Model output discussion - 21st Jan Onwards

[ANYWEATHER]

Evening! The Ecm has started the winter party, its cousin the gfs is not that interested!  Certainly good news for All of us who want to see some wintry weather ,yes even snow falling, but Im reserving hyping it up too much as at present the model output for cold is a fragile one ....

[Frosty.]

10 minutes ago, karlos1983 said:

Apart from hope, absolutely nothing yet, a bit like being a spurs fan I'd imagine 

Only lost 3 premier league matches so far this season, not bad

As for latest model output,  winter could be about to bite back next week and Feb could be a month for coldies to savour if the met office continue to firm up on a mid Atlantic ridge

Edited January 27, 2016 by Frosty.

[Lewisian Lass]

Hi folks, first post! I think the GFS is toying with the idea of rebuilding/ toppling the high pressure over the continental Europe (France). ECM looks more realistic (ever the optimist). I also think GFS will change its tune and begin to agree with the ECM.

 

 

[Singularity]

@nick sussex Sorry to have to take on your excellently detailed post like this, but I'm fairly sure the shortwave you highlight is there (near the Azores in the charts shown) avoiding phasing with the U.S. low on the GFS and GEM output, yet both power the U.S. trough on into the Atlantic.

 

The main difference actually looks to be south of Greenland - that little nose of lower heights, a weak disturbance that forms in that area due to the trough getting a bit further east before the ridge attempts to build.

The jet stream profile offers the tiniest bit of support perhaps. Seems to me though that if the pattern amplifies further from the Pacific, the jet stream changes in favour of a ridge there, making the shortwave more of a consequence than cause... I sure hope I'm right about that; the little feature in that sort of area that took down the weekend fun of mid-Jan remains a sore memory in my mind.

This sort of thinking is why I'm focused more on the ridge from the Pacific (upstream amplification) and the build of the Arctic High (also aiding height rises in the mid-Atlantic due to the expected orientation).

 

The BBC should make a drama series all about shortwaves. It'd have enough unpredictability, twists and turns to win an Oscar 

Edit: speaking of twists, I've just spotted that the shortwave might be there on the ECM run after all (below-left);

 

Spot the 1015 mb circle S of Greenland...

What saves things is that the feature is cleared away east without phasing with the low coming off the U.S.

UKMO (above-right) does phase the features, which is concerning. Could the profile over the Arctic still do the trick?
 

This is the point at which the best thing to do is stop reading so much into the det. runs 

Edited January 27, 2016 by Singularity

[Long haul to mild]

6 minutes ago, Lewisian Lass said:

Hi folks, first post! I think the GFS is toying with the idea of rebuilding/ toppling the high pressure over the continental Europe (France). ECM looks more realistic (ever the optimist). I also think GFS will change its tune and begin to agree with the ECM.

 

 

Yes, the last thing we need is that Euro high sticking around; it's one of the biggest problems we've had in getting cold here this winter.

Hopefully we will see the GFS back down from that idea, but I get the feeling we are in for an interesting but fraught period of model watching!

[Derbyshire Snow]

Evening,

the split jetstream over the US i mentioned last night that i thought just might slow down the atlantic or at least push the jet south a bit, and encouraging some developments on this side of the pond. That possibility is now being picked up by some models. I will be interested to see what the GFS run does this evening when i log on later. It would really be a positive move if we can obtain some better  heights over Greenland to push the jet stream even further south . It would be the perfect time now for an arctic high to make an appearance.A change is afoot.

[Timmytour]

21 minutes ago, Frosty. said:

Only lost 3 premier league matches so far this season, not bad

As for latest model output,  winter could be about to bite back next week and Feb could be a month for coldies to savour if the met office continue to firm up on a mid Atlantic ridge

Yep we've only lost three games....but that's like seeing promise in the models.....means nothing if we don't see success by the end of the season/ snow by the end of winter

For me it's been a good day ECM wise but it's not a complete turnaraound yet.  First of all we need the GFS to get on board and this could be a pub run to look forward to.  But, as this winter will have already proved to those who weren't aware of it before, you can have a whole battery of models and all their ensembles and pertubations lined up showing cold and snow on the way, but then one thing goes wrong and it all folds like a pack of cards.

So let's hope the promise continues to stack up and the curse of many a promising looking spell doesn't materialise......no I don't mean a Nick sussex shortwave I mean a Daily Express snowmageddon headline!

[Sky Full]

Comparing all four main models at +144 I can see two (ECM & UKMO) implying a possible incursion of PM air from the N/NW if the Atlantic ridge strengthens as modelled, and two (GFS & GEM) implying a continuation of the current Atlantic driven windy and wet conditions.  Unfortunately this is not conclusive enough to start placing bets on snow next week and I am also wary of any colder conditions being driven further East by the time they materialise leading to a lovely wintry spell, but in western Europe.  All we will end up with is more wind, more rain and disappointment - again.  Please tell me I am wrong?

[grca]

Sorry mods, please delete this immediately after reading..way too many Tottenham supporters posting tonight pretending to talk about model output :-)  where's all the Liverpool supporters tonight :-)

On topic now, ECM 15 day showing that the op was on the bottom end of the pack, not to say this is wrong and hopefully an emerging trend as this is 2 times in a row.

Apologies just noticed this was the midnight output not the 12Z...

 

Edited January 27, 2016 by grca

[nick sussex]

Singularity the ECM shortwave near Greenland isn't an issue because the upstream troughing is more amplified and the PV lobe in a more favourable location so this is less of an issue.

This of course then feeds into the other shortwave because the ECM manages to get a lobe of high pressure over the top because its more amplified.

You can't ignore the other shortwave because its positioning is related to the overall good to bad of the upstream pattern.

The output that clears that shortwave further east from the main trough and gets high pressure over the top will then of course have the better pattern going forward. And the ECM is best, UKMO next, GFS worst.

Anyway I'm sure the thread members are now suffering from shortwave fatigue so I promise to not mention anything more until the next GFS run! lol

The short ECM De Bilt ensembles and at least to day 8 theres good support for the operational run. The temps given the set up are likely to be colder for parts of the UK.

Edited January 27, 2016 by nick sussex

[Frosty.]

10 minutes ago, Timmytour said:

Yep we've only lost three games....but that's like seeing promise in the models.....means nothing if we don't see success by the end of the season/ snow by the end of winter

For me it's been a good day ECM wise but it's not a complete turnaraound yet.  First of all we need the GFS to get on board and this could be a pub run to look forward to.  But, as this winter will have already proved to those who weren't aware of it before, you can have a whole battery of models and all their ensembles and pertubations lined up showing cold and snow on the way, but then one thing goes wrong and it all folds like a pack of cards.

So let's hope the promise continues to stack up and the curse of many a promising looking spell doesn't materialise......no I don't mean a Nick sussex shortwave I mean a Daily Express snowmageddon headline!

More runs are needed but at least the fat lady isn't singing yet, she's not even in the building!...I'm very encouraged by the Euro runs today, hope it continues tomorrow with the gfs kicking and screaming towards acceptance of a significant wintry spell next week!

[Captain Shortwave]

This set up is a real pain in the proverbials in respect to consistent modelling. But in the end we have 3 options in reality.

1) The low engages the trough to our north east but is to far north bringing a spell of heavy rain and gales to most.

2) The low engages the trough much later and runs through the south of England with polar air digging south with a snow event on the north flank. The trough digging south allows a stronger northerly to develop, how things transpire is unknown but at least we have a real shot at some cold weather.

The ECM shows this nicely.

          

 

3) The low never reaches the UK and instead fills and weakens as it is absorbed by the Azores high. High pressure builds near the UK cutting off a brief polar maritime burst.

The GEM and GFS show this.

     

Too early to call the winning bet, the ideal solution would likely be a set up where the low slips through the Channel with a deeper Euro trough developing which brings snow to the south and snow showers to areas north of this as disturbances slip south/south east in the flow.

I must admit I am surprised by todays output, especially with the ECM, lets hope it is on to something but two runs on the bounce certainly gives more credence to the solution as it appears to not be a rogue run.

 

[Thunder Snow]

2 hours ago, Nick L said:

Just for fun...(this is not necessarily snow depth)

 

Push it a little further north lool. Not getting to excited, look what happened with the last cold spell and how great that was looking

Edited January 27, 2016 by Thunder Snow

[grca]

Updated info...

ECM short ensembles for De Bilt Netherlands, still showing that the op and control are at the bottom end of the clusters but a good sign in my opinion as they should be leading the way in picking up mid term changes.  

[nick sussex]

When you look at the ensemble means for the ECM and GEFS the key difference is the PV split.

In terms of the overall NH patterns they're quite similar.

However NCEP didn't think much of recent GFS runs past day 4 for the USA.

FOR DAY 3/SAT...ALMOST ANY COMBINATION OF MODELS LIKELY WORKS EQUALLY WELL AS THE SOLUTION SPREAD IS SMALL AND SYSTEMS OF LOW AMPLITUDE. BY DAY 4/SUN HOWEVER...THE LAST FEW RUNS OF THE GFS SHOW QUESTIONABLE PHASING OF SEPARATE PORTIONS OF THE NORTHERN STREAM OVER THE PLAINS RESULTING IN A MUCH STRONGER SURFACE LOW AND COLD FRONTAL PASSAGE COMPARED TO MORE LIKELY 00Z ECMWF AND THE ENSEMBLE MEANS THAT MAINTAIN MORE SEPARATION. GIVEN THE TYPICAL CHALLENGES OF CAPTURING SMALL-SCALE PHASING AND THAT FEW OTHER SOLUTIONS SUPPORT SUCH A VIGOROUS APPROACH...THE PREFERENCE IS FOR THE WEAKER SIDE OF THE GUIDANCE THAT IS BETWEEN THE 00Z ECMWF AND THE ENSEMBLE MEANS.

 

[Man With Beard]

NOAA 8-14 dayer is having none of this cold stuff - just the tiniest bit of amplification possible there, so this chart would be too flat for more than a cold breeze after a cold front passes through

ECM ensembles for London shows the op is again a massive outlier between T192 and T216:

But with the ECM control following the op, the colder option is not to be discounted - especially since the run brings in cold via micro-scale synoptics rather than the macro-scale

[Derbyshire Snow]

I like the way the jet stream predicted tomorrow for the US has a north south look. Should be interesting how GFS will interpret that about half way through the run. Will we get a proper blocking high develop, or one of the transient ridges which  would  still give our UK some welcome polar maritime precipitation and in this winter thats a bonus.

[Nick F]

12z EPS control looks very similar to the high res run - with a northerly t+192/216 and a split flow upstream over Greenland and Atlantic around a ridge just NW of the UK, the control sends a low SE on the southern split of the jet towards France and northern Iberia.

[booferking]

Just won,t be getting my hopes up until we have all models singing from the same hymn sheet we have to remember the GFS done rather well in the last cold spell. But we live and hope ECM UKMO are onto something here.

[winterof79]

4 minutes ago, Nick F said:

12z EPS control looks very similar to the high res run - with a northerly t+192/216 and a split flow upstream over Greenland and Atlantic around a ridge just NW of the UK, the control sends a low SE on the southern split of the jet towards France and northern Iberia.

I take it from that Nick,that we have agreement from early on too. Permission to be quite interested sir?

[Nick F]

5 minutes ago, winterof79 said:

I take it from that Nick,that we have agreement from early on too. Permission to be quite interested sir?

Yep, not a great deal of difference right up to day9 between the EC High res and EPS control.

Would still like to see more support from the GEFS towards the EC though ... let's hope the morning doesn't bring a round of disappointment!

 

[damianslaw]

31 minutes ago, booferking said:

Just won,t be getting my hopes up until we have all models singing from the same hymn sheet we have to remember the GFS done rather well in the last cold spell. But we live and hope ECM UKMO are onto something here.

In the reliable timeframe UKMO performed far better than GFS during the recent colder spell (I used colder as it wasn't especially cold), GFS kept bulldozing in the atlantic far too quickly - something it does all the time, but yes it did eventually perform well when the atlantic did crash through.

Back to the models, well yes ECM certainly an outlier today, but it is showing the continued trend towards more average temps at least as we enter February with the euro high shunted away and the Jetstream moving along on a more southerly path. I will be surprised to see a quick development of heights in behind the trough as shown, but some amplification looks likely next week which should help build in some heights which combined with the more southerly jet could lock northern parts into a polar airstream at least, with spillage into southern parts on occasion.

We are already seeing evidence of less warm sector intervention as we head into the weekend, Friday now looking quite a cool day in the north, and Sunday is seeing a marked temp gradient between north and south enabling colder air to dig further in from the NW.

I'm expecting the models in the next few days to start offering up some much colder polar blasts in the 7-14 Feb timeframe..

[Timmytour]

Then and Now...T150 v T144 on the GFS

    

Not too much difference...but what difference exists makes it better!   The Slug squeezed further south

Edited January 27, 2016 by Timmytour

[nick sussex]

The GFS 18hrs run has moved towards the ECM over the east Pacific, has a stronger Arctic high than its earlier run but the movement of that PV lobe over Greenland causes issues.

It also phases the shortwave with the upstream trough exiting Newfoundland and this stops any ridge development, the other shortwave northwest of Iceland then becomes more troublesome as theres not enough upstream amplitude to clear this.

Overall at least some backtrack performed by the GFS but its dragging this out, hopefully it will wave the white flag tomorrow morning and stop being such a pain!

[Eskimo]

Vortex split starting to appear on the GFS!?