Model Output Discussion - Into 2024

[Metwatch]

On today's edition of what snow cover does to modelled temperatures:

Edited January 8 by Metwatch

[MJB]

Looks messy against the 6z but a large amount on here would take this run, deep snow and still very cold as the LP whizzes away East

[Zero Visibility]

1 minute ago, Paul_1978 said:

VERY interesting output - as the low approaches from the south-west by T+192, there is clearly a lot of precipitation which could get interesting for many as it bumps into the cold air. THEN as it passes through by T+222 the cold air appears to start to dig back south again. Could be a snow-rain-snow or even a continual snow event for 24/36 hours or more. 

We often talk about showers not cutting the mustard but this could be the holy grail of a frontal snow event. The million dollar question will be where the snow/rain line is and of course there is a long way to go before that is anywhere near being nailed down.

Yes very reminiscent of March 2013, snowed none stop for 30 plus hours here, but the cold was quickly gone and winter ended the day after.

[tight isobar]

Gfs12z absolute snowfest- but drains the cold in stages.. and latter.. some run through on its own elaboration’s!!!- and just another sync on winter Synoptics going forward

Edited January 8 by tight isobar

[frosty ground]

I knew that Azores low was up to no good, crazy run for those in southern England and south wales.

First run I’ve seen the low interact like this so it’s either a trendsetter or outlier.

 

[MATTWOLVES 3]

36 minutes ago, Drifter said:

Is everyone holding their breaths!

High risk high reward in the making..some places could get a pasting.If we want significant widespread snow then we do need an attempt from fronts trying to dislodge that cold..This could be fun.

And remember folks the drivers still favour cold don't be losing your heads at the first sign of a warm up.

And yeh I can hold my breath for a long time.

Edited January 8 by MATTWOLVES 3

[ScottSnow]

Messy setup on the GFS 12z but not unlike some of the ensemble members that we see. Still cold and potentially snowy run and maintains the overall theme.

We are still five days  away from the beginning of the northerly flow so there is going to be some changes from run to run. The theme is the most important thing at this stage.

[Harsh Climate]

All irrelevant now as deep FI but this slider from the NW would bring in more snow.

[rwtwm]

35 minutes ago, Scott Ingham said:

This is very very nearly back to the nirvana charts shown 5/6 days ago and goes to show how it’s important not to be reeled in by mild blips in operational runs when the means were rock solid! 
 

I think disruptive snow is a strong possibility some exciting charts to look at when we get to the back end of this week and we get snow charts in range!

You've been a great contributor in the run up to this spell, but I think this is a bit of a mischaracterization. ECM means for 1am 15th:

240h

216h

192h

168h (This morning)

Until this morning the trend was for the ridge to become less pronounced, and for the core of the cold to move further East. And this is just illustrative. Even though other models had better means more scatter was appearing across all the ensembles. 

I've stayed fairly calm, because I've seen trends like this revert, and I've seen them continue to degrade. I think those that are better at teleconnections can be feeling pretty good, because as I said before, the lower end of the envelope looks like 'underwhelming' rather then 'bust', and the outcomes we're seeing today (though I'm typing this as the 12zs roll out) are back towards the best that we've seen this chase. But that doesn't mean that it was a rogue op run or two that was causing the twitches, and I think the suggestion is unfair on some who have been providing good analysis this weekend based on the genuine breadth of output that existed. 

 

[MidnightSnow]

GFS12z is an absolute snorker

[Malarky]

12 minutes ago, IDO said:

If we are being honest, something close to the GFS is what we want, even if the south has rain to snow.

Getting heavy snow on the ground before the colder air digs in would be ideal, assuming the rest of the run goes to plan!

D9 snow: 

I mean, the southerners have had their slice today, right?! Everybody else’s turn now

[TheJCInsights]

As a north Hampshire southerner, I have my fingers crossed that that low actually is further south so we get the snow not the rain - although over time the GFS usually moves the low south each time doesn't it!

[LetItSnow!]

6 minutes ago, Metwatch said:

On today's edition of what snow cover does to modelled temperatures:

Exactly. Snowfall will make ice days and severely cold nights a bigger possibility. Wouldn't be surprised if some spots with snow cover have temperatures a little lower than forecast due to this.

[ScottSnow]

2 minutes ago, Zero Visibility said:

Yes very reminiscent of March 2013, snowed none stop for 30 plus hours here, but the cold was quickly gone and winter ended the day after.

The cold persisted until early/mid April in 2013. Check the model archives.

There was a big frontal snow event on the 22nd March. The cold won and then persisted until mid April.

You may be thinking of Jan 2013 when after two weeks of snowy weather, the mild air blasted through very quickly.

[MATTWOLVES 3]

13 minutes ago, ICE COLD said:

Lol well over a foot of snow in wide area

Amazing mate..amazing!!

[Froze were the Days]

Strikes me it's still an evolving picture (other than UKMO - steadfast)...Big bulbous vortex over Scandinavia with the coldest north easterlies well to the north and the Am airmass not digging southwards and the dastardly Azores low wanting to make it's presence felt.

As Bluearmy said picking up on a theme at D8/D9 might not be good...lots of wriggle room to go pear shaped for the majority of the UK (gem) or snowy nirvana for the south/central parts (GFS).

[moochops]

There's a lot of model runs to go yet.  All looks promising.  North, south, east or west.  I think everyone is in with a shout at this stage.........

Interesting times.

[sebastiaan1973]

32 minutes ago, Mike Poole said:

UKMO excellent at T168:

Well, we all have our preferences. In my opinion the cold on the eastside of the anticlone will erode  it. Probably the area of low pressure at Scandinavia will push southwest, making it harder (longer way) for cold air to reach NW-Europe. 

Edited January 8 by sebastiaan1973

[Andy8472]

Split anyone?

[The Northern Ramper]

5 minutes ago, frosty ground said:

I knew that Azores low was up to no good, crazy run for those in southern England and south wales.

First run I’ve seen the low interact like this so it’s either a trendsetter or outlier.

 

When we factor in the standard southern corrections of a LP system coming up against a block, it will be lucky to hit Jersey.

[Geordiesnow]

In all honesty, the trend has been clear that we are going to see retrogression of some sorts of high pressure into Greenland which will allow the floodgates to open. What is not clear is just how strong will the floodgates open and that will determine whether we see a snowy northerly or a more tame one with high pressure to close from the west(or maybe even indeed low pressure to close to the SW if not enough cold air makes its way down).

So it did looked like shortwaves could be the spoiler but now looks like shortwaves are becoming less of an issue with recent runs so it's all down to how much ridging we see into Greenland and just how much cold air makes it way south and west. We are getting to the range where the next run will start to become nail biting because some runs will be better than others because the details are far from nailed if albeit a northerly flow of some description looks all but likely.

[keithlucky]

5 hours ago, Jayces said:

Sorry for the OT reply but with regard to sea ice in the Arctic, yes extent is back at long term average levels but that's just one piece of data, the true picture takes into account area, thickness and volume and the last two are both trending at our close to record lows which is a concern.

It's like taking two glasses of water, one with a thin layer of ice covering the top and frozen solid, viewing from the top they both look like the have the same amount of ice but looking at other angles tells a very different story.

Caution advised we normally see adjustment south,so it wouldn't be a surprise if front barely reaches the famous M4 corridor!

[Froze were the Days]

2 minutes ago, Andy8472 said:

Split anyone?

Back to the SSW again? ever since the beginning of December...that certainly waxes and wanes. 

[Penicuikblizzard]

I wouldn’t take GFS as gospel could all change yet again over the next week,, keep your feet on the ground people as there is still a lot time before that low even gets here or takes a widely different path 

[ML1996]

A GFS 12z that is enough to make me crawl out of the woodwork

 

Temperatures as low as -16 being modelled would suggest to me that locally there would be temperatures several degrees lower. Maybe sub -20 celsius in the usual frosty locations? Benson, Newport etc. 

FI I know, but with the scale an instability of cold hopefully heading our way from Scandinavia, I think these sorts of conditions somewhere, at some point, are becoming more likely than they have been at any point during the last few winters. 

Edited January 8 by ML1996