Model output discussion pm 13/01/2016

[Froze were the Days]

11 minutes ago, Minus 10 said:

Look at that cold air now out to the east, will we tap into it???

How earth can we tap into that?...no easterly showing, this is the first post I've looked at today surely we're not still hoping for undercutting? I'm model fatigued.

[gottolovethisweather]

1 hour ago, Mucka said:

Yeah and that is just the upper air, it would still be cold at the surface away from the far NW with night frost.

Indeed the forecast 850s aren't astonishing in truth though. Bar the weekend when parts of the East of England will feel genuinely bitter with Maximum Temperatures around of only 2c or so, especially on Saturday. The main story other than a dying front moving through will be the dry frosty crisp picture, overnight minimums of -10 or lower in some parts.  Come Monday the warming uppers (relatively speaking) very very slowly transfer their way Eastwards to all parts come Thursday. During Monday the only snow-producing 850s left are out towards the North and East of the UK. However, I ask this of you Mucka and perhaps one or two of the more experienced posters in here, am I painting a realistic picture here?

 

The 850s aren't everything, they are simply one of eight suggested requirements needed to guarantee snowfall yet, there is so much hope and excitement at this prospect (which is still 60-72 hours away) which is why I'm not following the hype just yet. Taking the ECM control literally (not a wise thing to do in isolation btw) the -6 850s have vanished from the UK which suggests rain by then but again, am I likely to be correct in my analysis?

 

I am NOT being deliberately unrealistic or realistic here, yet it looks such a difficult forecast ahead, I'd still suggest a slow demise of the cold by mid-week is the main certainty in all of this. Should the snow fall and more appropriately settle during the early part of the week, what with stalling fronts and all that, I guess the inevitable Atlantic breakdown will be a slow-burner itself, a week NOT to be a media forecaster.

 

 

Edited January 15, 2016 by gottolovethisweather

[Day 10]

2 minutes ago, Man With Beard said:

I'd say the T144 chart is a step towards a Scandi influence, though T168 bulldozes through as most previous ECM runs did ... 72 hours earlier. Well, it's failing on that one - another break-off from the Atlantic trough at T168 and that mild spell might be off! So another nail-biting 48 hours to come...

 

Agree totally it looks like a dam of cold air ready to burst over the UK, we just need that trigger low to undercut properly then we really do have winter on our hands, plenty good again tonight.

[mb018538]

I can't see us tapping into any cold either....when the Atlantic eventually wins out it will kick that cold all the way back out to Russia and beyond!

[nick sussex]

The logical conclusion from the vast differences between last nights ECM and tonights is that Alex was skewing the outputs.

Now that Alex is soon to depart the scene perhaps they might actually settle down. In terms of the UKMO although that did lead the way in terms of high pressure holding on to the north its view at T96hrs isn't shared by any of the major players.

Whilst its okay to view its recent T120hrs and T144hrs as going against the others at that range its more believable.

But at T96hrs against the others I think its probably wrong on this one. Its more amplified over the eastern USA and different over Arctic Canada.

Perhaps there might be one last hurrah from it but the odds are stacked against it.

 

[chris55]

6 minutes ago, Froze were the Days said:

How earth can we tap into that?...no easterly showing, this is the first post I've looked at today surely we're not still hoping for undercutting? I'm model fatigued.

Undercutting being upgraded in the short term vs the loger term...... never

[Ali1977]

Is it time to start looking for the next cold spell, been a bit of a damp squib so far for many, especially down South....5-6c daytime temps isn't really that cold nor is -1 to -2c nightime temps.

[chris55]

2 minutes ago, Ali1977 said:

Is it time to start looking for the next cold spell, been a bit of a damp squib so far for many, especially down South....5-6c daytime temps isn't really that cold nor is -1 to -2c nightime temps.

Ill carry on focusing on the current one if thats OK with you Ali. So much uncertainty regarding Sunday and Monday....even Swindon could be in the firing line!

Sit back, and take in all the data, before making to many rash judgements.

[Methuselah]

IMO, if we're to tap into that enormous wodge of cold air, currently languishing tantalizingly close-by to our east, one (or preferably both) of two things must occur first: either pressure falls to our south-east or rises to our north-east; either would increase the likelihood of some sort of easterly flow...Without those, I fear that milder westerlies will slowly creep across all areas??

But then, at the end of the day, with the models in chaos: who knows?

[Day 10]

I don't know how some people can be so confident the Atlantic is on it's way through when we have these selection of charts, the meto aren't even sure so how can we be!

[Captain Shortwave]

So lets compare the day 3 output.

ECM/GFS/UKMO

            

GEM/ARPEGE/JMA

             

 

All show the trough disruption but with various solutions as to how it pans out. The UKMO connects that low to the trough over Scandinavia even by this point which may explain partly why the model looks poorer beyond this point. Otherwise there is good scope for some sort of snow event at the start of next week. Beyond that, do we really want to buy into the thought mild southwesterlies returning?

Or could we see more Atlantic systems disrupting....

The JMA for example gets a second pocket of low heights to slip underneath the ridge.

This keeps the UK cold until the end of the week which is better than the rest of the output.

[Bullseye]

13 minutes ago, Ali1977 said:

Is it time to start looking for the next cold spell, been a bit of a damp squib so far for many, especially down South....5-6c daytime temps isn't really that cold nor is -1 to -2c nightime temps.

Beg to differ, up here in Glasgow we have been hitting 1-3c during day for past 4/5 days maybe more, plus further north and SE Scotland has had days with snow (some unexpected) with likely more to come. Its expected to hit -10/11 tonight up in highlands going by BBC weather. So in all good cold spell up here for past week to 10 days. As you say though maybe disappointing further south so far.

Edited January 15, 2016 by Bullseye

[Man With Beard]

CS - interesting to see complete agreement on the wedge of heights between Iceland and Greenland now. This must be counted as a victory for the UKMO, the only model to go for this time and time again in the last four days. Now will it also be right with keeping heights away from the south throughout the week?

[ANYWEATHER]

4 minutes ago, Nights King said:

That sounds just splendid although for the rest of us with 3 back to back snow-less winters this cold snap is not really up to par currently.. although I will reserve judgement until Monday, 

Please can we stick to model output please , rather than telling folks how much snow or no snow you've had in recent winters in your backyard. Thankyou..... There are other threads for this....

Edited January 15, 2016 by ANYWEATHER

[The PIT]

Well in FI land all models going to for a return to milder weather.  UKMO probably now being the most progressive of the the big three.

[gottolovethisweather]

Anybody got any ideas? This might aid the newbies in their search for snow too, or any other weather which might yet develop next week. It just seems we're all clinging onto the 850s right now, if they were high single-digits or double-digits then I'd be all up for a snowfest, perhaps I'm missing something here. Anyway tis still three days ahead of us yet.

 

 

 

 

 

Edited January 15, 2016 by gottolovethisweather

[Stuie]

2 minutes ago, gottolovethisweather said:

Anybody got any ideas? This might aid the newbies in their search for snow too, or any other weather which might develop next week.

 

 

 

 

Not sure of the question but ideally -8 850`s is required for snow. I know there can be other scenarios but in general that`s what I go by.

[Eskimo]

2 minutes ago, SaffW said:

Not sure of the question but ideally -8 850`s is required for snow. I know there can be other scenarios but in general that`s what I go by.

Depends what situation you're in though. Showers require something around that figure, however prolonged snowfall, especially battleground, only needs 0C. Annoyingly, there's no requisite when it comes to upper air temperatures. 

Edited January 15, 2016 by PerfectStorm

[gottolovethisweather]

Just now, SaffW said:

Not sure of the question but ideally -8 850`s is required for snow. I know there can be other scenarios but in general that`s what I go by.

Yeah I know, SaffW which is why when I looked at -7 850s being forecast at the most extreme end and no more than -5 ahead of the approaching breakdown on Monday, I couldn't understand why expectations were so high, especially from some of our more respected posters. A genuine question and one which when answered I hope will keep the majority in here on the right side of their own expectations. 

[Snowy L]

2 hours ago, CreweCold said:

Because you don't need uppers of -5 with an occluding front and a slight continental undercut. Anything under 0 at the 850 level should suffice- more especially if there's surface cold.

Some of the UK's best snow events have come with uppers above -5

Yep, the 3 best snow events I can remember all came from Atlantic fronts with uppers of between 0 and -2, vitally the wind was coming from the south/south East so cold air from the rest of England was mixing.

 

Funnily enough every time we get a Northwesterly/Northerly with -5 or below uppers the showes always fall as rain or sleet here.

Edited January 15, 2016 by Snowy L

[Hammer]

47 minutes ago, Ali1977 said:

Is it time to start looking for the next cold spell, been a bit of a damp squib so far for many, especially down South....5-6c daytime temps isn't really that cold nor is -1 to -2c nightime temps.

Take a break Ali if that's the case. 

Models are suggesting cold continuing for maybe another week, with still potential for surprise.

[gottolovethisweather]

17 minutes ago, Snowy L said:

Yep, the 3 best snow events I can remember all came from Atlantic fronts with uppers of between 0 and -2, vitally the wind was coming from the south/south East so cold air from the rest of England was mixing.

Ah, yours and Crewe Cold's post which I missed from earlier, in part answers my question above. Thank you. I still say it looks damn borderline and the further East and with elevation on your side you are, the better your chances come the Monday event. Anyway, enough of all that, on with the pub runs before long.

 

Edited January 15, 2016 by gottolovethisweather

[Stuie]

Probably worth a read of this for newer members. (and seasoned!)

http://www.weatherscientific.co.uk/Forecast_Guide_-_Lesson_Two.pdf

[gottolovethisweather]

3 minutes ago, SaffW said:

Probably worth a read of this for newer members. (and seasoned!)

http://www.weatherscientific.co.uk/Forecast_Guide_-_Lesson_Two.pdf

Nice link.

[johnholmes]

13 minutes ago, gottolovethisweather said:

Yeah I know, SaffW which is why when I looked at -7 850s being forecast at the most extreme end and no more than -5 ahead of the approaching breakdown on Monday, I couldn't understand why expectations were so high, especially from some of our more respected posters. A genuine question and one which when answered I hope will keep the majority in here on the right side of their own expectations. 

apologies for quoting this again, it should really be in the other thread but for checking will it snow look at the Guides, it really does work, IF the model has it correctly but best left until no more than 24 hours away and maybe better still at no more than 12 hours away. Remember how hard it is to forecast rain in the right place at the right time and intensity-add 7 more variables and you can see how complex it is!