Model output discussion - Post SSW - Will it turn cold?

[Allseasons-Si]

8 minutes ago, Daniel Smith said:

Here we go again then. 

ICON an improvement at 66hrs, shortwave further South, Easterly flow developing a little earlier

Oh!!!,i forgot about the IKEA model

yes looking good Dan,good start to the 18z

height's further north too,this at 75.

this easterly looks to be coming in quicker on the ICON.

 

Edited February 16, 2018 by Allseasons-si

[Catacol]

Time to take stock...

Stratospheric split complete, reversal in operation - ECM 10 day forecast for the lower strat is significant

With clear signal for the expected nose of high pressure through the north atlantic, with virtually no westerly impact at all across Eurasia and a canadian vortex under stress from warming over Greenland. No downwelling support for an sustained atlantic assault, that's for sure.

At the tropics an interesting picture: tendency of equatorial angular momentum may have bottomed out

and with MT turning strongly positive 

we have a current signature for GLAAM not falling too far or too fast. This may keep momentum positive over the longer term (lots going on here... is our Nina fading fast?? MJO renewal over the IO set to follow pretty swiftly??) and help maintain sufficiently low momentum profiles over the north atlantic to encourage the block further to the north. 

In layman's terms what does this mean? Complex. I think Feb 2018 might be a much discussed month, dissected and reanalysed many times by students of SSW and GSDM alike - but the best guess at present remains the same as was the case over 10 days ago - height rises to the NE and a storm track pushed to the south underneath the block. This to retrogress over time, so heights transferring from Scandy to Greenland. This may not happen at the first attempt next week (though it might....), but likely on the second shortly after. Evidence? I think op runs will be chucked all over the place tonight - so let's instead look at 3 key ensemble charts.

Firstly CPC human adjusted chart that is usually a strong guide - 6-10 anomaly favourable 

 

with EPS for day 10 also very good

and GEFS in line, though rather less strong in profile

Conclusion? CPC + ECM + GEFS (moderately) + strat profile (SSW, split and canadian vortex under stress) + pacific pattern (more neutral than supportive... but not overly negative) = a strong pathway of support pointing to cold inbound. Mid week as the jump off point, but early enough for snow lovers to get a fix before spring arrives, and longevity might be notable. Too early to be sure on that yet, but I dont think the trop pattern will recover swiftly from the present SSW.

 

 

 

Edited February 16, 2018 by Catacol

[Daniel]

ICON Is looking really good 

[Met4Cast]

ICON is now fully back on board with the Easterly after it's 2 run wobble. It has to be said it's been the best model in this mess, it's been the least chaotic and the most consistent.

[WalsallWeather123]

Big upgrade. Much colder air on ICON 18z vs 6z at T120

[ALL ABOARD]

1 minute ago, Daniel Smith said:

ICON is now fully back on board with the Easterly after it's 2 run wobble. It has to be said it's been the best model in this mess, it's been the least chaotic and the most consistent.

Yes have to say it has trumped both ECM and GFS for consistency over the last few days? 

[lorenzo]

Twitter is amazing to get the insights from the pro's I was lucky enough to catch this discussion today between Mr Masiello and Dir Mike around MJO programming and how it could be improved.

 

Point here is the analog for the MJO imprint that Dr Ventrice creates is probably the best in class the weather community has - and, just look at what is says...

 

 

Edited February 16, 2018 by lorenzo

[Optimus Prime]

8 minutes ago, lorenzo said:

Twitter is amazing to get the insights from the pro's I was lucky enough to catch this discussion today between Mr Masiello and Dir Mike around MJO programming and how it could be improved.

 

Point here is the analog for the MJO imprint that Dr Ventrice creates is probably the best in class the weather community has - and, just look at what is says...

 

 

Wow very interesting. From a fingerprint analysis standpoint (and this is thinking far ahead) I see plenty of similarity's with March 1962 there; quite uncanny infact. 

Edited February 16, 2018 by Optimus Prime
removed visuals

[Mike Poole]

I think this one might be going the right way.  GFS at T66

[inghams85]

The GFS looks like a downgrade in regards to the build of heights into Svalbard. What is going on?

[Fingers]

Mmnnnn..... silence is deafening, a lot being pinned on this run. Heights slightly lower and cold further east at t66-78.

[kold weather]

Well I've looked through the 12z ECM ensembles and they are just AMAZING.Seriously don't think I've seen so many runs go sub -14C! I was looking at some runs thinking ah they aren't so great. Then I see the scale and notice they are showing -11/12C at 850hpa, so still bitter cold!

[WalsallWeather123]

Downgrade from GFS vs 12z. Not building heights into Svalbard as well

Edited February 16, 2018 by WalsallWeather123

[mountain shadow]

Just now, Fingers said:

Mmnnnn..... silence is deafening, a lot being pinned on this run. Heights slightly lower and cold further east at t66-78.

Nothing is ever pinned on a GFS run, never mind the 18z.

[Mike Poole]

Surely the key question is whether the two Highs merge and the low to the WSW goes under,looks like this will happen to me

T90

[Allseasons-Si]

5 minutes ago, Mike Poole said:

I think this one might be going the right way.  GFS at T66

 

4 minutes ago, inghams85 said:

The GFS looks like a downgrade in regards to the build of heights into Svalbard. What is going on?

talk about comfused.com for the beginners in here

[supernova]

Good to know. Every model predicting -NAO.

[Mucka]

Busy in here, have I missed anything? 

ECM gave us the very best possible outcome, it would be a historic late cold spell if it came off.

Expected UKMO and GFS to move a bit further toward bringing in an Easterly second half of next week but at least they have moved!

You would like to think that they will be fully on board tomorrow morning.

[Met4Cast]

The 18z was a little slower on clearing the shortwave and it sent more energy Eastwards across Svalbard but I think it'll still evolve okay, heights are building North-Eastwards at 102

Messier and not clean by any stretch of the imagination, very little margin for error but possibly not the end of the world. 

[Weathizard]

Yup, GFS is having none of it I'm afraid. This is a turning into a mega tussle between the GFS and ECM

[cold snap]

Cold evolution will be slower but will get there.

Let's take stack and say Atlantic weather looking less likely 

[Met4Cast]

Yeah, GFS doing what the GFS does best.

ICON is back on board so I'll take that win, hopefully the GFS stops being useless on the 00z suite. It'll probably develop an Easterly later in the run but it's already out of kilter with the other models so it doesn't really matter. 

Night all 

Edited February 16, 2018 by Daniel Smith

[parrotingfantasist]

Yet again! Same as last night! Stop judging the entirety of a run and going apoplectic when its only T114 in, its already confusing in here at the best of times!

 

 

edit: sp mistake

Edited February 16, 2018 by parrotingfantasist

[jules216]

on 18z ICON, you can clearly see the importance of Gulf of Genoa low that will prevent High from sinking a classic trigger to some cold spells from past,lets hope she is there tomorrow

 

[Ruben Amsterdam]

The problem is the small low of the Norwegian coast shown here at +96. This prevents fusion between the two area's of high pressure.