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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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Looking at the 06 run I would say a less cold outlook by Friday is looking more and more likely,it seems to be the trend. Even the ECM shows the milder line affecting the south coast, so its hardly rock solid cold agreement.but in the meantime its looking very cold next week particularly Wednesday/Thursday. Daytime maxes -3 to 0 across them 2 days.

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5 minutes ago, Djdazzle said:

I do think that the GFS 6z is the more unlikely solution. But we also need to remember that there have been examples in the past where strong blocks of cold air have been easily shunted aside. Didn't that happen in Feb 1991?

Not sure, but synoptically I think something did happen like this and I think for the west there was some initial rain.

Anyway I'm going to closely watch the ensembles, then trawl through ECM ensembles and see exactly what support there is for this sort of set-up. The biggest issue is how far west it is AND the exact shape, if its a ball, then bad news. If it is somewhat flatter on the northern side we should keep enough of a surface cold flow to do ok even in the far south.

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1 minute ago, stainesbloke said:

Yawn. Let’s all believe the GFS that’s next to useless in easterly outbreaks. 

Some pointless panicking going on I reckon! It was only in December for that little slider low that the GFS had it so far north about 4-5 days out, and then it just kept on getting corrected further S each day! Infact it ended up so far south that I actually nearly missed out on it altogether! 

Worry about this thing when it comes to 12 hours out. This will be a NOW casting event for sure. 

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20 minutes ago, Djdazzle said:

True, but the ECM and UKMO has also trended further north, but to a lesser extent. Not saying GFS is right by any means though.

So as always it will probably be somewhere in the middle!

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4 minutes ago, Mr Frost said:

I have just read GFS displaces all the cold air and that the GFS is poor for long term cold. (both these events currently modelled to happen on 02/03/2018...:D)

So from Monday to Thursday there are currently Metoffice warnings out for most of the UK and Ireland - anywhere between 2cm and 20cm for again LARGE parts of the UK and Ireland. This would be a four day extremely snowy and very rare spell of cold weather. (Meteorological Spring starting during this) On top of ALL this the people who are looking way ahead to the low coming up from the South are also the  ones in the warning zones for the beast from the East snow showers which will be blowing through from Monday PM onwards...honestly my mind boggles at times in here! I am flabbergasted. :rofl:

With regards to the above...we are two days away from the start of the most sustained snowy period the UK and Ireland has seen in years, rare beast from the East making a grand entrance and hanging around, potential for again large parts of the UK and Ireland to remain in the freezer until mid March at least and high chance of a couple of blizzards blowing through Southern parts of England.

What more do people want? Honestly I come into this thread buzzing with excitement and energy and then when I leave feel like this...

I'm sorry but for people in the south west and parts of central southern England they are relying on the lows from the south/west to bring snow, its a cold week but for many of them if the GFS were to pan out as is they would have nothing of note, hence why people in these areas are concentrating on this event.

Just because yours or other locations are favoured by the initial spell, others aren't.

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So the gfs this morning is showing a cold snap from Monday to Thursday then brief heavy snow quickly turning to rain in the south overnight into Friday. The gem has a similar theme but keeps the low further south and the ECM has the low further south still. Its not encouraging that the gfs continues to show this happening but as per usual the gfs is renowned for over blowing lows and is more progressive generally than the other models. This should start correcting south and east slightly by this evening. However it's not too encouraging that the ukmo shows a similar chart to gfs at 144 so im very cautious at the moment. It just seems that every time there is a decent chance at some proper snow, it gets displaced. Before then obviously plenty of snow around this week but very dissapointing to see how it could potentially end. Not a great start to Saturday! Hopefully an improvement on the 12z. Lets all hope!! 

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Not at all bothered by what the GFS is showing at this stage. All models struggle with these scenarios and the GFS always struggles the most.

Not just saying that because it’s not showing what I want. It actually gives my area a prolonged period of snow. I just know it is hopeless in these setups.

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5 minutes ago, East_England_Stormchaser91 said:

Some pointless panicking going on I reckon! It was only in December for that little slider low that the GFS had it so far north about 4-5 days out, and then it just kept on getting corrected further S each day! Infact it ended up so far south that I actually nearly missed out on it altogether! 

Worry about this thing when it comes to 12 hours out. This will be a NOW casting event for sure. 

Absolutely. There’ll be masses of interest from tomorrow night onwards with the deep cold coming in and shower activity rapidly increasing with chances of snowy troughs moving over. Then a possible blizzard scenario from the S. GFS, whilst it could be on the right track with the low’s evolution, is not good at dealing with cold blocks. All to play for! So many children on here, unreal. 

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14 minutes ago, Captain Shortwave said:

The GFS actually does disrupt that low as it hits the UK, it is just that it manages to pull milder air across the south whilst the ECM keeps the UK cold, it would not take much for the GFS to keep the whole of the UK under the -8C isotherm. The GFS seems too keen to split and fragment that cold pool which allows that milder air to push further north. There is a risk of this happening but once the Asian vortex realigns towards Scandinavia we should see that Euro low redevelop and the low to our south should start to drift east rather than north.

The fact the GFS disrupts the low is a start to be honest.

tempresult_hdf4.gif

Also an eastwards correction on those low heights dropping south would be good too.

Great chart Capn S...

It emphasises the nature of the upcoming event.

It is an extreme example of a high risk for a very high reward.

For southern areas they will hardly ever get heavy snowfall without taking this risk.

Unless we see this type of situation occur there will be no 'reward' for them.

The graph above, if you follow it,  does show that the low is showing signs of disruption, with smaller cells of low pressure dashing off down to Italy via France, from the main low, which reels off each time in a balling ball type movement.

Another cell then moves in behind to enhance the process.

It is extremely finely balanced.

If it moves off down to France you will have no snow and it will be bitterly cold.

It is the balance of these forces which will determine how much energy is released northwards. 

All the really big snow storms of the past for the SW have had this balanced fine edge situation.

If it happens in the best way, then many in the South West will not be on here for a while.

Perhaps John Holmes is the expert who has suffered the most from this scenario many times in the 70's and 80's, as many times a forecast of warmer winning out has had to be reversed.

A fascinating week ahead is guaranteed.

MIA

 

 

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3 minutes ago, stainesbloke said:

Absolutely. There’ll be masses of interest from tomorrow night onwards with the deep cold coming in and shower activity rapidly increasing with chances of snowy troughs moving over. Then a possible blizzard scenario from the S. GFS, whilst it could be on the right track with the low’s evolution, is not good at dealing with cold blocks. All to play for! So many children on here, unreal. 

Exactly. This is about as good as it gets for the UK. Possibly the best since the Internet era! 

As my grandad always told me. "Wind from the east, no good for man, nor beast"! 

 

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Next week all precipitation will be snow everywhere, if it isn’t then send the pitchforks. :D

ECM 00z follows with Met Office, remaining very cold with chance of significant snowfall. The cold air will not be lightly pushes out it will take weeks IMO before we see a proper warm up.

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Be careful with the GFS, especially the 12z run. In my experience, it's has a flaw around the 120-144h mark for really blowing up lows. I expect this evening's 12z to be a complete stinker in respect of the low.

It may be correct, but would wait until 0z tomorrow before having and confidence at all in that track. 

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A lot of people being very definitive this morning in their judgements. The GEFS (from a quick run through) give around 50% support to the opp. Anybody saying the milder air wont creep into the south this weekend is plain wrong IMHO. Equally anyone claiming it def will is also talking rubbish. Its very finely balanced and whilst the 06 opp looks extreme the basic premise cannot be 'binned at all'.

Its the model thread peeps so this should be discussed (along with the fab stuff beforehand).

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06z ensembles area mess, basically all options are on the table, from it doing what the 06z GFS op does, to it being so far south it doesn't even leave France.

I would say on balance a milder set than the 00z (especially post 156hrs) BUT no real trend in terms of the GFS ensembles and on balance the op run will be one of the milder runs when eyeballing each ensemble member.

Time to check ECM ensembles!

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