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Model Output Discussion - Autumn 2018


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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

The pattern looks increasingly amplified during the next 10 days with some unusually strong mid-latitude ridging around. Ties in well with some strong MJO activity in the western Indian Ocean of late and with a recycle looking to get underway in the coming days (though GEFS way more amplified with this than ECM), though Arctic amplification is probably adding at least a little more to the ridge-trough amplitude; the situation is just crazy up north of us.

The MJO forcing will conflict with the current Nino-like state of the tropical Pacific SSTs - and in fact, it appears it (the MJO forcing) will be the more dominant factor, with the ridge tending more west of the UK during the final week of the month in a Nina-like fashion.

Meanwhile, there are signs of further WWBs to help those tropical Pacific SSTs rise further. A big ocean-atmosphere disconnect evolving - but how long can it last?

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
7 hours ago, mb018538 said:

Certainly the ensembles and models didn't pick this up too well...

Cluster chart for sunday:

ec-ens_nat_z500scenarios_2018101500_144.

5 days ago no real indication of any height rises into the weekend, let alone strong ones!

ec-ens_nat_z500scenarios_2018101012_240.

a good reason to be suspicious of long term trends to a cooler pattern until closer to, say, D5/D6

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Looking at tonight's Ecm 12z ensemble mean at T+240 hours the high is centred well to the west which to me would open the door to something considerably colder and more unsettled from either the NW or N so a very early taste of winter could be on the way towards the end of the month..☺

EDM1-240.GIF

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl
55 minutes ago, Frosty. said:

Looking at tonight's Ecm 12z ensemble mean at T+240 hours the high is centred well to the west which to me would open the door to something considerably colder and more unsettled from either the NW or N so a very early taste of winter could be on the way towards the end of the month..☺

EDM1-240.GIF

I remember Atlantic 252 dislikes this!

but some warm days to come first thank heavens

ECM1-96.GIF?15-0ECM1-120.GIF?15-0ECM1-144.GIF?15-0

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
6 minutes ago, I remember Atlantic 252 said:

I remember Atlantic 252 dislikes this!

but some warm days to come first thank heavens

ECM1-96.GIF?15-0ECM1-120.GIF?15-0ECM1-144.GIF?15-0

I think the Ecm 12z is over egging the weekend warmth, the BBC forecast i saw mentioned 15/16c..pleasant but nothing like as warm as recently, or tomorrow for that matter when temps further s / se could reach 22/23c...bring on the cold I say!!

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

EC32 has a mid Atlantic ridge and a trough just to the east of us in week 3 (or at least a strong enough anomaly to believe that's what the signal is), and as strong a blocking signal to the North / North East as I can ever remember at week 4. lets hope that week 3 pattern can colden the continent in week 3 enough to then smash the floodgates open in week 4.

The GFS(P) shows a similar evolution but obviously much quicker.

Edited by feb1991blizzard
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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)

Further to my post last thusday evening about the hp cell developing in the Atlantic,the latest from the cpc 6-10 and 8-14 day 500mb anomoly charts shows even stronger ridging in that area,it will be interesting to see how amplified this ridge gets nearer the time

610day_03.thumb.gif.5adb6342cf86df7bcf23c586eac1c155.gif814day_03.thumb.gif.011e6e1835d2b7d3126136449274f3eb.gif

and for the first time this season we see a forecasted neg NAO/AO>-2/-3

nao.sprd2.thumb.gif.f5e2cf3f664cb422ba474cbc140420ba.gifao.sprd2.thumb.gif.8571d0daed6e9ccdb042440c003db11b.gif

and the gefs/ecm ens(although the ecm doesn't go as far as the gefs),the gfs op clearly a mild outlier and the control clearly mild outlier

graphe_ens3_xbh2.thumb.gif.e8b87a987c27c154693cf69f9a24ccc9.gifgraphe_ens3_php.thumb.png.c456a77cea34c96d6935539a2a2bbd01.png

so in summery we will have a few fine days to come with the Azures high nudging in from the SW then migrate west a little to allow a cooler west to northwestly but a NNW/N direction cannot be ruled out,it all depends on how far the hp cell retrogresses west,the gfs has been toying around for the last few days if not a bit longer with a possible northerly at or just before the end of October,interesting times are starting early this year.

 

 

 

 

Edited by Allseasons-si
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

@Allseasons-si

Just cant seem to get that ridge right up into Greenland to really open up the Northerly but still very decent charts.

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
1 minute ago, feb1991blizzard said:

@Allseasons-si

Just cant seem to get that ridge right up into Greenland to really open up the Northerly but still very decent charts.

It is an anomoly though Feb and it shows a slight retrogression west,maybe in a few days it might show that,let's see but it is a strong anomoly.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
1 minute ago, Allseasons-si said:

It is an anomoly though Feb and it shows a slight retrogression west,maybe in a few days it might show that,let's see but it is a strong anomoly.

Surmising that that signal for the ridge would hold into week 3, then it fits perfectly with the EC32.

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
12 minutes ago, feb1991blizzard said:

Surmising that that signal for the ridge would hold into week 3, then it fits perfectly with the EC32.

For as long as we have the hp cell to the west of the uk or even over the uk,then europe will cool down with troughs invading from the north,cannot be a bad thing,we don't want it further east,yuk.

theres that saying every time we get into winter,get the cold in and the rest will follow:)

the latest gfs is doing that and there is WAA just off Newfoundland heading up into Greenland @240

gfsnh-0-240.thumb.png.d089b71817093b02451d92befce83014.png

 

Edited by Allseasons-si
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
19 minutes ago, tight isobar said:

 

 

 

anomnight.current.gif

 

 

 

I don't like that +PDO signature, that's been the death knell for the last 5 years, I had long since thought this but Gav confirmed in his video on sunday, that colder NE pacific waters correlate better with UK cold winters.

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Posted
  • Location: st albans
  • Location: st albans

Every autumn we have the chasing of early season cold and away from the north and higher ground it is generally a waste of energy and time ! 

Patience is a virtue and the ec46 seems consistent with the height rises to our north and northeast through November with subsequent low surfer temps to our east in general the consequence. Ours recover slowly as the mean flow across w Europe becomes less continental from the east and more from the south as the Scandinavian high becomes more sceuro in time. The story of November would seem to be the lack of precipitation in n and e Europe whilst frost and fog are likely to be prevalent.

the pattern is currently heading where most seasonal forecasts said it would ..... as Claudio once said .... 40 points, 40 points !!!  No need to get ahead of ourselves looking for winter in late October ......

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Posted
  • Location: uxbridge middlesex(- also Bampton oxfordshire
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(- also Bampton oxfordshire
19 minutes ago, feb1991blizzard said:

I don't like that +PDO signature, that's been the death knell for the last 5 years, I had long since thought this but Gav confirmed in his video on sunday, that colder NE pacific waters correlate better with UK cold winters.

That PD-OSCILLATION +sig-has done wonders for uk winters in times past...

And with the equitorial situ...along with dire accomplishment of the 4segment polar vortex....and angular basis....that oscillation, looks defined for aid of blocking situ's around the mid/upper latts....and given the overall advevtive-sequence's ...id suggest a near...or clear colder than average winter...into NW-●EURO as a whole...obviously other dynamics are in the mix....but sometimes...the basic of cooking....makes the best eating!!!

And the ingredients are certainly there.

Edited by tight isobar
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Posted
  • Location: Melbourne, Victoria, Australia.
  • Weather Preferences: Snowfall obviously.
  • Location: Melbourne, Victoria, Australia.
On 10/10/2018 at 04:30, jules216 said:

There is an Eastern Asian mountain torque event happening right now which will flip the pattern in north america that has persisted most of the summer and early autumn courtesy of pacific jet extension and a split jet at eastern side of north america. This may have subsequent effect on the Atlantic jet, unfortunately I am not skilled enough yet to predict what effect these EAMT events have on the long range circulation in our vicinity, for this I desperately need insight from likes of Tamara,GP,Lorenzo or Chionomaniac to explain it in layman terms, unfortunately non of them has posted for long time which is a pity.

 

 

 

Tamara still pops in from time to time, like myself. You might have a better chance of catching her here:

https://www.33andrain.com/topic/868-teleconnections-a-more-technical-discussion/

You were a tad early, but still largely right, with us now in a +EAMT event over the past few days. This as @Catacol states, we are in a +AAM phase, supported by the +EAMT and other torques. I don't expect the AAM to be very Nino-esque IMO, with SOI forecasts from the Met Office and ECMWF supporting a +SOI in Nov and Dec, supporting an atmospheric ENSO Nina-like phase. This would obviously translate to the AAM, and shows that there is potential for the Atmospheric ENSO component not to merge with Oceanic ENSO, which should be a weak-moderate basinwide event. This theoretically causes more NP-Jet extensions, which translates downstream to the UK, by methods of the GSDM. Context to this discussion here .

gltaum.90day.thumb.gif.f8fe3241a8e0b2f31ccffa0fc83ff5da.gif

And the +EAMT is helping a Pacific Jetstream extension over the next 10 days, according to GFS.

250hPaJet_prob_1.thumb.gif.f94ce1c485102e3d141006129eeccf8c.gif

 

 

 

Edited by Snowy Hibbo
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Posted
  • Location: Melbourne, Victoria, Australia.
  • Weather Preferences: Snowfall obviously.
  • Location: Melbourne, Victoria, Australia.
5 hours ago, Catacol said:

Half way through October. Time to stir....

Interesting reading RJS's comments in the seasonal forecast thread regarding extreme cold in central Canada and likely downstream trough from this event. If this can be given as a base state heading into the start of winter, then exact positioning of the long wave pattern becomes guessable. Note the MetO ENSO forecast

October 2018 Niño3.4

As many forecasted several months ago we are heading into a weak Nino winter with consequent pressure applied to subvert sub tropical high pressure belts and therefore the possibility of a more southerly tracking or split jet. GLAAM is in a moderate to strong positive phase 

gefsbc_aam_fcst_current.thumb.png.1417cf87d5208b493586dd5d28b93ed2.png

and the Nino imprint onto the atmosphere is clear from the GWO state which has been locked into the 5 - 8 orbit for weeks now

GWO_members_current.thumb.png.82ad006a802a27c3ec734f4e7f3e9f2b.png

For the foreseeable therefore a pattern that wont encourage flat westerlies, should instead see a good deal of jet wobble and curve, and an autumn that for now looks to remain fairly blocked. With an eastern US trough likely then the suggestions from a number of posters that a mid atlantic high may develop downstream looks about right to me in the context of the above. That might help to bring about a frosty and foggy passage into November.

 

7 hours ago, Singularity said:

The pattern looks increasingly amplified during the next 10 days with some unusually strong mid-latitude ridging around. Ties in well with some strong MJO activity in the western Indian Ocean of late and with a recycle looking to get underway in the coming days (though GEFS way more amplified with this than ECM), though Arctic amplification is probably adding at least a little more to the ridge-trough amplitude; the situation is just crazy up north of us.

The MJO forcing will conflict with the current Nino-like state of the tropical Pacific SSTs - and in fact, it appears it (the MJO forcing) will be the more dominant factor, with the ridge tending more west of the UK during the final week of the month in a Nina-like fashion.

Meanwhile, there are signs of further WWBs to help those tropical Pacific SSTs rise further. A big ocean-atmosphere disconnect evolving - but how long can it last?

I realise I added to the case for an oceanic and atmospheric disconnect, but what if the ENSO is helping to signal, particularly with CP Nino regions being warm (along with EP Nino regions theoretically warming as well), and cold SST anomalies around Maritime Continent. This would help MJO and other equatorial waves to avoid Phases 4 & 5, and stay around Phases 7-8-1, particularly the former two phases. This is all for in terms of the winter, but can also apply to the present day.

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Very settled outlook away from north east Scotland for the next ten days however hidden beneath the charts is a pleasant change of air-mass between days 5 and 6 which stays with us until day 10 (increased risk of fog or grass frost for some rural spots). 

GFSOPEU00_120_7.png

GFSOPEU00_144_7.png

GFSOPEU00_240_7.png

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

Meanwhile back in the here and now so to speak.

^-14 days ahead and the anomaly charts, at least the EC-GFS version have pulled the predicted upper ridge back a shade allowing a colder flow, at least, down the eastern edge of the UK. I wonder if this will continue with, as some have suggested, the upper and surface ridge being far enough west fot colder air to spread into the UK?

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

The last couple of runs from NOAA do show the centre of +ve heights to be around 20 West. So maybe most of the country could get on the cold side. How much cloud is open to speculation until nearer the time with a flow around the high off the Atlantic probable. At the moment these charts do not suggest, even as a one of within the mean any major Polar outbreak. The NOAA 8-14 keeps the +ve height anomaly in much the same place as the 6-10 shows.

Most of the models at 240h show something along these lines. Only GFS allows for a colder plunge from a more northerly area.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

 

Edited by johnholmes
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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
On ‎14‎/‎10‎/‎2018 at 10:59, carinthian said:

As  @tight isobar has shown in the above post and quite a few projections ( below chart ) now showing a colder phase by the last days of this month. Of course in forecast terms still a long way off but a interesting update this morning received for resort planners from our portal service have already given a fairly strong signal to expect summer to winter condition by the end of the month. Will keep you updated after tomorrows chat to obtain further thoughts from a foreign field.

C

2119477891_MT8_London_ens(7).png.8f3daec48704a4ae94f2899f36cf1dbd.png

Morning, as promised in the above post,I have an update this morning. Our portal service providers have given us a 30% chance of some significant snowfall in resort by 31st October . That in real terms equates to a relative high % prediction for 15 days out but as we all know is subject to change as we approach a more reliable forecast time. Their own model has hinted at a possible significant change in the weather pattern towards the end of October for a few days now as have some of the major global models. A powerful ridge over the North Atlantic to get established by the last week of October resulting in a more meridional flow into Europe ( as highlighted by the GFS upper flow chart below ). Of course the location of any dynamic weather will depend on the actual positioning of the ridge, so forecasting can change on a daily basis but Central and NE Europe looks favourites for a abrupt change from summer to winter type conditions.

 

untitled.png

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18 hours ago, Catacol said:

Half way through October. Time to stir....

Interesting reading RJS's comments in the seasonal forecast thread regarding extreme cold in central Canada and likely downstream trough from this event. If this can be given as a base state heading into the start of winter, then exact positioning of the long wave pattern becomes guessable. Note the MetO ENSO forecast

October 2018 Niño3.4

As many forecasted several months ago we are heading into a weak Nino winter with consequent pressure applied to subvert sub tropical high pressure belts and therefore the possibility of a more southerly tracking or split jet. GLAAM is in a moderate to strong positive phase 

gefsbc_aam_fcst_current.thumb.png.1417cf87d5208b493586dd5d28b93ed2.png

and the Nino imprint onto the atmosphere is clear from the GWO state which has been locked into the 5 - 8 orbit for weeks now

GWO_members_current.thumb.png.82ad006a802a27c3ec734f4e7f3e9f2b.png

For the foreseeable therefore a pattern that wont encourage flat westerlies, should instead see a good deal of jet wobble and curve, and an autumn that for now looks to remain fairly blocked. With an eastern US trough likely then the suggestions from a number of posters that a mid atlantic high may develop downstream looks about right to me in the context of the above. That might help to bring about a frosty and foggy passage into November.

Im afraid your base state in paragraph one & extreme cold into Central Canada is already an incorrect assumption - especially today as your -EPO ridge has been replaced by a +PNA / + EPO pattern... ( A negative -EPO Ridge what was the feature in early sept teleconnects to a -PNA ridge pattern on the east coast )

Wait to late November to see where the default Ridge trough pattern develops...

Edited by Steve Murr
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^^ Just to add

you have totally contradicted yourself in paragrah 1 V final paragraph-

The September pattern with the huge blocking high west of Alaska ( -EPO ) & the downstream trough over the central plains does not equate to a trough in the East- it encourages the opposite - A warm ridge in the East ( -PNA )

So if you go with Roger you get Ridge / Trough / Ridge in the East = - EPO / -PNA (1)

If you go with a trough in the east its trough Ridge trough = +EPO / +PNA (2)

You cant have it both ways...

1)3D9EE37F-D2F3-4E38-9218-59AEE8EE4F68.thumb.jpeg.4c0c670dc52655a3212874e20ca01014.jpeg281116A5-EAC9-4A2B-A2C4-89194DDFDB7F.thumb.png.44ddf8d971389c06b90e57be26595287.png

2)

Edited by Steve Murr
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

After the recent stormy and wet weather it’s looking a lot better for the UK.

High pressure looks like taking over. 

The GFS 12 hrs looks a bit more like the ECM 00hrs, quicker to remove those lower heights to the nw .

It throws in a mini tease around day 9 and 10, although the main cold looks a bit too far east . It could though bring some much colder nights .

For coldies something to look out for if upstream develops a bit more amplitude in future runs . A bit too early to see anything of note but interesting to see whether the ECM might add a bit more amplitude into the mix .

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