Model output discussion 13th Feb onwards

[Summer Sun]

ECM ensemble now showing something more settled trying to develop as we enter the first full week of March something Darren Bett hinted at on the country file forecast

 

 

[Gibby]

Good evening. Here is my Sunday review of the midday outputs issued by the NWP for today Sunday February 23rd 2014 as featured on my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm. I am now including links to the data from which each section of my report is compiled.

 

All models show a mild and broad SW flow across the UK with Low pressure to the NW. A trough lying SW to NE across NW areas is shown to slip SE through tonight and accelerate away East tomorrow morning to leave a Westerly flow briefly tomorrow before an active Low pressure systems streams in off the Atlantic towards NW Britain on Tuesday. So after rain in the NW tonight makes it's way across the UK slowly a showery interlude follows tomorrow before a fast moving spell of rain crosses all areas tomorrow night and Tuesday morning leaving a couple of blustery and showery days towards midweek with fresher temperatures.

 

GFS then shows a new Low cross into the UK later in the week and take a turn SE across the near Continent next weekend. This ushers in colder weather following a wet end to the working week. Showers will be wintry in the North and East before a ridge moves across from the west or NW damping down any showers and leading to a cold and frosty period next Sunday. Thereafter a typical changeable regime develops under Westerly winds with some rain at times chiefly but not exclusively in the North. The South will see rather drier weather for longer with High pressure sometimes not far away from the South and temperatures generally will return closer to average though still rather chilly in the North between weather systems under NW winds.

 

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=0

 

The GFS Ensembles show very changeable conditions tonight with Low pressure trending to come down from the NW in Week 2 maintaining a changeable theme with rain at times and snow over the hills, chiefly in the North. The South is shown by many members to have some reasonable drier interludes in accordance with High pressure close to the South or SW at times though even here rain and wind occurs at times.

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=0&mode=0&carte=0

 

UKMO closes today with next Saturday being a breezy and cold day under NW winds around Low pressure positioned over the North Sea. The weather will be generally showery with wintry showers over all high ground with some snowfall over the hills and not just in the North.

 

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=6&carte=1021

 

GEM also introduces colder weather from the weekend. A wet end to the working week under Low pressure is replaced by North or NE winds and wintry showers over the weekend. Then High pressure builds from the SW to show a very ECM'esque 00z run solution with fine and dry weather with night frosts and milder westerly winds filtering across the North later.

 

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=6&mode=0&carte=0

 

The GEM Ensembles though changeable do indicate a lot of dry weather to be found in the South from next weekend on as High pressure is in much closer attendance at times to the SE. Some rain events are shown, chiefly in the North and while winds become strong SW'ly at times it will also become rather mild too later.

 

http://www.meteociel.fr/modeles/cmc_cartes.php?code=0&ech=0&mode=0&carte=0

 

NAVGEM today ends it's run with a slack, cyclonic flow next weekend with wintry showers in places before Westerly winds return in the new week to return unsettled and changeable weather to many and temperatures just a little shy of average values.

 

http://www.meteociel.fr/modeles/navgeme_cartes.php?&ech=6&mode=0&carte=0

 

ECM's operational tonight is much more progressive in maintaining very changeable conditions as we move into the new week with Low pressure slipping ESE across the North and NE of Britain with rain and wintry showers at times across all areas.

 

http://www.meteociel.fr/modeles/ecmwf.php?ech=0&mode=1&map=0&type=0&archive=0

 

The ECM 9 and 10 Day mean charts look largely similar to those of this morning indicating the UK could lie in a weak ridge of High pressure with Low pressure to the NW and High pressure near the Azores with a West or NW flow of air likely over Britain with some rain at times, most coherent in the North with average temperatures for all.

 

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

 

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

 

The Jet Stream Ensemble group have reduced te amount of elevation in the axis of the flow through week 2 with the flow now shown to hold a position near to the UK meaning low pressure to the NW is allowed to dig further South through the British isles at times with High pressure held further South over Europe or the Atlantic.

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=0&mode=3&carte=0

 

In Summary this evening the improvements of this morning have become more muted again tonight as the Atlantic once again is shown to be more than a match for the synoptic setup in a weeks time, pushing the ridge steadily away back South as Low pressure pulls back down over Britain. So after a week to come of more wind and rain it looks as though there will still be some unsettled to be had in Week 2 as well though there may be a shift in emphasis of rain towards Northernmost parts while the South and East eventually see longer drier periods in between the wind and rain.

[Tim Bland]

As others have mentioned CFS is showing some potent north / north easterlies into March

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=516&code=0&carte=0&mode=0&run=10

[SE Blizzards]

Does anyone have any idea of what the uppers are for today's UKMO 12z 144h as they are not showing on meteociel.

[Man With Beard]

Here's a nice snowflake

 

 

It's about the only one you're likely to see anytime soon.

I have to say I think this is right based on most models. The -6C line rarely makes much progress into the UK on any run and I think that's a must on a westerly in March without surface cold already in place. North and Western hills may do well though.

[JK1]

As others have mentioned CFS is showing some potent north / north easterlies into Marchhttp://www.meteociel.fr/modeles/cfse_cartes.php?ech=516&code=0&carte=0&mode=0&run=10

CFS seems kinda useless, i remember looking at it in january and it was showing really cold weather for winter but as we know never happened

Edited February 23, 2014 by JK1

[West is Best]

Well I guess like everyone else I've been waiting, and waiting. The latest 0z runs put the final nail in the proverbial of snow during official winter. The mini and pale northerly progged for Fri/Sat has pretty much vanished and instead we now have an FI developing Azores high extension with the jet kicking north, finally, but something more redolent of summer than March and leading to mild south-westerlies.

I am sure there have been winters this devoid of snow, or even signs of snow, before. I just can't remember any.

[The PIT]

Downgrade of the cool spell continues. Although it never showed anything really wintry away from the highest ground. GFS which originally was the keenest to bring colder air in now swings to a Spring like outcome. Probably explains it's poor six day score recently.

[Captain Shortwave]

Well we are back to the Azores high building in again this morning

 

GFS more progressive with the Atlantic jet and hence more developed high to the south 

 

Not really a cold spell now with the 850's not even reaching -4C in the south, maybe wintry showers over the hills in the north for a time.

[IDO]

A complicated setup with the Atlantic energy split at D5 developing a cut off low into S Europe. The last few days GEFS have not really resolved what happens afterwards. This morning's GEFS 0z again shows uncertainty. With the Russian high moving east its a battle between the Azores High or the Atlantic, those low heights will be ideal for the AH to sustain a ridge from SW to E as per the GFS op: 

 

T180:  T240:  T300: 

 

The GEFS have this scenario as the main cluster, to one degree or another, but another cluster develops, more like the GEM (T240):

 

 Remaining more Atlantic driven.

 

ECM is between the two, with the AH being squeezed from the Atlantic and the Med low heights: 

 

Not sure which way this is going but the GFS op is probably the best possible outcome we could get if higher pressure arrives; the London ens highlights this (outlier material):

 

 

So the ECM op looks more in line with my thoughts. The uppers look cool to average but nothing cold as we enter FI:

 

 

Not too bad rain wise this week, Thursday the wettest day, as the daughter low cuts off SE into the Med. Relatively mild in the SE up till then.

Edited February 24, 2014 by i'm dreaming of...

[Purga]

Looking to turn very mild from GFS this morning

 

and later

 

 

A lovely chart for Summer Sun! 

 

briefly cooler from ECM

 

But then on the mild track thereafter

 

 

To counterbalance however, the ENS show the GFS Op run very much on them warm side with a fair few colder runs.

The main indication is still going for average to mild though and precipitation much reduced.

 

Edited February 24, 2014 by Purga

[johnholmes]

The 500mb charts did, a few days ago, hint at a possible colder spell, maybe 3-4 days. This was on the basis of the Atlantic upper ridge in combination with the upper trough over/just east of the UK turning the upper flow to north of west with relatively low 500mb heights. How unsettled was never clear. Over the last 3 days this idea has looked increasingly unlikely as the upper ridge was predicted to push in to move the upper trough away. There is still the possibility of a temporary surface high pressure over/close by the western side of the country but no cold air from the NW. What the charts below show is the upper ridge dominating and the strong westerly flow out of North America being north of the UK area. The risk of the ridge declining away SW allowing the major trough to become the dominant player seen on both the charts below is a real probability it would seem. Thus returning us to a more unsettled Atlantic flow. It should not though mean a return to incessant rain for the areas least needing any rainfall. The main thrust seems to be likely for the far NW if this does happen.

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

the charts above have the support of the NOAA 6-10 and 8-14 last evening, see below; more especially the 8-14 with the 6-10 still showing the earlier idea of a coldish flow n of west.

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

[Gibby]

Good morning. Here is my Monday review of the midnight outputs issued by the NWP for today Monday February 24th 2014 as featured on my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm. I am now including links to the data from which each section of my report is compiled.

 

All models show a Westerly flow briefly today before an active Low pressure systems streams in off the Atlantic towards NW Britain on Tuesday. So after remaining rain clears it's way across the UK this morning a showery interlude follows before a fast moving spell of rain crosses all areas tonight and Tuesday morning leaving a couple of blustery and showery days towards midweek with fresher temperatures. A new Low then brings rain and wind back over the UK towards the end of the week with some colder air developing with showers turning wintry over Northern hills towards the weekend.

 

GFS then shows that thereafter a typical changeable regime develops under Westerly winds with some rain at times chiefly in the North with the South staying largely dry close to high pressure to the South. Temperatures generally will return closer to average though still rather chilly in the North between weather systems under NW winds.

 

http://www.meteociel.fr/modeles/gfse_cartes.php

 

The GFS Ensembles endorse the operational this morning with a lot of dry and bright weather for Southern areas as High pressure lies to the South and SW. Some rain filters across the North at times from the Atlantic but overall conditions shown are far better than of late.

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=0&mode=0&carte=0

 

UKMO closes today with next Sunday being a breezy day under NW winds around Low pressure positioned over the North of Scotland and another over Biscay. The weather will be generally unsettled and showery with wintry showers over  high ground. The model has taken a step back by delaying the progression of fine weather early next week following the unsettled weekend.

 

http://www.meteociel.fr/modeles/ukmo2.php?nh=0&ech=6&carte=1021

 

GEM continues to show changeable weather well into next week as further troughs round a High pressure area to the SW with rain at times for many gradually becoming more pronounced to Northern and Western Britain.

 

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=6&mode=0&carte=0

 

The GEM Ensembles though changeable to begin with do indicate a lot of dry weather to be found in the South from next weekend on as High pressure ridges NE to be positioned over Britain late in the run. Isolated rain events are shown in the North and while winds be much lighter than of late it will also become rather mild in places later but with an increased risk of night frosts.

 

http://www.meteociel.fr/modeles/cmc_cartes.php?code=0&ech=0&mode=0&carte=0

 

NAVGEM today ends it's run with Low pressure well in charge across and around the UK to start next week with further rain at times in a blustery westerly wind and temperatures close to average, at least in the South.

 

http://www.meteociel.fr/modeles/navgeme_cartes.php?&ech=6&mode=0&carte=0

 

ECM's operational today has reverted back to a more settled phase of weather next week as High pressure builds strongly from the SW steering rain bearing systems away to the far North and keeping the UK in fine and bright daytime conditions with frosty night probable with light winds.

 

http://www.meteociel.fr/modeles/ecmwf.php?ech=0&mode=1&map=0&type=0&archive=0

 

The ECM 9 and 10 Day mean charts look largely similar to those of last night indicating the UK could lie in a weak ridge of High pressure with Low pressure to the NW and High pressure near the Azores with a West flow of air likely over Britain with some fine weather at times, most coherent in the South with average temperatures for all with any rainfall slowly becoming more confined to the NW.

 

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

 

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

 

The Jet Stream Ensemble group continue to promote a lifting of the flow to higher latitudes across the Atlantic as the Azores High becomes more dominant promoting better weather for Southern areas at last while the North too sees less frequent spells of rain. Overall temperatures remain close to average with a flow on this trajectory NE across the Atlantic and the North of the UK in Week 2.

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=0&mode=3&carte=0

 

In Summary there still seems strong support for pressure to rise from the west and SW next week. To what extent this occurs is open for debate still as UKMO and NAVGEM for example holds Low pressure over the UK still as late as next Sunday with only marginal improvements suggested at next week from them. ECM and some of the other output shows a much stronger improvement leading to High pressure over the UK later next week with some much welcomed fine and dry conditions for many with some night frosts. I feel there will be plenty more twists and turns as we battle are way through another week of wind and rain at times before perhaps we can look forward to something more akin to early Spring as we move into next week. 

[Tim Bland]

GFS still on its own with how quickly it allows high pressure in at the weekend / early next week. Other models keep low pressure and allow it to slip south. Lots of uncertainty in the models beyond day 5

[Summer Sun]

GFS 00z precipitation amounts till March 12th look like they'll be a lot low than of late

 

[Tamara]

I wouldn't be too certain of a dominant westerly airstream as we move into March - there are stirrings the azores high could ridge sufficiently NE to kill of the atlantic advances at least in the south and thus weaken its influence in the north at the same time.

 

March sees the northern hemisphere undergo rapid changes in response to increasing strength from the sun and land warming up markedly those cold anomalies over NE USA/east Canada will undergo some rapid warming over the coming weeks..

 

 

I've been saying for a while now in previous posts about shortening wave lengths and natural seasonal changes having an impact and it will happen at some stage - however we need to see consistent modelling at the 10 day period, and more, that this is going to happen that soon. There are no predictions at this stage for the cold in North Canada to break down, albeit the jet stream could well start to head north in our atlantic sector

Highlighted from Friday an exchange of views in terms of where the pattern might head after the upcoming further atlantic phase this week, and simply posted here as a measure as to how things have been evolving model-wise since then

 

I think the caution expressed about seeing models staying consistent in bringing the Azores High much more into prominence to settle things down (though much more especially in the south) is proving to be borne out with the changes we have seen since Friday with the pattern already looking flatter than suggested, and the colder incursion now restricted beyond what was previously shown. Not that it had much suggested cutting edge anyway. 

 

In terms of making this judgement we ignore face value operational output and look at the upper pattern and what the ensemble data can tell us.

 

There remains doubt about the jet stream pattern in our atlantic sector after the surface trough disruption in tandem with the increasingly hesitant atlantic amplification that follows the next unsettled sequence in the coming days

 

The winter pattern, as suspected, looks to prove harder to completely break down than might be hoped for. Some progress is certainly being made, but whilst there is clearly no return suggested to anything like the intensity of the pattern seen for much of the winter season, the extent of any proper improvement I think remains uncertain and continues to be liable to set backs. Despite what the operational Euro output might be currently showing. I agree completely therefore with what John H has suggested in that there is a risk of the upper trough dominating more than may seem currently apparent, and with the Azores High more suppressed than recent modelling has shown.

 

The amount of scatter there is in the latest London ECM ensembles, (beyond the attempted downgraded colder incursion) with a significant number of higher rainfall and wind strength solutions indicated than the operational, underpins the thinking and suggested possibility that the upper trough might stay more dominant and extensive, and with the Azores High to be further south than currently suggested by the latest ECM operational. (The ECM yesterday evening produced one of those much more unsettled solutions)

 

http://www.weathercast.co.uk/services/ensemble-forecast.html

 

Its too soon to tell but, just for now and certainly subject to change, the most likely outcome is a continuing changeable westerly pattern for the UK, but with the most unsettled conditions reserved further NW. The clustering of the individual ensembles is not depicted here to give the truer story that enables reading between the lines, but for purposes of a rough guide the ECM ensemble mean gives a suggestion that the operational might be too bullish with the Azores High

 

 

Edit: This evenings ECM operational is more reflective of the thoughts given above I think and more in line with the last ensemble mean

 

Edited February 24, 2014 by Tamara תָּמָר

[summer blizzard]

ECWMF0z sticking to it's guns for a third day..

 

[Mucka]

So even the brief Northerly has been removed from the output this morning, the warmth of Spring can not come soon enough now (should we get any)

It doesn't look too mild for early March though, generally cool especially in the North but there at least signs the Azores high will begin to ridge in bring some drier weather, more particularly to the South with any storms being forced further North. More wind and rain at times to see out February though.

 

Looking further ahead the pattern is looking flatter than previously modelled, as Tamara states, so the Azores high getting far enough North and bringing anything from the East looks quite unlikely at this stage. More probable is that after a reasonably settled first week of March we will see a strong trough set up to the North/Northeast of the UK displacing the Azores high West with possible Northerly outbreaks in the second week or perhaps the Azores high will hang on and get a little further North and East continuing the more settled weather (mostly in the South, could still be unsettled at times in the North and West- depends how strong the Azores ridge is). If either of those ideas are correct I think I would prefer the mild settled route at this stage.

[Frosty.]

There is a risk of isolated patchy frosts for the south next week which leads me to the conclusion we will have high pressure or at least ridging across southern uk during next week with most of the wind and rain further north..this means the weather going forward can be described as changeable in the south and more generally unsettled for the north, especially scotland and n. Ireland.

[Summer Sun]

GFS 12z maintains the possibilities of high pressure building into next week

 

 

Cloud dependent some could see more frosts next week than they did in the 12 weeks of winter combined!

 

Met office / beeb talking about the possibilities of something drier developing into March, must be some decent confidence at Exeter now otherwise they wouldn't be talking and tweeting about it

 

@bbcweather Looking into March, there are signs of a change to drier weather. Welcome news for flood-affected parts of the south. John H"

Edited February 24, 2014 by Summer Sun

[SE Blizzards]

GEM 12Z not really that interested in building High Pressure early next week...

 

 

 

 

UKMO 12Z not too bothered with that idea either....

 

[Tim Bland]

Add ECM and NAVGEM to the "not interested list" makes the GFS look like the odd one out at the moment

http://www.meteociel.fr/modeles/ecmwf.php

http://www.meteociel.fr/modeles/navgeme_cartes.php?&ech=180&mode=0&carte=0

Edited February 24, 2014 by Tim Bland

[Summer Sun]

Add ECM to the "not interested list" makes the GFS look like the odd one out at the moment

http://www.meteociel.fr/modeles/ecmwf.php

 

ECM still builds pressure next week on its 00z run

 

 

I certainly wouldn't say GFS is the odd one out for now though tonight's 12z run from ECM could change that of course

[Man With Beard]

GEM 12Z not really that interested in building High Pressure early next week...

 

 

 

 

UKMO 12Z not too bothered with that idea either....

 

hmmmm, is this another window of settled weather slipping away? I guess there will be a very transient ridge for a couple of days but that might be it. Not all bad for the south and east though if dry/sun is what you're after, we've had a few fairly spring-like days since the weekend before last and I guess we'll have a few more off these in the next 10 days judging by these charts.

GEM later stages are interesting, could possibly squeeze some snow out of this set-up. (sorry can't post charts, on phone)

[SE Blizzards]

hmmmm, is this another window of settled weather slipping away? I guess there will be a very transient ridge for a couple of days but that might be it. Not all bad for the south and east though if dry/sun is what you're after, we've had a few fairly spring-like days since the weekend before last and I guess we'll have a few more off these in the next 10 days judging by these charts.

GEM later stages are interesting, could possibly squeeze some snow out of this set-up. (sorry can't post charts, on phone)

 

Yep. And to add to that further, the mighty Navgem 12Z also not going for High Pressure.