the ecm suite is certainly trending away from where it had been going whilst naefs is headed away from its trend. trouble is ecm is shortening the fine spell whilst naefs is now extending it.  whilst these discrepancies persist, i think we should  be enjoying the sunshine and not worrying about week 2 !

[Skeggy Winter Storm]

I think IMBY will come into play here , if your taking into account day to day conditions , for example if you look at where I live in Weston-Super-Mare, We have at least another 7 days of Mid to High 20's with the exception of a little sea mist in the mornings , blue sky's light winds and Sunshine . Where as if You lived in Skegness , you could be looking at low 20's and cloud for 3 days. I think the High will win in the SW out until at least day 10 , and if next weekend turns out to be 29-32 deg then the Models will have done a wonderful job , as by then that would have been showing for over 7 days . By law of average we are due a good Summer , and the rinse and repeat of the Azores high would be a very possible outcome at the moment . The NW will always be more likely to receive attempted pushes from low pressure , but even here should see some high 20's before this is all done .

im in skegness and its currently 14 or 15c very depressing here low cloud grey skies feels quite cold for early july sick of these north easterlies from imby pov i need the high to move south and east no doubt it will in winter

[Methuselah]

Can we stick to models, please?

[WillinGlossop]

Like the look of the 06z gfs for nw england .......

[shedhead]

The GFS 06 appears much keener to push the cooler air southeastwards, with Sunday's predicted maxima around 20-22c in the south and only 13-15c across a good part of the north, indeed it wouldn't be an exaggeration to call the bulk of Scotland downright cold!  Maybe this will prove to be rather progressive, but there's currently no denying that the predicted synoptic pattern is starting to reflect the latest 500mb anom charts, with the likelihood of a significant cool down by this time next week gathering pace.

 

[johnholmes]

re the low cloud in the east right up into the Forth area.

Hard to say what temperature is needed to burn it back to the coast as none of the skew-t diagrams available on Net Wx, and one can call up just about anywhere along the east coast on Extra, show the ascent profile one would expect with St showing on the visual sat picc and from the observations. So no idea how thick it is but I would suggest it probably needs at least 19C to start making holes in it?

[Buzzit]

The GFS 06 appears much keener to push the cooler air southeastwards, with Sunday's predicted maxima around 20-22c in the south and only 13-15c across a good part of the north, indeed it wouldn't be an exaggeration to call the bulk of Scotland downright cold!  Maybe this will prove to be rather progressive, but there's currently no denying that the predicted synoptic pattern is starting to reflect the latest 500mb anom charts, with the likelihood of a significant cool down by this time next week gathering pace.

 

In the last 18 hours the GFS Op has lept on the idea that the 14-16 July will see the transition to much cooler weather, while also being the only model to make anything of the tropical storm heading towards the lesser antilles at the moment (with respect to keeping it together after it passes through Cuba. In both cases I am trying to figure out what the Good For Something Model is good for but am struggling

[Milhouse]

The GFS 06 appears much keener to push the cooler air southeastwards, with Sunday's predicted maxima around 20-22c in the south and only 13-15c across a good part of the north, indeed it wouldn't be an exaggeration to call the bulk of Scotland downright cold!  Maybe this will prove to be rather progressive, but there's currently no denying that the predicted synoptic pattern is starting to reflect the latest 500mb anom charts, with the likelihood of a significant cool down by this time next week gathering pace.

 

 

Then a rebuild of pressure from the SW going by the GFS 6z supported by the the GEFS mean.

 

 

But before then we could see another attempt at reaching 30c on Friday and Saturday.

[Milhouse]

UKMO and ECM do want to prolong the settled spell for the southern half of the UK into next week with a ridge still presisting. The Northern half of the UK would see more cloud and would be cooler as a result. But still scope for the mid 20s to continue across southern England to the end of the ECM op.

[Milhouse]

GEM throws in another fantastic run with high pressure persisting well on into next week and signs of a renewed push of high pressure from the Azores later on.

 

[Costa Del Fal]

Rather disappointing GFS from Sunday IMO. Azores high looks to become anchored well away from the UK really with just very weak ridging really. Cool for some though perhaps staying warm in the southern half most of the time. Not a washout but seems a stick in the middle with nothing really exciting IMO. GEM is increasingly on its own. Saying that recent CFS runs are very keen on more Azores ridging throughout the month and August.

[Frosty.]

More great charts from the Gfs 06z for this week and even next week the 6z shows a lot of very warm or hot weather for the south but I have a feeling the 6z is a cool and unsettled outlier for the north of the uk, if that is the case, the warm and sunny weather will be more widespread across the north and the south will be even hotter than the 6z op run shows, however, if I lived in the south I would still be happy with this run as very warm or hot and sunny weather easily outweighs the cooler unsettled weather which is chiefly restricted to scotland with only brief unsettled less warm blips further south.

Edited July 8, 2013 by Frosty039

[Buzzit]

Also worth pointing out GFS is in 3rd place at the moment for the preceding 30 days with respect to every single Geo-potential Height accuracy at 1000, 750, 500, and 250hpa and at 1, 3, 5, 6, 8, and 10 days. ECM is the clear leader (as usual)

Edited July 8, 2013 by Buzzit

[rmc1987]

The GFS 06 appears much keener to push the cooler air southeastwards, with Sunday's predicted maxima around 20-22c in the south and only 13-15c across a good part of the north, indeed it wouldn't be an exaggeration to call the bulk of Scotland downright cold! Maybe this will prove to be rather progressive, but there's currently no denying that the predicted synoptic pattern is starting to reflect the latest 500mb anom charts, with the likelihood of a significant cool down by this time next week gathering pace.

Blimey that is some downgrade, few days it showed 32c for Sunday.

[bluearmy]

there is a large chunk of ecm ens runs for london which have high teens for london on sunday. this will either firm up over the next couple of runs or we will revert to the hotter scenario.

[Evening thunder]

A bit irritated I must admit at the GFS 06z and runs moving towards the GFS today , even the BBC were confident enough to say hotting up again to 30C at the weekend and possibly after, but not sure that will happen if the GFS comes off (maybe very locally on Saturday), as the Met Office forecast maps don't show temps quite as high on Friday and Saturday even as they were yesterday/today in places.

It seems like ECM = most accurate model - unless it shows something you want to happen, then it follows the GFS instead.