Model Output Discussion - Christmas week and beyond

[TEITS]

Quick summary from me because there has been some odd posts tonight and some members must be very confused.

A non biased honest assessment is this. Next week will remain largely unsettled with the N/W being more unsettled than S England who may have a drier week compared to recent days. Around 7th Jan onwards potentially turning cooler/colder and possibly very stormy with gales, maybe even severe gales at times. A greater threat of snowfall especially for the higher ground of Scotland/N England but not exclusively. As the winds start veering from a W,ly to a NW,ly and possibly N,ly then snowfall at lower levels becomes more likely.

[feb1991blizzard]

No GFS yet.

[Kasim Awan]

9 minutes ago, feb1991blizzard said:

No GFS yet.

Coming out now.

 

[geordiekev]

The heights in the Med well & truly rid of, signs of changes ahead

[Daniel*]

I’ve seen much worse, theme now for vortex to drain away from Greenland to Scandinavia. Scandi trough being quite influential…

[geordiekev]

Will it go up to Greeny in the gap? Not on this run but Scandi HP showing promise. Just good to see solutions come mid month with PM shots in the meantime.

Edited December 31, 2022 by geordiekev

[geordiekev]

Good the see the polar express heading from the East & snow returning to the continent

[Daniel*]

GEM making more out of Atlantic ridging which is plausible that’s pretty much classic cold zonal. It definitely seems a bit of a shake up is on the way. 

[geordiekev]

Well think this coming week could be interesting viewing with heights in Arctic, helping to keep the vortex split & hopefully sending lows on a more Southern track. Will the European heights want to find somewhere else to set up?

Certainly something more interesting than these last couple of days.

[geordiekev]

9 minutes ago, Daniel* said:

GEM making more out of Atlantic ridging which is plausible that’s pretty much classic cold zonal. It definitely seems a bit of a shake up is on the way. 

Yep, think the more interesting charts just out of reach

[nick sussex]

The UKMO gets the award for a very frustrating set of charts ! 

The upstream troughing is sharper and the intense cold is building to the ne , not enough ridging though  between that and the UK low .

The day 5 screamed potential , but the PV is just too strong and the weak Arctic high can’t disrupt the low as it drops se .

There are differences earlier at day 4 between the UKMO and GFS.

Norway upto Svalbard . The former has a clean flow the latter sticks a shortwave there .

We really want the main high to be as the UKMO has it and not two separate cells with shortwave in between like the GFS . The main forcing needs to come from the ne and the Arctic high given the overall set up .

Edited December 31, 2022 by nick sussex

[nick sussex]

The ECM is a hybrid between the UKMO and GFS at day 5 but crucially develops a stronger cell of high pressure further north over Scandi orientated ne sw  which is fine  .

Day 6 that annoying shortwave just sticks there and the ECM halfway house means day 7 it’s phased in an unfavorable position . We need that to be either much further nw so it gets absorbed there or much further to the se .

 

Edited December 31, 2022 by nick sussex

[KTtom]

20 minutes ago, nick sussex said:

The ECM is a hybrid between the UKMO and GFS at day 5 but crucially develops a stronger cell of high pressure further north over Scandi orientated ne sw  which is fine  .

The frustration is the low heading our way to give us a chance of a north westerly is actually not doing us any favours regarding opportunities to tap into that high as it gets shunted away by 168

Edited December 31, 2022 by KTtom

[nick sussex]

Both the ECM and UKMO have the most  potential . A word I know is annoying as potential often comes to nothing trying to get cold into the UK!

They have a more amplified upstream troughing , you can see its sharper day 5 and wants to send some energy se wards .

The mess of shortwaves around the UK are the main issue and not sure the models have decided what’s the plan there yet ! 

With that bank of cold air to the ne and some energy heading se it would be premature to write off a surprise development in the coming days .

It will be very interesting to see what the ECM ensemble spreads show when they update later .

Edited December 31, 2022 by nick sussex

[Daniel*]

When looking at ECM 00z my eyes can’t help but be drawn to deep cold across Scandi which remains firmly in place, frigid all the way through. T144-240

 

 

 

 

[northwestsnow]

GFS is much better than ECM by day 10

 

I've attached GEM ,thats much better than ECM too

From my POV we absolutely do not want EC 00z to be anywhere near correct..

Edited December 31, 2022 by northwestsnow

[nick sussex]

8 minutes ago, northwestsnow said:

GFS is much better than ECM by day 10

On the face of it yes but its  recent performance has been woeful and in the earlier stages it has the rounded troughing . Also the ECM keeps the colder bank of air to the ne and you’re then relying on the GFS and its bias in depth of cold re PM flows.

If only we could squeeze out a bit more amplitude upstream to develop a better ridge between the troughing and the UK low day 5 on the Euros .

 

Edited December 31, 2022 by nick sussex

[northwestsnow]

Just now, nick sussex said:

On the face of it yes but its  recent performance has been woeful and in the earlier stages it has the rounded troughing . Also the ECM keeps the colder bank of air to the ne and you’re then relying on the GFS and it’s bias in depth of cold re PM flows.

If only we could squeeze out a bit more amplitude upstream to develop a better ridge between the troughing and the UK low day 5 .

 

Both GFS  and GEM have pulled the High out into the N Atlantic to allow for a potent Polar maritime blast 

EC does no such thing which means it's probably nailed the pattern

[northwestsnow]

Im not sure how looking at the modest uppers but EC 00Z manages to produce some decent accumulations by day 10..

Altitude will almost certainly be a big factor I guess..

@Kasim Awan looks a good dollop on your house

Edited December 31, 2022 by northwestsnow

[That ECM]

T168 all 3. I’m still interested mid month onwards. I’m still of the belief that nw blocking is more likely than ne. Of course no blocking which helps us is on the table but with a nhp as Ukmo and ecm  show there is much interest moving forward. 
 

plenty of wind rain and some wintry weather(for favoured areas) to get through.

[nick sussex]

6 minutes ago, northwestsnow said:

Both GFS  and GEM have pulled the High out into the N Atlantic to allow for a potent Polar maritime blast 

EC does no such thing which means it's probably nailed the pattern

Potent at the moment . Factor in the GFS bias . The day 5 UKMO is a tweak away from some drama ! 

[northwestsnow]

Just now, nick sussex said:

Potent at the moment . Factor in the GFS bias . The day 5 UKMO is a tweak away from some drama ! 

Oh I wouldn't trust GFS with my last £ Nick.

No argument from me there.

[Ali1977]

Getting hotter still, and slowing edging closer 

[bluearmy]

I mean we actually have a ticket for the raffle of the century ….

It’s only one ticket unfortunately- would like to have a book of tickets but given that it’s the raffle of the century I suppose beggars can’t be choosers

the Siberian vortex is expanding towards nw Russia and ne scandi - it shouldn’t reach that far and a chunk of it should break off and traverse toward n Canada whilst the remainder drifts back east . That’s the expectation- BUT the Arctic high comes into play here and it’s feasible that it prevents that chunk from reversing west and if the AO can be negative enough it could reach scandi/svaalbard/w Russia . If the slp patterns then drop into place then who knows ….

This isnt necessarily a one off one chance in the next week or so opportunity either. The NH profile could try this passage of heights transfer several times - if it’s proceeds as per expectation then it ramps up the n Atlantic jet stream as a chunk of pv passes east to west. 
 

incidentally, the gfs at the v top of the strat is still keen on a massive reduction of zonal flow as the top of the spv ends up displaced to Greenland. A little lower down the repeated warmings are keeping a generally average strength chap displaced around svaalbard. The spv is ever stretched as we head down through the strat.  It still looks like the trop’s dance to me although if we do see some surprise developments high up then that could well shake things up in that respect. Given the lack of coupling this season you wouldn’t expect a quick response but perhaps a strong and v rapid reduction in zonal flow could change the dynamics. 

[bluearmy]

9 minutes ago, Ali1977 said:

Getting hotter still, and slowing edging closer 

The initial warming was progged anywhere between -28 and -4 when it appeared at day 16/15/14.  It looks to verify around -20 to -16 now we see it around day 8/9.  I reckon that should be our current expectation- strong warmings that keep the spv displaced around svaalbard. But if we can get something hotter above zero then we can stretch that spv and who knows, possibly even split it. anyone for a cold spring ???