Model Output Discussion - Spring Has Sprung

[TEITS]

I haven't posted recently as to be honest the inconsistent output has made commenting pointless to me. The 06Z is such a great example as the difference to the 0Z is frankly laughable.

All I can say is the chances of turning colder as we enter the 2nd week of Feb is looking likely with a NW, N,ly flow. The big question mark is how cold or prolonged any spell would be.

The GFS at +276 reminds me of a classic 1980s E,ly archive chart. Cannot remember when but shall go and have a look through the archives.

[legritter]

Hi Gang, My dog as just shot upstairs murmurings of The hunt is on , lets all sit back , Relax and be good to each other. I dont post so much these days as looking after a friend .But i do Lurk and thank all the fellow posters for their input of charts and interesting articles .I'm excited but i need more time to hopefully see some Winter wonderland synoptics at T 120 , and do some curtain Twitching and perhaps get the sausage baps out , cheers Gang and heres to the best weather Forum on the Planet .

[ANYWEATHER]

As many are musing, little interest for coldies in the reliable , and even further ahead ,very sketchy outlook for coldies at best. 06z paints a rather potent northerly by day ten ,whilst its 00z output really shows none of it. Ecm paints the same tune at day ten with stubborn heights around Iberia , any major pattern change is not any time soon, patience ,and a lot of it is required ,cant see this pattern changing to at least mid-February at the earliest........

[Ali1977]

Control at day 7 following the op 

[Duane S.]

  @TEITS  100% what I was thinking. The 06z has got an old school Easterly formation written all over it. I’m not so sure heights would naturally fill back in underneath us again a couple of days later on, as the 06z FI charts would simply have it.

I’d  happily bank that chart at D11 and take my chances thereafter. I think upstream forcings would be more in our favour at this point.

[Ali1977]

Control and mean at day 8, strong signal for cold that - even if it’s only a 2-3 day spell it may be better for more widespread snow 

[Harsh Climate]

We are going to see a very good set of assembles GFS 6z

Heres Just a few at 211h:

Like I said yesterday,chase well and truly underway, Let's see if we can start reeling in some crackers in the <180t range over then next day or so!

Great Average aswel 

[Chesil View]

  @TEITS

I was thinking along similar lines TEITS. 

Edit : I see Duane S has beaten me to it.

[Eagle Eye]

Second high-rise GLAAM by mid Feb possible, stronger than this one. Would have a response into March depending on the MJO. However, not sure of it yet as its kept being delayed by the CFS. 

[Mcconnor8]

GFS 06z ensemble pack is much colder than the 0z run, with the mean isotherm almost reaching -5 in London on the 6th and Control/OP on the same page, let's hope this trend continues on the 12z runs.

[WYorksWeather]

For the south (using Reading) - the ECM 0z meteograms still look very unconvincing right until the very end. At most, the flow possibly turning north-westerly bringing something closer to average, but the mean remains above average at the surface.

Looking further north (using Aberdeen) - just the earliest signs of a drop in temperatures to below average by around the 11th. A lot of variation though, and some ensemble members continue to retain a flatter westerly or even a very mild south-westerly flow.

It looks like we may get somewhere eventually, but it's taking its time about it. The key point is whether we get there before rapid warming begins in late February through early March, at which point we would need synoptics akin to BFTE 2018 to deliver anything.

[Rain All Night]

14 hours ago, RainAllNight said:

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.

0z/6z deterministic runs, Sun 28th to Sun 4th

It looks as though the disturbance running to our north on Wednesday will not be noticed by the southern half of the country. Most of the T+168h frames see us poised to be denied much impact from the anticipated PV surge by the high pressure to our south, though note the more ambitious 6z GEFS ensemble mean below.

0z/6z ensemble means, Sun 28th to Sun 11th

The 6z GEFS is relatively generous with giving us a taste of the Scandi trough around the 5th of Feb. We then see suggestion of cooler mean surface winds from north of west into the second week of February, the influence of high pressure to our south seeming to have moved further west over the ocean rather than over the continent by this point.

[MJB]

Control is quite snowy 

192

204

216

228

 

[chris55]

Certainly trending much colder on the 6z ensembles from GfS. Once again coldest set since the last cold spell. 

(Gloucestershire)

[Battleground Snow]

Latest mjo plots..

ECM BC always seems to differ from rest at moment. It wasn't keen at all a few days ago for any decent amplification into 7, make of that what you will 

As Tamara stated these plots are probably not capturing the correct level of activity over the west Pacific.

We should now get at least some days in 7 at decent amplitude.

Cfs keen to follow the BOM long term into 8.

Does feel like the end of Feb will be perhaps be a prolonged colder spell 

Edited January 28 by Battleground Snow

[Duane S.]

Much better signs of a change in our favour, albeit possibly quite a slow transition, from second week of Feb onwards. Very difficult to pinpoint many (any?!) details at this stage though…

The MJO dipole progression out of the Indian Ocean, through East Asia and into the Pacific was fairly rapid. It has continued motoring and has already powered through the western Pacific, where it will probably slow down. That quick-ish eastward propagation I assume was aided by the existing ENSO state. Although interference between the two tends to create a lot of noise and especially downstream in model output.

Net result though, it is virtually into P7 at a decent (maybe surprising?) amplitude.

Then perhaps… a slowly decaying El Niño may (just) prevent a more natural slide back into the COD later in the month, and the MJO even potentially progressing further to phase 8

Certainly not a prediction, just musings, but I think it will definitely be worth watching. A decent amplitude 7/8 for a period of time would (in all probability) greatly improve our late winter prospects.

 

Longer term output…

 

[offerman]

  @ANYWEATHER agree completely . It’s a setup unfortunately that has differed is this winter so far. Cold potential but either stubbourn heights to our south or too much mobility mid Atlantic preventing cold sinking south and holding but instead mobility returns. 
Any cold at present too far out and of any verifies will require dispersion of azores/iberian heights and also a nice mid Atlantic/greeny or scandi block. 

[AO-]

Good afternoon,

Imo we can dismiss GFS06. I will show you why. In the 144-168 charts there is a shortwave near the eastcoast of Canada  with a huge amount of colder air right next to it. My question hence is: why doesn't the shortwave deepen more. If it would have been across our side of the ocean  the shortwave would have become a huge depression it it would have merged. I really don't have any explanation for the evolution as shown by GFS. Maybe someone else has an explanation? 

 

The rest of the run is better untill day 13, but who knows what happens when the shortwave is calculated "correctly". At 216 it shows exactly what I mean. But maybe I'm wrong though. I just found it an odd evolution. 

[Cambrian]

There’s a clear trend in the 0z ECM ensemble mean towards a markedly colder week 2, a clearer trend than yesterday. Looking out for straight northerlies on the means is probably premature, but it’s good to see the surface westerlies and positive T850s at day 6…

 

…being replaced by day 14 by surface northwesterlies with a fetch from Greenland, a cyclonic setup with a good deal of Arctic air in the mix, and subzero T850s throughout the UK and Ireland. 

 

It’s difficult to expect much more than this from the means if we’re looking for a credible movement in the models over the next couple of weeks away from a mild, zonal pattern to an increasingly colder one. 

A mean like that is probably blending out a good number of more direct solutions and occasional colder phases but looks to have a sensible core theme, as it does a believable job of tracking the steady movement of the trough from Newfoundland to Scandinavia between days 6 and 14, the animation sliced here in between the 0z EPS for those days - 

  

- all suggesting a gradual transition in air mass through the period from tropical maritime to polar maritime to what we’re increasingly seeing in the ops in the form of regular incursions that are more earnestly Arctic. 

[joggs]

  @TEITS Don't suppose you could posted the chart once you've found it could you?.

Tia

[nick sussex]

A nice GFS 06 hrs run which shows an evolution that doesn’t require a strong block.

Holding the upstream troughing for long enough whilst ejecting some shortwave energy se to support some weak height rises to the n ne .

Hopefully we can see this trend gather pace across the other models this evening .

[Duane S.]

  @joggs  It had a ‘91 feel about it to me. In no way would I predict we get what followed that though

 

[Derecho]

Well we've been stuck in quite a rut! but given the MJO progression this isn't all too surprising. This winter does seem to oscillate with chilly and unsettled and exceptionally mild. Little in the way of 'average'

I also think that things could turn chillier, maybe one last hurrah for the winter? (of course we can still get cold in March and April but I'm not keen on that unless it is exceptional...)

Looking at my MJO thoughts on January 14th, it was clear we would go into strong phase 5 and 6 to end this month and it turned out to be a write off. However here were the thoughts in early Feb...

and now we look as though we have some support for a polar maritime incursion as luckily we've managed to get a decent phase 7 at the turn of the month. 

The control is pretty bullish and turning things chillier right on call... early next weekend...

ensemble guidance suggests it may be a bit later overall for the period of interest... more like February 7th.

 

EC as it stands as far less bullish across its ensemble set but still some support. As ever heights to our south could prove a spanner in the works.

but I wouldn't be surprised if we can get some kind of northerly incursion, whether its brief or more prolonged is uncertain.

As has been posted on here already. It looks as though an amplified phase will last for a while but huge uncertainty after that. Phase 7 is very blocked for Jan but less so for Feb. A mix between both of these is my punt at the moment

Then a strange loop back into phase 6 into February.... so northerly incursion followed by unsettled?

 

[Dennis]

newest AO 

lots will change soon

[AO-]

  @Dennis

 

Hopefully it doesn't affect the wrong side of the NH.  Negative AO is not like 1+1=2 sadly enough. I have seen it turn out wrong too many times. Anyway it is a start. It implies that most members calculate high pressure over the Arctic.