Model output discussion - into 2018

[karyo]

12 minutes ago, kev238 said:

There is no doubt ECM and GEm got in wrong - lots of praise about how consistent the latter was but that's no good when it's consistently wrong.

The GFS was also way off but there was far too much wishing for the ECM/GEM to be correct. 

Personally , I was enjoying the cold westerly driven weather we had been experiencing and consider this interlude to be somewhat tiresome. Hopefully some active weather with a NW/SE jet resuming . What I fear is shaping up though is a milder second half of January with the more traditional SW/NE jet and a block to the east merely preventing anything interesting from occurring over us. 

Indeed this is my concern too! We have lost the favourable jet axis and the sinking high is going to rise pressure over the continent with the jet to our west and north.

[pureasthedriven]

4 minutes ago, stodge said:

Morning all

Oh dear, it's all doom and gloom here this morning, isn't it ? We aren't even half way through winter and you'd think we'll never see a frost let alone a flake of snow again.

It's not a question of "learning lessons" and being all "I'm not believing it until every model agrees at T+3" - fine, but it'll be a grumpy old place if we all thought like that. It's chaotic science at best looking 6-10 days out - the Ens are helpful because there are more attempts to get it right - think infinite number of monkeys and Hamlet.

Anyway, before the Mods throw me off for hesitation, obfuscation and obstruction, my take on where we are this morning looking forward:

ECM goes for a full Atlantic breakthrough and a serious old storm at T+240 but we can probably ignore that. Neither GFS 00Z OP nor GEM bring the Atlantic through in strength and indeed the HP rallies later next week so could be quite a quiet, chilly spell for southern and eastern parts in particular.

The other observation is the continued negative tilt in the trough going forward so it's less a case of positive tilt and blowtorch SW'lies than back to square one with the jet running over or just to the south so while I wouldn't call it "cold zonality", the periods of PM air are and would be noticeable but not what most want.

UKMO at T+144 looks worrying as the Azores HP is coming in and the trough is tilting positive but we'll see and I also note the GFS 00Z OP scrubs the PV out of NE Canada by the end of FI and I wonder if that could be the next direction of travel in 10-14 days or so. Until then, after our brief flirtation with something colder and drier we have to accept that in the words of the song "all we can do is just sit and wait".

There's plenty to look at and the medium term is far from resolved this morning.

I’m guessing the angst is because once more - and it seems ever thus - the really good Synoptics are always 10-14 away. I know there was some good December snowfall, not that I saw a flake here. In fact, no lying snow here since March 2013. That’s nearly five years. Five! 

[nick sussex]

The differences between the ECM and GFS start very early and theres an unusually large spread given the timeframes of T72hrs and T96hrs on the ECM.

You can see here the main spread is in relation to how much energy gets east and how far north the initial ridge gets:

T72hrs:

 

T96hrs:

 

I think its a real struggle to hang onto the block given todays ECM op and even the UKMO at T168hrs looks more unsettled although it might still have better ridging to the ne given its T144hrs timeframe.

In terms of the MJO I'm wondering whether the ops are caught in between two stalls, are they seeing a phase 1 or phase 2 signal. The MJO forecast which screens out interference from Kelvin waves etc:

 

You an see there the low amplitude phase 1 which in terms of rough composite would be a ridge to the ne whereas the phase 2 would bring troughing close to or over the UK.

So phase 1:

 

Phase 2:

The ECM op does develop into something close to that phase 2 , is it too quick to do that. The issue here is perhaps one of timing but of course the angle of the approaching trough might be another issue .

Anyway we should know by this evening which is the correct trend.

Edited January 5, 2018 by nick sussex

[booferking]

32 minutes ago, karlos1983 said:

Just remember folks, before this attempt at an easterly, the outlook was very bleak indeed with no sign of cold on the horizon!  So although we may see a more mobile period of weather again, (after a significant weekend cool down) We could very well be sitting here in a weeks time eying the next bout of possible cold weather. Who knows , it might even verify next time 

good opportunity to recharge the old model watching batteries me thinks! Unless we get an historical reversal in the output and I’ll be back quicker than a moaning football fan when your team wins again.

There was cold zonal hinted at which was ticking along nicely until this easterly appeared and wrecked havoc in here hopefully the fi in gfs is correct and we get back into what was delivering to many this winter and that was cold zonal jet heading South.

Edited January 5, 2018 by booferking

[West is Best]

2 minutes ago, pureasthedriven said:

I’m guessing the angst is because once more - and it seems ever thus - the really good Synoptics are always 10-14 away. I know there was some good December snowfall, not that I saw a flake here. In fact, no lying snow here since March 2013. That’s nearly five years. Five! 

The real angst is because the wondrous synoptics were 72-96 hours away and, quote, 'a dead cert.'

That's the real issue: that models of some esteem can be so massively wrong at such short range. Whilst others may pick away at the GFS on the fundamental point about the position of the Scandi high it got it right. And that's why it was on the right track when all others lost it: the difference between a split jet powering south which opened the floodgates on the alleged easterly (GEM, ECM and to an extent UKMO) and a sinking Scandi high that returned us eventually to zonal rubbish (GFS).

The real lesson here is that we have to avoid wishcasting. Actually, I'd put it more simply than that. Unless the GFS comes on board any cold scenarios might as well be the product of my son's primary school drawing class.

[karlos1983]

5 minutes ago, booferking said:

There was cold zonal hinted at which was ticking along nicely until this easterly appeared and wrecked havoc in here hopefully the fi in gfs is correct and we get back into what was delivering to many this winter and that was cold zonal jet heading South.

Cold Zonal delivering to many this winter.... thanks but no thanks! Cold rain isn’t for me cheers. 

The point is if we go back to Zonal then it doesn’t mean it’s there to stay, like we’ve seen recently, things can change quickly.

 

[Glacier Point]

Today

Very coherent MJO Phase 2 signature in the Indian Ocean

Composite and next few days 500hPa mean anomaly

Week 1 very coherent MJO Phase 3

 

Allied to the GWO composite for phase 2 (low angular momentum)

Sound support for the mean trough to edge over / closer to the UK.

Week 2 continues to progress as a Phase 4/5 MJO evolution. Composites:

But, the nuances of the GWO may well kick in if we get angular momentum on the rise,. Composites for phases 4 and 8 are relevant and very different to the MJO (as are the composites filtered for weak / east based La Ninas). Additionally, the MJO composites may also contain El Nino years which would bias the outcome.

So two different takes on where week 2 and 3 might be heading. I would hedge to the weak La Nina being a crucial thing here, in which case your GWO composites are the ones to follow in the very extended period, January 20th onwards - but crucial here to monitor for signs of not just the MJO being the only show in town.

[carinthian]

Morning all, not to be to down beat for cold lover. Still some interest shown by our forecast providers.  Their short range charts still develop a low to the SW of England by next Thursday  that may hold a cold flow for your part of the continent. More later.

 C

Edited January 5, 2018 by carinthian

[carinthian]

Just now, carinthian said:

Morning all, not to be to down beat for cold lover. Still some interest shown by our forecast providers.  Their short range charts still develop a low to the SW of England  that may hold a cold flow for your part of the continent. More later.

 C

 

[nick sussex]

Thanks GP but given the time lag are the outputs reflecting that? 

Phase 2 is certain but before that where exactly was the MJO.

Wasn't there a conflict with two areas of convection one further east so could the outputs have been misreading that as the MJO when it wasn’t ?

Edited January 5, 2018 by nick sussex

[Nick F]

There's no point sugar coating any of the  output this morning, although UKMO and GFS prolong the undercut of the block over NE Europe, the block is too far east to advect any decent cold our way to interact with Atlantic frontal systems and bring snow away from hills, more likely source for any snowfall would come from Polar maritime flow from the NW. The EPS and GEFS point to an extension / lobe of tropospheric PV over N Canada have increasing influence again on the weather over NW Europe, i.e. +NAO signal and this has been showing in the ENS for a while, despite what the now ridiculed EC op has shown earlier in the week.

Looking longer term, +EPO signal showing for a while in the ENS with low pressure/troughing over NE Pacific replacing the -EPO ridge that was a familiar feature through December, so the upper flow flattening out across N America, with deep cold over mid-west and Ern U.S. retreating back to Canada with time and the flow flatter over the N Atlantic as a result.

10-15 day mean 500mb heights from both GEFS and EPS indicate low heights anomaly over UK/Ireland - which indicates low pressure systems a plenty crossing the UK, but could contain some cold Pm shots, best we can hope for until the pattern changes.

The MJO is headed through the 'warmer phases' in next few weeks, i.e. the wave is too far west (Indian Ocean) to have an effect on providing poleward upper divergence and effect changes in upper flow over N Pacific, so the flow will remain zonal across the N PAC, N America and N Atlantic. However, the EC weeklies out last night did show a return of the -EPO later this month and we may see the MJO orbit back into colder phases later this month too.

But for now, think I will have a break from analysing the models in any great depth for cold and do more constructive things with my time, obviously keeping an eye on them, because I don't think the block over NE Europe will have much influence before it fades, more the Atlantic will. Hard to swallow, but that's life being at the windward end of a large ocean. Its seems that recent years (post 2011) that unless you live on the eastern side of the large continental landmasses of the Northern Hemisphere, being N America and Eurasia, the moderating effects of the warm oceans and the anomalously warm arctic will keep the cold away.

Edited January 5, 2018 by Nick F

[Jason T]

59 minutes ago, karyo said:

Really? Where? Unless you mean a bit of frost and a cold wind.

Apologies for misleading @karyo  I should have said a more wintry feel, For how long who knows. Enjoy your Friday.

https://www.netweather.tv/weather-forecasts/news/8660-winters-chill-takes-hold-this-weekend-with-brisk-winds-off-the-north-sea

[The Enforcer]

10 hours ago, The Enforcer said:

This is the key timeframe to watch as each run comes out. In order to break the aforementioned 7 day hoodoo, we really need to see incremental changes in the form of the green over the UK getting replaced by blues and the darker blues continuing to edge further from Eastern into Central Europe. All of which is realistically possible.

Could anyone post the 850 meteociel charts for the 00z and 06z GFS for 6am next Wednesday.

3 hours ago, Weather-history said:

ECM op 0z run has gone from that 3 days ago to this now at the same time frame. A 1035mb high cell around Iceland to a 975mb low southwest of Iceland, It maybe just the op run but its almost embarrasing.

I don't think the ECM is particularly reliable at T+168. It is conceivable that the block could move back gradually westwards at that timeframe over the next 14 runs.

[Frosty.]

14 minutes ago, Jason T said:

Apologies for misleading @karyo  I should have said a more wintry feel, For how long who knows. Enjoy your Friday.

https://www.netweather.tv/weather-forecasts/news/8660-winters-chill-takes-hold-this-weekend-with-brisk-winds-off-the-north-sea

Certainly an increasingly wintry weekend with severe frosts in the north with minus double digits celsius for some according to the Gfs 6z.. the weekend looks like gradually becoming drier from the north as high pressure builds in, sunday the best day of the weekend.

Edited January 5, 2018 by Frosty.

[TEITS]

Im going to have to disagree with virtually everything said on here. I think the best way of illustrating what I think is going to happen for the period between 15th Jan and beyond is by simply drawing the charts I feel will become the reality.

Shall post these in around 1hr.

[wintermaster]

40 minutes ago, pureasthedriven said:

I’m guessing the angst is because once more - and it seems ever thus - the really good Synoptics are always 10-14 away. I know there was some good December snowfall, not that I saw a flake here. In fact, no lying snow here since March 2013. That’s nearly five years. Five! 

Thats stange because i live in Crawley and we had Lying snow in Jan last year.

[JOPRO]

 

Well, if we have learnt one thing from this it is that MOGREPS is just as fallible as the other tools we have available when it comes with forecasting a cold spell,  wasn't it the other day the all members bar one were going for an easterly next week? I for one have been waiting for the last 3 winters for it to pick up a cold signal out in FI and run with it down to 0hrs. Despite this its performance of the last few winters has been very good, just a kick in the teeth when it has had a wobble its when its been showing a period of easterly flow!

Anyway as have said before to tweak a quote from Hemmingway :- ‘There is no hunting like the hunting for snow, and those who have hunted snow long enough and liked it, never care for anything else thereafter’

Or is that just me?

[nick sussex]

Now the GFS is trying to disrupt the trough with that shortwave developing at the base at T162 hrs.

The trough moving in is certain but the angle is still less so.

[ArHu3]

3 minutes ago, wintermaster said:

Thats stange because i live in Crawley and we had Lying snow in Jan last year.

Snow can be very local, 10-15cm in one place and nothing just 10-15km away 

[carinthian]

27 minutes ago, carinthian said:

Morning all, not to be to down beat for cold lover. Still some interest shown by our forecast providers.  Their short range charts still develop a low to the SW of England by next Thursday  that may hold a cold flow for your part of the continent. More later.

 C

Maybe this is what they had in mind. Might as well stop there at 144t.  Upper 850mb temp profile also shows widely below 0C temp isotherms on Thursdays chart. Lots still be resolved yet and still hope for fans of colder weather but hopefully less wind and rain for you guys.

C

Edited January 5, 2018 by carinthian

[feb1991blizzard]

The upshot of all this nonsense with the ECM anyway is that its chewed up most of January and we are going to require the services of S.S.W but that needs to hurry up if its going to happen because of lag times involved.

[nick sussex]

The issue of how shortwave energy over the UK clears does effect that trough.

As soon as that attaches to the upstream trough it’s going to pull that east and stop the energy going se.

[That ECM]

6 minutes ago, TEITS said:

Im going to have to disagree with virtually everything said on here. I think the best way of illustrating what I think is going to happen for the period between 15th Jan and beyond is by simply drawing the charts I feel will become the reality.

Shall post these in around 1hr.

You might not need to, gfs doing it for you? But if not and your not happy with the output millions of pounds worth of computers are generating, draw your own!!

[ItNeverSnowsInWindsor]

6 minutes ago, nick sussex said:

Now the GFS is trying to disrupt the trough with that shortwave developing at the base at T162 hrs.

The trough moving in is certain but the angle is still less so.

Also the block over Scandinavia looks a bit stronger.

[karyo]

3 minutes ago, nick sussex said:

The issue of how shortwave energy over the UK clears does effect that trough.

As soon as that attaches to the upstream trough it’s going to pull that east and stop the energy going se.

At least the 6z re-introduces some continental air and this time the uppers are just below 0. Better than the ECM for sure but still not be right.