Model output discussion - 7th January onwards

[Mike Poole]

.??? GFS only out to T126, here

Interesting part yet to come, surely!

[Don]

5 minutes ago, FiftyShadesofSnow said:

Regarding the 1st slider, the gfs will never back down at t 96.....expect the Euro to blend in tmw morning...

Why won't the GFS back down at t96 and why should the ECM?

[bluearmy]

Help me out here - which gfs is right?  The old one (which would be toast this month if not for the Mexican wall) or the new one ????. 

[Met4Cast]

Not sure i’d be putting my money on GFS with UKMO/ECM/GFS PARA in agreement re: slider low

[snowice]

1 minute ago, bluearmy said:

Help me out here - which gfs is right?  The old one (which would be toast this month if not for the Mexican wall) or the new one ????. 

FV3 

[Nick F]

19 minutes ago, Allseasons-si said:

Wouldn't warmer sst's produce more convection if the 850's/tm2's are low enough,seems possible?

Yep, warmer SSTs = steeper lapse rates with deep cold crossing seas and thus deeper convection = heavier snowfall. Just need to get deep cold in first place, ie below -10c T850s, which is a tall ask with many cold incursions coming to the UK!

[karlos1983]

13 minutes ago, CreweCold said:

10+ years of model watching experience and analysis 

If we were talking UKMO or EC vs GFS maybe. But both? Nah it’s not likely, it’s an outside bet!

Edited January 13, 2019 by Paul

[shaky]

The differences at 144 hours between gfs against ukmo and ecm are ridiculous!!!if the gfs has not backed down by 00z then i expect the ecm and ukmo to push that low eastwards!!

[ICE COLD]

Well a few backing the GFS @ T 96 . Mmm so we reckon ECM and UKMO are wrong at day 4 ? I honestly can’t see that . I could see a blend tho . Not that it matters anyway it’s after that what matters . 

[Cheshire Freeze]

1 minute ago, bluearmy said:

Help me out here - which gfs is right?  The old one (which would be toast this month if not for the Mexican wall) or the new one ????. 

Can't believe this needs clarifying... But here goes. IMO the GFS at 96 hours will be broadly how things play out with regards to the first 'slider'. More likely a GFS weighted blend of ECM/UKMO/GFS. 

That's the 'old' GFS may I add. 

Anything after that first slider attempt is not what we're really discussing here. 

[Ice Day]

Well maybe the GFS is in disagreement with the Euro's at short range, but it's also in disagreement with itself.  At 144.....

18z  12z 

Still, as Mike said just now we're not at the interesting part of the run yet

[kumquat]

GFS 18z is modelling a very complex 3 centre low at 42hrs, so wouldn't be surprised at changes at that range

[weirpig]

reagrdless how the low acts  the GFS brings snow across a large part of England at 138

[Djdazzle]

The one positive outcome (if the GFS did prove to be correct) would be to stop the annoying “it’s only GFS, bin it” comments!

[Allseasons-Si]

2 minutes ago, Nick F said:

Yep, warmer SSTs = steeper lapse rates with deep cold crossing seas and thus deeper convection = heavier snowfall. Just need to get deep cold in first place, ie below -10c T850s, which is a tall ask with many cold incursions coming to the UK!

I guess we have been unlucky the previous years,surely we are due one.

[northwestsnow]

Wonderful to have such a difference of opinion!!

Truth is, no-one knows which model is correct..

PS GFS will take the walk of shame in the morning..

[Cheshire Freeze]

Just now, FiftyShadesofSnow said:

Because the gfs models lows coming out of Eastern USA much better than the Euros...this debate could run an run but when noaa gets pages up and running I'll show you local verifications. Euros far too amplified and will back down by tmw afternoon. Gfs at t96 in this scenario will not be far off. Expect a blend tmw.

Absolutely, the GFS strength over the others has always been in modelling that area better. A few years ago this was always pointed out. I'm surprised that people have forgotten it. 

[ghoneym]

12 minutes ago, CreweCold said:

I still vividly remember a bbc forecast early 2000s sometime presented by Rob McElwee showing a N'ly topper scenario with max temperatures around 0c for large parts of the country. This was the end of January sometime. 

We struggle to get Arctic Northerlies that potent anymore. 

I presume it's due to the amount of sea ice we've lost over the years. 

Sea ice extent is overall in an emergency state. No doubt about that. 

the slight recovery the website refers too is, in my opinion is due to the current SSW. The warming reduces the chances of PSC clouds (ozone destroying clouds) forming due to the stratosphere temperatures being relatively warm for an unusually prolonged period and allows ozone to reform.

 

  

A healthy ozone layer reduces solar input hence the chances of ice cap recovery. Now bear in mind we are at or very close too the solar minimum and the fact we are looking at "4th and 5th lowest levels of polar ice" the next 20 years look bleak. Sorry to put a downer on things but we need to enjoy these colder and snowy spells as they are modelled because one day it may be a thing of the past

[The4Seasons]

The position of the slider can change even hours before it arrives. Dec 2017 slider was never 100% accurate until 24 hours before the event. 

[Djdazzle]

2 minutes ago, CreweCold said:

The 'arrogant' answer befitted the original blase comment. 

My original comment to you was merely questioning how you were able to see into the future. If that’s not arrogance, I don’t know what is!

FWIW I do tend to agree with your point regarding a blended solution.

 

[Snowman.]

5 minutes ago, FiftyShadesofSnow said:

Because the gfs models lows coming out of Eastern USA much better than the Euros...this debate could run an run but when noaa gets pages up and running I'll show you local verifications. Euros far too amplified and will back down by tmw afternoon. Gfs at t96 in this scenario will not be far off. Expect a blend tmw.

I've seen the GFS wrong at 72. Outed by the UKMO, if the UKMO is with the ECM then I'm sorry but I can't say no to it.

Blend I can see however. Who knows what tomorrow holds.

Edited January 13, 2019 by Snowman.

[shaky]

Not even bothered to look at the rest of the gfs cos its just back to the boring flat pattern that we have just endured weeks on end!!

[Yarmy]

3 minutes ago, FiftyShadesofSnow said:

Because the gfs models lows coming out of Eastern USA much better than the Euros...this debate could run an run but when noaa gets pages up and running I'll show you local verifications. Euros far too amplified and will back down by tmw afternoon. Gfs at t96 in this scenario will not be far off. Expect a blend tmw.

Hurricane Sandy was a fairly large low off the Eastern USA that ended in utter humiliation for NCEP. 

Anyway best wait for the para, eh?

[matty40s]

With the Trump shutdown, NOAA is operating on skeleton staffing, with Trumps denial of anything weather /climate related, I am suprised it is operating at all. The GFS will be lacking input of a normal level and this is probaby why it is fighting its own little corner. 

I expect the arpege to start showing some interesting charts soon, it certainly led the way along with the ICON last March.

[northwestsnow]

GFS has no clue, the difference between 12z and 18 z is laughable..

Hope its had a change of clothes with it for the walk of shame in the morning..