Model Output Discussion - Spring Has Sprung

[lassie23]

Handle the GFS with care folks although if it can pick up a weather pattern change to mild conditions and end up being correct, then the same should apply to spotting a change to colder weather.

[Harsh Climate]

  @Vikos

IMO you have nailed the date of the next chase  

[AO-]

1 hour ago, damianslaw said:

If it has things right expect greater consolidation in about 2-3 days time. It also often can be too progressive, but ultimately shows the path

My experience has taught me that GFS can be too progressive with throughing as well once a block is formed. It is often swept away too easily. I give EC more credits in that sense. 

[Lukesluckybunch]

Well the ecm is a complete mess..certainly not joining the party!

[AO-]

EC is a bummer tonight. A very unlikely evolution in the charts this evening (not shown by any other EC runs or other models I guess). It stays flat and moves the Scandinavian part of the Vortex towards the Urals. Besides, it creates a reinforcement of the Vortex over Greenland where GFS is more keen on a blocking scenario. Certainly not the best EC as the EPS improved over the last 24-48 hours. Of course it is still FI, but I'm curious about where it is in the ensemble

Edited January 27 by AO-

[Chesil View]

Complete lack of continuity from 0z ecm to 12z ecm .  Major difference over the arctic. 

[Dennis]

EC is deeply poor now ... deeply not good

they miss some....why is it always into the circle in EC ideas.....?

Edited January 27 by Dennis

[feb1991blizzard]

Hello sir!

[bluearmy]

Ec op is fine for cold - just a little slower on its evolution than we’d like to see. Perhaps the slower route is more likely to stick ??

[feb1991blizzard]

  @bluearmy

This is a slow burner (or hopefully the opposite), anyone expecting to see deep cold verify at D10 is going to be disappointed, that said any such synoptics (Greenland high favourite) does have a very wide spread in terms of onset date, anywhere between 10th to 25th Feb, that's assuming such a scenario verifies at all of course.

Edited January 27 by feb1991blizzard

[sebastiaan1973]

 I am amazed by the consistency of EC46.

[Chesil View]

  @sebastiaan1973 well it had better be on the ball other wise this could be a very frustrating chase indeed.

Edited January 27 by Chesil View

[stodge]

Evening all

Oddly enough for all the excitement about the GFS 12Z OP, I much prefer Control as it fully flushes the vortex out of Greenland and leaves a moribund Atlantic which offers the possibility of an extended colder spell.

At this stage it's all speculation and hopecasting.

[Dennis]

deeply nothing on EC ENS , MJO4 it seems 

but after 10th MJO7 signs

Edited January 27 by Dennis

[Chesil View]

  @bluearmy

Having now taken a look at the gfs control. I can see where you're coming from regarding the ecm op slower evolution Blue. 

[feb1991blizzard]

EPS - no alarms imo - expected direction of travel.

[bluearmy]

  @Chesil View or the eps control which obviously follows on from the op 

[damianslaw]

One of those timescales where you have to let the models 'flush' through so to speak before we can gain a handle on longer term prospects. Early next week should begin to solidify a direction for first part of February and give better indications for likely path of travel further into February. I mentioned the interesting synoptical developments early next week which have developed suddenly, this winter does feel one prone to sudden unforeseen developments and significant abrupt changes, bear in mind when looking beyond 5-6 day timeframes.. with that I've contradicted myself somewhat, but I think I'm saying don't be alarmed for expected patterns to disrupt quickly... but we are entering the time of year when 'blocking' has a far greater chance of holding its own against the atlantic.. unlike July - Jan period. 

[Dennis]

UKMO 2-3 febr 

[syed2878]

Interesting, GFS run this 12 hours. How if it’s another northerly, we chasing then no thank you last overhyped cold northerly spell did nothing for here cold and dry it was.

[Rain All Night]

7 hours ago, RainAllNight said:

0z/6z deterministic runs, Sat 27th to Sat 3rd

This doesn't look like it will manage to be an uninterrupted dry period for all of us, with disturbances running over various parts on Monday and perhaps again on Wednesday (UKMO is most aggressive with that).

0z/6z ensemble means, Sat 27th to Sat 10th

Some obvious interest emerging to the northwest from around 3rd Feb (beginning just after the T+168h frame of the op runs that I've presented above), peaking around 6th/7th. A week later and the signal has faded but it isn't gone completely, which at that range should be enough to sustain our interest.

12z deterministic runs, Sun 28th to Sat 3rd

All I can say is I hope the high to the south can fend off the fronts from the west at day 7 and beyond.

12z ensemble means, Sun 28th to Sat 10th

We have a monster vortex to our north. It may begin to relax a bit from around the second week of Feb, but otherwise, it is what it is.

[WYorksWeather]

I do think there's a risk of some over-enthusiasm in looking for cold at day 10 at this stage. Notwithstanding the chaos of the individual OP runs, the signal at the moment looks to be still fairly weak. For the south, the signal is mild through at least the first few days of February, and then something closer to average, possibly slightly below average right at the end, but highly uncertain.

If we look further north, the signal is that little bit stronger, and right at the very end we're now getting the mean down to around -3C or -4C.

However, it has to be said that it's not the most robust signal.

At the moment, I'd probably say that we're seeing the first hints of something on the ensembles. But we need to see this signal develop and strengthen. The last cold spell in mid-January was widely signalled by the ensembles as much as 10 days out or more, the mean dropping well down to -5C and lower. We need something similar to that to show up.

Next benchmark is probably the turn of the month. By that point you would expect a strong signal in the ensembles, if a cold spell is coming around the 10th. In the shorter term, a very mild next week to 10 days overall.

The meteogram for Reading shows increased support for some sort of north-westerly at day 14, and a consequent reduction in temperature to near-average. Reasonable support also for the flatter westerly option which would be probably a little above average, and less support compared to of late for south-westerlies.

So, the progression to cold looks like it would go through a few stages. We have a current mean south-westerly flow for the next 7-10 days. Beyond that, early signals are things will turn westerly and then north-westerly. That would deliver a seasonal feel, but is unlikely to deliver anything truly wintry for most of us. It would be the next change in flow after that which could potentially open up more interesting options. If you look at the wind direction diagram in the chart above, the chances of a northerly or easterly within the next two weeks are very low.

This also fits with the idea from EC46 of a nearer-normal week 3, from the 12th-19th February, which would probably be the first chance for a cold week if the uncertainties resolve in a colder direction.

In short, probably some interest beginning to build, but not much to support the idea of anything cold in the next 10-14 days, most likely option being a transition to near-average, with any cold spell only becoming more likely from around 10th Feb onwards.

CFSv2 remains less interested, though.

 

 

[Dennis]

Vortex lobe diving

[Metwatch]

Very good reprensentation of that Greenland / north Canada heights on this plot for the GFS 12z, with the blue colours in the troposphere up to around 250hPa on the 6-8th February, which means slightly reversed zonal winds for a short time, changes each run though as it is in the less certain time frame post day 10.

Interesting to note that it's quite certain now that the westerlies in the stratosphere (above 30 hPa) are going to become even stronger at 60N during the start of next month. So a more pronounced strat - trop disconnection IF Greenland heights does set up, but then maybe the risk of the SPV over-riding any tropospheric led drivers to blocking. The chart below is just another depiction of looking at a model run through different levels of the trop / strat at the same time. NOT a teleconnection / driver like the MJO or velocity potential charts that you may see posted by others.

Edited January 27 by Metwatch

[Scandinavian High.]

  @syed2878 yep I agree the far north most probably do fine north facing coast I just can’t get excited over a northerly very dry I just hope something pops up from the east otherwise the same old bore fest .

Edited January 27 by Scandinavian High.