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Model Output Discussion - The final stretch to Christmas


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Mean while in the real world away from the MOD... A tragic accident has cost 6 lives in Glasgow. yes this is off topic but a timely reminder of just how unimportant the weather really is in our lives.

There is an enormous lack of respect for other people in this thread at the moment. I suggest that if one doesn't have something to add to the model discussion with a salient chart or pertinent inf

Model uncertainty throwing both operational and ensemble data into discontinuity has proved as rife as was expected a week ago - when AAM flipped to negative tendency along with GWO phasing that was i

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CFS is about as reliable as a flea! GFS I usually look to

thanks for that constructive critique....lol

 

The CFS is a long term model and as such is a very useful tool for trend spotting and if it were as bad as you infer, I'd be very surprised that NOAA have invested so heavily in it  :)

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Could the GFS and its naughty sister GFSp be any different? Yet again, GFSp wants to carve out a cold solution,  building a Scandi high by New Year's Eve, whereas the original model goes for a near Bartlett at the same juncture. 

 

If you track the origin of that Scandi high on the GFS P at D9 it is the wedge that came out of the US at T0. In the last 5 days the P has tried to build this wedge of heights into a Scandi High, Greenland High and a cold UK high (none came close to verifying). It is now trying the Scandi High again. This is typical ECM teaser charts and putting any faith in the P at the moment would be highly risky.

 

D10 GFS Op showing consistency: post-14819-0-07257200-1419331231_thumb.p

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hmm.... hints of pressure rise to finish off/start the year, on the plus side its looking dry after the weekends stormy weather, but this morning it looks like we might slip into a benign period of chilly overcast weather after initial fog/frost issues have receeded (going of the ecm). with any fog lifting to low cloud over a period of a few days.

benign, overcast, chilly, dry.... suits me fine IF we get that.

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If you track the origin of that Scandi high on the GFS P at D9 it is the wedge that came out of the US at T0. In the last 5 days the P has tried to build this wedge of heights into a Scandi High, Greenland High and a cold UK high (none came close to verifying). It is now trying the Scandi High again. This is typical ECM teaser charts and putting any faith in the P at the moment would be highly risky.

 

D10 GFS Op showing consistency: attachicon.gifgfs-0-240 (4).png

Trusting the GFS op given its stark difference day 4/5 days out may also be a bit risky and might suggest that the GFS is too flat. The GFS op has no support, not even from the likes of the GEM or NAVGEM on the track of that low.

GEM

gem-0-120.png?00

NAVGEM

navgem-0-120.png?23-11

Both take the low either south or south east

I can't see true cold (snow bringing cold) coming our way outside any frontal snow from this weekends low perhaps. But I do feel a cold variable or continental feed may be possible as opposed to a mild south westerly flow that the GFS op suggests.

 

Not that I am ruling out a proper cold easterly setting up ;)

Edited by Captain shortwave
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Trusting the GFS op given its stark difference day 4/5 days out may also be a bit risky and might suggest that the GFS is too flat. I can't see true cold (snow bringing cold) coming our way outside any frontal snow from this weekends low perhaps. But I do feel a cold variable or continental feed may be possible as opposed to a mild south westerly flow that the GFS op suggests.

 

 

No I agree the op has been a mild outlier on too many occasions of late to believe in its "pure" zonal FI. However the GFS P goes to the other extreme with blocks, undercuts, easterly's, snow storms, etc. When the GFS op is dumped its going to be a cold ramper's dream, with ECM and GFS P throwing up a constant diet of wintriness in FI. At least the GFS op keeps some sanity.

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The weather will do what it will do but dartboard lows have been downgraded, as per usual. So I wouldn't be forecasting acopalypse personally.

 

Hi Downpour,

 

Yes it is nice to see the low slightly downgrading as normal, but as you and I know, this can change from run to run, and they don't always downgrade. I agree in that it would be wrong to forecast the apocalypse with so much uncertainty, but given the scenario I alluded to is not outside a realistic timeframe and most definitely a possible outcome, I would rather have people aware and more likely to pay attention to what is happening than to find out last minute once everything is firmed up.

 

It looks as though GFS is keeping it a deep low although tracking more East than SE, this would still produce a storm surge down the North sea wouldn't it?

gfs-0-108xsz2_mini.png

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CFS is about as reliable as a flea! GFS I usually look to

You could argue the same about GFS if it turns out it has modelled the positioning of this LP all wrong , at the moment it is at odds to GFSP / ECM and UKMO

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Loving the latter part of this GFS(P) run, for amusement purposes. From Russia With Love....the low on this chart over Poland is heading towards us from the East, under the Scandi high.

 

gfsnh-0-216.png?6

 

Then at the end of the run it drops the PV on top of us.....

 

gfsnh-0-372.png?6

 

As I said, probably for amusement purposes only!

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So you're putting faith in the GFS (old) which is being replaced?....

Surely, a model which has verified pretty poorly in the last 5-6 years (due to a move away from typical standard Atlantic fare) would not be the form horse to back...

It's been shown time and time again that in scenarios that go against the grain ie a weaker PV, displaced jet stream etc and any kind of block, the GFS flaps about like a fish out of water.

I do agree that the GFS (P) can't be suddenly adopted as the new king just because it's showing a colder scenario (than the old GFS), especially since it's completely in its infancy.

We may not be digging ourselves out with shovels anytime soon but a quick transition to 'zonal' and 'westerly' conditions looks equally unlikely given background conditions and quite a few OPs runs hinting at the contrary, all IMO of course :)

There does seem to be a tendency from some members to highlight the GFS whenever it finds a milder solution. My personal view is that it won't verify this time and we'll wind up with a fairly benign colder picture with some mediocre snow showers for the favoured areas in the north and east but we shall see. 

Edited by Downpour
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in regards to the ECM | UKMO V's GFS Op. 

 

It's not all that often the ECM and UKMO agree at + 120, so when they do it's more likely they will be closer to the mark than another model showing something different, after all your talking about 2 models with the highest overall consistency at that time frame, both in agreement. 

 

The UKMO at +120

UW120_21_GIF_23_06.gif

The ECM at + 120

ECM1_120_GIF_23_12.gif

Against the CFS Op at +120

gfs_0_120_png_6.png

GFS P

gfs_0_120_png_6.png

 

My money is on the UKMO being closer to the mark. 

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A decent run from the GFS(P) - Cold & Snowy is the main theme all the way through the run.

Event the Operational towards the end gives snow from a cold Westerly feed.

 

No faith or confidence at the moment though, need another 24-48 hours to see if we can get a cross model agreement on what path the LP system takes.

 

We could end up in a Westerly wet feed, or a cold & snowy one.

 

Long way to go chaps.

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in regards to the ECM | UKMO V's GFS Op. 

 

It's not all that often the ECM and UKMO agree at + 120, so when they do it's more likely they will be closer to the mark than another model showing something different, after all your talking about 2 models with the highest overall consistency at that time frame, both in agreement. 

 

The UKMO at +120

UW120_21_GIF_23_06.gif

The ECM at + 120

ECM1_120_GIF_23_12.gif

Against the CFS Op at +120

gfs_0_120_png_6.png

GFS P

gfs_0_120_png_6.png

 

My money is on the UKMO being closer to the mark. 

Totally , now the time frame is so close you would expect ECM and UKMO to be quite accurate......especially as they agree

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Looking at the T126 GEFS to see if I can get some sort of connect with the ECM D5 handling of the low. The short answer is a definitive no. Maybe a 5-10% chance if I am generous of the GEFS going the ECM route. I would be surprised if ECM is right:

 

post-14819-0-48849500-1419333745_thumb.p

 

Still around 20% chance snow this weekend for London: post-14819-0-80483500-1419333945_thumb.g

 

D9 mean very similar to this morning: post-14819-0-18318000-1419333784_thumb.p

Edited by i'm dreaming of...
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Cold - yep. Snowy?

Really think we aren't much further on than yesterday re what follows a MLB next week.

The proposed movement of the vortex from Siberia to Canada seems assured. That opens up many evolutions and the models are making the most of the options available!

The subsequent push of low heights into the n Atlantic following the vortex's arrival in Canada is what is responsible for the general flattening of the week 2 pattern. I suggest this flattening response on a wsw/ene axis is far from assured as yet though clearly, the statistical favourite.

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No I agree the op has been a mild outlier on too many occasions of late to believe in its "pure" zonal FI. However the GFS P goes to the other extreme with blocks, undercuts, easterly's, snow storms, etc. When the GFS op is dumped its going to be a cold ramper's dream, with ECM and GFS P throwing up a constant diet of wintriness in FI. At least the GFS op keeps some sanity.

I've been watching the GFS opp in recent days and its been a complete joke. Every single time it hits low res it spins up zonality pretty much instantly. In some cases its so marked that an observer could be fooled into thinking the model is forcasting that the earth will start spinning faster on its axis!!

Maybe we will go zonal, but there will be no kudos for the GFS opp here. The GFSP's higher resolution in the crucial 192 to 240 range is important. Also GFS Control is essentially the old opp run with slightly changed starting data if I recall correctly. No shock therefore that it just does the same as the Opp run.

GEFS rolling out and a more marked attempt to build heights to our NE yet again.

I've seen worse charts than this......

http://www.meteociel.fr/modeles/gefs_cartes.php?ech=204&code=14&mode=0&carte=0

Its not without some support either.

Edited by Jason M
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Will it won't it... That really is the big question... 

 

Models really struggling to pick this one up and I have been sitting in the wings watching it for a week now and a VERY exciting bit of model watching up and comeing... 

 

Anyway... Here is something iv'e spotted... 

 

CHECK THAT TEMP DROP OUT IN THE DEW POINTS!

 

post-12648-0-73957300-1419334368_thumb.j

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Will it won't it... That really is the big question... 

 

Models really struggling to pick this one up and I have been sitting in the wings watching it for a week now and a VERY exciting bit of model watching up and comeing... 

 

Anyway... Here is something iv'e spotted... 

 

CHECK THAT TEMP DROP OUT IN THE DEW POINTS!

 

attachicon.gifwarm sector.jpg

Lol what have you noticed exactly thats of interest? I would expect dew points to drop nothing unusual.

I like your enthusiasm though.

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No I agree the op has been a mild outlier on too many occasions of late to believe in its "pure" zonal FI. However the GFS P goes to the other extreme with blocks, undercuts, easterly's, snow storms, etc. When the GFS op is dumped its going to be a cold ramper's dream, with ECM and GFS P throwing up a constant diet of wintriness in FI. At least the GFS op keeps some sanity.

You say sanity but of course the GFSo has no support from the other models. Just because it is showing a mild solution doesn't make it any more 'sane' than its competitors.

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You say sanity but of course the GFSo has no support from the other models. Just because it is showing a mild solution doesn't make it any more 'sane' than its competitors.

 

 

Sanity because 99 times out of 100 we get the Atlantic. Even in this "promising" winter we had a CET of +2c in November, currently at +1.1c. I know it was more than likely to be a backloaded winter, if we indeed get cold, but GFS has been pretty good so far at predicting the FI despite the bigger picture. 

 

IDO, both the ECM and UKMO agree at 120 hours. If the GFS is right I will jump into the North sea naked on Christmas day.

 

I recommend Scarborough, not too far to go, has some nice cliffs and the Castle is a good marker to get back to land!

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