The hunt for cold - Model discussion (late November)

[Methuselah]

One would think (hope?) that having cold air to both our east and west, ought to presage a better than average winter? Surely we can't stay inside a s**t sandwich for three months?

Edited December 7, 2018 by Ed Stone

[edinburgh_1992]

1 hour ago, swfc said:

-3 AVERAGE IN DECEMBER????

The 30 year mean around the 19th of December looks like -3 to me. 

Edited December 7, 2018 by edinburgh_1992

[Chesil View]

It seems to be coming Increasingly clear that despite what many hoped for namely some widespread worthwhile prechristmas snow fall that the coming winter is much more likely to follow the pattern of most of our winters that have had decent cold and snow and not really get going until the Xmas /new year period at the earliest. We have a great deal to look forward to with many of our more learned members and some members of the meteorological profession itself. GP Mr Hammond. Met office et al giving good reasons why the Atmospheric dynamics are in favour of something interestingly wintry during the timeframe 19th Dec onward.

I know it's an old chestnut but I,m nearly sixty years old and barring 1981 and 2010 all the really cold and snowy episodes I can remember have come in the period from Xmas onwards. Another old chestnut for you and repeated here again because it is true. The coldest winter of the since 1740, namely 1962/63 didn't,t really get into its stride until Christmas yes the first three weeks of December 1962 were cold but cold and quiet not cold and snowy. And the final old chestnut the snowiest winter of the last 223 Years namely 1947 didn't get into its stride properly until 21st of Jan and just days before it had been 14c across Southern England

Remember old chestnuts are old chestnuts because they,re true.

Let's just enjoy the ride.

[feb1991blizzard]

The GEFS 6z though shows why we cant be complacent regarding an SSW.

[ArHu3]

16 minutes ago, feb1991blizzard said:

The GEFS 6z though shows why we cant be complacent regarding an SSW.

Matt Hugo blames the oncoming zonal spell on the pv displacement 

 

De Tweet bekijken van @MattHugo81: https://twitter.com/MattHugo81/status/1071007978990522373?s=09

[BLAST FROM THE PAST]

3 hours ago, feb1991blizzard said:

Am i the only one buzzing in here? i am really happy with the output, i would rather an absolutely blistering spell further down the line than a half baked one now, perhaps its because i only really very fleetingly and usually only for 1 run or 2, actually bought into anything significant in December, January was always the one that was going to bare fruit.

Still time for significant in Dec,  Feb1991, Xmas week (for me and not targeted at my location) still lined up for that (arctic maritime rather than arctic continental)....BUT need Sunday onward to be remain generally on the chilly side rather than mild.  I’m not overly concerned at the moment (and certainly not worried about no deep cold yet) but I hope the block has tad more influence than what GFS etc say...more like UKMO would be plenty suffice in grand scheme of things at this early winter juncture.

 

BFTP

Edited December 7, 2018 by BLAST FROM THE PAST

[Purga]

1 hour ago, winterof79 said:

I have gleaned  enough information via this thread and other sources to hop off my hastily built fence for another memorable winter to unfold.

Major warming around exmas now odds on starting to show on the NWP,and we will be deep into winter as it downwells. A RTR most welcome

Posted this in media thread too from John Hammond

MONDAY 24TH DECEMBER – SUNDAY 6TH JANUARY

Signs of major change

There are signs of more severe cold as we head into the New Year

You’ll have inferred, then, that I am not yet going to commit: Green or White Christmas? It’s simply too far off!

However, there are several reasons within the set-up of the atmosphere this winter that suggest the cold air will be back sooner rather than later. El Nino is one; the cycle of spots on the sun is another even more distant influencer.

Additionally, in the last few weeks I’ve spoken of signs that the usually strong stratospheric westerly winds that circle the Arctic (know as the Polar Vortex) may weaken markedly as December ends. This signal is becoming more ominous. It’s important because it introduces the possibility of a ‘Sudden Stratospheric Warming’ in which the Polar Vortex goes fully into reverse. Ultimately, it was this which led to the severely cold spell that struck the UK late last winter.

From start to finish, this process takes several days, if not weeks, before such a reversal works its way down to ground level. But on balance, there is an increasing chance that cold air will return from the north or the east as we go later through the Christmas period, and more particularly into the New Year.

Exciting times ahead – for the child and the weather enthusiast in all of us! 

 

EDIT

Apologies to Summer Sun didny see you had posted same.

METO are still very much hedging their bets, so despite the encouraging signs, we have been here before a year or two ago when a potential SSW was being flagged.

It came to nothing, so whereas I & most of us would dearly love it to come off, there's a lot of water (literally!) to flow under the bridge yet!

 

Edited December 7, 2018 by Purga

[Mucka]

6 hours ago, Seasonality said:

Worrying about the old soon to be replaced GFS output is akin to complaining about how your old banger keeps breaking down when you have 2 or 3 new reliable cars sat in the garage. Treat the GFS as pure entertainment only, whether that be positive or a horror show. Save the real worry and analysis for UKMO, ECM and the FV3. 

Debatable comment as GFS was always much less keen on an Easterly than the Euros. (overall operationals 00z/12z) but tbf ECM ensembles were never solid by any means and GFS even less willing to show a cold signal.

We always get the NH stats to show ECM is better overall but that difference is not huge and almost negligible when taking about the focus for our small part of the world.

GFS tends to overdo the Atlantic, ECM underdoes it

GFS tends to put too much energy N/NE where there could be a split and ECM too much S/SE but these are generalisations and on any given output the reverse can be true.

I can't count the times GFS has the Atlantic winning while ECM was showing a block winning and we either ended up with a blend or GFS being right.

I think because we have a cold weather bias we cheer on the ECM so when it gets it right and we do get a block GFS was sinking or forcing E it is better remembered than the many times it ended up a blend or worse GFS was right.

I see it like this.

I think if we are looking for a ridge to form then it is likely ECM will pick it up before GFS, but if we are looking for a block to fail it is likely GFS will pick it up before ECM all other output then try to see what a  blend might look like in the output immediately after they diverge.

It easy enough to get our faces covered in egg without dismissing some output while assuming other output will be correct.

 

 

[Frosty.]

In a nutshell, it's a finely balanced outlook, not seeing a full scale unsettled period, there should be some frosty icy nights, especially further e / n...not seeing any mild sw'ly trash which pleases me the most!...I feel it won't take much to tip us into a proper wintry pattern.

[knocker]

1 hour ago, phil nw. said:

You would be very welcome Blue, the more the merrier.

Just to add there is a special discount for those who have been excommunicated or accused of Apostasy.

[Purga]

15 minutes ago, knocker said:

Just to add there is a special discount for those who have been excommunicated or accused of Apostasy.

LOL - do you accept died-in-the-wool, incorrigible coldies into this rarefied and exclusive club perchance?

 

PS: I'm not quite knocking on 70 but not far off!

Edited December 7, 2018 by Purga

[knocker]

4 minutes ago, Purga said:

LOL - do you accept died-in-the-wool, incorrigible coldies into this rarefied and exclusive club perchance?

 

PS: I'm not quite knocking on 70 but not far off!

Completely out of the question. The list of those already banned sine die stretches into the horizon.

[terrier]

Looks like we are now pinning our hopes on a ssw for late December January onwards. But I recall this been progged a few years back. And unfortunately that came to nothing. Now I’m not suggesting this will go the same route. But a ssw doesn’t guarantee us anything for our tiny island. So think its going to part of the fun of the chase. But just because we are hearing the right noises regarding the strat warming let’s try and not throw our toys out the parm if it doesn’t materialise. 

[winterof79]

Might just be me but does this hint at high pressure across  Scandi and Siberia and low pressure running under the block through central and Eastern Europe?

Hence above average precip down Eastern flank of UK.

Picture courtesy of Michael Ventrice

[karyo]

1 minute ago, winterof79 said:

Might just be me but does this hint at high pressure across  Scandi and Siberia and low pressure running under the block through central and Eastern Europe?

Hence above average precip down Eastern flank of UK.

Picture courtesy of Michael Ventrice

I think so as Scandi and Siberia have below normal rainfall. However, the same applies to Iberia and Italy which is not what we want to see.

[winterof79]

17 minutes ago, terrier said:

Looks like we are now pinning our hopes on a ssw for late December January onwards. But I recall this been progged a few years back. And unfortunately that came to nothing. Now I’m not suggesting this will go the same route. But a ssw doesn’t guarantee us anything for our tiny island. So think its going to part of the fun of the chase. But just because we are hearing the right noises regarding the strat warming let’s try and not throw our toys out the parm if it doesn’t materialise. 

Or we could look on the positive side and realise we got a bullseye after the last SSW in Feb 

Here are before and after stills 

After

Before

Edited December 7, 2018 by winterof79

[MattStoke]

While a SSW doesn’t guarantee cold for the UK (around 70% of the time it does bring cold), a lot points to blocking in January and February being favourably positioned for the UK. A lot to be positive about. A winter of patience but hopefully  with rich reward.

Edited December 7, 2018 by MattStoke

[Iceaxecrampon]

2 hours ago, Broadmayne blizzard said:

It seems to be coming Increasingly clear that despite what many hoped for namely some widespread worthwhile prechristmas snow fall that the coming winter is much more likely to follow the pattern of most of our winters that have had decent cold and snow and not really get going until the Xmas /new year period at the earliest. We have a great deal to look forward to with many of our more learned members and some members of the meteorological profession itself. GP Mr Hammond. Met office et al giving good reasons why the Atmospheric dynamics are in favour of something interestingly wintry during the timeframe 19th Dec onward.

I know it's an old chestnut but I,m nearly sixty years old and barring 1981 and 2010 all the really cold and snowy episodes I can remember have come in the period from Xmas onwards. Another old chestnut for you and repeated here again because it is true. The coldest winter of the since 1740, namely 1962/63 didn't,t really get into its stride until Christmas yes the first three weeks of December 1962 were cold but cold and quiet not cold and snowy. And the final old chestnut the snowiest winter of the last 223 Years namely 1947 didn't get into its stride properly until 21st of Jan and just days before it had been 14c across Southern England

Remember old chestnuts are old chestnuts because they,re true.

Let's just enjoy the ride.

 Cumbrian snowfall is charted at its most in February - I have charts courtesy of the Mountain rescue teams - somewhere on old fashioned paper pre internet.

 

[swfc]

Better ridging from icon at the 130 hr mark .may not alter the earlier outcome on the models but its there

[booferking]

3 minutes ago, swfc said:

Better ridging from icon at the 130 hr mark .may not alter the earlier outcome on the models but its there

Yea it's clearing sending more energy under but might not mean much in the grand scheme of things. 

Edited December 7, 2018 by booferking

[stodge]

5 minutes ago, booferking said:

Yea it's clearing sending more energy under but might not mean much in the grand scheme of things. 

Yes but the longer the ridge persists over Scandinavia the more the energy off the Atlantic will be drawn SE through the British Isles into Europe which keeps us in colder PM air and offers some snow possibilities for Scotland as LP swing SE through central Britain and into the Low Countries.

[booferking]

Just now, stodge said:

Yes but the longer the ridge persists over Scandinavia the more the energy off the Atlantic will be drawn SE through the British Isles into Europe which keeps us in colder PM air and offers some snow possibilities for Scotland as LP swing SE through central Britain and into the Low Countries.

Yep to all of the above but iv moved on from this failed easterly looking something more nationwide and end of Dec is without interest..

[Seasonality]

2 hours ago, Mucka said:

Debatable comment as GFS was always much less keen on an Easterly than the Euros. (overall operationals 00z/12z) but tbf ECM ensembles were never solid by any means and GFS even less willing to show a cold signal.

We always get the NH stats to show ECM is better overall but that difference is not huge and almost negligible when taking about the focus for our small part of the world.

GFS tends to overdo the Atlantic, ECM underdoes it

GFS tends to put too much energy N/NE where there could be a split and ECM too much S/SE but these are generalisations and on any given output the reverse can be true.

I can't count the times GFS has the Atlantic winning while ECM was showing a block winning and we either ended up with a blend or GFS being right.

I think because we have a cold weather bias we cheer on the ECM so when it gets it right and we do get a block GFS was sinking or forcing E it is better remembered than the many times it ended up a blend or worse GFS was right.

I see it like this.

I think if we are looking for a ridge to form then it is likely ECM will pick it up before GFS, but if we are looking for a block to fail it is likely GFS will pick it up before ECM all other output then try to see what a  blend might look like in the output immediately after they diverge.

It easy enough to get our faces covered in egg without dismissing some output while assuming other output will be correct.

 

 

To be fair, I did go on to say use the the new GFS, aka the FV3, I just don't see any point using the old one anymore to be precise. You make some good points about using various models to take into account their biases and thats exactly why I said to use the UKMO, ECM and the FV3 (new GFS) in my original post. 

[Mucka]

15 minutes ago, Seasonality said:

To be fair, I did go on to say use the the new GFS, aka the FV3, I just don't see any point using the old one anymore to be precise. You make some good points about using various models to take into account their biases and thats exactly why I said to use the UKMO, ECM and the FV3 (new GFS) in my original post. 

Yes that is fair, not sure why I missed that reference to FV3. Sorry about that.

[Mucka]

 

GFS in its early stages a fair bit better than any of its other runs recently, unlikely to be enough though. But nice to see the block fighting back?

UKMO 144

Edited December 7, 2018 by Mucka