Model output discussion - mid-winter

[johnholmes]

1 hour ago, feb1991blizzard said:

If its a specific target date (yes I know if they are too far away then its pointless looking at specifics) then I want to know what weather is likely, surely better interpretation of the chart is if you can see where the ridges and troughs set up, for instance you can have a +ve anomaly over Greenland and it still be low heights - you might as well just see what the actual height / pressure / temps are, I see it a little different wrt ensembles because at longer ranges (which is what ensembles are essentially designed for) the mean of 50 members is unlikely to show a Greenland high, but if the anomaly is +ve, then that suggests a higher than normal probability - not necessarily odds on favourite just a slightly increased chance.

EDIT : For instance if you were from Qatar and were about to go on an expedition to the North pole, a +ve temp anom of 15c would show off the scale on those meteociel charts but that's useless, you want to know what the temperature would be and it would still be bloody freezing.

We have to agree to disagree. I have used them, with a fair amount of success, for changes in wavelength and subsequent weather types for getting on for 10 years. They are not intended to give detail in any form. One does have to use them carefully and I suppose being an ex forecaster that is inbuilt in me anyway. One of their main attributes is being 'mean' charts and at 500 mb they are less volatile for the 6-10 day time frame than the 2x or 4x synoptic outputs in that time frame. Like all things they are used in conjunction with anything else we get free and an overall assessment can then be made of some detail, but like I say each to their own-best wishes and good luck.

[frosty ground]

Just now, Northern Sky said:

Strange because usually with these kind of situations you see the uppers becoming moderated the closer they get to reality. This run has actually upgraded the cold in a reasonably close timeframe. I'm not convinced as yet but interesting nonetheless

Not sure that's the case.... I think each situation is unique. Plenty of time the cold gets moderated only to regain strength near the time.

[Day 10]

Windchill Weds morning!

[feb1991blizzard]

1 minute ago, johnholmes said:

We have to agree to disagree. I have used them, with a fair amount of success, for changes in wavelength and subsequent weather types for getting on for 10 years. They are not intended to give detail in any form. One does have to use them carefully and I suppose being an ex forecaster that is inbuilt in me anyway. One of their main attributes is being 'mean' charts and at 500 mb they are less volatile for the 6-10 day time frame than the 2x or 4x synoptic outputs in that time frame. Like all things they are used in conjunction with anything else we get free and an overall assessment can then be made of some detail, but like I say each to their own-best wishes and good luck.

BTW I agree (or don't mind them) the way you use them - for 5 day periods averaged out - I just see them as a bit pointless for the exact chart at 144 etc.

[Ali1977]

Next week starting to look really good - plenty of snow around for most , with blizzards at tines

[mulzy]

6 minutes ago, Northern Sky said:

Strange because usually with these kind of situations you see the uppers becoming moderated the closer they get to reality. This run has actually upgraded the cold in a reasonably close timeframe. I'm not convinced as yet but interesting nonetheless

Remember, the GFS has a known bias of overplaying the 850s.  Just be careful not to get sucked in...

[Northern Sky]

Just now, frosty ground said:

Not sure that's the case.... I think each situation is unique. Plenty of time the cold gets moderated only to regain strength near the time.

You might be right. I've no charts to back me up it just feels like I've watched potent incoming PM air slowly moderate as the days tick down many, many times. So often the synoptics look pretty similar but the depth of cold is - in my memory at least - usually overdone, especially in low res. For me what's interesting is that this PM blast has pretty much ticked down intact right from around 10 days out. Hopefully it will continue to do so, or even better, get even colder

[Paul]

I'm sure I've said this a few times before, but anyway. For bantery stuff, which isn't model discussion, please use the banter thread not this one...

 

[karyo]

The Atlantic ridge at around 180 hours has become a recurring theme on the GFS. For once the Azores high could help by pulling west and joining the high exiting Canada.

[frosty ground]

Bigger Ridge in the Atlantic Uppers are now getting mixed out but its what follows that is of interest. 

[Day 10]

Better ridging north of that high in the Atlantic, good runs so far this eve.

lol just seen your post above frosty ground

Edited January 11, 2018 by Day 10

[Glacier Point]

Gfs becoming more and more apparent with the southern arm of the jet over the US day 8 onwards...

Edited January 11, 2018 by Glacier Point

[Rocheydub]

18 minutes ago, That ECM said:

-8c 850's coming south of the m4 on this run

That chart does not show that at all!

[andymusic]

and so we get to this by next Friday - steady as she goes gfs

 

[Singularity]

 

Yes... this is what I've been waiting for as tropical signals feed across; the US jet tracking more S with the Canadian trough getting held-up rather than moving bluntly east as ECM has kept on doing and GFS to a lesser extent until this 12z run.

[Weegaz]

Best chart I have seen in a long time, didn't even get to look past this chart.....bank bank bank bank bank bank bank bank

[mulzy]

Snowcharts = chocolate fireguard

When will people learn?

[Day 10]

Just now, mulzy said:

Snowcharts = chocolate fireguard

When will people learn?

NEVER, like you that's why we keep coming back

[northwestsnow]

25 minutes ago, That ECM said:

-8c 850's coming south of the m4 on this run

Wow Gfs really ramping this up!

[nick sussex]

The race continues between the sinking trough and energy upstream .

The sooner the bloated trough sinks and flattens out the better.

[andymusic]

right out to a week Saturday and now a northerly

[mulzy]

1 minute ago, nick sussex said:

The race continues between the sinking trough and energy upstream .

The sooner the bloated trough sinks and flattens out the better.

Indeed Nick - that's where my interest lies.

Day 9 chart not without interest.

Edited January 11, 2018 by mulzy

[Ali1977]

1 minute ago, northwestsnow said:

Wow Gfs really ramping this up!

Agree, way better than a stagnant weak Easterly !! I think this is being totally underestimated by some !!

[northwestsnow]

21 minutes ago, Day 10 said:

Windchill Weds morning!

Thats inctedible!!( from a westerly) !!

[frosty ground]

1 minute ago, mulzy said:

Indeed Nick - that's where my interest lies.

Day 9 chart not without interest.

No interesting charts until day 8.....