Model Output Discussion - Into Winter

[bluearmy]

1 hour ago, mountain shadow said:

That was exactly my thinking too. 

The ECM Op has consistently underplayed the ridge.

And it could be said that the gfs has generally overplayed it. (How times have changed!)

this upcoming trough is down to tpv movement rather than ridging. Just as we squeezed more out of early dec than looked possible in the weeks before, so we may well do likewise in the run up to Xmas with the sceuro trough.  But todays runs are definitely drifting towards yesterdays more nw/se gem solution.  gfs has lost its weaker NH profile late on due to events higher up which are likely flushing down the last knocking of mobility to the trop. but that’s a story for the strat thread whilst it’s only gfs op on that page with such extremity. 
 

beyond the troughing remains ‘up in the air’ …….. all suites bring back euro high anoms. Could be that we stay cool zonal for Xmas to new year period.  the tpv retains its desire to hang onto n Greenland 

Edited December 14, 2023 by bluearmy

[Nick F]

4 hours ago, Ali1977 said:

528 cleared the U.K., cold dew points, severe wind chill - charts for the end of next week off this run - just one run but pretty mad!! 
Oh and 100 mph winds from Greenland 

Looks pretty wild for a week's time on 00z GFS and EC, very strong northwesterly jet stream could spawn one or two deep lows late next week onwards. GFS and EC show a deepening low moving southeast from Greenland towards Scotland next Thursday, air becoming cold enough for snow in the north, so could be blizzards given the wind speeds both show. 

EC

GFS

 

 

Edited December 14, 2023 by Nick F

[carinthian]

5 minutes ago, BartyHater said:

Whilst not a perfect match the differences between ECM and UKMO are relatively small at 168hrs, so unfortunately I can see no good reason for the latter to go in a different direction to the former….if it extended to 240hrs of course.

Of course 10 days is far out. However, the real point I was making is the potential for powerful winds to develop rather rapidly with-in this type of low formation as previously explained in the earlier post.

C

[sundog]

What looks like happening next week  reminds me a bit of around the  20th Dec 91. Briefly cold for a day or 2. Think that was the only time I saw a few snow showers that winter. 

[johncam]

Just now, sundog said:

What looks like happening next week  reminds me a bit of around the  20th Dec 91. Briefly cold for a day or 2. Think that was the only time I saw a few snow showers that winter. 

They way it's going be lucky to see a frost in the next two weeks 

[Vikos]

32 minutes ago, Nick F said:

Think many on here will disagree with regards to the UK, many saw snow last week, while around 11th/12th Dec 2022 it snowed a lot in places, and Dec 2022 was below average. For Germany in your location, there's been cold and snow this December, e.g, Munich 40cm of snow.

 

If I say that it was an cold interlude will you agree? Happens in every mild winter for a couple of days…

here, in Germany, it’s all flushed away, even in priorized areas. In my town, the snow lasted for 12 hours and was gone by noon  

[TSNWK]

So  unless you're a goat up a hill in the north..  this chase for end of next week is a dud.. 

Where to now gang?

 

[Lukesluckybunch]

Let's see if in the 6z we can try and develop some proper heights out west toward greenland rather then Atlantic ridge that is just likely to topple after a few days of cold..the long range outlooks don't currently support anything cold and prolonged.

[TSNWK]

Just now, Lukesluckybunch said:

Let's see if in the 6z we can try and develop some proper heights out west toward greenland rather then Atlantic ridge that is just likely to topple after a few days of cold..the long range outlooks don't currently support anything cold and prolonged.

Looks a long shot matey... jet is so powerful and the jet is usually well modeled at long-time frames.

[Lukesluckybunch]

2 minutes ago, TSNWK said:

Looks a long shot matey... jet is so powerful and the jet is usually well modeled at long-time frames.

2 minutes ago, TSNWK said:

Looks a long shot matey... jet is so powerful and the jet is usually well modeled at long-time frames.

Right I see ,I'm no expert here,I just try to keep things simple..so what your trying to say is there's too much energy around greenland?

[weathercold]

Morning, as expected 24 hours on any cold/wintry looking charts seems to be reducing rapidly.

Whilst not wanting to be that person who said ‘told you so’ I really couldn’t see the over egging optimism of some yesterday.

There is no concrete support for anything wintry for most of the UK, in fact quite the opposite. I’m not even confident hills up north will see much if anything over the Xmas period.

A chilly few days possible, nothing more than that and temps around average for Dec UK wide.

Some calling a cold and wintry Jan are making a brave call, fair play if correct. I’m not seeing much evidence to support this currently. 
 

Taking into account all available info, it’s looking very Atlantic driven through to the end of the month. A rather mild and wet Xmas period is a sound punt right now.

WC

[Jordan S]

I understand there has been slight disappointment from a few from some not so cold model outputs over the last few days, taking a look back to my last post

Of course when a possible forecast looks like flopping completely according to model charts, even when I know that the overall signal is rather similar and backs up my post forecast, and have faith the models will “catch” up, it does still make you sweat slightly.

A few things haven’t changed likelihood since my last post and that will be mentioned below..

There are 2 changes at least aswell to note in comparison to my previous post…

What hasn’t changed…

northerly component to the wind between 20-24th overall but overall northwesterly, wintry showers still likely for parts of the north for a time and even further south over Wales , central and northern England for example some snow possible especially high ground.

Stormy potential though just before Christmas for north in particular, northwesterly wind gusts could reach 80-90mph for some exposed locations..

What has also changed..

For Christmas itself and beyond to new year there is a fair amount of change in comparison to my previous post, although there is still likely to be snow showers in the north at times and wintry showers in the south at times is possible in clearer intervals between weather systems, it looks like snow will now be mainly for high ground more often than not and while unsettled is more likely still overall, it is now more likely to be of a slightly milder variety for the most part at the end of December particularly the south and southwest of the UK over Christmas itself with a dominant high pressure to our south at times.

What does remain a risk as demonstrated by the Gfs recently too at Christmas and beyond is the risk of any more prolonged precipitation being significant snow on the northern and eastern part of the fronts in northern areas particularly where a ridge of a high pressure sits over us within a colder northwest airflow preceding it when low pressure systems arrive from the west or northwest. In this case it’s possible this coincides with Christmas Day but some uncertainty.

Gales or even severe gales possible anywhere during last week of December.

 

What has changed.. high more likely centred over Spain through the last week of the year as supposed to the mid Atlantic but it’s important to note that while it may be easy to dismiss the next couple of weeks as mild and cyclonic, it really isn’t as clear cut as that and I expect continue ridging of higher pressure out in the Atlantic between low pressure at times, threatening a return to more blocked and colder weather from the north or east post Christmas and around new year, but that’s fairly low likelihood now.

Overall then temperatures look to be average or slightly above average after Christmas with snow at times in some northern areas most likely and very unsettled. will give an update on that in the next few days.

In the slightly shorter term there is the chance of really significant rainfall for western and northwestern Scotland during the weekend and especially round the Christmas period probably just before Christmas with the potential for 150-200mm isolated possibility of 250mm to fall altogether within a 10day timeframe on some hillier parts in the west/northwest of Scotland causing potential flooding problems sadly. Hopefully less than this will be the reality and given the timescale it could be.

 

Still a potentially colder post Christmas but less likely now than before, less of a blocked month as a whole than perhaps anticipated by me and a few others but it hasn’t erased the chance of more blocked and cold scenarios to end the month yet, I don’t anticipate that the blocking will fade for long periods of time with the tendency for this as well as potentially cold weather and heightened snow risk to increase in early January once again.

 

But before then the year looks to end mild and unsettled for the most part.

Edited December 14, 2023 by Jordan S

[Lukesluckybunch]

4 minutes ago, weathercold said:

Morning, as expected 24 hours on any cold/wintry looking charts seems to be reducing rapidly.

Whilst not wanting to be that person who said ‘told you so’ I really couldn’t see the over egging optimism of some yesterday.

There is no concrete support for anything wintry for most of the UK, in fact quite the opposite. I’m not even confident hills up north will see much if anything over the Xmas period.

A chilly few days possible, nothing more than that and temps around average for Dec UK wide.

Some calling a cold and wintry Jan are making a brave call, fair play if correct. I’m not seeing much evidence to support this currently. 
 

Taking into account all available info, it’s looking very Atlantic driven through to the end of the month. A rather mild and wet Xmas period is a sound punt right now.

WC

Haha the gfs would say otherwise..but as I said without any decent blocking around Greenland,I would agree..sooner or later the Azores high will wake up and ruin the whole lot!

[TSNWK]

4 minutes ago, Lukesluckybunch said:

Right I see ,I'm no expert here,I just try to keep things simple..so what your trying to say is there's too much energy around greenland?

I'm no expert either.  However with such a powerful jet circulating throughout the northern hemisphere at a northley latitude I can't see how any heights that are positioned good for extending the chilly blast into a cold Christmas period can possibly form 

[Lukesluckybunch]

2 minutes ago, TSNWK said:

I'm no expert either.  However with such a powerful jet circulating throughout the northern hemisphere at a northley latitude I can't see how any heights that are positioned good for extending the chilly blast into a cold Christmas period can possibly form 

Yea that's a good point..anyway 6z is around the corner let's hope for the best!

[Alexis]

This was a 1 day event, but still got a good inch in the middle of Christmas Day. Snow events are virtually always a 24h deal when you think about it!

[AO-]

23 minutes ago, TSNWK said:

I'm no expert either.  However with such a powerful jet circulating throughout the northern hemisphere at a northley latitude I can't see how any heights that are positioned good for extending the chilly blast into a cold Christmas period can possibly form 

Maybe with help of background drivers it might end up well. With througs at the right place seemingly impossible charts turn out wintry in just a few days. I think december '78 and '62 show nice examples. Does someone know the current MJO forecast? Is mjo stil forecasted in the COD? 

[northwestsnow]

3 hours ago, Cheshire Freeze said:

One more from me- be wary of assuming a return of Euro heights in FI. We’ll likely see this signal muted as we tick down towards the Christmas-New Year period.

I see nothing to suggest we’ll see any form of sustained Euro heights going forward.

Hmmmmm

The last paragraph I'm afraid all the evidence suggests the complete opposite.

Hope you  are right of course.

[sebastiaan1973]

6 minutes ago, AO- said:

Maybe with help of background drivers it might end up well. With througs at the right place seemingly impossible charts turn out wintry in just a few days. I think december '78 and '62 show nice examples. Does someone know the current MJO forecast? Is mjo stil forecasted in the COD? 

Yep. You can find them here  https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[Ruzzi]

45 minutes ago, weathercold said:

Morning, as expected 24 hours on any cold/wintry looking charts seems to be reducing rapidly.

Whilst not wanting to be that person who said ‘told you so’ I really couldn’t see the over egging optimism of some yesterday.

There is no concrete supijuuport for anything wintry for most of the UK, in fact quite the opposite. I’m not even confident hills up north will see much if anything over the Xmas period.

A chilly few days possible, nothing more than that and temps around average for Dec UK wide.

Some calling a cold and wintry Jan are making a brave call, fair play if correct. I’m not seeing much evidence to support this currently. 
 

Taking into account all available info, it’s looking very Atlantic driven through to the end of the month. A rather mild and wet Xmas period is a sound punt right now.

WC

Why was it expected to reduce 24 hours later? 

And what's all the available info you're referring to for the next 2 and a half weeks to be Atlantic driven? 

[TSNWK]

3 minutes ago, Ruzzi said:

Why was it expected to reduce 24 hours later? 

And what's all the available info you're referring to for the next 2 and a half weeks to be Atlantic driven? 

06z gfs should give a clue on that.. look at jetstream and heights post vortex plunge end of next week

[northwestsnow]

7 minutes ago, Ruzzi said:

Why was it expected to reduce 24 hours later? 

And what's all the available info you're referring to for the next 2 and a half weeks to be Atlantic driven? 

Without any Blocking highs at northerly latitudes polar maritime attacks will almost always end with azores heights ridging into Europe via Spain.

The firm favourite is then an ugly NH profile.

Hopefully background drivers save the day later down the line..

In the meantime I'm hoping for a decent cold blast 

Edited December 14, 2023 by northwestsnow

[Lukesluckybunch]

Day 6 on the 6z there's a slight shift east with the heights,compared to the 0z don't think this will be as good run tbh..probably going to rely on a trigger low for some sort of amplification..let's see how it goes...and here comes that trigger low at 162

Edited December 14, 2023 by Lukesluckybunch
Adding

[TSNWK]

where's the the newfoundland low go? not sure if this bad as nothing to pump up heights or good  as less mess in that local and more room for the heights to get into.

[bluearmy]

Just noticed a new AI model on ec website - fuxi 

it has been verifying notably better than the ec and Google models which were the best performing.