Model Output Discussion - Spring Has Sprung

[baddie]

 WYorksWeather If this promises dry and sunny conditions then its fine

[Cheshire Freeze]

 jamesthemonkeh The blocked March signal in the seasonals has been there for months.

We’ll have to wait and see I guess.

Edited February 15 by Cheshire Freeze

[Penrith Snow]

If you don't like wet weather don't look at this mornings GFS, it relentlessly wet up north and these conditions spread south next week to give a soaking FI everywhere with slow moving low pressure systems.

ECM is similar with both models bringing in a cool North westerly next week so we may get snow on high ground in Scotland and a slight frost further south.

It's terrible output to finish off a terrible winter with not even a sign of an early spring to make up for it, it's no stop cloud and rain.

I remember the mild winters of the mid 70's but they were nothing compared to this years car crash, even in 1974/75 which was a very mild winter for its time the weather was often bright and dry with few gales, January 1975 brought widespread snow on the 24th and February was mild but benign. Then March brought some great weather with frequent very cold easterly and northerly winds, widespread frost and heavy snowfalls which continued well into April, May was unusually cold, frosty but sunny, while June brought freak snow on the 2nd then a 3 week heatwave.

The weather in other words was 'interesting', I find nothing interesting about mild, sunless southwesterlies that persist for weeks on end, maybe that's just me

Andy

[Dennis]

1 chanche still there......setup from 20-22th 

Edited February 15 by Dennis

[northwestsnow]

Guys there is a post mortem thread

00z runs all suggest an angry looking Atlantic midterm with potential for some very snowy weather for high ground up North .

For the majority of the country it just looks crap though.

Edited February 15 by northwestsnow

[northwestsnow]

 Dennis thanks for providing excellent analysis through the winter.

I'm sure you are as fed up as we are but you manage to keep optimistic somehow.

Sometimes the charts come off ,sometimes they don't ,that's life i guess ..

Edited February 15 by northwestsnow

[Purga]

Cool & a vague chance of the odd ground frost, as long as as you behave & have a good dollop of luck. Whoopee - not.

PS: Forgot to mention, we may get 16cm of snow next weekend - don't die laughing.

Edited February 15 by Purga

[Dennis]

 

 northwestsnow i was yes not anymore

[Dennis]

Vortex lobe over the UK with northwinds

[Dennis]

 AO- yes Jackpot here  days are mostly cold , but this week not all the time 

dangerous icerain for norway in South parth tomorrow 

[Mike Poole]

 Cheshire Freeze I think now the signal for March will go the way of the signal for the rest of winter.  Down the toilet.  Shocking performance by the seasonals this winter, and don’t get me started on the ECM 46!

[Flub136]

Round 2....ding ding! 

[Dennis]

NOAA 22th 

[Anthony Burden]

Morning all,Looking at the charts this morning with no sign of SSW showing any high level blocking a possible end to hope of some wintery weather to end this winter.I will wait another week before I close the book on this depressing winter.

[Purga]

A Bartlett by any other name would smell as foul

[Rain All Night]

12 hours ago, Rain All Night said:

12z deterministic runs, Thu 15th to Wed 21st (day 7)

Whilst there is divergence on the finer details from Tuesday onwards - ECM lets the high pressure put up more of a fight before presumably being blown away - ultimately the same outcome looks inevitable in about a week's time, based on the ensemble means below.

12z ensemble means, Thu 15th to Thu 29th (day 15)

We seem agreed on the arrival of the big purple blob on either 21st or 22nd Feb, but ECM is now losing interest in subsequent troughing to our east; GFS still makes more of an effort in that regard, around 26th Feb, but beyond that, it converges with the ECM in suggesting quite a significant-looking build of pressure approaching us from our west - could we be heading for a more settled start to spring?

Just for fun, here's a cherry-picked ECM ensemble member that illustrates the outcome I'm imagining, based on those ensemble means...

0z deterministic runs, Thu 15th to Thu 22nd (day 7)

ECM still wants to bring in the big purple blob a little more gradually than the other models do.

0z ensemble means, Thu 15th to Fri 1st (day 15)

It's now the ECM that's most keen on showing us a glancing mean northwesterly flow between a ridge to the west and a trough to the east on 26th Feb, whereas for ages that had been the GFS's signature.

The high pressure signal out to our west unfortunately doesn't linger as much at the end of these runs as it did on the 12z runs yesterday.

Edited February 15 by Rain All Night

[MisfitDog3]

Interesting to compare GFS with ECM runs for the next 10 days or so. ECM likes the ongoing westerly approach and blows up a large mid-Atlantic High for the middle part of next week. It doesn't really know quite what to do with it after that and I am suspicious about the lack of any notable low pressures being generated over the run. GFS is a lot more active on the cyclogenesis front and projects the High closer to the UK. Given the rapid development of the High on both models (though very different placement) and dubious rapid retreat of the High given the projected size of it, I am not convinced we are seeing a convincing picture just yet. I have a nasty feeling we might just get kicked back into endless lows belting in off a lively Atlantic, which is rather a depressing prospect to be honest......every dog walk is a mud-fest already.....

 

 

[LRD]

Absolutely remarkable warmth today. Took the dog out wearing just 2 layers this morning. Feels like April

And little sign of anything cold over the next couple of weeks. It's going to turn less mild, of course but nothing out of the ordinary looking at these ensemble suites from GFS and then ECM

 

[Mike Poole]

14 hours ago, LRD said:

Agreed. The ECM clusters have been useless this winter (and last). But they're anomaly charts which are not to be trusted in the slightest.

Just to correct this point.  One of the main benefits of the clusters presentation is that they are not mean charts - i.e. the  charts are representative members best representing each identified cluster.  So they are physically real, and not some averaged mess.  While the shading is indeed an anomaly, the height contours are not - they are the actual height contours of an individual run.  So the best way to read them is, yes take the colours as a guide (if they are dark colours) but bear in mind they are an anomaly, but look in detail at the height contours which give the upper wind flows which are real.  For example, here’s today’s T264+ chart:

Look at the top right one, cluster 1 T360, here is the representative member at that time:

You can see that the height contours on the cluster plot match the height shading on the Meteociel plot.  

The clusters are a probabilistic representation - whether any of the clusters at day 10-15 have actually included the weather that eventually verified is a question that needs to be answered probabilistically (my view is sometimes, but quite often this winter they have showed blocking with quite high probability that hasn’t happened).  But that is a judgement on the verification of the EPS, not because part of the cluster chart shows a shaded anomaly, as I say, when reading them it is best to focus on the contours.  

[LRD]

 Mike Poole Totally agree and, as I say, it's an anomaly chart so can easily mislead. I distrust all anomaly charts and how they represent data. How many times have reds been shown over Greenland and Scandi and nothing has happened? What is the point of all the pretty colours if it's the contours that are important?

You do a sterling job reporting back on these but I guess it's just my personal taste. I don't like them and don't feel they present data (both forecast and present) that well

[Mike Poole]

 LRD I agree with you about anomaly charts - particularly ones which are both an anomaly, and averaged over many runs, or indeed many days as well - they can be misleading.  For two reasons primarily, first you can’t infer wind direction around an average anomaly very well.  And second, a high anomaly may still mean low pressure/heights, just not as low as climatology - this can be particularly misleading in areas such as Greenland when climatology would have the vortex plonked over there, so a slight high anomaly does not mean a Greenland high.  

But as I have explained, the averaging problem does not apply to the cluster charts, and the anomaly issue is only relevant to the shading.  

[Johnp]

 Mike Poole I hope people remember this when they start pumping out EC46 charts next winter. Literally a (proven) waste of time. 

Edited February 15 by Johnp

[LRD]

 Mike Poole Yep, sure, I get that they're not an averaging product. In that sense I think they've been even MORE misleading as it's not uncommon to have many clusters showing reds where we want them (in winter, anyway) and nowt happens. But, it could be that they are actually pretty accurate. As reds over G'land (where pressure is usually low) could just mean a weaker low pressure than normal - but that is still an anomaly but still doesn't lead to wintry conditions. Similar to blues over Europe where pressure is usually fairly high even in winter. Could just be a weaker area of high pressure but still high pressure

But average or not, I really, REALLY dislike pressure anomaly charts.. As you can probably tell 

Edited February 15 by LRD

[LRD]

 Johnp EC46 does have temp and precip anomalies though. Much more useful and much less ambiguous. Not saying it's accurate but it does at least give a more 'real-world' view than pressure anomaly charts

[feb1991blizzard]

How about -12c uppers with a deep wrap around low.