Model Output Discussion 19th January 2014-18z onwards.

[Paul]

I know it's Monday morning, but is there really any need for sniping at eachother - if you're in a bad mood please just keep it to yourself! 

[Severe Siberian icy blast]

today's output for the back end of this week should not be a surprise to those who were following all the output from the last 48 hours. Thereafter, we have to wait to see how all the big players interact. Although many would like to see a big greeny block, that takes a big leap of faith from an Atlantic perceptive but its just about possible as an xtension of the polar high. Therefore, given the enormous pressure from the vortex, a broad continuation of what we've been looking at seems to continue. That's disrupting systems against a scandi /Svalbard block. Sliders, undercutters - all possible but so are systems getting east of us. the continent should be colder so we have better chances of occlusions bringing snowfall. No easy predictions here.

Morning mate, I'm really happy to see the models correcting westwards this morning , it has to be the first time this year the gfs showing the block to be a lot stronger than anticipated , normally because of its progressive nature it hurdles the lows straight through , but it has to be said it's been right a lot this year because of the strength of the vortex , but it's good to see , because of this it makes me think its definitely onto something with regards this weekend , and because of this it effects the whole set up going forward and the scandi high dominates our weather in some way or another. Of course aided by the -AO set up , which also shows up well on the ECM in its later frames .It's possible the reason why we saw progressive models this wkend just gone is because they had only just picked up on the strong arctic plunge into the states which therefore fuels the Atlantic , with the PV the strength it is , it over egged everything in sending us back toward a zonal outlook , we often see the models do this . Pick up on something (in this case the massive -AO signature ) drop it , (in response to another trend been picked upon , in this case the ramp of the jet ) only to pick back up on the original idea , but with a better handling of the pattern .So to summarise if I were to make a forecast I would go with the front disrupting this wkend pushing southeast into Europe , with snow a distinct possibility for many , (remember Europe is becoming cold now finally so any southeast flow could well be enough for snow, ie similar to last years set up ) then into next week, fronts following suit , undercutting giving us a continental influence , I'm much more positive of things now going to February and I'm happy with the gfs coming on bored .

[Frosty.]

All I can say about the ukmo 00z is I would love to see T+168 hours..trough disruption undercut with cold air being sucked into the uk mixing with low pressure = winter has arrived.

[Troubleatmill]

Looks close for the back end of this week for snow to fall in some areas, 850-1000hpa temps look ok in the east off the slack easterly flow, dew point and wet bulbs look a bit  blah however, snow to rain, rain to snow? could be a sweet spot somewhere

Edited January 20, 2014 by Nicholas B

[Gibby]

Good morning folks. Here is the report from how I see things developing over the coming few weeks using the data from the midnight outputs from the NWP and lifted from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models follow a similar pattern of events through this week and the weekend. The UK lies in slack pressure currently with light winds, bright weather with clear or sunny intervals and frost and fog a feature over the next 24 hours. Tomorrow sees a new frontal system move slowly into the West and cross over to the East by Wednesday. Rain will move East slowly tomorrow and Wednesday before clearing in the West to showers and a cool NW breeze. All areas then see NW winds and scattered showers on Thursday before a ridge of High pressure crosses East late in the day and overnight with the return of frost and patchy fog. On Friday the ridge gives way slowly to a new frontal system with increasing SW winds and rain moving down from the NW through the day. The weekend is then shown by all models to remain changeable with further showers and some drier and brighter weather, this most likely on Sunday.

 

GFS then shows deteriorating conditions next week as a deep Low slips SE across the UK with gale force winds and heavy rain with colder weather sinking down behind to reach Southern areas by midweek. Some snowfall is possible on high ground for a time almost anywhere for a time on the exit SE of the Low and in the NE winds. Towards the end of the run the weather reverts to a chilly NW air mass type with further Low pressure areas sliding SE down over the UK or just to the NE with further rain and showers with sleet or snow on the hills at times in rather windy conditions.

 

The GFS Ensembles show very ordinary levels of temperature through the period with plenty of rain events still scattered about through the run from most members as the Atlantic continues to remain the source of our weather. The operational was one of the colder options later in the run but there is some other rather chillier options shown too but never desperately cold.

 

UKMO closes it's run next Sunday with a ridge of High pressure moving across from the West clearing away the early wintry showers from the NE to a dry and bright if rather chilly day with increasing cloud from the NW late in the day as the next system approaches.

 

GEM shows a much stronger NW flow next Sunday with plenty of showers, wintry in places under a strong NW wind. Towards the end of the run the weather remains often unsettled and windy with further rain and showers turning to snow in places as it, like GFS shows a brief NE flow across the UK.

 

NAVGEM shows Atlantic systems based to the North of the UK continuing to influence the UK weather with further fronts crossing West to East over the UK with rain and showers at times in brisk winds and temperatures close to average.

 

ECM today has Low pressure following next Sunday's ridge crossing ESE to the NE of Scotland and dragging blustery NW winds with rain followed by showers affecting the UK early next week with snow on hills in the North. This then sets the tome and pattern for further unsettled conditions at the end of the run as a Westerly flow continues to bring further unsettled weather later.

 

The ECM 9 and 10 Day Mean Charts continue to show it's ongoing theme of the most likely pattern in 10 days time. The favoured option looks to be a trough down the North Sea attached to low pressure to the NW. High pressure lies to the SW and NE with the UK likely to be just on the western fringe of the north sea trough indicative of West or NW winds and rain at times and some periods of cooler and showery weather with some wintry showers possible on the hills in temperatures generally near or just below average.

 

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

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

 

The Jet Stream shows the flow maintaining it's current pattern for some time yet before a strengthening of the flow spawns some deeper Low pressure areas next week. The overall position remains uncertain then with a mix of options taking it more NE towards Scandinavia while others maintain the flow much like it's current position.

 

In Summary very changeable weather remains the most likely pattern for the weather over the UK in the next 10-14 days. It looks very likely that Low pressure areas will continue to feed down from the NW over the period with further rain and showers at times. There will be colder air across the other side of the North Sea with fronts becoming slow moving at times close to the East coast and any shift of these further West could bring Eastern areas at risk of some snow at times. In general though snow is more likely on polar maritime incursions from the NW between weather systems. While it is unlikely that disruptive rainfall is likely over the period in view that ground water levels are at saturation point any rain that falls over the period will continue to be unwelcome and there will certainly be some wet weather at times.

[UV-RAY]

A lot better output today and I'm more than happy that we have the GFS and UKMO more or less singing from the same hymn sheet. At +144 it could still go either way and if I was a betting man I would say there's a good chance of those in Central England and Eastern parts seeing a rain to snow event out of this set up, small steps in the right direction this morning.

[Downpour]

This morning at least felt like winter in London, a notable frost and chilly air. Here's hoping for a westerly shift of the pattern and a surprise at the weekend.

[I remember Atlantic 252]

A lot better output today and I'm more than happy that we have the GFS and UKMO more or less singing from the same hymn sheet. At +144 it could still go either way and if I was a betting man I would say there's a good chance of those in Central England and Eastern parts seeing a rain to snow event out of this set up, small steps in the right direction this morning.

 

Very much like same weekend last year then Friday 25th- Sat 26th Jan, this could produce snow for the north/east, not expecting any here mind you

 

then like last year, less cold air moving in on Sunday 26th (Sun 27th) last year

[nick sussex]

NAM 06hrs  run update follows the SREF 03hrs , holds the Newfoundland low further west, jet digs se further to the west. Will the GFS 06hrs run follow that? it would be nice !

 

NAM 06hrs run to T84

 

 

 

GFS00hrs run to T90

 

 

The NAM is the mesoscale short range model for the USA and generally I only refer to it when its a very finely  balanced situation downstream. Its not global so we best not get too excited unless that is the GFS follows it!

Edited January 20, 2014 by nick sussex

[Man With Beard]

A question to the more experienced membersWith all models with the exception of the ECM at the moment, showing that once they come up against the block it's proving to be stronger than we all once thought.So if the block to our east is being so under estimated by the time we get to fri will this not stop the Atlantic even getting past Ireland for example .Sorry if it's a dumb question still trying to learn .Thanks very much in advance

Doubt it will move back to Ireland but yes, big corrections as you describe are not that uncommon!

[Summer Sun]

GFS 00z is a colder run with out doubt as the 8 day temperature anomaly shows

 

Edited January 20, 2014 by Summer Sun

[legritter]

I feel we are starting a good period of cold model watching ,just hoping that as the week goes on our block to the n/east gradually influences the atlantic .and hopefully if it does hold to our n east and we get a major low dive s east that could be Game on ,But patience i think is required still yet .

[R.P. McMurphy]

GFS 00z is a colder run with out doubt as the 8 day temperature anomaly shows

 

 

Quite a change that Gav from a couple of days ago. That is VERY cold, and Europe is freezing over as well.

 

I don't hold these charts in high regard though because of the amount of chopping & changing they do on a daily basis, but it does tie in nicely with the current output. Long way to go though yet !

 

Looking ahead around the same time period, we almost have a countrywide snow event:

 

[shaky]

Waiting for ian fergusons update with interest!!!

[Dancerwithwings]

At 72h Yesterdays and todays, you can clearly see the pust westwards and thats in just 24hrs.

 

 

[weather eater]

Waiting for ian fergusons update with interest!!!

I rather suspect that it will be a case of as you were, whilst we have seen some reasonable output this morning the MO don’t tend to jump their opinions about based on every run.

Edited January 20, 2014 by weather eater

[iamgazza]

This morning's runs sum up nicely what was been said yesterday (by the wise, sensible people) about how uncertain the outlook is at the moment. It's frustrating to watch if you crave snow (and I do!) but it's also interesting (which is the other reason I'm here) I remain on the fence, ready to jump down on the snow laden colder side... but todaytomorrow and possibly into Wednesday I shall be a bag of nerves.

All to play for... just please take in what the professionals are saying - reliablility at the moment is 72hrs... Anything past that and we'll get a range of outcomes (snowno snow) but look at the bigger picture and be patient before writing winter off.

Edited January 20, 2014 by iamgazza

[nick sussex]

The GFS 06hrs run is similar to the 00hrs but a bit flatter upstream, slightly disappointed it didn't pick up on that upstream trend from the USA region models but at least it doesn't follow the ECM.

 

Given the often progressive bias of the 06hrs run this isn't bad and keeps things boiling up for tonights outputs.

[snowmadchrisuk]

 

 any shift of these further West could bring Eastern areas at risk of some snow at times. In general though snow is more likely on polar maritime incursions from the NW between weather systems. While it is unlikely that disruptive rainfall is likely over the period in view that ground water levels are at saturation point any rain that falls over the period will continue to be unwelcome and there will certainly be some wet weather at times

 

Just goes to show that saying no chance of Snow for the next 10 days in January is a bad idea. Not singling you out Gibby and I enjoy reading your thoughts , but just trying to get a point of cross to the members that keep calling Winter's over are being very premature ...

 

I like GFS's Heavy PPN on Saturday , with the Warm front not even getting as far as the Midlands, Midlands North will get some very heavy snow fall , if it comes off like that shows .

[Derecho]

http://wxmaps.org/pix/temp4.html

 

Some noteworthy cold appearing over the continent for the first time this winter especially over Scandanavia, the block to our east may become more stubborn and stronger then is currently shown....

 

http://wxmaps.org/pix/temp1.html

 

Also worth noting is another vigourous cold wave across Eastern USA, making its way down to Florida too unlike previous cold spells there, this could help weaken the gradient off the Eastern Seaboard finally.

 

So while there is no negative NAO at the moment the pattern across the Northern Hemisphere developing could help develop more favourable synoptics further down the line.

[Frosty.]

I rather suspect that it will be a case of as you were, whilst we have seen some reasonable output this morning the MO don’t tend to jump their opinions about based on every run.

It's the best output for coldies since last march / april..I expect further upgrades.

[shaky]

I remember steve murr mentioning a couple of days ago that we could see some snowfall with the front coming in later tonight and tomorrow!!he said something like there were -2 and -3 uppers with a southerly drift or sumin could potentially be enough for a bit of snow!!just wondering if that is still the case?

[Yarmy]

The last 4 GFS 0z runs out to this coming Friday:

 

Friday 17th (T174):

 

Saturday 18th (T150):

 

 

Sunday 19th (T126):

 

 

This morning (T102):

 

 

Scandi block proving more robust (assuming this gets close to verifying) than originally modelled. Kudos to the older heads on here who suggested that would happen.

[nick sussex]

Well after a slightly dodgy middle part the GFS 06hrs run improves as it removes that  shortwave near Svalbard which allows for more forcing on the low to the west.

 

This is turning into a real thriller, can the energy separate upstream?

[Weather Boy]

All I can say about the ukmo 00z is I would love to see T+168 hours..trough disruption undercut with cold air being sucked into the uk mixing with low pressure = winter has arrived.

 

Not so sure.  Taking that chart in isolation, wouldn't you expect the little trough in the east Channel/south North Sea to be squeezed out by the HP cells to the SW and NE, which then link up and covering 3/4 of the UK (excluding NW)?

 

That would probably bring milder conditions with rain at times to the NW and Scotland with colder more stagnant continental air, especially towards the SE with possible fog and frost although damp cold drizzly weather possible and maxima 2-5C.

 

That's been a possible solution for some of the output for a while, and for me is still possible.  Probably wouldn't be a great solution for coldies, it producing little chance of snow, but at least it would be dry or dry-ish for many.

 

What do you think, Frosty?

Edited January 20, 2014 by Weather Boy