Cold hunt - models and chat

[Summer Sun]

Just now, Jackski4 said:

Are the UKMO precipitation charts out yet for Tuesday?

Not yet. Pop back in about 25 minutes

[Dean E]

1 minute ago, Mike Poole said:

Well by T234 on GFS all hell seems to have broken loose as far as the northern hemisphere is concerned, 850s still modest for us at the moment, but I'm liking this run.

Am liking the continued hint from the GFS of the Canadian vortex moving away. Clearly this winter hasn't turned out as many thought, mainly due to part of the vortex sitting there.

Shift it and we may become more favourable towards NHB, something the GFS FI is suggesting recently.

[kold weather]

GEM is somewhere in the middle of the pack, its not as far north with the frontal zone on Friday as the GFS OP is, but still looks JUST on the wrong side of marginal for south of M4 brigade. Timing is poor as well, could do with it arriving either side of when it actually does as that would extend the snow time.

Still no real sense of agreement though is there!

[northwestsnow]

1 minute ago, kold weather said:

GEM is somewhere in the middle of the pack, its not as far north with the frontal zone on Friday as the GFS OP is, but still looks JUST on the wrong side of marginal for south of M4 brigade. Timing is poor as well, could do with it arriving either side of when it actually does as that would extend the snow time.

Still no real sense of agreement though is there!

Nothing is straightfoward!!

No agreement at 96 although GFS/UKMO look a decent match at 72..to me anyway..

[ghrud]

5 minutes ago, Deep Snow please said:

-3236 uppers over the north pole on chart 2. Another ice age?

I think there might be a minus sign hiding under the snow somewhere!

 

[kold weather]

GFSP running the system similarly to the GFS OP. Also has a very similar frontal distribution as well for Tuesday, so it feels like we are broadly getting agreement on at least the frontal aspect of the low.

[snowray]

T48 Fax chart out, looking rock solid there, 10/10 for consistency. 

[Mike Poole]

The tortured death throes of the polar vortex:

I like watching the eyes!

Edited January 27, 2019 by Mike Poole

[offerman]

1 minute ago, Mike Poole said:

The tortured death throes of the polar vortex:

I like watching the eyes!

While of northern heinsophere on our latitude in deep cold bar uk. Typical . 

Even below our latitude across is pretty cold too. 

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

The fabled f-shaped euro high

Can f-off

[Ice Day]

Looking at the GFS op, I think it's fairly safe to say that there's going to be some outlandish FI options on offer this evening!

Onto the GFSP and the precip charts for Monday evening look good for Ireland, Wales, NW England, West Midlands and most of the SW (although rush hour could be a bit tricky!).  The South and East get into the action late evening

 

 

[kold weather]

Yep Iceday, although verbatim that run can do one, slight weakening of the front goes right over my location with little snow. Ah well I won't be losing any sleep over that

Anyway ensembles coming out, I'll be back soon after looking at them. Wonder what fun we will have in store this time!

[Guest]

3 minutes ago, RAIN RAIN RAIN said:

The fabled f-shaped euro high

Can f-off

Yes a disappointing end to the 12z but the general pattern evolving in the mid-term is a positive change from the 06z at least. Not to be taken too seriously yet, but tentative steps forward if we're looking towards a cold February.

Edited January 27, 2019 by Liima

[Penicuikblizzard]

51 minutes ago, MKN said:

So the most likely outcome next week. Tuesday's low to far south for any meaningful snowfall. Thursday's low to far north bringing rain to many. 

Snow for many in the North though on Thursday

[Methuselah]

6 minutes ago, Mike Poole said:

The tortured death throes of the polar vortex:

I like watching the eyes!

Well it's been through quite a few small, furry animals (at least one wabbit and two Scrappy Doos, so far) to get there...?

[SMU]

At this stage Thursdays snow is unlikely to reach The North Midlands !

Anyway last 3 GFS P for thurs 1pm

starting 144 2 days ago 120 1 day ago then todays 96

A firm move to the UKMO which was a firm move west...

GFS eastward bias showing again...

[shaky]

4 minutes ago, Steve Murr said:

At this stage Thursdays snow is unlikely to reach The North Midlands !

Anyway last 3 GFS P for thurs 1pm

starting 144 2 days ago 120 1 day ago then todays 96

A firm move to the UKMO which was a firm move west...

GFS eastward bias showing again...

Yup and this run gives snowfall more widely across england thursday before pushing east!!

[Lampostwatcher]

fax t48 looks great for tues for most

thursdays low more so south of manchester

very interesting lampost watching period

coming up

[snowice]

Country file forcast not sure on the position of the low at + 96, so that tells me FI is 72,  Drama on the models this week! 

[JeffC]

1 hour ago, WhiteFox said:

This is a key point. We are well aware that a small difference in data has a huge impact on the SLP further down the line; even without an SSW we often see big variations because of chaos theory.

Now, throw into the mix a downwelling SSW which has caused forecasting issues in the upper atmosphere. What you get is an even greater level of error as you progress through time on an NWP model.

What are we seeing at day 8 on the ECM? Something that is very different from what was shown on the day 10 two days ago. 

We do not know what the Met Office are seeing in their models, but they clearly have an indication that either the Arctic profile will shift towards blocking in our part of the world, and/or tropical forcing helping this along. As with all medium to longer term forecasts, this is based on an element of probability and no doubt there is still a probability that we will not see the cold outcome.

There is absolutely nothing run with commenting on models and their output, but it is very clear that solutions are subject to large amounts of uncertainty beyond four or five days. If the Met Office and those of us who have/are saying that there is still a good chance of a colder outbreak are wrong, then so be it. However, it is all about learning where we went wrong this time and incorporating the lessons into future forecasts. That is science, and that is how we make progress...

Absolutely agree, but it's how the results of what verifies vs the previous expectations are entered into the algorithms, and also how quickly so the benefit can be gained in terms of improved forecast vs verification stats...

[Summer Sun]

UKMO precip charts now updated

Tuesday and into Wednesday

Thursday & Friday

Edited January 27, 2019 by Summer Sun

[shaky]

3 minutes ago, Summer Sun said:

UKMO precip charts now updated

Tuesday and into Wednesday

Thursday & Friday

Seems so light compared to gfs!!wonder why that is??

[Mark wheeler]

3 minutes ago, swfc said:

Country file shows snow Tuesday then dry most of the week.cold tho before turning milder temporary

Should I ring weathercall and see what they say

[Lampostwatcher]

Just now, shaky said:

Seems so light compared to gfs!!wonder why that is??

doesnt in the SE

[Ice Day]

The GFSP at 168 is going the same way as the Op with heights raising towards Greenland and the Canadian vortex shrivelling like a salted snail.