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Model output discussion - here comes the beast!


Message added by Paul

Please only post model discussion in this thread 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

We also have a special post SSW cold spell discussion open here:
https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

Thank you!

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Early guidance forewarning of next weeks weather was issued earlier on, and this has been further enhanced with extended outlooks in bulletins. AFAIK (comms not being my area) public agencies and majo

Come on those looking for the breadown before the major cold and snow has begun You will be very lucky if that is the correct word to see this in ANY winter in the rest of your lives I would sugg

Microscale detail absorbing an awful lot of attention on here, when in reality it is a waste of emotion. The macroscale pattern is now fixed - it will not change significantly now for the start of nex

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4 minutes ago, Purga said:

Thanks - but is this still valid for the latest output or from earlier today when the Met forecasts were formulated? The main models seem to have shifted unfavourably for coldies after the 12z runs.:)

From the very latest output and had very strong ensemble support. This has been steadfast in cold until the middle of the month 

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Guys a Question. Today we seen on some of the outputs Gfs Ukmo and Ecm Trying to bring in mild air by 144h.  These runs today showing these cynoptics could this have anything to do with second strat warming?

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10 minutes ago, inghams85 said:

From the very latest output and had very strong ensemble support. This has been steadfast in cold until the middle of the month 

Cheers - good to hear that as i'm sure a good few more in here will! :good:

Edited by Purga
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18 minutes ago, Mike Poole said:

 

Don't know why I have quote above??? Mike has invaded my post :D

Anyways, looking through GEFS its not game over as yet. Some better options in there. Who knows maybe models over reacting to something today. 

Mornings runs will be eagerly awaited I suspect :)

Edited by Jason M
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Significant differences in the GEFS as early as day 4.  I need to revise my previous pessimistic post.  This is not a done deal yet.  Matching any ensemble member to the UK fax for day 5 leads to a positive outcome for coldies.

Edited by mulzy
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3 minutes ago, Mike Poole said:

GEFS ensemble mean at T144 might just calm the nerves:

gens-21-1-144.png?18

gens-21-0-144.png?18

Still think this will go further south, we'll see!

Nope! The HP above Greenland retrogresses too fast and LP's coming in from the SW will create a big mess of changing conditions, merely S to SE driven..

Although the ECM12 was at the end clearly a warm outlyer, it presents the trend in the models. After next weekend it is clearly gone with the cold.

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The GEFS in the reliable looks fine to me. Fun to speculate what might happen thereafter but remember if this low fails to fully break the cold we'll see a very different long-term picture emerge in the models. Time will tell.

Anyone got a coin to flip? 

Edited by Reverse Zonality
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14 minutes ago, Winter Hill said:

 This Gibby is a weather Guru? 

That' it..the cold spell is over because some amature weather enthusiasts says the ECM and The GFS are calling it right.

 

 

No weather Guru but 50 years of studying weather and using mid range model charts for trends I then report on them. It’s worked for me with a few exceptions for years. I can of course be as wrong as the next man and yes there are a lot of ‘ifs’ and ‘buts’ in the coming week but because we seem to have a strong shift in ‘trend’ coupled with the fact we have lost a lot of northern blocking away to Greenland or even worse Canada  by the end of the week I feel the verification is very feasible.

As a side note I also think that the deep cold uppers over us midweek may work against us in allowing that Low pressure from the SW to spin up much deeper as it engages the cold than it otherwise might but I have no evidence to support that. Let’s hope the 00zs revert to what we were seeing yesterday

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More of a thread watcher than a participator, due to lack of knowledge, but do we have the possibility of a Thames Streamer occurring? From memory in 2009 there wasn't much on the cards even a few hours before it began to snow in my neck of the woods, and we had 6-9inches of unforcast snow that night?

 

 

   

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35 minutes ago, Hotspur61 said:

Yeah it was an interesting one with "coldie" Tomasz.Looks like snow showers starting midday onwards on Monday and Monday-Weds looks like showers will become widespread with some prolonged snowfall although he did stress some areas will get more than others(graphics showed some could get 20cms+ while others 3cms or less.Friday could be a possible blizzard for Southern Britain but did stress alot of uncertainty.Whilst models as i write this post have much of South in milder air by end of week the BBC graphics didnt indicate this but Friday is so far away in met terms we wont i feel know  until Tuesday night how far North this low pressure will go.I am just looking forward to the next 48-72 hrs unfold and then take it from there.Lets just enjoy this epic cold for the time of year and hope this ST cold snap turns into a cold spell and this time next week we will still be enjoying it:cold::)

Is this the forecast you mean?   https://www.bbc.co.uk/weather/features/43184987

 

If so, it's indeed interesting to see how much uncertainty is still being placed on the scenario from Thursday onwards, but that the the risks of blizzards into next weekend are now being emphasised.    

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2 minutes ago, The Eagle said:

While we are all here may I offer up some NAVGEM?

 

tempresult_zmo0.gif

 

 

Keeps the the low a lot less intense ? Is that right ? Or am I talking ?? 

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6 minutes ago, ICE COLD said:

Keeps the the low a lot less intense ? Is that right ? Or am I talking ?? 

I would love to have this but Navgem over-estimates the HP above Greenland. ECM, UKMO and GFS don't see this.....

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Right compared to yesterday some themes are now starting to emerge.

1) The Azores low is going to take a northwards path towards the UK
2) There is potential for mild air to make inroads towards Friday.

However on closer look things are pretty unchanged from this morning. The 18z ensembles for example still show plenty of runs with cold air winning out down south. Up north there would be many snow showers (or persistant snow in the runs where weather fronts push further north). Anyway I've updated my graphs showing different scenarios again.

image.thumb.png.869a6c4aab55f6f41722442ca1770ac6.png

Clearly the only thing on here that has changed is that a scenario where the cold pool covers the whole of the UK till saturday appears much less likely now.

However as I mentioned earlier, battleground scenarios where the UK is still under continental air will still see snowfall even if uppers are less cold.

The number of runs supporting a scenario with colder air hanging on until saturday remains unchanged.

Two things could work in our favour:

1) The low weakens as it moves towards the UK and therefore its northwards movement is stunted
2) Northerlies from the Greenland high set in more quickly and keep the warmer uppers away from us.

Both scenarios are very plausible still. A third scenario is that the low remains well to our south but that I think is a low possibility now.

I looked at a group of ECM ensembles, 6 showed milder air taking control by saturday, 16 kept colder uppers over us at the same time.

You could say that the ECM has caught up on the fact that low pressure is coming up from the south but whether this wins out is far from certain. In simple terms ECM is catching up to the GFS. The ops have favoured milder air winning, but that could easily change. The 00z's could show cold air still over the UK by next weekend.

Edited by Quicksilver1989
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Cast your minds back to the first SSW. The models were in chaos dealing with the outcome. Many favoured a mild solution, but they were wrong, and at a short time frame.

Since then, we’ve had a secondary warming. The models will now be in the same position and trying to work out the solution (but with the additional chaos following the first warming)

I firmly believe they will correct to a colder solution, as before.

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