Model Output Discussion - Into Autumn 2019.

[MATTWOLVES 3]

14 minutes ago, Quicksilver1989 said:

Those NW winds are looking like a pretty persistent feature for the first 10 days of the month. If they carry on we could get a rather chilly September and this Thursday for example looks below average temperature wise.

Would rather see some blocking head towards Greenland though from a winter perspective, to reinforce the Tripole SST pattern.

The other question is about what Dorian does, its that time of the year when an ex-hurricane can cause sudden pattern changes.

Yes your correct QS. Dorian could completely scupper the current trends! I only hope that Azores ridge is not going to become a semi permanent feature throughout the winter. It literally ruined our chainces last year of any meaningful cold spells. 

[knocker]

[knocker]

Looks like the gfs is still taking Dorian though a stiff ET which, amongst other things, would enhance the jet. Just speculation at the moment

Edited September 2, 2019 by knocker

[Frosty.]

Well I'm not going to beat about the bush, the Gfs 12z operational is a very autumnal run, becoming much cooler even across the still warm s / se from Wednesday onwards and temps generally below / well below average across the north. Plenty of unsettled weather and only short-lived settled interludes. This of course doesn't mean the game is up for further warm anticyclonic spells, it's only based on this particular run.

Edited September 2, 2019 by JON SNOW

[MATTWOLVES 3]

23 minutes ago, JON SNOW said:

Well I'm not going to beat about the bush, the Gfs 12z operational is a very autumnal run, becoming much cooler even across the still warm s / se from Wednesday onwards and temps generally below / well below average across the north. Plenty of unsettled weather and only short-lived settled interludes. This of course doesn't mean the game is up for further warm anticyclonic spells, it's only based on this particular run.

Doesn't look to unsettled on the Ensembles! Rainfall spikes remaining quite low throughout the period, perhaps pointing to this more settled mid month and final 3rd period. 

Edited September 2, 2019 by Mattwolves

[Frosty.]

40 minutes ago, Mattwolves said:

Doesn't look too unsettled on the Ensembles! Rainfall spikes remaining quite low throughout the period, perhaps pointing to this more settled mid month and final 3rd period. 

Agreed, the 12z GEFS mean looks better longer term, probably a N / S split..mid month onwards may be a quieter more pleasant period for many with the jet further north.

Edited September 2, 2019 by JON SNOW

[knocker]

The ecm and Dorian

This evening's gfs

Edited September 2, 2019 by knocker

[Methuselah]

Nothing too untoward in this evening's GEFS 12Z ensembles...And, at least the impending short-day misery will be offset by a nearby advertisement for Santa's Magic Christmas Grotto? Ho, ho, bloody ho!

   

   

No sign of any major snowfalls just yet -- but watch this space...the building blocks are already starting to get into place. More runs needed!

[knocker]

The trough tracking south east that facilitates the movement north of Dorian

[Frosty.]

The Ecm 12z operational doesn't look too bad, there's some unsettled weather, mainly further north but there's also plenty of ridging from the azores / atlantic high, especially across southern uk and although there are some cool days / nights to come from Wednesday, there are also some warm days too further ahead..day 10 for example!! 

 

Edited September 2, 2019 by JON SNOW

[Singularity]

Judging by this, a boost to dateline convection ought to encourage some subtropical ridge extension through NW Europe & the UK by 10 days from now, which makes the 12z ECM look a lot more sensible than the 12z FV3. Not that this is saying much; the amount of ridge retraction (i.e. staying west of the Azores High) in the 12z FV3 is unfathomable (at least to me...).

[Blessed Weather]

A couple of posts with charts from the Climate Forecast System (CFS) showing forecasts for next year have been moved to the Seasonal Forecast Thread: https://www.netweather.tv/forum/topic/72635-the-seasonal-forecast-thread/page/42/

[Methuselah]

Well, judging from the GEFS 00Z ensembles, the next 16 days look like being fairly mundane, with temps maxing at around the 18C mark much of the time...Not three bad?

   

   

Meanwhile, today looks good for a Vitamin D top-up!

[northwestsnow]

EC 00z looks OK this morning.Looks mainly dry out to day 9 , hopefully some usable walking weather ,always nice to see Autumn and all the lovely colors nature has afforded us at this time of year.

Could be an outlier but its very nice by day 9 ..

Edited September 3, 2019 by northwestsnow

[Sky Full]

Looking ahead to around +210/216 hrs (11/12 September), the GFS shows a much diluted ex-hurricane Dorian scoring pretty much a direct hit over the UK, followed hot on her heels by her younger sister:

GFS +210                                                   GFS +216

   

ECM and GEM on the other hand currently believe that the Azores high will strengthen towards the UK keeping ex-Dorian away to the north west.....

ECM  +216.                                                  GEM +216

    

They can't all be right but the actual evolution of Dorian's interaction with the Jetstream and its route across the North Atlantic will probably determine our weather for most of mid-September.  Many of us will be watching these developments with interest I am sure.

Edited September 3, 2019 by Sky Full

[I remember Atlantic 252]

13 hours ago, JON SNOW said:

The Ecm 12z operational doesn't look too bad, there's some unsettled weather, mainly further north but there's also plenty of ridging from the azores / atlantic high, especially across southern uk and although there are some cool days / nights to come from Wednesday, there are also some warm days too further ahead..day 10 for example!! 

 

way out that I reckon, GFS probably leading the way, storm Dorian likely to batter us next tues

[Paul_1978]

4 hours ago, I remember Atlantic 252 said:

way out that I reckon, GFS probably leading the way, storm Dorian likely to batter us next tues

Not sure about "battering" us - just looks like it turns into a normal autumnal depression.

[Jimmyh]

2 hours ago, Paul_1978 said:

Not sure about "battering" us - just looks like it turns into a normal autumnal depression.

was thinking exactly the same. The jet stream is not fired up and far too many characteristics to fall into line yet.

[Singularity]

http://mikeventrice.weebly.com/hovmollers.html

The discrepancy grows larger still.

GFS now predicts a decent strength of Nino walker cell configuration with enhanced rising motion over the Central Pacific, yet it shows no classical response to this over the N. Atlantic and Europe. Well, the 06z briefly tried but that rapidly fell down and the 12z hasn't even given the Euro height rises a go to begin with.

Meanwhile, the 00z ECM shows exactly the sort of pattern shift that I'd expect in the D8-D10 range... if it wasn't for a lot of tropical activity taking shape in the N. Atlantic. This inevitably lowers confidence.

Either this is an impressive spot of an unusual pattern development relating to Atlantic basin tropical activity, or GFS is making a right mess of how they influence the planetary waves. Going to be really interesting to see which way things go.

Edited September 3, 2019 by Singularity
Elaboration

[Frosty.]

According to the Gfs 12z operational we are looking at a cool unsettled outlook with temps below average for most of the time, some transient ridging but plenty of depressions including Ex Hurricane Dorian next Tues / Wed.

[Methuselah]

The GEFS 12Z ensembles hardly paint a 'glorious' picture...but things really could be worse!

   

   

We could certainly do with some rain -- down here in sub-Saharan Suffolk!

[Frosty.]

Looking at the Ecm 12z operational one thing is clear, Dorian is much less of a deal as far as the UK is concerned towards next midweek compared to the Gfs 12z op, indeed, this ecm run isn't too bad, yes it's much cooler than we've been used to, there is some rain from time to time but there's plenty of azores ridging, there's a drier and brighter weekend ahead too, even some warmth for a time later in the run..could be a lot worse!!

Edited September 3, 2019 by JON SNOW

[Frosty.]

The Gfs 0z operational shows a scandi high later in the run.

[Methuselah]

I think there's even some potential for a mini-plume in there too, karl? Not a bad run anyways.

   

   

As far as snow goes: wake me up when we're lying under sub -10C T850s!

[Frosty.]

6 minutes ago, Ed Stone said:

I think there's even some potential for a mini-plume in there too, karl?

Indeed Ed, I noticed that too.