Model Output Discussion - 1st July Onwards 18z--->

[Milhouse]

Temperatures still looking good over much of eastern England on Monday. East Anglia looking like the favoured spot with 29c, possibly 30c.

 

[Milhouse]

And the whole of next week looks much more like summer on the 6z. A brief cool down midweek before temperatures and humidity rises, which brings the threat of heavy pulses of rain coming up from the south, but also some drier spells too.

 

[Frosty.]

If anything, the Gfs 6z is a slightly warmer run than the 00z across the southern half of the uk but the main theme remains much the same with a nw/se split for most of the time, the driest, sunniest and warmest conditions across the south / southeast of the UK. The reliable timeframe shows a lot of fine and sunny weather but also a few sharp showers although quite isolated, chilly nights for late summer but daytime temps improving. Next week the nights look milder and the days look warmer than this week away from northern uk so it will feel more like summer further south, there is a chance of thunderstorms clipping the southeast later on Monday. I had a look through all the 00z runs and none of them show any sustained settled weather, it's predominantly unsettled but by far the worst of it across the northwest of the BI, at least the chill will soon be replaced by more respectable temps but the dreadful summer for n.Ireland and Scotland seems like continuing.

Edited July 30, 2015 by Frosty.

[Man With Beard]

That low to our north-west is not getting anywhere fast, and none of the GEFS 06Z options have brought the main upper-trough over bulk of the UK by Thursday next week. In fact, there are a fair few tasty members in this ensemble suite that have re-established a continental flow by this time, and not just for the south-east corner:

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=174

 

though a number of the warmer runs are quickly swept away by a thundery low on Friday morning:

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=192

 

The GEFS ensembles for London shows 9 of the 21 members with 850s above 16C on either Thursday or Friday - that's hot:

 

http://www.meteociel.fr/modeles/gefs_table.php?ext=1&x=306&y=141&ville=Londres

 

ECM ensembles do not agree though, with the main spread for 850s only getting to 11C/12C.

 

http://www.meteociel.fr/cartes_obs/ecmwfens_display.php?x=306&y=141&ville=Londres

 

So warming up Sunday/Monday, cooler Tuesday and low but not insignificant chance of heat returning by the end of the week

[summer blizzard]

Nothing to get excited about as far as i'm concerned..

 

[Skullzrulerz]

Nothing to get excited about as far as i'm concerned..

 

No offence but it could be a lot worse with a cold northley or the train from the west bring a loud of rain with it stopping exclusively at the UK.

From my untrained eyes it seems it is at least warmer then last week so that's something

[Frosty.]

The Gfs 12z is the most unsettled of the three gfs runs so far today during low res but the reliable timeframe is as per the earlier runs with a depression to the west of the UK helping to draw up warmer and more humid air from the continent, especially through sun/mon with temps in the south up to 25c on Sunday and even higher on Monday. The next 3-4 days look largely fine with good sunny spells and isolated showers although Scotland looks very showery on Saturday. Sunday looks fine for most of England and Wales but rain returning to the northwest of the UK. Early next week looks very warm and humid, especially further east and southeast but with a band of showery rain pushing east and then tues/wed look cooler and fresher with a brisk swly breeze bringing sunshine and scattered showers, later next week shows a risk of thunderstorms spreading across the far e/se from the hot near continent and the further outlook is changeable / unsettled, especially for the n/w where it's also coolest, the best of any fine and warm weather for the south/southeast but unsettled at times there too.

Edited July 30, 2015 by Frosty.

[knocker]

Although this evenings GEFS anomalies are still showing the pattern change post T168 namely losing the eastern Pole HP and the trough NE Canada, the change to low pressure over Greenland is a negative move as it serves to reinforce the mid/eastern Atlantic trough later in the run. Consequently the general outlook is much the same with perhaps the best of the weather next weekend. Low pressure to the NW and the better weather dependent on interjections of the Azores ridge. Again the outlook favours the southern half of the UK.

Charts weatherbell

Edited July 30, 2015 by knocker

[summer blizzard]

Euro has the low victorious..

 

[Methuselah]

But it still has the trough out west...

[Frosty.]

The Ecm 12z shows a generally changeable / unsettled outlook but at least it looks like being warmer next week by day and night than this week and occasionally humid with very warm air early next week then a fresher, breezier few days before the isobars spread out and winds fall lighter with warmer 850's flirting with the SE again later next week, could be some thundery weather for the southeast early and later next week. The most unsettled atlantic weather is further northwest, the south and east looks like having some fine and warm weather between the more unsettled spells

Edited July 30, 2015 by Frosty.

[Man With Beard]

Well the NOAA 6-10 day paints yet another "corridor of uncertainty" picture for the UK. Pressure certainly looking to build from central Europe towards Scandinavian. A tight low on our doorstep. There will be a squeeze of Mediterranean air somewhere between the two, but will it clip our shores, and to what extent? Wouldn't like to place any bets regarding Tuesday - Saturday next week at the moment, certainly for England, as 200 miles could separate autumn from high summer. Clearly, though, the further south-east you are, the more likely to join the party.

[johnholmes]

I would suggest that the 6-10 shows little sign of anything other than the odd day of summer like weather even for the SE. The 8-14 shows that the upper pattern 'may' be starting to move. It shows the trough, for so long out west, is predicted to move over the UK giving a westerly 500mb flow. Not that it brings any sign of summer, probably remaining fairly changeable or unsettled whichever word you prefer.

links below as usual

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

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

showing, unusually for me, the 12z output as the 00z had no ECMWF, and anyway I suspect that, much as GFS, it is a pretty close copy anyway.

Interesting that just 1 day from August this evening and the oft suggested return to summer is just as far away, and the anomaly charts have been rock solid with their refusal to join this idea. They really are very good IF used carefully for about 2 weeks ahead.

Edited July 30, 2015 by johnholmes

[knocker]

Latest EC32 update (very brief)

 

Starting at the ext ECM  period on the 14th where we still have the uper trough over the UK bringing mainly unsettled weather to Britain with below average temps.

 

By the 19th the upper trough has waned and a westerly airflow from the Azores high to the SW dominates bringing more settled weather to the whole of the UK although temps still below average.

 

Essentially this patter continues until the 31st with below average temps giving way to average.

 

Summary

 

Remaining unsettled until the 16th, particular in the north, with quite cool temps thereafter until the end of the month more settled for the whole of the UK and gradually warming up. So last half of the month certainly looking better.

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON FRIDAY JULY 31ST 2015.

 

THE CURRENT GENERAL SITUATION. A ridge of High pressure covers Southern Britain while a trough of Low pressure in association with a Low to the NW of Scotland will move across Northern areas later.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif 

 

MODELS-2 WEEK HEADLINE Still rather changeable with some dry and bright conditions mixed with occasional rain or showers. Generally on the cool side but a few warmer interludes possible in the South.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows a continuation of the flow troughed over the near Atlantic and returning over the UK in a NE'ly direction. This pattern is maintained for the next week before the flow becomes more West to East aligned over the Atlantic and across the UK through the second week, still well South of it's normal position for this time of year.

 

http://www.netweather.tv/index.cgi?action=jetstream 

 

GFS OPERATIONAL The GFS Operational Run today has a message of SE is best over the coming week with a SW flow across the UK between deep Low pressure to the NW and High to the SE. The flow will carry frequent bands of rain and showers to the North and West with more occasional bursts in the South and East where it will be quite warm at times. Through Week 2 a return to cooler air for all is shown as winds veer West and source from a more Northerly latitude over the Atlantic which could bring rain and showers for all at times then.

 

http://www.wetterzentrale.de/pics/Rtavn1441.gif

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif 

 

THE GFS CONTROL The GFS Control Run has a very similar theme running throughout it's duration with the same trends as shown by the operational with just small synoptic differences overall day to day.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters at 14 days doogedly show a theme that has been shown by these for some time now in that in 14 days time the UK will most likely lie under a NW or West flow between High pressure to the SW and Low pressure to the North or NE. The likely result would be average to below average temperatures at times along with some rain or showers, more focused towards the North than elsewhere.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO today shows a deep Low up to the NW of the UK controlling the weather from the late weekend and well into next week. The resultant and sometimes strong SW flow would bring rain at times to all but more so towards the NW. It could be rather warm in the SE for a time with a trend to cool these higher temperatures down a little from midweek.

 

http://www.wetterzentrale.de/pics/Rukm1441.gif 

 

THE FAX CHARTS The Fax Charts this morning follow the raw data closely and indicate the deepening Low to the North-West eearly next week with a SW flow and fronts crossing East.

 

http://www.weathercharts.org/ukmomslp.htm#t120.

 

GEM GEM looks rather different longer term. In the first 5-7 days the story is as the rest with Low pressure out to the NW with some rain and showers for all fuelled by smaller disturbances crossing East in the flow across the UK. Later in the run one such disturbance forms it's own Low pressure close to the South and SE drawing cool cyclonic winds and rain for all with a cool North wind towards the West to end the run

 

http://www.wetterzentrale.de/pics/Rgem2401.gif 

 

NAVGEM NAVGEM follows the main stream models in maintaining Low pressure up to the NW with rain and showers at times for many, least in the SE where some fine and warmer interludes are likely.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

 

ECM ECM shows a variation on a well supported theme in that Westerly winds will remain dominant across the UK under Low pressure to the North and NW and areas of High pressure to the SE, South or SW, these never making enough inroads into the UK to guarantee prolonged dry weather and warmth.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows a Westerly flow across the Atlantic and the UK from a depression held up to the NW. High pressure out to the SW will likely keep the NW/SE divide in the weather going well into August

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models remain rather mixed in detail but common ground does indicate that there is still little prospect of High pressure making any real impact on the UK weather as a whole within the next two weeks

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 95.8 pts followed by UKMO at 95.1 pts and GFS at 94.5 pts. At 5 days ECM is stll king at 85.4 pts followed by UKMO at 82.5 and GFS at 82.4 pts. Then at 8 Days ECM still leads at 57.0 pts over GFS's 52.1 pts. Finally at Day 10 ECM leads GFS at 36.9 pts to 32.4 pts from GFS.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

MY THOUGHTS At the expense of sounding like a broken record the models throw very little change in the overall patterning of things as far as the UK goes. Broadly we still have a Jet Stream flow that is well South across the Atlantic and likely to remain so for some considerable time yet. This is not all bad news especially for the SE of the UK as on the Eastern side of the troughed flow across the Eastern Atlantic we have a NE moving Jet Stream over the NW and this allows the potential for some warm conditions to be drawn up across the UK in the coming 5 days or so. However, this doesn't look like lasting long after that as the longer projections turns the flow more West to East across the South of the UK again returning cooler air to the SE as well in Week 2. In other parameters of weather all this means a continuation of changeable conditions as Low pressure lies up to the NW or North for much of the period with rain and showers at times and this may well reach the SE at times, perhaps thundery in places. In between times in the next week the SE may turn out pretty good with a lot of dry and warm weather about between any showers but as we look to the second week it looks likely that a more West or even NW flow may return with it's attendant mix of rain and showers too with any warm temperatures left in the SE then easing back again. Even then the South may not see too much rain but may not be enough in itself to make sunworshippers happy due to the lack of any guaranteed and extensive high Summer temperatures through the period. Nevertheless we have what we have and I'm sure many of us will fine some opportnity to enjoy the best of what's on offer over the period and while it may not be like high Summer for much of the time it could be a whole lot worse for many especially in the South.

 

Next update from 09:00 Sunday Aug 1st 2015

[Nick F]

00z GFS going for 30-34C over far north of France and Belgium on Monday, so close the real heat, though the SE may get high 20s from the southerly flow. But low pressure moving in across Ireland early next week keeps the heat well at bay again for the majority of the Uk.

 

At least it looks pleasantly warm through much of next week, given the predominantly southwesterly or southerly flow, temperatures in the low 20s across much of England and Wales, high teens across Scotland - so more 'summery' than the past week. Showery though, but not everyone will catch one. We could see the heat return briefly across the SE on Thursday if GFS is to believed. 

 

However, longer-term, it still looks like we can't shake off the persistent upper trough and surface lows close to the northwest as we head towards mid-August. A look at the 00z GEFS H500 mean/anomaly and last night's CPC H500 prognostic chart points to this scenario continuing, but hopefully the cold northwesterlies may stay at bay too if the trough stays NW

 

 

Edited July 31, 2015 by Nick F

[Tamara]

I think that the 'oft mentioned return to summer' needs to put back into the perspective of what was actually said at the time - which was that a NW/SE split would predominate and not a homogenously warm anticyclone over the UK. 

 

What was not picked up clearly in the anomaly charts was the emphasis away from the cool pattern of the last week to the warmer (in relative terms) shift we are seeing start in the here and now time period.

 

As mentioned to look out for in previous posts, the models in recent days have caught on with the fact that Atmospheric Angular Momentum is set to increase again, and hence the pattern has responded with a return to higher pressure and warmth/heat over Europe advertised once more, with the last of this more widespread cool spell fading out.

 

Focussing exclusively on UK prospects, the UK remains on the periphery of the boundary between the heat to the south and east over mainland Europe, and the Atlantic air to the north and west.  In this way, although quite generally temperatures are set to recover from the depressed state of this week, a return to a NW/SE split stays favoured in overall conditions.

 

The upstream signal is responding to the Global Wind Oscillation heading into Phase 5, rather than Phase 4 more ideally which would achieve better trough orientation in the Atlantic and hold the upper trough up a little further west and north into the Atlantic away from NW Scotland, so that downstream heights would be a little stronger and influential for more of the UK away from the SE corner. Think August 2004 as a close match to this type of pattern. Still some unsettled incursions as lows head northwards to our west (rather than NE) but with less westerly push and inroads from the Atlantic and consequent lack of polar maritime air masses

 

As stated recently, its down to whether or not the atmospheric circulation forces the most conducive pattern for a sharpened stalled trough in the Atlantic and stronger amplified downstream heights over NW Europe and the UK rather than any cold pool in the Atlantic on its own preventing warmth from advecting further north and west over the UK itself.

 

The GWO progressing from Phase 5 through Phases 7/8 as the MJO progresses into the East Pacific and the dateline increases the sub tropical jet stream and encourages height rises to the north which occur as a consequence of this signal, supressing this active phase of the jet southward in our Atlantic sector.

 

However, caution continues to be required with tropical forcing modelling and its effects downstream. Small incremental changes, as we have seen already, make a large difference to a relatively small island like the UK. Not just temperature boundaries in this particular pattern scenario, but where the most unsettled, and where the least changeable conditions are likely to be found.

 

The modelling will be keen to flatten the pattern out beyond the upcoming warmer incursions from the south but suspicion remains they will try to be over progressive with signals (and longevity) for any return to southerly tracking lows.

 

Its not the best summer pattern and clearly divisive in fortunes, but its one that is close to being much more appealing with a little tweaking from upstream. There lies the frustration for many   

 

@mushymanrob: I have always stated that the anomaly charts are a very good guide to future patterns but that these derive from model interpretations of the atmospheric circulation and if the signals they pick up are either over progressive and/or prone to bias (as f.e he GEFS is wrt undercooking atmospheric angular momentum) then this can skew the anomaly chart readings). By looking at the direction of travel of AAM against the background ocean/atmosphere signals it becomes possible to question whether the models are handling these accurately)

 

@knocker: The GEFS modelling is anticipating another GWO 5/6/7/8/0 orbit such as we saw in the first half of July. However, MJO signalling is weak this time around with no positive frictional and Asian M/T activity such as we saw then. Time will tell whether the amplitude forecasts are accurate. Phases 7/8/0 would re-fire up the pacific jet stream and supress it downstream over the Atlantic with sustained heights over Greenland  leading to another cool and unsettled phase more generally as we have seen this week - but with the El Nino atmosphere/ocean coupling then any further drop back in AAM tendency may prove to be overstated as it has been recently by the GEFS suite

Edited July 31, 2015 by Tamara

[Skullzrulerz]

Just looked at the cfsv2 model and it's showing near to below average temperatures for the UK.

Can not post a image due to being on a tablet sorry.

[mushymanrob]

 

 

What was not picked up clearly in the anomaly charts was the emphasis away from the cool pattern of the last week to the warmer (in relative terms) shift we are seeing start in the here and now time period.

 

with respect, i disagree.

the noaa anomaly charts have depicted a scandinavian trough and heights over to our west and greenland area for some time. that put us in the cool northerly sourced air which we (bloody well (lol) ) got. they have moved away from the scandi trough/western heights and a several days ago (unsure of the exact date) suggesting a westerly flow which i hoped would allow pressure rise over us. (initially from the azores high ridging in) this obviously didnt occur and they went for the trough to our northwest that we will get. (that was in the transition period when the scandi trough was dropped)

the general pattern we have had for several months now is precisely what the noaa charts suggested we would when they were consistent, which has been most of the time.

Edited July 31, 2015 by mushymanrob

[knocker]

I would tend to agree with that as I think the GEFs

 

I think that the 'oft mentioned return to summer' needs to put back into the perspective of what was actually said at the time - which was that a NW/SE split would predominate and not a homogenously warm anticyclone over the UK. 

 

What was not picked up clearly in the anomaly charts was the emphasis away from the cool pattern of the last week to the warmer (in relative terms) shift we are seeing start in the here and now time period.

 

As mentioned to look out for in previous posts, the models in recent days have caught on with the fact that Atmospheric Angular Momentum is set to increase again, and hence the pattern has responded with a return to higher pressure and warmth/heat over Europe advertised once more, with the last of this more widespread cool spell fading out.

 

Focussing exclusively on UK prospects, the UK remains on the periphery of the boundary between the heat to the south and east over mainland Europe, and the Atlantic air to the north and west.  In this way, although quite generally temperatures are set to recover from the depressed state of this week, a return to a NW/SE split stays favoured in overall conditions.

 

The upstream signal is responding to the Global Wind Oscillation heading into Phase 5, rather than Phase 4 more ideally which would achieve better trough orientation in the Atlantic and hold the upper trough up a little further west and north into the Atlantic away from NW Scotland, so that downstream heights would be a little stronger and influential for more of the UK away from the SE corner. Think August 2004 as a close match to this type of pattern. Still some unsettled incursions as lows head northwards to our west (rather than NE) but with less westerly push and inroads from the Atlantic and consequent lack of polar maritime air masses

 

As stated recently, its down to whether or not the atmospheric circulation forces the most conducive pattern for a sharpened stalled trough in the Atlantic and stronger amplified downstream heights over NW Europe and the UK rather than any cold pool in the Atlantic on its own preventing warmth from advecting further north and west over the UK itself.

 

The GWO progressing from Phase 5 through Phases 7/8 as the MJO progresses into the East Pacific and the dateline increases the sub tropical jet stream and encourages height rises to the north which occur as a consequence of this signal, supressing this active phase of the jet southward in our Atlantic sector.

 

However, caution continues to be required with tropical forcing modelling and its effects downstream. Small incremental changes, as we have seen already, make a large difference to a relatively small island like the UK. Not just temperature boundaries in this particular pattern scenario, but where the most unsettled, and where the least changeable conditions are likely to be found.

 

The modelling will be keen to flatten the pattern out beyond the upcoming warmer incursions from the south but suspicion remains they will try to be over progressive with signals (and longevity) for any return to southerly tracking lows.

 

Its not the best summer pattern and clearly divisive in fortunes, but its one that is close to being much more appealing with a little tweaking from upstream. There lies the frustration for many    

 

I'm not sure I agree with your comment regarding the anomaly charts either but that's by the by. But a quick question to clarify my mind a bit. Given the current phase of the GWO, just 5, and it's not forecast to get very high, what would be the rough timing of the progression through phases 7 & 8 and what would be the expected downstream pattern for these phases. I ask because I'm interested to see whether this accords with latest EC32 output.

 

[johnholmes]

 

sorry T just off to catch a plane so no time to make a constructive reply but I do feel that for the time scale 6-15 days, at times a little longer, then careful use of the anomaly charts will give about the correct idea on the upper pattern on about 70% of occasions. I have never attempted to go beyond 15-18 days so I have no quarrel with you or others attempting to make some sense of various signals beyond those time scales.

I also more or less agree with the comment from mushy

like I said sorry cannot make any real input as dashing off.

maybe another time?

[Man With Beard]

The GEFS 06Zs, like yesterday, are again playing with a short, sharp burst of heat next Thursday across England. Friday sees a swift breakdown but beyond that, I'd say the above-average runs outweigh the below-average ones (taking average 850s for London as 8C/9C at this time of year?) - first time I've seen that in a long while?

 

http://www.meteociel.fr/modeles/gefs_table.php?ext=1&x=306&y=141&ville=Londres

[Frosty.]

The Gfs 6z shows some surprisingly good charts next week with high pressure building to the east and very warm / hot and increasingly humid air spreading into the south of the uk with spells of sunshine and a chance of thunderstorms in places. The warmer weather starts this weekend, 23c in the south tomorrow and 26/27c in favoured spots on Sunday, very warm and humid in the east on Monday, then a fresher blip before the heat builds across the s/e through the 2nd half of next week.

[Nouska]

I would tend to agree with that as I think the GEFs

 

 

I'm not sure I agree with your comment regarding the anomaly charts either but that's by the by. But a quick question to clarify my mind a bit. Given the current phase of the GWO, just 5, and it's not forecast to get very high, what would be the rough timing of the progression through phases 7 & 8 and what would be the expected downstream pattern for these phases. I ask because I'm interested to see whether this accords with latest EC32 output.

 

It looks to be doing a less amplified version of where it has been - my question, does the GWO have very different outcomes on a month to month basis,similar to the MJO. For example, if MJO amplifies in same phase as July, the outcome for August is much more trough dominated than the composites show for July.

 

 

We'll see the new ECM monthlies for the MJO this evening, the Tuesday run showed no inclination for amplification.

 

MJO composites.   http://www.americanwx.com/raleighwx/MJO/MJO.html

[knocker]

As far as I can see Nouska none of the models show any inclination for amplification of the MJO, certainly for the first two weeks of August.

http://www.frontierweather.com/MJOGraphics/mjoanalogs.html