Model output discussion - Closing in on Christmas

[johnholmes]

Last evening I did suggest that if the NOAA 500 mb anomaly showed similar to the last two days then there was a 70-75% probability of meridional being the pattern day 4/5 from now out to day 6 or beyond. This was confirmed by the NOAA chart, see below, and its 8-14 has a not very different view. Not just immediately upwind of the UK but also the far west with the trough-ridge set up. This morning the EC-GFS output is also a similar looking pair of charts. Make of it what you wish. The cold will arrive, how cold, will it snow etc are for the synoptic outputs EC-GFS Met to indicate through this period.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[TSNWK]

11 minutes ago, johnholmes said:

Last evening I did suggest that if the NOAA 500 mb anomaly showed similar to the last two days then there was a 70-75% probability of meridional being the pattern day 4/5 from now out to day 6 or beyond. This was confirmed by the NOAA chart, see below, and its 8-14 has a not very different view. Not just immediately upwind of the UK but also the far west with the trough-ridge set up. This morning the EC-GFS output is also a similar looking pair of charts. Make of it what you wish. The cold will arrive, how cold, will it snow etc are for the synoptic outputs EC-GFS Met to indicate through this period.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

Thank you John. Over the years your analysis has been a reliable source of how things might shape up broadly speaking. As a coldie I take heart in this assessment you've made today. Nothing particularly note worthy just yet but we have an option to buy  tickets for the period post Christmas for now which im  content to do so.  one for 06z please..

Edited December 17, 2020 by TSNWK

[Tim Bland]

15 minutes ago, bluearmy said:

No need to analyse it captain - it ain’t gonna  happen ! 

It must be theoretically possible for the PV to drop over us like that? Otherwise why would any model show it ? I know it’s a slim chance but it’s possible?
 

Worth a punt on a white Xmas in Aberdeen this year. I got 3-1 last week so sold the kids Christmas presents and put everything on! 
 

Great 00z GFS / UKMO this morning, ECM a bit disappointing. Great set of GEFS set of ensembles, looks like cold into the New year is most likely. Off to watch the Weather Channels coverage of the snow storm in the US now ️

[Battleground Snow]

Not much change on the 06z icon from the 00z, the low in the states is further west, maybe it will track further west up Greenland to help with amplification in the Atlantic later on?

[feb1991blizzard]

For those who say a vortex chunk has never hit the UK with bitter cold before, i refer them to this chart.

All snow convective event even for Liverpool, not even close to being rain.

[DavidS]

18 minutes ago, Tim Bland said:

It must be theoretically possible for the PV to drop over us like that? Otherwise why would any model show it ? I know it’s a slim chance but it’s possible?
 

Worth a punt on a white Xmas in Aberdeen this year. I got 3-1 last week so sold the kids Christmas presents and put everything on! 
 

Great 00z GFS / UKMO this morning, ECM a bit disappointing. Great set of GEFS set of ensembles, looks like cold into the New year is most likely. Off to watch the Weather Channels coverage of the snow storm in the US now ️

Was 2010 not n example of the PV ‘dropping’ on us? Or have I got that wrong?

Feb beat me to it.

Edited December 17, 2020 by DavidS

[Anthony Burden]

Models beginning to at last show a likely scenario weather wise over Christmas.

Looking good for a more festive temperatures,in regards to after Christmas still

time for changes but looking like mild will not be on the agenda.Just one other

issue is the low pressure at 144 hrs all show it close to U.K. except ukmo interesting.

[SMU]

3 minutes ago, DavidS said:

Was 2010 not n example of the PV ‘dropping’ on us? Or have I got that wrong?

Yes. Correct.

 

Just rewound all those posts from last night on the 18z lol  

The model was wrong over the states at t72-96 with the pacific jet not digging at all creating no downstream amplification.

That went straight in the scrap book.

The wedge has gained momentum today - whether it can be sustainable to develop a more continental flow aided by the arctic high is another story to be resolved over the next 72 hours. > Just for the lemmings thats another 12 suicide runs of the GFS...

Edited December 17, 2020 by Steve Murr

[Ali1977]

T144 off the 00z below,  we need the WAA line to move West and ideally up into Greenland (red line)  to give a more potent Northerly and a better change of sustained U.K. cold - we shall see what happens In 10 mins or so!! 

Edited December 17, 2020 by Ali1977

[Day 10]

22 minutes ago, feb1991blizzard said:

For those who say a vortex chunk has never hit the UK with bitter cold before, i refer them to this chart.

All snow convective event even for Liverpool, not even close to being rain.

I concur with this, we got 6 to 8 inches here on the coast the evening before. Showers clumped together crossing the Irish Sea and kept going well into the night, perfect for the weekend!

[northwestsnow]

6z looking good to me at day 6..

[Battleground Snow]

4 minutes ago, northwestsnow said:

6z looking good to me at day 6..

The further west that low goes up Greenland the better!

[MATTWOLVES 3]

6 hours ago, Snowfish2 said:

Lol Matt!!  

Think about it folks...How would you feel if everyone was putting you down all day,and constantly talking about you. GFS needs anti anxiety medication come the evening run,and does tend to get groggy! It wakes up fresh and alive come the morning and serves us up something much appealing...we need to back off it folks,before the poor thing suffers a breakdown..

[alexisj9]

46 minutes ago, feb1991blizzard said:

For those who say a vortex chunk has never hit the UK with bitter cold before, i refer them to this chart.

All snow convective event even for Liverpool, not even close to being rain.

Yep, I'm still trying to decipher why that caused so many complaints, it was cold and snowy, just not the easterly people were expecting.

[TSNWK]

Felt it was looking a tad better between 144 and 174 with that low climbing further west up against Greenland.. however it really seems to have become progressive afterwards and this 186 is flatter that the previous by day 9 we are much flatter upstream, high topples and vortex forming to our next west. Appears that gfs wishes to remind of us last night.....

Edited December 17, 2020 by TSNWK

[swfc]

Atlantic in lockdown at 192 hrs.  The tpv will either flatten things out or Bring a nnw wind altho already well into fi

Edited December 17, 2020 by swfc

[Battleground Snow]

1 minute ago, TSNWK said:

Felt it was looking a tad better between 144 and 174 with that low climbing further west up against Greenland.. however it really seems to have become progressive afterwards and this 186 is flatter that the previous 192.

 

The low under the under the Azores high at 192 might help with a 2nd phase of amplification later on... I feel it's gone wrong after 144 though

[northwestsnow]

Another attempt at pulling the PV east in FI ?

[frosty ground]

2 minutes ago, swfc said:

Atlantic in lockdown at 192 hrs.  The tpv will either flatten things out or Bring a nnw wind altho already well into fi

I think the second option is probably favourite at this point, the Ensembles do back up a second northerly / north westerly. 

[frosty ground]

 

Might get a bit windy, and as expected the second northly is taking shape.

[swfc]

PV at day ten to the nnw under a lot pressure from Heighths from the east, Atlantic and esb. All academic but still. Heighths building threw svalbard, not a bad thing also

Edited December 17, 2020 by swfc

[Matt H]

GFS parallel run also looks great for Christmas Day!

[Daniel*]

Certainly doesn’t revert to normality similarly to 00z but quite a bit faster ridge sharpens to our west and a cold trough plunges into Europe...

[IDO]

A run which we can probably ignore post-d8 due to the progged Azores cut-off low:

At this range very difficult to know it will even exist at T0 let alone influence the flow as it does. On this run it pushes the pattern of dropping trough east.

How the trough drops on the 06z is more likely than the 0z, disruption and a smaller chunk being dismantled from the main PV over Greenland. That possibly due to the better upstream amplification than on the 0z:

06z>  0z> 

That allows the Greenland pv to trough towards the US rather than ScEuro.

This pattern is not a wintry nirvana for most of us asl, but seasonally feeling cold I would have thought and a repeating NW'ly flow?

[Matt H]

GFS 18z last night at t192 vs the 06z at t180. Seems as if we’ve moved away from the woeful and overly progressive output that was being churned out last night, but again it highlights how fickle this model is. 18z first.

 

Edited December 17, 2020 by Frosty Winter