Model output discussion - Closing in on Christmas

[Griff]

7 minutes ago, swfc said:

Yes your correct Griff. Thing is it does seem the UK being a small island surrounded by sea is always unlucky. That said Id give my grandmother's wooden leg for a severe winter

Might get Japan lucky one of these days, small islands currently benefiting from warm seas and cold air mass...

[KTtom]

48 minutes ago, SLEETY said:

No good concentrating on day 9 charts if the output is wrong at the much earlier timeframe and the ukmo is not good its too flat, hopefully ECM doesn't follow it

This is an intriguing point, ive been thinking how odd, with all the possible scenrios the models have been churning out, none seem to match the Mets outlook, frost and fog indicate high pressure probably over the UK...is this where the UKMO is heading?

Good point by SWFC in that you look at the profile on gfs at 200ish hours and can be fooled into thinking its a snow bomb....but check the 850 first...for me, the gfs and ecm last night have the trough too far west. 

[Harsh Climate]

Not sure why anyone would be downbeat this morning, very strange. From looking at this mornings output the main thing is we are still seeing a greenland high on gfs and I believe ukmo  would leave to one two. What would be bad is if we woke up and there was no greenland high being shown. Looking for specifics this early and if quite ridiculous..

gfs is still a pearler. And Ukmo is only going one way and that's a greenland high.

 

[Mucka]

ECM 120 no dreaded UKMO low so far

[swfc]

3 minutes ago, Harsh Climate said:

Not sure why anyone would be downbeat this morning, very strange. From looking at this mornings output the main thing is we are still seeing a greenland high on gfs and I believe ukmo  would leave to one two. What would be bad is if we woke up and there was no greenland high being shown. Looking for specifics this early and if quite ridiculous..

gfs is still a pearler. And Ukmo is only going one way and that's a greenland high.

 

That's a ridge towards Greenland tbh. A true greenland high is a rare beast

[TSNWK]

ECM 144 looks flatter than previous 168.. is 12 hours earlier difference enough time to recover... squeeky bum time.

[Mucka]

ECM 144 the upstream amplification looks to be there but that low is throwing up an even stronger ridge ahead than GFS 00z

Seems to be a trend so it will be interesting to see how this turns out.

[swfc]

Ec a bit flat at 168 hrs imo. On we go tho

[Mucka]

6 minutes ago, TSNWK said:

ECM 144 looks flatter than previous 168.. is 12 hours earlier difference enough time to recover... squeeky bum time.

 

Squeak! 

I think it is slightly faster and flatter upstream but that is exacerbated by the low not digging S because the ridge it is throwing up - if it wasn't for that I think it would be much more amplified behind.

Look at yesterdays 00z for comparison and how much further S the low is and already phased with sceuro trough

Edited December 19, 2020 by Mucka

[Kentspur]

Another very good set of GEFS This for London. Can't remember the last time I saw so many snow % opportunities albeit low atm

[TSNWK]

Drat this.. it’s noticeable flatter at 168 against previous 198.. 12 hour gap or not it’s step backwards.

[Mucka]

I think 192 emphasises the amplification is there but the trough being prevented from digging South is the main issue.

May still be salvageable but we want to see that ridge being watered down in future runs 

[KTtom]

2 minutes ago, TSNWK said:

Drat this.. it’s noticeable flatter at 168 against previous 198.. 12 hour gap or not it’s step backwards.

Dont bother with 192 then, were back into westerlies

[carinthian]

10 hours ago, carinthian said:

With all the excitement of cold weather coming as shown some way off still on the day 10 charts, there is a little matter of whats to happen in the shorter term. The ECM chart below at 120 t shows a deep low  crossing the heart of the British Isles which would produce a lot of rain and possible snow to the mountains. There is a difference at this stage between ECM and that shown by GFS and UKMO  with the track and positioning of the low.. However, all models show a clearance by Christmas Eve into Christmas Day ,

C

Good morning . Following on from the above post, seems ECM have down graded that pre Christmas low and tracked further south but still shows it affecting the south with possible snow to the highest ground of the Southwest.  All main models seems to show the same chart profile now at 144t ( below from UKMO ) which seems to have been the most consistent of the models out at that range. Now whats is to develop during the period 144t-240 I ask our team ?   After a temporary warm up over Boxing Day , a cold front will move through the British Isles next weekend introducing a NW ly flow with the Greenland low expected to be centred near to the Low countries by the 29th ( still a long way off I ask )? Yes, but they think that is what the UKMO charts will be showing out at that range. So risk of snow increases towards New Years Eve for Blighty . Too early to predict location .

C

Edited December 19, 2020 by carinthian

[swfc]

10 minutes ago, TSNWK said:

Drat this.. it’s noticeable flatter at 168 against previous 198.. 12 hour gap or not it’s step backwards.

Yes ec Dosnt split the PV and it moves east. The low Dosnt move south altho the run is still heading cool  and minor changes on the PV nhp could pull it back

Edited December 19, 2020 by swfc

[TSNWK]

I felt it was already trending flatter 144 and that’s a worry as pretty close range and the changes there then magnify on 168 and 192.. so in summary it’s GFS v UKM and ECM up to 192.. where’s your money ?
 

[That ECM]

T216 ECM and GFS hence why t120 plus is always JFF. 
 

for sure there will be many posts saying told you so even though nothing is resolved. We have seen an easterly at T72 being called by the meto and all output not happen previously. 
 

Still much to be resolved.

 

T240 is not the worst chart you’ve ever seen.

Edited December 19, 2020 by That ECM

[Mucka]

2 minutes ago, TSNWK said:

I felt it was already trending flatter 144 and that’s a worry as pretty close range and the changes there then magnify on 168 and 192.. so in summary it’s GFS v UKM and ECM up to 192.. where’s your money ?
 

It may be a little flatter upstream but I think it is still amplified enough if downstream plays ball.

I would honestly see that ridge as the issue.

If you look at the comparison I posted  with yesterdays ECM where it doesn't throw up that ridge and the low digs South you will see that the E flank of the Atlantic high is more vertical due to the low digging further South because that strong ridge isn't thrown up ahead of the low.

That is unrelated to the upstream low and what causes the flatter pattern thereafter IMO.

Of course a anything flatter upstream is undesirable in its own right.

[swfc]

Ec day 10 brings in a long fetch northerly and still the 850s arnt great?? All in fi so bring on the 6z

[TSNWK]

1 minute ago, Mucka said:

It may be a little flatter upstream but I think it is still amplified enough if downstream plays ball.

I would honestly see that ridge as the issue.

If you look at the comparison I posted  with yesterdays ECM where it doesn't throw up that ridge and the low digs South you will see that the E flank of the Atlantic high is more vertical due to the low digging further South because that strong ridge isn't thrown up ahead of the low.

That is unrelated to the upstream low and what causes the flatter pattern thereafter IMO.

Of course a anything flatter upstream is undesirable in its own right.

Thanks.  And if I recall you were highlighting a concern with this ridge being thrown up ahead during yesterday's 12z.. we got away with it then but on this ECM it impacts..

[Mucka]

1 minute ago, swfc said:

Ec day 10 brings in a long fetch northerly and still the 850s arnt great?? All in fi so bring on the 6z

Indeed but I have seen much worse day 10 charts, still plenty of wintry potential going into Jan from that chart. If that was worse case scenario I would bite your hand off 

[Valleyboy]

8 minutes ago, TSNWK said:

I felt it was already trending flatter 144 and that’s a worry as pretty close range and the changes there then magnify on 168 and 192.. so in summary it’s GFS v UKM and ECM up to 192.. where’s your money ?
 

My money is firmly on a mobile weather pattern.  Cool / cold blip latter half of next week, then milder westerlies to take us into the new year.  The cold plunges into the USA are going to power up the Atlantic.

[swfc]

Just now, Mucka said:

Indeed but I have seen much worse day 10 charts, still plenty of wintry potential going into Jan from that chart. If that was worse case scenario I would bite your hand off 

Yes true, I find it so frustrating tho. Tbh early doors is the key so onwards and upwards

[Daniel*]

2 minutes ago, swfc said:

Ec day 10 brings in a long fetch northerly and still the 850s arnt great?? All in fi so bring on the 6z

They do look strangely high. Well it is FI.

[Mucka]

7 minutes ago, TSNWK said:

Thanks.  And if I recall you were highlighting a concern with this ridge being thrown up ahead during yesterday's 12z.. we got away with it then but on this ECM it impacts..

Yeah, but then I have a lot of concerns 

It is a worry because GFS has trended the same way but the ridge wasn't significant enough to really impact the pattern though it does have a bit of negative impact with how much cold air we feed in.

Let's see if future runs go back the other way and we maintain the upstream amplification. If they do we should be home free for some sustained blocking. 

 

Oh, and have UKMO come on board as well of course.

Edited December 19, 2020 by Mucka