Model Output Discussion - Autumn 2018

[Polar Maritime]

Some posts have had to go, Can we please stick to Model Output discussion as per thread title, And cut the tickle tackle. Any problems please report said post or PM a member of the team.

Thanks.

Edited September 25, 2018 by Polar Maritime

[mb018538]

ECM clusters last night:

High pressure dominant up to and including day 10:



Hints of something flatter and more westerly based emeerging around day 15, though no clear prognosis:

[Frosty.]

High pressure continues very much the dominant feature through the late sept / early oct period according to the Ecm 00z ensemble mean. 

Edited September 25, 2018 by Frosty.

[No Balls Like Snow Balls]

 

Edited September 25, 2018 by No Balls Like Snow Balls

[Derecho]

11 hours ago, ICE COLD said:

I get excited about a cold October . I would rather have a cold/cool October than a mild or warm one . Why can't we have a different October for once ? Why can't we have a below CET for once ? We've had sunny hot weather all summer , with every month being above average . But as you say Mike the CFS is not the most reliable . But it has showed a cool October in quite a few runs lately . 

I can think of a reason why it is becoming harder to achieve with time, though people may not like the reason 

Interesting outlook this morning with the behaviour of hurricane Leslie critical to the future outlook. Here we see the outlook for saturday:



Hurricane Leslie is SE of Newfoundland but in contrast to earlier runs this is no longer a cut of low. Originally it was heading further SE and high pressure was maintaining itself to the North of it.

However that doesn't look like happening so no retrogression for later on in the weekend / earlier next week thankfully. The high is therefore slap bang over the UK with warm days and nights being rather chilly.



Then what we see the the 00z is rather strange, you'd think the next step would be for the high to move east, bring up a tropical SW'ly whilst the remnants of Lesile move to our NW.

This is not the case as low pressure forms towards the Azores, just about helping the high pressure maintain itself. We then get a chilly NW'ly by mid October.



ECM meanwhile increases the energy of the Atlantic pushing the high east and preventing any regression. Hurricane Leslie however also sinks towards the Azores though keeping the high over us. Plenty of good weather to be had in this run.

Interesting to see that the ECM also has a medicane in the Med meandering around, it looks quite nasty!

 

So the key to the outlook is hurricane Leslie, another thing to note is that if we get westerlies or NW'lies things will be notably cooler then usual because the SSTs in that region are also very cold, upto 4C below normal!

[feb1991blizzard]

Huge split PV, good run coming up here.

 

A very different run to the last - the butterfly effect shown very visibly here.

 

Edited September 25, 2018 by feb1991blizzard

[Yarmy]

10 minutes ago, feb1991blizzard said:

Huge split PV, good run coming up here.

It's more or less the same as the GFS Parallel 0z at the same time.

 

The latter is currently verifying better (slightly) than its sibling at that range:

[feb1991blizzard]

2 minutes ago, Yarmy said:

It's more or less the same as the GFS Parallel 0z at the same time.

 

 

The latter is currently verifying better (slightly) than its sibling at that range:

It looks like its now going to turn out the same as the parallel as well, the last regular GFS run was better than this for bringing cold in, one GEFS member went below -7c on the 850hpa temps, that would be cold enough for snow in early October around here anyway.

[Rayth]

Just now, feb1991blizzard said:

It looks like its now going to turn out the same as the parallel as well, the last regular GFS run was better than this for bringing cold in, one GEFS member went below -7c on the 850hpa temps, that would be cold enough for snow in early October around here anyway.

An October with a difference 

[feb1991blizzard]

5 minutes ago, Raythan said:

An October with a difference 

Not bad at all, what we don't want however is the FI pattern in the trop that is setting up on this run, you could practically write off anything in Oct or Nov apart from brief PM incursions if that setup verified.

PV over Greenland.

Edited September 25, 2018 by feb1991blizzard

[Man With Beard]

The amount of clusters pushing a trough down towards Europe between D10 and D15 is on the rise - clusters 1 and 5 achieve it, and cluster 2 is "thinking about it". But the overall outlook still favours a cool high for the UK

[tight isobar]

4 minutes ago, feb1991blizzard said:

Not bad at all, what we don't want however is the FI pattern in the trop that is setting up on this run, you could practically write off anything in Oct or Nov apart from brief PM incursions if that setup verified.

PV over Greenland.

 

7 minutes ago, Man With Beard said:

The amount of clusters pushing a trough down towards Europe between D10 and D15 is on the rise - clusters 1 and 5 achieve it, and cluster 2 is "thinking about it". But the overall outlook still favours a cool high for the UK

The cooling trend has begun!..

And certainly some interesting anoms/features begining to raise as we walk slowly into the new season.

The format feels somewhat like a jigsaw with missing parts that are starting to be found.

And solar activity 'im sure will have a climatalogical impact....this quickly coming winter.

And the dice ....i hope will roll a 6...for our shores.

An iberian/baltic sea heat spike...and a cooling and a rapid cooling around the arm of northern most scandinavia...is a characteristic  fond to the eye...at this stage and for priming the desired blocking formats.....its good 2 b bk!!!.

#winter 2018/19......

[Singularity]

Thanks for your thoughts @tight isobar. 

I for one am really interested in what impacts the exceptional warmth in the Baltic Sea May have as the surrounding land cools. A strong anomalous heat input surrounded by a large sink. Hmm...!

[Interitus]

2 hours ago, Quicksilver1989 said:

So the key to the outlook is hurricane Leslie, another thing to note is that if we get westerlies or NW'lies things will be notably cooler then usual because the SSTs in that region are also very cold, upto 4C below normal!

Those are air temperatures not SSTs and it is 2°C below normal.

[feb1991blizzard]

7 hours ago, Interitus said:

Hmm it showed this beaut on one of the runs the previous day -

To be fair, the CFS trend has been for a cool October.... but then a mild winter.

 

The chart in that video frame is sea level pressure but no matter, assuming that the video covers z500 geopotential later on, this was dealt with on the stratosphere thread recently. Regarding the slp, it shows a slight tendency towards a southerly displaced jet - the positive anomalies to the north are quite meagre between 1-2 mb peaking between 2-4 mb over a small area of Scandinavia in DJF. Hence the T2m charts are near average and show nothing out of the ordinary.

Allowing for the fact that these charts are diluted over an average of three months, they certainly aren't a Dec-Feb 2009/10 -

 

or a NDJ 2010-11 -

 

+14mb, those are anomalies.

Yes I did see your post in strat thread, I thought perhaps this was a different run but its not, regardless anyway, I would think with the charts seen that there would be some potent cold spells involved amid milder spells and the temps overall would be colder than average, plus I bet there was not many model runs that show 14mb anomalies over 3 months - the models wouldn't have been showing those 09 and 10 anomalies in the septempber before hand - not with any kind of run to run consistency anyway although they did show blocking I remember.

Edited September 25, 2018 by feb1991blizzard

[Interitus]

7 minutes ago, feb1991blizzard said:

Yes I did see your post in strat thread, I thought perhaps this was a different run but its not, regardless anyway, I would think with the charts seen that there would be some potent cold spells involved amid milder spells and the temps overall would be colder than average, plus I bet there was not many model runs that show 14mb anomalies over 3 months - the models wouldn't have been showing those 09 and 10 anomalies in the septempber before hand - not with any kind of run to run consistency anyway.

That 09 and 10 anomalies probably wouldn't have been forecast is fair comment but comparison with those reanalysis charts show that these forecasts are nothing to get particularly excited about at the moment. With regards to the overall temperatures however, there is no need to speculate, the forecast temperatures are there and show that they aren't colder than average, either around normal for the UK, possibly slightly above for the late autumn/early winter. They also show the anomalous arctic warmth which gives rise to exaggerated geopotential heights that don't totally reflect the sea level pressures as mentioned on the strat thread.

Explore the charts here - https://climate.copernicus.eu/charts/c3s_seasonal/c3s_seasonal_spatial_mm_2mtm_3m?facets=Plot type,Maps%3BCentres,C3S multi-system,ECMWF,Met Office,Meteo-France%3BParameters,MSLP,SST,T2m,T850,geopotential height 500hPa,precipitation&time=2018090100,2184,2018120100&type=ensm&area=area20

[sebastiaan1973]

+14mb, those are anomalies.

I don't think that's possible whith these charts. The differences are always small.

[Yarmy]

3 minutes ago, sebastiaan1973 said:

+14mb, those are anomalies.

I don't think that's possible whith these charts. The differences are always small.

It's not possible with an ensemble mean because if you assume the 51 (or whatever) members are more or less normally distributed about the mean and there's enough spread, then some of those individual members would be off-the-scale crazy.

 

[Derecho]

1 hour ago, Interitus said:

Those are air temperatures not SSTs and it is 2°C below normal.

Ooops my bad, thought it was a mix of air temperature and SSTs, here is the SST map



Still below average to our west at least.

[sebastiaan1973]

35 minutes ago, Yarmy said:

It's not possible with an ensemble mean because if you assume the 51 (or whatever) members are more or less normally distributed about the mean and there's enough spread, then some of those individual members would be off-the-scale crazy.

 

in theory but not in reality (of the seasonal models). I have never seen larger than 2-3 hPa anomaly.

[BLAST FROM THE PAST]

HP to keep a good holding influence over the U.K. according to the models....I’m fully behind this.  Don’t expect any ‘real’ change until around mid Oct generally.  Beautiful warm autumn weather with chilly nights mostly Eng and Wales.  Scotland and NI will join in soon enough.

 

BFTP

Edited September 25, 2018 by BLAST FROM THE PAST

[Man With Beard]

1 hour ago, Quicksilver1989 said:

Ooops my bad, thought it was a mix of air temperature and SSTs, here is the SST map



Still below average to our west at least.

Looks like a storm feeder to me - big contrast in Atlantic temps

[feb1991blizzard]

5 minutes ago, Man With Beard said:

Looks like a storm feeder to me - big contrast in Atlantic temps

The only consolation I can see is that just right on the very tip of Greenland looks like it wants to warm up, if the cold band would just shift a bit further South we might have a tripole, wheras at the moment we have a reverse tripole, the worse setup possible.

[I remember Atlantic 252]

cool FI, but just what it is FI, won't happen

[feb1991blizzard]

13 minutes ago, I remember Atlantic 252 said:

cool FI, but just what it is FI, won't happen

That's above average temperatures, well above.