Model output discussion 25th Jan onwards

[winterof79]

This may have been asked already but the weatheronline charts that previously showed the NAE have now the EURO4.It may be me but they seem far less superior to the old ones with regard to snowfall projections.

[MPG]

I wouldn't bank on a polar westerly especially with the new trend developing, the ECM I think has been trying to find a new way forward and that IMO is why we saw it become much less bullish about how long the block would hold to the east.The other models were lagging behind a bit, the UKMO was obviously asleep given its last few days outputs. Overall putting aside the UKMO which has veered from one solution to another in the space of 12hrs the outputs okay with some snow potential, but  we have to wait to see how those upstream changes get incorporated, its best to view any outputs with that in mind.

What's the new trend nick?

[Man With Beard]

This may have been asked already but the weatheronline charts that previously showed the NAE have now the EURO4.It may be me but they seem far less superior to the old ones with regard to snowfall projections.

Well a good opportunity to test it out tomorrow, going for 10cm plus in parts of the south (yes really!!!) and plenty over northern hills:

Or will the GFS be more accurate - surely not!!

Edited January 25, 2014 by rjbw

[bryan629]

I wouldn't bank on a polar westerly especially with the new trend developing, the ECM I think has been trying to find a new way forward and that IMO is why we saw it become much less bullish about how long the block would hold to the east.The other models were lagging behind a bit, the UKMO was obviously asleep given its last few days outputs. Overall putting aside the UKMO which has veered from one solution to another in the space of 12hrs the outputs okay with some snow potential, but  we have to wait to see how those upstream changes get incorporated, its best to view any outputs with that in mind.

HI NIck, looking at the models , i have noticed they do thier best to either flatten or push the scandi high back east...clearly this is because the pv is firing out loads of energy at it and it gives way...however i have noticed on most models the energy over the US  is over amplified .

with your post on page one...will this mean that the jet should weaken ?

just taking last march as an example...the scandi high then was always premuturely flattened by the models...is it not possible that here we are seeing a repeat of that ? just wondering

[Downpour]

Must be the hills because the chart Steve posted just looks quite wet too me, surely too get snowfall from low uppers from the continent, there has to be a significant cold spell there and what we are seeing in the outputs is not a significant cold spell, plus we are approching February now so daytime heating would more than likely turn any snow to rain.  Anyways, its all pointless and irrelevant as the detail will be different on the next run.

You may be right about the lack of snow but where on earth do you get this nonsense that February days are too long and warm to keep snow?

[Joe Levy]

Well a good opportunity to test it out tomorrow, going for 10cm plus in parts of the south (yes really!!!) and plenty over northern hills:

Or will the GFS be more accurate - surely not!!

Well the GFS has settling snow in the sea off the coast of North Devon... EURO4 is in line with what is being modelled for Sunday night into Monday morning with wintry showers across South-West and Central Southern England. The areas where settling snow is shown in Southern England are Dartmoor, the Dorset Downs and Salisbury Plain

Edited January 25, 2014 by Joe Levy

[cooling climate]

The ECM along with the GFS have moved west with the easterly tonight

and there is no reason why this should not continue tomorrow or at

least a better orientation of the high to introduce colder uppers

quicker.

I am hopeful for a even more amplified pattern from the ECM and GFS

as well. The ECM t240 synoptics seem to portray the changes that Nick

spoke of on the American side of the pond.

[Weather-history]

The ECM op run goes for a sub 964mb low at 144hrs to west of Western Isles. The ECM mean goes for instead a flabby 995 one instead.

Says to me that not many of the ensembles support that deep low, the mean would be deeper and low more round if they did.

Or is there a flaw to my logic?

[Jason M]

What's the new trend nick?

After two months of warm rain, its a transition to cold rain :-)Joking aside its difficult to tell what comes next as there is just so little agreement in the medium term. As nick said, a deep cold easterly is off the table (for now).Edit. I'll probably regret the easterly comment come the morning but its a price I'd willingly pay ;-) Edited January 25, 2014 by Jason M

[Duane S.]

Very little has changed at all - that is if one doesn't chop and change opinions and expectations in line with every chop and change from one model output to another .

 

The evolution of the pattern to encompass ever tighter trough disruption since the mild zonal spell has been a very gradual one, but it has been a very consistent one. That is in contrast to the swings in model and ensemble output that have been every bit as progressive in modelling the pattern too far east as it has been at the other end of the spectrum on the odd occasion with the more optimistic easterly solutions. In this way it gives a false impression of just what the reality has been (and how such reality is likely to continue).

 

There should be no undue disappointment about the UKMO this evening - its solution of yesterday always looked to make too much of the ridge to the NE too soon. But then it will be what is at the end of this protracted trough disruption tunnel we are travelling through that stands us the best chance of delivering the cold opportunties we look for. On that basis, an easterly a little later, would stand a greater chance of being sustained than any the UKMO has recently suggested

 

More energy transport indeed to be bled downstream from the Canadian blob down the line , much as expected, and the models are falling in a line of agreement with this. Nothing to fear here either as tonights output, f.e, from the ECM illustrates in terms of the overall upper pattern and also some good snow opportunities for the north most especially

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014012512/ECH1-216.GIF?25-0

 

The westward migration and weakening of the Azores High is now being modelled very consistently in the NWP, having transcended from the annals of FI ensemble data. This stands us in good stead for trough disruption phase 2 to start to transition towards phase 3 as a much more amplified pattern over the Pacific works it way afterwards downstream....Good strong poleward ridging of the Aleutian High in evidence on the ECM

 

Slower than many would like as it may be, the current modelling sets us up to still be on course towards proper cold blocking opportunties during February. Again, much as anticipated.

 

Some snow potential even in the coming days to look forward to for some - so a start is being made at last

 

Edit: That update from across the pond helpfully posted below by nick highlights the changes referred to in my post

 

Another cracking post Tamara. I've highlighted one part in particular which I wholeheartedly agree with (although I agree with the rest as well). With all the euphoria today of the UKMO 00z +144 chart, it was bothering me (and I posted as such) that even if it did verify, I really didn't like where 168+ would have taken us anyway. But anyway that looks to be academic now.

 

It does seem we will have to go for a further period of energy being spawned and spat at us from the vortex first. I do think though that the slow descent into cold has begun but it isn't likely (nor possible?) to happen quickly.

 

I reckon the end game for the Atlantic will be played out with the slow retreat of the Azores High, full on trough disruption and energy being dropped SE'wards under the UK. Add to that a good looking projected wave 2 event and linked warming and then the proper fun and games will begin as HLB at last should be able to form.

 

2nd week of Feb for me and I am becoming increasing excited in could be well worth the wait!

 

EDIT: And I should have also put in that for some, possibly many, the lead up could be snowier than a HLB setup itself, should it take hold...

Edited January 25, 2014 by s4lancia

[Gibby]

Good evening. Here is the report on the midday outputs from the NWP for today Saturday January 25th 2014 taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show Low pressure crossing the Atlantic sending a set of troughs quickly East across the UK later tonight and tomorrow with wind and rain sweeping East, heavy at times and giving rise to further flooding problems tomorrow. Through the afternoon and behind the cold front skies will brighten with squally showers of rain and hail likely with thunder in places and sleet or snow over the hills tomorrow night. through the early days of the week the parent Low responsible for the wind and wintry showers sinks South over the UK and away to the South by midweek with the outbreaks of rain and wintry showers clearing away South soon after midweek.

 

GFS then shows unsettled weather returning from the NW with Westerly winds with rain at times being the order of the day with snow at times over the hills of the North as temperatures only recover slowly from the rather cold levels that will be present this coming week. Late in the run the disturbed weather remains to be shown courtesy of deep Low pressure to the NW with strong SW winds and rain at times and average temperatures for early February.

 

The GFS Ensembles tonight show a short rather colder spell through the early and middle part of the coming week before temperatures recover to more average levels. The weather remains unsettled throughout with rain or snow at times through this week and strong winds and rain at times through week 2.

 

UKMO has a new Low pressure up to the NW of the UK next Friday with strengthening West or SW winds with rain sweeping East again over the UK preceded by snow for some places in the East for a time.

 

GEM also shows the Atlantic winding up again later next week as Low pressure moves in towards the NW of Britain with less cold and windy weather with rain at times and snow over the hills of the North in the showery spells between the rain bands.

 

NAVGEM keeps Low pressure areas slipping SE over the UK later next week maintaining rather chilly and unsettled weather over the UK with mostly NW winds and rain followed by wintry showers the most likely sequence of events.

 

ECM tonight also shows an altogether milder outlook from later next week as Low pressure begins to take a more Northerly route as the block over Europe collapses. The weather will remain no less wet with further spells of rain and very breezy conditions returning after a short drier interlude soon after midweek.

 

The ECM 9 and 10 Day Mean Charts show a trend towards a much shallower circulation over the UK around Low pressure to the NW. With a bias towards a windflow from the South or SW this is at last a departure from a UK or North Sea based trough and I would suggest that with a switch of winds from a NW bias to that shown is indicative of a rather less cold and still unsettled pattern looking likely.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

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

 

The GFS Jet Stream Forecast shows a strong flow across the Atlantic and Southern Europe. The general strength of the flow remains unchanged with the basic proximity of the flow remaining close to the UK throughout the period and occasionally to the South.

 

In Summary tonight the weather has stepped back from the predicted cold of yesterday to something much less wintry again with Low pressure off a volatile Atlantic continuing to pile drive Low pressure areas in towards the British Isles from the NW and west. With the block to the East now showing signs of collapse the door is opened for more progressive Atlantic wind and rain bands to cross over and away to the East of the UK with temperatures slowly recovering to average values later.

[Mucka]

I don't think people should get too disappointed re the UKMO,  its output would not have brought anything more than  a briefish easterly, low pressure was always likely to move in and the issue still remains as it did last night how much if any trough disruption occurs.

 

I don't see a deep easterly occurring within the next ten days and I think we need to move on from trying to find one because its simply not going to happen, and this is me a hardened coldie saying this!

 

The likeliest solution always has been  a continental flow not desperately cold but sufficient for a decent undercut and really that's still a possibility even with tonights UKMO not interested because the models often make a mess of that type of set up, as for any easterly and the one we'd like to see with deep cold and snow showers that will have to wait but in the meantime there is still the chance of some decent snow depending on the trough disruption.

 

Hi Nick 

 

I agree with all of that except I'm not sure I would rule out a more prominent Easterly flow just because the models are more progressive to day with sinking the Scandi high.

You may be talking about a very strong Easterly flow with snow showers being brought in from the East and penetrating well in land in which case I agree that does look very unlikely.

It really would only take minor changes though to bring a more direct Easterly flow, even if relatively short lived, across the UK rather than a slack continental flow.

It is the least likely solution certainly but I expect to see it modelled again at least and even if it doesn't succeed the first attempt it may well be we still have enough blocking left for a second attempt and it could well be the pattern is more amplified behind by that stage. Obviously we need a few things to fall into place before that can happen but no drastic changes necessary.

I really wouldn't be surprised to see ECM model a decent Easterly flow tomorrow for early February if not for end of Jan as was originally hoped.

 

All fascinating stuff though and certainly a slack SE feed followed by by  a battle of air masses as the Atlantic attempts to push in could still be a very nice set up if we get lucky.

Edited January 25, 2014 by Mucka

[Long haul to mild]

You may be right about the lack of snow but where on earth do you get this nonsense that February days are too long and warm to keep snow?

Yes I can assure people that this chart did not bring any rain!

[MPG]

Good evening. Here is the report on the midday outputs from the NWP for today Saturday January 25th 2014 taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm All models show Low pressure crossing the Atlantic sending a set of troughs quickly East across the UK later tonight and tomorrow with wind and rain sweeping East, heavy at times and giving rise to further flooding problems tomorrow. Through the afternoon and behind the cold front skies will brighten with squally showers of rain and hail likely with thunder in places and sleet or snow over the hills tomorrow night. through the early days of the week the parent Low responsible for the wind and wintry showers sinks South over the UK and away to the South by midweek with the outbreaks of rain and wintry showers clearing away South soon after midweek. GFS then shows unsettled weather returning from the NW with Westerly winds with rain at times being the order of the day with snow at times over the hills of the North as temperatures only recover slowly from the rather cold levels that will be present this coming week. Late in the run the disturbed weather remains to be shown courtesy of deep Low pressure to the NW with strong SW winds and rain at times and average temperatures for early February. The GFS Ensembles tonight show a short rather colder spell through the early and middle part of the coming week before temperatures recover to more average levels. The weather remains unsettled throughout with rain or snow at times through this week and strong winds and rain at times through week 2. UKMO has a new Low pressure up to the NW of the UK next Friday with strengthening West or SW winds with rain sweeping East again over the UK preceded by snow for some places in the East for a time. GEM also shows the Atlantic winding up again later next week as Low pressure moves in towards the NW of Britain with less cold and windy weather with rain at times and snow over the hills of the North in the showery spells between the rain bands. NAVGEM keeps Low pressure areas slipping SE over the UK later next week maintaining rather chilly and unsettled weather over the UK with mostly NW winds and rain followed by wintry showers the most likely sequence of events. ECM tonight also shows an altogether milder outlook from later next week as Low pressure begins to take a more Northerly route as the block over Europe collapses. The weather will remain no less wet with further spells of rain and very breezy conditions returning after a short drier interlude soon after midweek. The ECM 9 and 10 Day Mean Charts show a trend towards a much shallower circulation over the UK around Low pressure to the NW. With a bias towards a windflow from the South or SW this is at last a departure from a UK or North Sea based trough and I would suggest that with a switch of winds from a NW bias to that shown is indicative of a rather less cold and still unsettled pattern looking likely. http://www.wetterzentrale.de/pics/Reem2161.gifhttp://www.wetterzentrale.de/pics/Reem2401.gif    The GFS Jet Stream Forecast shows a strong flow across the Atlantic and Southern Europe. The general strength of the flow remains unchanged with the basic proximity of the flow remaining close to the UK throughout the period and occasionally to the South. In Summary tonight the weather has stepped back from the predicted cold of yesterday to something much less wintry again with Low pressure off a volatile Atlantic continuing to pile drive Low pressure areas in towards the British Isles from the NW and west. With the block to the East now showing signs of collapse the door is opened for more progressive Atlantic wind and rain bands to cross over and away to the East of the UK with temperatures slowly recovering to average values later.

So the gfs moved towards the yesterday's UKMO. The ECM is better than recents runs, but the UKMO shows one run as a downgrade and you go for much less cold outlook. What will you say tomorrow if the gfs and ECM stay the same and the UKMET improves?...cold back on?

[Ali1977]

So euro4 predicting 10cm over Hillier parts of Wiltshire on latest chart for tomorrow night....if only!!!!

[SMU]

Evening, I will manage to dunk in a message or 2 - luckily landed last minute tickets to wolf of wall st!

 

 

So why does the model go from 1 extreme to another.- The ukmo being a fine example today.

 

I think ive maintained since day dot weather is about timing, & how things interact.- If one thing doesn't happen it has repercussions to other predicted events, also what was seen to develop in 1 model run whether that be upstream or downstream at T X- then as that T edges to T 0 the model reacts to what is actually happening and suddenly corrects.

 

Depending on what was expected & what intricate interactions were expected the corrections can be huge- especially at 144 - as demonstrated by the UKMO today.

 

Anyway lets knock the UKMO,  & indeed the JMA-

 

The chart for T96 is now aligned by all models tonight.( with the exception of the speed of the system coming out of the states)

 

ECM 96

http://www.meteociel.fr/modeles/ecmwf/runs/2014012512/ECH1-96.GIF?25-0

UKMO 96

http://www.meteociel.fr/ukmo/runs/2014012512/UN96-21.GIF?25-18

GFS 96

http://modeles.meteociel.fr/modeles/gfs/runs/2014012512/gfsnh-0-96.png?12

 

If we cast our minds back X2 days- it was the ECM that was the closest- ( UKMO in the middle )

http://www.meteociel.fr/modeles/ecmwf/archives/2014012312/ECH1-144.GIF?12

http://modeles.meteociel.fr/modeles/gfs/archives/gfsnh-2014012312-0-144.png?12

 

Interesting. As the ECM, whilst a bit on the rough side with the cold to start with has always been onside with a slider- with varying degrees of penetration east, & varying levels of snowdepth for the North.

 

 

This is where we stand tonight, Models agreed to 96, with broad agreement to 120- with a push of cold uppers west as the low exits on a southerly track-

At 96, depending on angle & depth of cold some back edge snow & accompanied snow flurries will dig into the East / NE & SE-/SW demonstrated here

http://www2.wetter3.de/Animation_12_UTC/96_30.gif  & flurries

http://www2.wetter3.de/Animation_12_UTC/120_30.gif

 

At 72-96 there is also a chance of HEAVY snow for the Eastern part of Scotland- which thus far hasn't been raised,- perhaps up to 30cm if we can get the cold in quick enough.

http://www2.wetter3.de/Animation_12_UTC/150_35.gif

 

 

Post 120 it gets tricky- & this wont get resolved down to 50 mile margins until T24. so 4 days to go!

 

The Slider!!

 

As it stands the big risk stands for Midlands North into Scotland- that's because the angle of attack has a slight nudge of high pressure ahead of the low in SW, so the forward winds when the pick up will be south westerly in the south west but southerly veering south easterly in the North.

 

ECM 144

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014012512/ECH1-144.GIF?25-0

 

That's no good for the South of the SE or SW- the mild air will get in to the SW, however ahead of that -8c moving into Eastern & SE England *MAY* preclude some snow.

 

The ideal slider scenario sees break away trough disruption that acts as a barrier for the mild air & all the forward winds are Southerly or SE-

 

take these Sliders.

http://modeles.meteociel.fr/modeles/reana/1996/archives-1996-2-5-12-0.png

http://modeles.meteociel.fr/modeles/reana/1996/archives-1996-2-6-0-0.png

 

&

 

http://modeles.meteociel.fr/modeles/reana/1982/archives-1982-1-8-0-0.png

http://modeles.meteociel.fr/modeles/reana/1982/archives-1982-1-9-0-0.png

 

 

Interesting the ECM @ 216

http://www.meteociel.fr/modeles/ecmwf/runs/2014012512/ECH1-216.GIF?25-0

 

Has another slider, which is great for all for the extreme south because the breakaway low just isn't far enough south.

 

 

In summary as I hinted at earlier the longwave pattern looks set out to 120, almost 144 as well, however the finer points of the shortwave pattern mean that for the next 2/3 days we are left wondering if we will be knee deep in snow or mud by the end of the week.

 

Behind that - some decent polar blocking forcing its way south again, could be jackpot after jackpot for some nearer the NE, but equally troublesome could be rainstorm after rainstorm for the SW..... Locations in the middle could do well- especially at slight elevation circa + 100m

 

S

[Duane S.]

Must be the hills because the chart Steve posted just looks quite wet too me, surely too get snowfall from low uppers from the continent, there has to be a significant cold spell there and what we are seeing in the outputs is not a significant cold spell, plus we are approching February now so daytime heating would more than likely turn any snow to rain. 

 

Anyways, its all pointless and irrelevant as the detail will be different on the next run. 

 

So misleading. If you swap 'February' with 'March' you would have a point.

[chicken soup]

 

 

 

Good evening. Here is the report on the midday outputs from the NWP for today Saturday January 25th 2014 taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models show Low pressure crossing the Atlantic sending a set of troughs quickly East across the UK later tonight and tomorrow with wind and rain sweeping East, heavy at times and giving rise to further flooding problems tomorrow. Through the afternoon and behind the cold front skies will brighten with squally showers of rain and hail likely with thunder in places and sleet or snow over the hills tomorrow night. through the early days of the week the parent Low responsible for the wind and wintry showers sinks South over the UK and away to the South by midweek with the outbreaks of rain and wintry showers clearing away South soon after midweek.

 

GFS then shows unsettled weather returning from the NW with Westerly winds with rain at times being the order of the day with snow at times over the hills of the North as temperatures only recover slowly from the rather cold levels that will be present this coming week. Late in the run the disturbed weather remains to be shown courtesy of deep Low pressure to the NW with strong SW winds and rain at times and average temperatures for early February.

 

The GFS Ensembles tonight show a short rather colder spell through the early and middle part of the coming week before temperatures recover to more average levels. The weather remains unsettled throughout with rain or snow at times through this week and strong winds and rain at times through week 2.

 

UKMO has a new Low pressure up to the NW of the UK next Friday with strengthening West or SW winds with rain sweeping East again over the UK preceded by snow for some places in the East for a time.

 

GEM also shows the Atlantic winding up again later next week as Low pressure moves in towards the NW of Britain with less cold and windy weather with rain at times and snow over the hills of the North in the showery spells between the rain bands.

 

NAVGEM keeps Low pressure areas slipping SE over the UK later next week maintaining rather chilly and unsettled weather over the UK with mostly NW winds and rain followed by wintry showers the most likely sequence of events.

 

ECM tonight also shows an altogether milder outlook from later next week as Low pressure begins to take a more Northerly route as the block over Europe collapses. The weather will remain no less wet with further spells of rain and very breezy conditions returning after a short drier interlude soon after midweek.

 

The ECM 9 and 10 Day Mean Charts show a trend towards a much shallower circulation over the UK around Low pressure to the NW. With a bias towards a windflow from the South or SW this is at last a departure from a UK or North Sea based trough and I would suggest that with a switch of winds from a NW bias to that shown is indicative of a rather less cold and still unsettled pattern looking likely.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

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

 

The GFS Jet Stream Forecast shows a strong flow across the Atlantic and Southern Europe. The general strength of the flow remains unchanged with the basic proximity of the flow remaining close to the UK throughout the period and occasionally to the South.

 

In Summary tonight the weather has stepped back from the predicted cold of yesterday to something much less wintry again with Low pressure off a volatile Atlantic continuing to pile drive Low pressure areas in towards the British Isles from the NW and west. With the block to the East now showing signs of collapse the door is opened for more progressive Atlantic wind and rain bands to cross over and away to the East of the UK with temperatures slowly recovering to average values later.

 

This post is very perplexing, goes against what all the other experts on here are saying.

Edited January 25, 2014 by chicken soup

[Frosty.]

I'm very pleased to bring you the GEFS 12z perturbations noon temperatures, for the second half of next week, emphatic support for a change to much colder weather spreading down across the uk next week, by thursday, some areas struggle to get above freezing and with low pressure in control. According to the 12z mean, once the cold weather arrives, it will become entrenched for a fair while, especially further north and I expect there will be snowy weather for many areas, in the form of flurries, showers or longer spells of snow. There are no lingering doubts anymore, as there were yesterday, real winter will arrive next week with snow, ice and frosty weather..tomorrow brings an early taste of things to come with heavy snow for higher ground in the north but it's next week when we all see a big pattern change by midweek with Easterly winds blowing in from russia / scandinavia...Brrrrrilliant     .

[SW Saltire]

So misleading. If you swap 'February' with 'March' you would have a point.

Exactly, I was wondering if it was just me that remembered the giant snow event for a large proportion of the UK that occurred on the 23rd of March 2013. After the equinox!!! This is not a sunshine and showers situation, a slider with copious precipitation is quite different as has been expressed by numerous posters in here

[Cloud 10]

Looking at the day 10 ensemble means from GFS,GEM and ECM reveals the apparent

demise of the Azores high,which should result in the jet stream heading further south which is

fine as long as heights remain low over Southern Europe.

 

Note also the Polar Vortex remains well split.

 

Edited January 25, 2014 by Cloud 10

[weather eater]

This post is very perplexing, goes against what all the other experts on here are saying.

I don’t think so, its Gibby’s summery of how he sees things others have other ideas, all are fair comment, the weather has a way of dumbfounding the wise, plenty of expert opinions have flounded when faced with the complexity of forecasting for our small island, even in these days of saturation model watching.

[Frosty.]

Looking at the day 10 ensemble means from GFS,GEM and ECM reveals the apparent

demise of the Azores high,which should result in the jet stream heading further south which is

fine as long as heights remain low over Southern Europe.

 

Note also the Polar Vortex remains well split.

 

EDH1-240.GIFgensnh-21-1-240 (1).pnggensnh-21-1-240.png

Good riddance azores high it's been a constant thorn in the side of coldies so far with a southwest / northeast aligned jet...that's all about to change

[Vorticity0123]

I'll try to give a short summary of today's output (mainly trends), regarding the 500 mb charts, and the surface charts in the mid- to long term. For the large scale, the 500 mb charts will be shown. Thereafter, I'll go in somewhat more detail.

 

500 mb trends

 

First, the 500 mb forecast chart (6-10 day) with anomalies is given below:

 

NOAA 500 mb heights and anomalies output for day 6-10

 

The first thing that shows up is a persistent 500 mb trough (as shown by the green isohypses) over northeastern Canada. This trough has been apparent for a long time now, and it is causing the numerous arctic outbreaks over central United States.

 

Secondly, note the diffluent flow over Europe (isohypses flowing out of each other over central Europe). As a result, there is a 500 mb ridge over the western part of Russia. The position of the ridge is somewhat more to the east compared to earlier outputs a few days ago.

 

Next, we will focus on the anomalies. Note the sharp negative anomalies over the UK, the Benelux and France, indicative of surface troughing being likely near that area. As a result, the Azores high is forecast to be deflected toward the south, as noted in Tamara's post above. Moreover, the anomalies become more positive toward the north. 

 

A synopsis like this would create southerly-positioned westerlies. Moreover, there will most likely be a sequence of lows diving into central Europe. As the sharp negative anomaly is also located over the UK, the weather there will most likely be wet as well.

 

Next, the 8-14 day outlook by NOAA is given below:

NOAA 500 mb heights and anomalies output for day 8-14

 

The general forecasted pattern is about the same when one looks at the 500 mb heights, but with the anomalies there are some subtle (and perhaps important) differences. Firstly, the negative anomalies over the UK have shifted to the west, now being concentrated just to the west of Ireland. This could induce a possibly more southerly flow over the UK, with some milder conditions, if this verifies.

 

Moreover, the Azores high has moved somewhat more to the west as well, as can be seen in the positive anomalies. The Azores high will therefore most likely have very little direct impact on our weather.

 

The wind direction "pluim" from De Bilt, the Netherlands confirms the trend in the long range, though there is a large scatter, as can be forecast in this timeframe.

 

De Bilt wind direction "pluim", showing 50 members from the ECMWF.

 

What can be seen is a trend for the "pluim" to veer toward the south from eastern directions (including Oper and Control), but there is indeed a wide scatter after T168.

 

Detailed synoptic evolution (short range)

 

For the detailed synoptic evolution, I'll use GFS charts from Wetterzentrale.

 

Over the first few days, a general trend for lows to dive into central Europe can be seen, as also seen on T84:

GFS T84 (12Z)

 

The diving low scenario is mainly causing very wet weather over the UK, as consistent low pressure activity is located there. However, on the northern side of the lows, there is a risk of an easterly developing with possible snow chances on higher elevations. 

 

850 hPa temperatures in this situation are generally near -4*C over the UK, giving rise to marginally cold conditions, as can be seen in the chart below:

http://www.wetterzentrale.de/pics/Rtavn965.png 

 

The 144h surface pressure chart can be seen below:

GFS T144 (12Z)

 

What can be seen is a rather messy situation to the northwest, though generally low pressure is observed there. This is consistent with the 500 mb anomaly charts as given above (though I do think the GFS has somewhat more northerly troughing than I would expect with the 500 mb surface charts). Moreover, the high pressure over Russia has moved somewhat southward. The result is a southerly flow, but as usual, there are many uncertanities at this timeframe. 

 

Concluding, there will be a change in steering in the near future, possibly resulting in somewhat milder conditions. All models show a low pressure area to the northwest of the UK, though. It will be interesting to see how this situation plays out.

 

Sources:

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

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim&r=midden

http://www.wetterzentrale.de/topkarten/fsavneur.html

Edited January 25, 2014 by Vorticity0123

[nick sussex]

What's the new trend nick?

Take a look at last nights ECM T144hrs and 168hrs then look at todays UKMO 12hrs run at T120 and 144hrs, then look at todays ECM, sharper troughing more amplification to the west.

 

The models seem to be  playing catch up to the ECM, the UKMO is a day late with the change.