Model Output Discussion - Spring Has Sprung

[Daniel*]

8 minutes ago, BarnetBlizzard said:

I've noticed that wedge of high pressure to our northwest around Iceland being suggested on a few runs. If we can get the wedge there then the low pressure from the Atlantic gets forced south-east and it could bring in easterly winds for a time. 

Was shown on ECM 12z yesterday but dropped overnight. Clearly NWP are toying with something they don’t yet have a good grip on. Likely MJO  related I’d say. 

[feb1991blizzard]

There's the 79 chart, SW England burial job.

[BarnetBlizzard]

  @Daniel*

1 minute ago, Daniel* said:

Was shown on ECM 12z yesterday but dropped overnight. Clearly NWP are toying with something they don’t yet have a good grip on. Likely MJO  related I’d say. 

With MJO moving to phase 7 and a relatively strong vortex, you'd hope this could be a realistic possibility. 

[sebastiaan1973]

  @BarnetBlizzard It has some credit, as EFC46 is hinting in this direction for some time. 

[MJB]

  @Jacob Looks like the PV is gaining again which could scupper the cold before it even gets south

Nothing wrong with that PV

 

 

[MJB]

  @feb1991blizzard

We would take that .........................I guess  

[TEITS]

  @TillyS  You seem to have gone AWOL for the 06Z run. Not surprising really.

The reality is the difference between 0Z, 06Z GFS & yesterdays ECM 12Z & 0Z run points to one thing. It doesn't matter whether you have a preference for mild or cold or an obsession for high pressure across Iberia. The fact is the models have been very inconsistent lately as recent ECM runs have highlighted. Due to this I cannot see any strong signal from the models either way. My instincts however are to look E like the 06Z.

I shall just add that we need to practice what we preach. I may at times only post a cold chart but then again you seem to do the same with any milder charts. 

[Met4Cast]

The MJO has moved into the western Pacific and this eastward progression over the past couple of weeks has resulted in a strong rise in total AAM following the recent very strong +MT events. The impact of the +EAMT event in particular has led to another strong Pacific jet extension eastwards (warm USA signal and down stream propagating Rossby waves) Cyclonic wave breaking in the western Atlantic may help to amplify heights northwards towards Greenland but modelling this is extremely complex, some runs manage it but many don't. Quite a complex setup as per usual.

This surge of momentum into the atmosphere should begin to reshuffle weather patterns somewhat into February. On balance for the UK - I'd expect the persistent Iberian heights to begin weakening into the 2nd week of February with the possibility of weak heights developing to the north/north west allowing for the risk of colder weather & increasing snow risks, particularly in the north, things are less clear cut further south but NWP modelling is signalling a cooling trend across the board in any case.

I'm not currently seeing anything to suggest prolonged deep cold or widespread significant snowfall within NWP modelling or otherwise, but certainly an increasing risk of colder weather as we go through February (more primarily week 2 into 3)

[LRD]

Underwhelming GFS ensembles. 6z not especially representative 850s-wise in FI

[Froze were the Days]

06z run throwing up the cold DET run again...hardly backed up by even the other GFS runs for what they are worth

If we are to get any real cold from an easterly or northerly I fancy back end of Feb or beginning of March (again)...it's all a bit meh currently with the output.

[johncam]

  @LRD so what is they point of it if it gets it wrong most of the time.

 

[LRD]

Not an outlier but GFS 6z remains right at the bottom of the pack all the way from the 10th/11th

[LRD]

  @johncam To push science and understanding?

That's what's always happened throughout human history. Push the science. Test things, see if they work. If they don't, learn why and how can it be made to work. What can we learn from mistakes and how can we improve things - medicine, computing, technology, engineering. travel, space exploration. You name it, we've improved scientific (and other) understanding and improved how we make/design things by learning from failures

Humans haven't advanced by not trying to improve science and understanding

What's your solution - forget the weather modelling and don't try to improve it? While I acknowledge that chasing cold/snow in winter is increasingly tedious, that doesn't mean that computing, meteorology and climatology should give up improving just cos things are less than perfect

[Dennis]

some for tomorrow here in Norway

Det er venta lokalt ekstreme vindkast på 35-50 m/s frå sør seinare sørvest, og orkan på kysten. 

Edited January 30 by Dennis

[johncam]

  @LRD your missing the point , the EC46 gets quoted all the time as if its always going to be correct when we all no its not. On that point is there any stats on how it does perform?

[LRD]

12 minutes ago, johncam said:

the EC46 gets quoted all the time as if its always going to be correct

No it doesn't. You're putting words in people's mouths. I gave you a response to the point of your first question and now you're making another one so, no, I'm not missing your original point at all

The models will do what they do - it's not the fault of some silicon chips and electronic circuits that people misinterpret them or put their emotions and hopes in what they show. Nor is it a machine's fault that people misread what other people are saying about them

Edited January 30 by LRD

[damianslaw]

For what it's worth, today's GFS6z is the first run I've seen that looks very plausible as the direction of travel first half of Feb. A slow evolution to something colder and more settled but with perhaps a bit of a fight between atlantic and emergent northerly heights during the transition stage of the iberian/ france heights easing away to our south west scrubbed out by falling heights to our SW, and a more southerly jet that then merges with the scandi trough.

Edited January 30 by damianslaw

[Rain All Night]

16 hours ago, RainAllNight said:

12z deterministic runs, Tue 30th to Mon 5th

This afternoon we see very little difference in the model outputs over the UK until day 6. All agree on a mostly dry week for the southeastern half of the UK. The system running to our north on Wednesday PM will provide some rain for those further north.

12z ensemble means, Tue 30th to Mon 12th

What catches the eye here is the suggestion of a cooler, cyclonic spell of weather beginning around the 9th Feb (day 11). How long this might last is unclear. The high pressure to our southwest looks poised to return to our shores whenever it may feel like it.

The signal for the return of precipitation to the southeastern half of the country (Reading used as a proxy) does not become significant until around 8th Feb on the ECM ensemble, over a week away.

0z/6z deterministic runs, Tue 30th to Tue 6th

Still not a lot of variation between the models prior to Monday 5th. GFS and JMA are still trying to bring a taste of the northerly to northern Scotland. Otherwise, not a lot new to see for the next week.

0z/6z ensemble means, Tue 30th to Tue 13th

We see suggestion of the arrival of an appreciable sphere of low heights from the west around 8th Feb, which coincides with the return of the precipitation signal on the ECM meteogram (Reading shown), as well as roughly coinciding with a signal for a drop in temperatures. Since this has been shown consistently for a few days now, I'd say we can reasonably expect a spell of unpleasant weather for most of us during the second week of February, so maybe don't go planning any outdoor activities for that week.

Right at the end, on the 12th/13th, you can see hints of the low pressure perhaps progressing eastwards and pressure rising a little in the Atlantic behind it, but that's probably too far away to read much into.

Edited January 30 by RainAllNight

[feb1991blizzard]

The way the output is (including 46), we could be looking at record breaking mild early feb, average to cool mid feb, record breaking cold end feb.

[Chesil View]

  @feb1991blizzard

I'd Happily take that for starters Feb.

[Jacob]

Seems like at the end of the GFS run the jet stream continues to head south. Can somebody explain what should happen after since I've never seen these synoptics before

 

[Mike Poole]

29 minutes ago, damianslaw said:

For what it's worth, today's GFS6z is the first run I've seen that looks very plausible as the direction of travel first half of Feb. A slow evolution to something colder and more settled but with perhaps a bit of a fight between atlantic and emergent northerly heights during the transition stage of the iberian/ france heights easing away to our south west scrubbed out by falling heights to our SW, and a more southerly jet that then merges with the scandi trough.

I agree the 6z is plausible.  I have said for a while that wedges of high pressure rather than a big block look to be a more likely evolution to a colder outlook for the UK.  Of course, any detail on such an evolution will only firm up much closer to T0, so at the moment it is just about seeing these runs crop up, and noting whether the signal grows over the next few days.  It is consistent also with more confidence (I think) from the EPS and 46 in lower heights taking hold to our south, but less confidence on where any blocking to the northwest might set up.  

[Jacob]

I doubt that this would verify but here is some snow depth eye candy from the ECM 

[feb1991blizzard]

  @Jacob can't be the latest ECM it was garbage.

[Jacob]

  @feb1991blizzard Its from the ensembles