Model output discussion - The run up to Christmas

[KTtom]

6 minutes ago, Kasim Awan said:

ECM has a muchhh flatter Greenland ridge. As explained this is a positive, allows for a build in low heights to our east. Please don't misinterpret this as a negative. It is actually a potential route to prolonging cold.

Yes, a move away from a potential Greenland High, but the all important  Mid Atlantic ridge looks solid and likely to ridge north again around New Year. Also interesting to see features meandering around the trough over the UK at the end of the year...snow chances increasing...

Still can't see where the Met are getting high pressure over the UK from?

 

[Cheshire Freeze]

ECM D10 trop vortex looks more like something you'd see in April rather than December/January...and that is really not a bad thing!

Edited December 21, 2020 by CreweCold

[Kasim Awan]

3 minutes ago, KTtom said:

Yes, a move away from a potential Greenland High, but the all important  Mid Atlantic ridge looks solid and likely to ridge north again around New Year. Also interesting to see features meandering around the trough over the UK at the end of the year...snow chances increasing...

Still can't see where the Met are getting high pressure over the UK from?

 

The ECM provides an ideal set up for continued bouts of meridional amplification following trough disruption around southern GL. Other output i.e. GFS keeps us looking to the NE instead. 

Anyway, that'll be all from me this AM.

[IDO]

It is rare, of late, to see such a consistent signal from the gefs for a sustained cooling down:

London 0z: 

No extreme temp profile but a consistent upper flow 3-5c below average. Should feel very seasonal.

Looking at my road map, it still remains variable as to post Atlantic ridge (2) after d8. An Atlantic high seems the fav rather than a full-on Atlantic ridge as per 18z. Then the d11 high from the conus, how does that react with the Atlantic sector? After that, the 0z run has a hiatus, and the HP train from the west quietens, so if we get a good setup by post-d12 our region will be relatively stalled.

d8-16 gfs 0z> 

gefs has of course varied cluster solutions so more clarification needed.

[swfc]

Morning. Good start to the day all round imo. Getting some decent cold to our east going forward would be very beneficial. Looks like a slow burner here going into the new year but looking at the tpv and warming in the strat could be an exciting few weeks coming up

[sheikhy]

Fantastic output this morning!!!ukmo decides to join in yeh!!bout time fellla!!

[Sky Full]

Here is the current GFS evolution from the 29th December to the 6th January.....

                         500s.                                                        850s

  

That Atlantic ridge allows the colder uppers to remain in place over the UK for a full week, but it just seems unlikely to me that it will be able to maintain that position for seven days on the trot.  It will be interesting to see whether reality is anything like this......not long to wait!

[Met4Cast]

10 hours ago, Met4Cast said:

A true Greenland high isn't supported by the EPS, GEFS or the background signals, MJO isn't supportive of a Greenland high. The UKMO doesn't even have a Greenland high, in actual fact it's likely the low over Canada would move eastwards cutting the very weak link on the next frame as that's where energy is heading at 144.

 < This isn't supported.

 What IS supported within the EPS & GEFS & UKMO is an Atlantic ridge that temporarily extends up into S Greenland before "toppling" to a N Atlantic ridge. There's no doubting it's going to turn colder, and I agree with you that these things usually shift eastwards as the time-frame nears, indeed we're already seeing the ensemble means further east with the low than the det runs.

The GEM is pretty much bang on with how I think the pattern will evolve.

 < Brief riding up to S Greenland, a more direct northerly, GEM bang in-line with the GEFS/EPS means.

 < Block unsustained, too much residual vorticity over Canada for the block to build into Greenland. 

What we're left with is a northerly blast, colder than current modelling suggests though likely nothing "exceptional' with a snow risk primarily across N hills, but depending on small bumps in the flow/shortwaves perhaps a more widespread threat, but not worth looking at those sorts of details at this range. 

A period of below average temps xmas > new year with a risk of snow, probably a few surprises given we do see a slightly cooler airflow than currently modelled. I wouldn't be surprised to see the signal for the high to topple over the UK to grow given the signal from GLOSEA favouring HP over the UK into January, GLOSEA did exceptionally well with the call for milder weather during the middle part of this month, was one of the first model to switch to that idea I believe.

On-going strat disruption and hopefully low heights into Europe mean the chances of mild weather are low into Jan, and with a potential SSW early-mid January the rest of winter is all to play for. 

(Not sure what going on with the forum, but for some reason my post is at the top of the page in red? I assume that'll be removed because I'm not a king, so I'll repost it)

It looks like the GFS & ECM has now done exactly what I said it would do. No Greenland high but rather a brief ridge up to S Greenland.

Decent runs this morning, pretty much exactly the position we want to see that low.

Edited December 21, 2020 by Paul

[mountain shadow]

The broad scale synoptic pattern does look good, but I remain concerned about the lack of proper cold air.

I guess we'll know in a week whether it's snow or cold rain.

[AdrianHull]

38 minutes ago, Met4Cast said:

It looks like the GFS & ECM has now done exactly what I said it would do. No Greenland high but rather a brief ridge up to S Greenland.

Decent runs this morning, pretty much exactly the position we want to see that low.

But this is a day 10 chart so it's not exactly what it's going to do... Bit misleading....

Edited December 21, 2020 by Paul

[BLAST FROM THE PAST]

15 minutes ago, sheikhy said:

Fantastic output this morning!!!ukmo decides to join in yeh!!bout time fellla!!

It hasn’t only just joined, just that the plunging N /S LP and ridge to west is now in it’s range. You could see it was heading that way

 

BFTP

[Penicuikblizzard]

39 minutes ago, Met4Cast said:

It looks like the GFS & ECM has now done exactly what I said it would do. No Greenland high but rather a brief ridge up to S Greenland.

Decent runs this morning, pretty much exactly the position we want to see that low.

Miles away and very likely to change in that time scale 

Edited December 21, 2020 by Paul

[Met4Cast]

4 minutes ago, AdrianHull said:

But this is a day 10 chart so it's not exactly what it's going to do... Bit misleading....

Hardly, I said the Greenland high wasn't supported but rather a mid-Atlantic high with a brief ridge to S Greenland was the most likely option and that's exactly what the UKMO, ECM & GFS is showing. 

Obviously the details will chop and change in terms of exact positioning, but the broad-scale pattern looks about right to me now & is well backed by the ensembles.

Edited December 21, 2020 by Met4Cast

[Osbourne One-Nil]

Stop the sniping or the biting back. If you're being baited, report it to a moderator, if you have a problem, report it to a moderator. 

[BLAST FROM THE PAST]

7 minutes ago, mountain shadow said:

The broad scale synoptic pattern does look good, but I remain concerned about the lack of proper cold air.

I guess we'll know in a week whether it's snow or cold rain.

It’s raining outside now and the rain feels cold.  So it’s likely to be ‘very cold rain’ or snow?

BFTP

[Weathizard]

Sensational ECM mean

[AdrianHull]

7 minutes ago, Met4Cast said:

Hardly, I said the Greenland high wasn't supported but rather a mid-Atlantic ridge with a brief ridge to S Greenland was the most likely option and that's exactly what the UKMO, ECM & GFS is showing. 

Obviously the details will chop and change in terms of exact positioning, but the broad-scale pattern looks about right to me now & is well backed by the ensembles.

There is no point looking at the finer details this far out and you shouldn't treat the ensembles as gospel. They are a guide...

Personally I think you're right but I know from experience we could be baking in an Azores high this far out so I would never call it.

Focus on the day five charts and anything else after that as a trend. 

Edited December 21, 2020 by AdrianHull

[Mr Frost]

Morning all!

If you live on the Eastern side of the UK...Christmas Eve might be good for a bit of radar watching! 

Consistent signal at the moment for wintry showers to fairly low levels throughout that day - again North York Moors looks a good spot for snowfall.

Few snapshots from the latest UKV run:

24/12: 12:00

 

24/12: 15:00

 

24/12: 18:00

 

Then into the early hours of Christmas morning...Norfolk area again flagging up - wee risk of a technical White Christmas! 

25/12: 0:00

 

Quite exciting! Subject to change at this range as ever but no matter what happens it will feel very festive/cold for many - Christmas Eve especially! 

All the best to you all. 

Edit: @sheikhy post below...850’s are -7/-8/-9 

Edited December 21, 2020 by Mr Frost

[Skullzrulerz]

What's trying concerning is though that has been some eastward corrections overnight is that it continues to do the same thing in the next few runs meaning we will miss out 

 

[sheikhy]

8 minutes ago, Mr Frost said:

Morning all!

If you live on the Eastern side of the UK...Christmas Eve might be good for a bit of radar watching! 

Consistent signal at the moment for wintry showers to fairly low levels throughout that day - again North York Moors looks a good spot for snowfall.

Few snapshots from the latest UKV run:

24/12: 12:00

 

24/12: 15:00

 

24/12: 18:00

 

Then into the early hours of Christmas morning...Norfolk area again flagging up - wee risk of a technical White Christmas! 

25/12: 0:00

 

Quite exciting! Subject to change at this range as ever but no matter what happens it will feel very festive/cold for many - Christmas Eve especially! 

All the best to you all. 

Whats the 850s looking like mate?

[Jeremy Shockey]

ECM 0z ensemble mean 850s

Another improvement in the ECM 0z ensemble mean this morning after 27th , ( and 24th / 25th still looks tasty too ) 

GFS 0z precipitation charts

Increasing snow chances for the East during Christmas Eve too

Edited December 21, 2020 by Jeremy Shockey

[Kasim Awan]

2 minutes ago, Skullzrulerz said:

What's trying concerning is though that has been some eastward corrections overnight is that it continues to do the same thing in the next few runs meaning we will miss out 

 

Extremely unlikely given the WAA is glued to the lows near Newfoundland. Will keep the strong Mid Atlantic omega ridge well west.

[Tim Bland]

Morning gang. Loving the ECM this morning. Position is obvious subject to massive change but that low / PV ruminants drops 20cm of snow on its way down ️

[iowpompeylee]

18 minutes ago, Mr Frost said:

Morning all!

If you live on the Eastern side of the UK...Christmas Eve might be good for a bit of radar watching! 

Consistent signal at the moment for wintry showers to fairly low levels throughout that day - again North York Moors looks a good spot for snowfall.

Few snapshots from the latest UKV run:

24/12: 12:00

 

24/12: 15:00

 

24/12: 18:00

 

Then into the early hours of Christmas morning...Norfolk area again flagging up - wee risk of a technical White Christmas! 

25/12: 0:00

 

Quite exciting! Subject to change at this range as ever but no matter what happens it will feel very festive/cold for many - Christmas Eve especially! 

All the best to you all. 

Edit: @sheikhy post below...850’s are -7/-8/-9 

Normally in these set ups, those showers will always drift inland, dependent on the wind direction. especially on those cold winds! Maybe the odd streamer chance. Fascinating model watching. 

[Hotspur62]

20 minutes ago, Weathizard said:

Sensational ECM mean

Just a quick one from me.Although I have reasonable knowledge it is nothing like most on here so hence the hypothetical question-To me if that was a 9 day chart it would seem the high in the Atlantic would topple over to the UK as angle looks that way?Is it the high to the East that is stronger that keeps firmly in place or am I totally wrong in that assumption?thanks in advance to anyone.