Model Output Discussion - 23rd Jan - 12z onwards

[shaky]

Better ridging in the atlantic at 162 hours!! Very similar to 12z run if not better!

[I remember Atlantic 252]

Bit of a kick in the teeth really whilst we are bathed in the heady temps of -4 850's the Yanks in the north east have -24 850's to contend with http://modeles.meteociel.fr/modeles/gfs/runs/2015012418/gfsnh-1-150.png?18!! I for one am not getting my hopes up about this upcoming cold spell. Lots of cold rain i suspect away from the Scottish mountains. 

 

yeah, very wet for the South, could be a trend to bring low pressure closer to the UK/north sea, see what 00Z's bring, but maybe northerly cut off due to lows too close

[A.J]

numerous posts removed for being either off topic, posting in the wrong thread, or replies to posts that would be better served being reported....please think before posting,,,,,,ta!

[Daniel*]

Not as good as ECM 12z but at face value very good by looking at GFS it'll be hard to tell if it is very wet or snowy, any upgrades on the uppers and you would be looking at deep snow, nice viewing.

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=150&code=0&mode=12&carte=1

[BLAST FROM THE PAST]

seen enough of 18z already to say, game on big style....good night folks

 

 

BFTP

[Continental Climate]

Completly lost by this!! Contradicts what all the charts are showing?? Cold rain away from Scottish mountrains? Complete IMBY post if you ask me.

How does my post contradict what the charts are showing I just posted a chart showing -4 850's which will equate to cold rain for 99% of the pop of uk!! Nowhere in the entire 18z gfs run up to 180 does the temp get below -6 850's which from a maritime source will not deliver snow for lowland uk. 18z in high res is not a cold run!! In fact none of the model output is particularly snowy for the lowland uk. Im not saying it wont change but as it stands it isnt a snowy picture. 

 

Staggering cold into the CONUS http://modeles.meteociel.fr/modeles/gfs/runs/2015012418/gfsnh-1-210.png?18!!! -32 850's that is killer cold usually reserved for eastern siberia. Dont think ive ever seen that before such cold at such a low latitude. A true Continental Climate!!

Edited January 24, 2015 by Continental Climate

[Cloud 10]

Not much change on the 18z with a large-scale trough establishing over Scandinavia and in no particular hurry to move.

 

[Weathizard]

Better aplificaton but GFS having none of the ECM's much colder 850's pre 192hrs. I suspect FI may be decent...

 

 

 

(edit; The Vortex looks to be gesturing 'COME ON THEN'.... perhaps in response to warmings  )

Edited January 24, 2015 by Weathizard

[Cheshire Freeze]

How does my post contradict what the charts are showing I just posted a chart showing -4 850's which will equate to cold rain for 99% of the pop of uk!! Nowhere in the entire 18z gfs run up to 180 does the temp get below -6 850's which from a maritime source will not deliver snow for lowland uk. 18z in high res is not a cold run!! In fact none of the model output is particularly snowy for the lowland uk. Im not saying it wont change but as it stands it isnt a snowy picture.

Are you ignoring the low thicknesses because they will certainly help matters in that respect.

[Harsh Climate]

Yes the charts are promising but away from the scottish highlands and north sea facing coasts it will be essentially dry.

 

 

This could very well be a 2/3 day northerly toppler, which I'm pretty sure is about to come on this run so caution will be very well advised at this stage.

[Ali1977]

Tomorrows ECM as well as tonight's UKMO will be interesting, they seam slightly more severe in terms of cold and to be honest sound more in line with the METO medium range. This place could be V busy if they are the same as today, around 20 pages today and still 600 people at 2250

[Harsh Climate]

Even looking at this chart which you would think would be bitterly cold

 

 

Uppers of only -4, not really conductive to low lying snow in this set-up.

 

[Eugene]

Yes the charts are promising but away from the scottish highlands and north sea facing coasts it will be essentially dry.

 

 

This could very well be a 2/3 day northerly toppler, which I'm pretty sure is about to come on this run so caution will be very well advised at this stage.

 

Yeah thats how i see it, not sure where people are getting very wet for the south from, thats not what you get from Arctic Northerlies, most people will get beautifully crisp clear blue skies.

[ukpaul]

Are you ignoring the low thicknesses because they will certainly help matters in that respect.

Can't yet see the figures for the 18z but wet bulb fl temps were fine throughout most of the latter part of next week, along with dewpoints even though 850s were higher than might otherwise be needed, rising up to -4 at times. 850s alone are a poor predictor of snow potential.

Edited January 24, 2015 by ukpaul

[alex12]

Tomorrows ECM as well as tonight's UKMO will be interesting, they seam slightly more severe in terms of cold and to be honest sound more in line with the METO medium range. This place could be V busy if they are the same as today, around 20 pages today and still 600 people at 2250

 

What time does the UKMO come out? 

[Mucka]

What time does the UKMO come out? 

 

4 AM

 

I'm not going to get involved but some odd comments re the output IMO. (not you)

Edited January 24, 2015 by Mucka

[Ali1977]

What time does the UKMO come out?

About 0330....

[Kentish Snowman in Yorks]

I'm just astounded by the negativity of some on here today and tonight!

What are people expecting from this setup? We are a tiny island surrounded by a relatively warm ocean.

-15 uppers and drifting snow from a deep sourced Northeasterly ain't gonna happen every winter! Would people prefer we are staring down the barrel of a long fetch Southwesterly Bartlett setup until May?!

I just wish some on here could accept that it is turning much colder and there is potential in the charts (even the 18z GFS 'rainfest') for for some falling and yes settling snow for a significant proportion of the UK population.

I would go as far as to say the upcoming cold spell looks more potent than anything we have seen for a couple of years, and in my opinion could develop into a significant pattern change.

I am very confident of seeing some snow over the next 7 days and who knows we may even (say it quietly) see some genuine northern blocking being modelled in the charts over the next couple of days.

Apologies for the rant but I just needed to get that off my chest!

[alex12]

About 0330....

I'll wait till the morning for that one!! I keep asking in here for the times! How do I find them on the forum

[LomondSnowstorm]

I think it's a bit odd to be both cautioning against buying into the current outlook while simultaneously taking the less cold upper air temperature projections from the GFS at face value at the same range. Even over the course of 18 hours we've seen the GFS upgrade the upper air temperatures by about 2C for Friday, for example:

 

 

Now, these still aren't that impressive at face value, but a few other things to note:

1) the euros have a cleaner Arctic source and therefore the upper air temperatures from Thursday onwards are a notch lower

2) you don't need as cold upper air temperatures with SLP of 980mb as you do with SLP of, say, 1030mb, and similarly with a slack flow you don't need to be pulling in as cold uppers as you would with gale force winds as we had in early January, so at the surface, while the Friday midday chart doesn't look all that great, at the surface it still looks like it does the job:

 

Now there are some warm sectors in this run when secondary features move south which do turn snow to rain, and that's definitely an issue, but for now we're looking at some of the best runs of the winter, a spell which over the last 4 days has upgraded from a vague possibility to something which looks like at least a 5/6 day cold spell, and potentially more if we can get slightly more amplification upstream (something which doesn't look too outlandish given the monster cold heading for the eastern US early February). Let's just enjoy the fact that we have this at +168:

rather than endless zonality.

 

 

Also worth mentioning this chart:

 

Incredibly rare to see -8C uppers into Scotland off a straight westerly and with such low heights there's potential for some big snowfall totals for large swathes of not just Scotland but also Northern England, Ireland, Wales, the Midlands, even into Southern England.

Edited January 24, 2015 by LomondSnowstorm

[Harsh Climate]

Yeah thats how i see it, not sure where people are getting very wet for the south from, thats not what you get from Arctic Northerlies, most people will get beautifully crisp clear blue skies.

 

Yes, too right. I see people cherry picking a few charts from +180 hours showing kinks and possible disturbances giving POTENTIAL snowfall, but experience tells us that atleast 9/10 northerlies are bone dry away from the favoured areas (scottish highlands/north sea coasts.)

 

The only exceptions I have seen to this rule is when you get those magical -10 uppers right down the UK, I find with these colder uppers blowing down our relatively warm north sea really does boost convection towards the coast (with a greater risk of a few making it inland), at this point the temperature and dew points are that low, you only need to catch one or two rogue showers and you get instant accumulations, with no melt in between.

[Mucka]

I'll wait till the morning for that one!! I keep asking in here for the times! How do I find them on the forum

 

UKMO 4 AM, 4 PM

GFS 4AM, 10 AM, 4PM, 10PM

ECM 6AM, 6PM

 

Take notes. 

Edited January 24, 2015 by Mucka

[Gael_Force]

How does my post contradict what the charts are showing I just posted a chart showing -4 850's which will equate to cold rain for 99% of the pop of uk!! Nowhere in the entire 18z gfs run up to 180 does the temp get below -6 850's which from a maritime source will not deliver snow for lowland uk. 18z in high res is not a cold run!! In fact none of the model output is particularly snowy for the lowland uk. Im not saying it wont change but as it stands it isnt a snowy picture. 

 

Staggering cold into the CONUS http://modeles.meteociel.fr/modeles/gfs/runs/2015012418/gfsnh-1-210.png?18!!! -32 850's that is killer cold usually reserved for eastern siberia. Dont think ive ever seen that before such cold at such a low latitude. A true Continental Climate!!

 

There is even a -40c 850 temp just north of the Great Lakes area. They'll not need to quibble about thickness, dew points and marginality.

 

[Geordiesnow]

How does my post contradict what the charts are showing I just posted a chart showing -4 850's which will equate to cold rain for 99% of the pop of uk!! Nowhere in the entire 18z gfs run up to 180 does the temp get below -6 850's which from a maritime source will not deliver snow for lowland uk. 18z in high res is not a cold run!! In fact none of the model output is particularly snowy for the lowland uk. Im not saying it wont change but as it stands it isnt a snowy picture. 

 

Staggering cold into the CONUS http://modeles.meteociel.fr/modeles/gfs/runs/2015012418/gfsnh-1-210.png?18!!! -32 850's that is killer cold usually reserved for eastern siberia. Dont think ive ever seen that before such cold at such a low latitude. A true Continental Climate!!

 

The initial WNW'ly looks pretty potent too me and with those low thicknesses there is bound to be snowfall away from areas that are close to the Coast, of course the flow gets more modified as mild sectors come into play but Wednesday into Thursday has certainly got potential too see lying snow quite widely across Ireland/Northern Ireland, South and Western parts of Scotland, Wales, and parts of NW England. 

 

I got to say, the GFS evolution is different to the UKMO/ECM so i'm a little skeptical at this moment in time with what its showing and in all fairness, I probably would prefer the UKMO/ECM set ups, looks safer too me than the messy GFS! 

 

What happens after that will probably depend on how much of an Atlantic ridge we get, it would be nice to get a true Northerly so we can tap into that more significant colder air, no doubt tomorrow runs will give another day of drama. 

[Captain Shortwave]

Day 6 charts for this afternoon/evening

GFS

 

UKMO

ECM

GEM

 

The GFS looks by far the messiest out of the four outputs and hence the more modified 850s (ignoring the GEM's issues). 

 

Anyway over the past 36 hours, we have seen the colder spell brought forward from Friday to Wednesday afternoon, given the faster route to deepen the Euro trough which was a recent development. Beyond that we can only go with looking at how the trough aligns itself and making sure we are far enough west of the centre of the low surface heights to allow a colder north/north westerly to develop. At this point I think we have achieved this, the ECM has moved to a better solution today, whilst the UKMO and GEM look good to a certain point. We can't predict where and when places could get snow but I would be surprised given the deep Euro troughing that we would get a series of troughs or even secondary lows forming within the western flank of the trough which would move southwards and bring a widespread snow event. No point going on about the detail just yet (though those in the west may only have to wait until later on Wednesday to start filling their boots).