Model Output Discussion - 15th April Onwards

[Summer Sun]

Wednesday is looking quite stormy and wet for some with a deep low pressure system tracking south of the UK,

Into the weekend the North on Sunday should get a dry day if not cloudy whilst the south and more so the south west looks like been in for a soaking

Edited April 23, 2012 by Gavin D

[Milhouse]

Typical

Still, the GFS shows high pressure more in control over the north and east of the UK keeping low pressure far enough away to bring a greater chance of settled contitions. The south west of the UK looks to remain wettest whereas in the low res part of the GFS the northeastern portion of the UK would be reasonably dry and quite warm.

[Isolated Frost]

Not been in here for a while!

That plume is of real note- some lovely temps in the Benelux and south of that.. That LP looks crazy on Wed- certainly nothing I've seen in late April

[PubliusEnigma]

Some real concerns now that we could be heading for a record cool, dull and wet May. ECM out to +240 maintains the southern jet and the conveyor

belt of Low pressures across the UK. Although with a hint to a more mobile westerly regime towards the end of the run. Interestingly the MET O 6-15 and

16-30 paints a gloomy prospect out as far as a months time heading towards the Witsun week. What troubles me the most with what the models are painting

is an a repeat of the spring and summers of 2007 thru 2011. A trend of the modern summer seems to be this southerly tracking jet. A strong Russian High

which seems to set up residence for months, and a Greenie High which locks us into northerlies interchanging with lows on a southerly trajectory. Looking

back at the last 5 years the pattern established in May, seemed to repeat through the following three summer months bringing more traditional summers of

the seventies and eighties. Ironically March could end up being warmer than April and Maybe May.. ;oO.. There are no downwind signals to signify any major

pattern change.. The polar vortex has lost a lot of its seasonal strength. Useful rain to help abate the winter droughts, however for sun worshipers and crop

growers, concern to say the least. GFS is showing the first summer heat to be some 500 or so miles further east in the coming weeks..

[Cheshire Freeze]

Some real concerns now that we could be heading for a record cool, dull and wet May. ECM out to +240 maintains the southern jet and the conveyor

belt of Low pressures across the UK. Although with a hint to a more mobile westerly regime towards the end of the run. Interestingly the MET O 6-15 and

16-30 paints a gloomy prospect out as far as a months time heading towards the Witsun week. What troubles me the most with what the models are painting

is an a repeat of the spring and summers of 2007 thru 2011. A trend of the modern summer seems to be this southerly tracking jet. A strong Russian High

which seems to set up residence for months, and a Greenie High which locks us into northerlies interchanging with lows on a southerly trajectory. Looking

back at the last 5 years the pattern established in May, seemed to repeat through the following three summer months bringing more traditional summers of

the seventies and eighties. Ironically March could end up being warmer than April and Maybe May.. ;oO.. There are no downwind signals to signify any major

pattern change.. The polar vortex has lost a lot of its seasonal strength. Useful rain to help abate the winter droughts, however for sun worshipers and crop

growers, concern to say the least. GFS is showing the first summer heat to be some 500 or so miles further east in the coming weeks..

I agree that the pattern over the last few years has been for pressure to build strongly out east giving places like Moscow record warmth. I have noticed myself that weather patterns have been repeating and persisiting for some time for a good while now. I have no idea what is causing it.....could be low solar activity or even as a result of climatic shift resulting in positive reinforecement/feedback of a certain weather type in certain geographical areas.

Still too early to comment on summer weather though as even within broad patterns, smaller pattern changes cannot be precluded.

I notice that it hasn't been given much recognition by certain members, possibly for fear of sounding 'out there' or sensationalist, but I have noticed it and IMO it's not normal. I have no scientific basis when I say this, but I get the impression that the building blocks for a southwards migration of the arctic tundra could be being laid. Something which my (very clued up) geography lecturer is convinced will occur within the next 50 years.

Edited April 23, 2012 by CreweCold

[PubliusEnigma]

I agree that the pattern over the last few years has been for pressure to build strongly out east giving places like Moscow record warmth. I have noticed myself that weather patterns have been repeating and persisiting for some time for a good while now. I have no idea what is causing it.....could be low solar activity or even as a result of climatic shift resulting in positive reinforecement/feedback of a certain weather type in certain geographical areas.

Still too early to comment on summer weather though as even within broad patterns, smaller pattern changes cannot be precluded.

I notice that it hasn't been given much recognition by certain members, possibly for fear of sounding 'out there' or sensationalist, but I have noticed it and IMO it's not normal. I have no scientific basis when I say this, but I get the impression that the building blocks for a southwards migration of the arctic tundra could be being laid. Something which my (very clued up) geography lecturer is convinced will occur within the next 50 years.

Very good reply. There is more than a sinister pattern developing. Not only is the mid spring / season developing a pattern. We are seeing a trend of absurdly warm spells in March / early April and also similarly around the equinox in autumn - we recorded 30oC here on 2nd October last year !! It is a result of climate change - of that I am sure.. Climate change rather than global warming. Like you I think we need to look north for the reasons.. Could it be the copious amounts of water released into the North atlantic from melting ice ? Could it be warmer surface temps over the arctic supporting greater anticyclonic conditions above. It cannot just be down stream signals otherwise we'd have to look to the tropics for the cause. Something is also causing the jet to dive south from April / May until the end of August.. over the UK. I can't see how this can be sensationalist as the last 5 years have already happened so we are looking back rather than forecasting 5 years henceforth. What drives the adjustments to the flow of the jet in the northern hemisphere. why is it not tracking NE Over iceland and into Northern Norway as it used to do for weeks on end during summers from only 5-10 years ago. The thing of concern IS The fact the British weather is appearing to become predictable.. Something previously unheard of. If you look at all the models they all show the jet tracking northwards again over the next 10-20 days across central Europe and up to the SE of Finland and into Russia. Heat is already building in Russia and Ukraine. If this trend continues similar to last year, on a serious note we could see temps close to 40oC for the European Chamionships in Ukraine.. One to look out for !

[Cheshire Freeze]

Very good reply. There is more than a sinister pattern developing. Not only is the mid spring / season developing a pattern. We are seeing a trend of absurdly warm spells in March / early April and also similarly around the equinox in autumn - we recorded 30oC here on 2nd October last year !! It is a result of climate change - of that I am sure.. Climate change rather than global warming. Like you I think we need to look north for the reasons.. Could it be the copious amounts of water released into the North atlantic from melting ice ? Could it be warmer surface temps over the arctic supporting greater anticyclonic conditions above. It cannot just be down stream signals otherwise we'd have to look to the tropics for the cause. Something is also causing the jet to dive south from April / May until the end of August.. over the UK. I can't see how this can be sensationalist as the last 5 years have already happened so we are looking back rather than forecasting 5 years henceforth. What drives the adjustments to the flow of the jet in the northern hemisphere. why is it not tracking NE Over iceland and into Northern Norway as it used to do for weeks on end during summers from only 5-10 years ago. The thing of concern IS The fact the British weather is appearing to become predictable.. Something previously unheard of. If you look at all the models they all show the jet tracking northwards again over the next 10-20 days across central Europe and up to the SE of Finland and into Russia. Heat is already building in Russia and Ukraine. If this trend continues similar to last year, on a serious note we could see temps close to 40oC for the European Chamionships in Ukraine.. One to look out for !

Well put it this way, I'm not convinced that something isn't in the process of occurring; or at least in initiation phase. If it carries on, sooner or later someone is going to have to acknowledge the fact.

The issue is that we rely on crude data far too much which masks actual synoptics and patterns and the deviations/anomalies within these. We ridicule scientists for their predictions of climate in 50 years (even those who predict another ice age onset) but in reality and from my perspective, they aren't as outlandish as some people think.

[Summer Sun]

ECM remains unsettled through the weekend and into next week, however the north could be the best place this weekend with the rain mainly in the south and south west

Edited April 23, 2012 by Gavin D

[ANYWEATHER]

Very good reply. There is more than a sinister pattern developing. Not only is the mid spring / season developing a pattern. We are seeing a trend of absurdly warm spells in March / early April and also similarly around the equinox in autumn - we recorded 30oC here on 2nd October last year !! It is a result of climate change - of that I am sure.. Climate change rather than global warming. Like you I think we need to look north for the reasons.. Could it be the copious amounts of water released into the North atlantic from melting ice ? Could it be warmer surface temps over the arctic supporting greater anticyclonic conditions above. It cannot just be down stream signals otherwise we'd have to look to the tropics for the cause. Something is also causing the jet to dive south from April / May until the end of August.. over the UK. I can't see how this can be sensationalist as the last 5 years have already happened so we are looking back rather than forecasting 5 years henceforth. What drives the adjustments to the flow of the jet in the northern hemisphere. why is it not tracking NE Over iceland and into Northern Norway as it used to do for weeks on end during summers from only 5-10 years ago. The thing of concern IS The fact the British weather is appearing to become predictable.. Something previously unheard of. If you look at all the models they all show the jet tracking northwards again over the next 10-20 days across central Europe and up to the SE of Finland and into Russia. Heat is already building in Russia and Ukraine. If this trend continues similar to last year, on a serious note we could see temps close to 40oC for the European Chamionships in Ukraine.. One to look out for !

With all respect to your viewpoint, I dont agree with all you say! The British weather is not predictable, look at this April and compare it to last April. Chalk and Cheese come to mind. Yes youre right in saying that the last 5/6 years have seen somewhat familiar synoptics especially in Spring. But there is cycles within cycles and as yet, mankind/scientists have no idea what-so-ever to decifer the enourmous and extremely complex nature of the weather, we certainly can give our numerous ideas but clearly along with computer models outputs we have no idea! Back to the model output, and the weekend looks quite concerning at the moment with some big deluges in some places. The Devil in the Detail on this one!

[A.J]

Some thought provoking posts from PE & CC, but with respect probably better suited to the 'Climate & Environment' sub-forum, best to stick to the actual model output here....thanks

[Cheshire Freeze]

Some thought provoking posts from PE & CC, but with respect probably better suited to the 'Climate & Environment' sub-forum, best to stick to the actual model output here....thanks

Oops sorry AJ

[Scorcher]

Interesting that the ECM brings that plume closer to our shores over the weekend than previously- perhaps some eastern counties of England could end up with some warmer temperatures at the weekend.

[phil nw.]

A new low moving in from the west later tomorrow will bring a wet and windy period around mid week for many.

This feature looks like dominating the scene untill the weekend so continuing the unsettled and showery theme.

Just a suggestion of some improvement for northern areas into next week with both GFS and ECM modelling rising pressure towards Scandinavia as the UK trough finally splits with the remaining low cell just off to our south west,

Edited April 23, 2012 by phil n.warks.

[Robbie Garrett]

Some thought provoking posts from PE & CC, but with respect probably better suited to the 'Climate & Environment' sub-forum, best to stick to the actual model output here....thanks

http://forum.netweather.tv/topic/73096-uk-weather-predictability-and-the-effects-of-the-jet-stream/

[Geordiesnow]

Interesting that the ECM brings that plume closer to our shores over the weekend than previously- perhaps some eastern counties of England could end up with some warmer temperatures at the weekend.

Not with an easterly wind off a chilly North Sea, would be alot of cloud aswell so sunshine would be limited.

Actually the weather patterns this spring has been interesting in the Northern Hemisphere, quite a few warm spells appearing, most noticetably, the March warm/hot spell over USA/Canada and the heat has already been building across parts of Russia prompting another early snowcover melt there, be interesting how this will end up regarding our summer. It would seem things are hinting to return to normal across Russia with more cooler air arriving but this is because the models are hinting at some sort of blocking pattern which normally ends up cool and wet for us!

Going to be interesting when the models will backdown regarding this persistant low pressure system and you have to admit, this spring has been interesting thus far with persistant warm temperatures and settled weather in March to cool, wet and at times windy weather!

[Frank Trough]

Some real concerns now that we could be heading for a record cool, dull and wet May. ECM out to +240 maintains the southern jet and the conveyor

belt of Low pressures across the UK. Although with a hint to a more mobile westerly regime towards the end of the run. Interestingly the MET O 6-15 and

16-30 paints a gloomy prospect out as far as a months time heading towards the Witsun week. What troubles me the most with what the models are painting

is an a repeat of the spring and summers of 2007 thru 2011. A trend of the modern summer seems to be this southerly tracking jet. A strong Russian High

which seems to set up residence for months, and a Greenie High which locks us into northerlies interchanging with lows on a southerly trajectory. Looking

back at the last 5 years the pattern established in May, seemed to repeat through the following three summer months bringing more traditional summers of

the seventies and eighties. Ironically March could end up being warmer than April and Maybe May.. ;oO.. There are no downwind signals to signify any major

pattern change.. The polar vortex has lost a lot of its seasonal strength. Useful rain to help abate the winter droughts, however for sun worshipers and crop

growers, concern to say the least. GFS is showing the first summer heat to be some 500 or so miles further east in the coming weeks..

the coming weeks are still spring. The ECM goes out as far as 3rd of may. May is still spring. The met office update hints at less unsettled conditions than recently and also suggests temps to be average or just below. Hardly record breaking?

There are definitely "hints" at more of a flow of the near continent for the start of May. Surely to break records in may you would need constant reload northwesterlies or a trough just stuck over the UK? That met office update doesn't back that, does it?

Edited April 23, 2012 by A horse called man

[Snowy Easterly]

Urgh, GFS 18z gives us a horrible easterly in FI, i bet it comes off as well, as they usually do in spring, if it were showing in winter it would downgrade at T 96

also this weekend 26c in holland and 12c in the east of england, just ridiculous

Edited April 23, 2012 by Snowy Easterly

[Thundery wintry showers]

The easterly showing on the GFS 18Z FI would certainly bring a lot of snow showers to eastern areas at any point before mid-March, but in May it would most likely bring a lot of low cloud and perhaps some shallow convection over the North Sea with light drizzly showers (as happened quite often during May 1996). North-easterlies are capable of bringing a mix of sunshine and wintry showers at this time of year, but only if the airmass source has a strong arctic maritime element to it- arctic continental air tends not to be cold/unstable enough at high altitudes as we head into May.

The models have now shifted away from the mid-Atlantic high setup and are bringing continental air in, which may promise some significantly higher temperatures, but the setup is extremely messy and I think it will take a couple of days for the models to firm up on the detail. Regarding an improvement for northern areas, if this pattern verifies the most likely result is a west-east split- dry, sunny and warm to the west of high ground, but somewhat cooler with persistent stratus near the east coast. Southern areas are traditionally more prone to belts of rain moving in from the continent and from southerly tracking Atlantic lows, which can sometimes be thundery in nature, particularly if the wind direction veers to more of a south-easterly or southerly.

[Robbie Garrett]

Southern areas are traditionally more prone to belts of rain moving in from the continent and from southerly tracking Atlantic lows, which can sometimes be thundery in nature, particularly if the wind direction veers to more of a south-easterly or southerly.

I take it that's what the models are highlighting for the end of April? Something similar?

[picog]

The ensembles seem to indicate that the much-needed rain may start fizzling out come early May. Very striking in the London set, but apparent in the Manchester ensembles too.

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

[Timmytour]

The models are showing this trend for showers to prevail in April and then possibly some sun in May.

Such unusual weather. There must be a reason for this. I can see the phrase "April showers" entering the lexicon of the language!

[Thundery wintry showers]

Yes, a strong signal for an easterly type as we head into early May which would promise warmer weather for western and southern areas- that sort of setup tends to be sunny, dry and warm in north-western Britain, with southern Britain more prone to outbreaks of potentially thundery rain. For eastern Scotland and NE England, though, it usually translates to a lot of stratus and chilly winds off the North Sea.

The ECMWF ensemble mean is inconclusive, going for just a weak easterly flow at T+192-240, implying that there is still scope for change at that time range. For this week, a rather wet and windy spell tomorrow, persisting over parts of Scotland and northern England on Thursday, brighter showery weather away from the rain belt, before becoming dry and sunny in the north-west for the weekend and wet in the south, dry/cloudy in the north-east.

[Jezzer]

The models are showing this trend for showers to prevail in April and then possibly some sun in May.

Such unusual weather. There must be a reason for this. I can see the phrase "April showers" entering the lexicon of the language!

Yep, does seem that over the last few years we've grown used to April being a stunning month with endless blue skies and warm temps!

[phil nw.]

Yes, a strong signal for an easterly type as we head into early May which would promise warmer weather for western and southern areas- that sort of setup tends to be sunny, dry and warm in north-western Britain, with southern Britain more prone to outbreaks of potentially thundery rain. For eastern Scotland and NE England, though, it usually translates to a lot of stratus and chilly winds off the North Sea.

The ECMWF ensemble mean is inconclusive, going for just a weak easterly flow at T+192-240, implying that there is still scope for change at that time range. For this week, a rather wet and windy spell tomorrow, persisting over parts of Scotland and northern England on Thursday, brighter showery weather away from the rain belt, before becoming dry and sunny in the north-west for the weekend and wet in the south, dry/cloudy in the north-east.

Yes an Easterly of sorts looks more possible in early May based on some of todays output, although as you say the models are still to firm up on this.

If the low pressure situates far enough away from the south a Scandi.high can dry the ground out quite quickly although as already said the East coasts of Scotland and England can be cool and dull with sea mist slow to clear if the flow is north of east.

However inland such a setup can be quite sunny and pleasantly warm as we go into May with the proviso that overnight low cloud clears fairly quickly in the mornings.

I can certainly remember May Easterlys of past years which can bring days of dry and sunny weather with temperatures exceeding 21C on occasions.

Still we are a few days away yet and in the meantime we have a very unsettled few days to get through,especially tomorrow.

[Cheshire Freeze]

Yes an Easterly of sorts looks more possible in early May based on some of todays output, although as you say the models are still to firm up on this.

If the low pressure situates far enough away from the south a Scandi.high can dry the ground out quite quickly although as already said the East coasts of Scotland and England can be cool and dull with sea mist slow to clear if the flow is north of east.

However inland such a setup can be quite sunny and pleasantly warm as we go into May with the proviso that overnight low cloud clears fairly quickly in the mornings.

I can certainly remember May Easterlys of past years which can bring days of dry and sunny weather with temperatures exceeding 21C on occasions.

Still we are a few days away yet and in the meantime we have a very unsettled few days to get through,especially tomorrow.

Yes and I've been saying for some time now (coming up to 8 weeks) that an early May settling down was on the horizon. Judging by some of the CFS charts I have seen (and which I used to base my spring forecast on) I wouldn't get used to any dry weather we see in early May as the second half and into June looks to have the potential to be decidedly wet IMO as low pressure starts to erode the block from the south and southwest and pressure migrates N&W once more.

Edited April 24, 2012 by CreweCold