Model output discussion - is the beast awakening?

[nick sussex]

This low is like one of those infamous nor’easters in the USA which runs ne and engages cold air being pulled se into the flow from the interior.

It’s a fine margin in this set up between a flood and huge snowfall ! I know a lot of attention is on this low as it has an impact on the depth of cold for certain regions but it has little chance of verifying in the manner shown .

Importantly that’s another run which clears the limpet shortwave se earlier on before this low drama .

[IDO]

The gfs 12z showed us this is on a knife's edge and there are about three pivot points that could be a bust for longevity of the easterly. By d7 we are back to the 06z scenario where the easterly runs to the north of Scotland:

Not saying it is a lost cause from d8 on the 18z, no idea TBH (but not where we want to go), but there is def a chance of this scenario happening as we have seen it twice in four gfs op runs, which is not really what we want to see especially as it only needs minor changes for it to go bad. At least we get a cold pool in on the 18z IMBY, whereas the 06z was poor from start to finish in the south!

 

[kold weather]

6 minutes ago, Geordiesnow said:

I would not fully discount it, we have seen lows heading up the North Sea after an easterly flow(like it did in Feb 2009 but bought heavy sleet in the NE) but I do agree we do have to bear in mind the GFS can and do blow up low pressure systems too deep and the deeper the low the cold mixes out quicker. 

Maybe the GFS is deepening the low because milder air is mixing in with the cold air and that is something can and does happen anyways. 

Either way, let's not worry too much about the details, too far out for that, aslong as the trough does not become stuck over the UK then it's a good run as far as I'm concerned. 

Oh yeah it definately can happen...

Its just i've never seen a dartboard low blow up in that position.

It almost deepens under rapid intensification rates at points! 

The moment I see the GFS in particular pull that trick out of the bag, knowing how poor it can be with overblowing lows, I chunk it out of the window because reality rarely if ever matches that kind of low system doing what it does in that position with the kind of embedded airmass its in.

IF another model besides the GFS pulls that card, I will pay more attention. 

PS - Feb 09 low was at 995mbs over the UK, it did strengthen but that was when it was getting absorbed into the stonger flow further west. No such forcing is obvious on the 18z GFS though.

Edited February 1, 2021 by kold weather

[MKN]

In summary after today's runs... Another day closer to some cold/very cold weather from saturday onwards with variable amounts of snow depending on small differences in the overall pattern which will effect our little island significantly. Overall a good day of model outputs. It will be weds to thurs until snowfall detail can really be looked at providing we are still looking at a cold outbreak then. 

[Man With Beard]

The 4 GFS runs from today for Sunday. If you haven't been following the runs, you'd be hard pressed to rank them from coldest to mildest, and you'd probably get it wrong. And you probably won't know that one of them is rain for the south, and another is borderline.

That's how tricky it is to forecast this coming weekend.

          

Edited February 1, 2021 by Man Without Beard

[MJB]

114h mean

[Gowon]

Guys.. can we stop dismissing the run because it's not what we want to see 

[feb1991blizzard]

1 minute ago, nick sussex said:

This low is like one of those infamous nor’easters in the USA which runs ne and engages cold air being pulled se into the flow from the interior.

It’s a fine margin in this set up between a flood and huge snowfall ! I know a lot of attention is on this low as it has an impact on the depth of cold for certain regions but it has little chance of verifying in the manner shown .

Importantly that’s another run which clears the limpet shortwave se earlier on before this low drama .

I know you don't like ensembles but i think if that low was going to behave in that manner, then it would have to be signposted in the ensemble mean that follows these ops, we are talking shorter timeframes now.

[Allseasons-Si]

1 minute ago, Cloud 10 said:

Nearly a metre of snow in Eastern Scotland.

 

Great Scot,...(no pun intended)...

[jamesgold]

Just now, MJB said:

114h mean

That looks a lot cleaner than the OP doesn’t it?

[Ice Day]

The 120 mean looks pretty solid.

[Geordiesnow]

3 minutes ago, kold weather said:

Oh yeah it definately can happen...

Its just i've never seen a dartboard low blow up in that position.

It almost deepens under rapid intensification rates at points! 

The moment I see the GFS in particular pull that trick out of the bag, knowing how poor it can be with overblowing lows, I chunk it out of the window because reality rarely if ever matches that kind of low system doing what it does in that position with the kind of embedded airmass its in.

IF another model besides the GFS pulls that card, I will pay more attention. 

Would usually be the ECM so it's one to watch but aslong as the trigger low is not too far north before any potential deepening, the idea of a day of easterly winds and then a low heading northward giving more prolonged PPN is plausible even if the strength of the low is likely to be weaker than the 18Z shows. 

 

[booferking]

11 minutes ago, kold weather said:

Exceptionally rare for it to blow up in THAT type of pattern though. I've got to say in all my years on here I've never seen that happen once like that in fact.

Not to say there won't be a low too far north, thats very possible as I've been warning for the last 2 days.

However a sub 980mbs low in that position from that origins and with the set-up as it is a totally extreme solution and therefore has to be thrown into the bin even if the broad strokes are right.

PS - poor run for the SE and south in general, cold but little snow other than the back end of the front that clears out on Saturday evening. Better run north of the Wash and moving WSW from there.

Extremely cold air sourced from Siberia meets relatively warm air sucked up from the Mediterranean has the right ingredients to blow up a low one run yes, likely  change next run yes the danger is there but can't rule nothing out.

Edited February 1, 2021 by booferking

[Updated_Weather]

2 minutes ago, D.V.R said:

Guys.. can we stop dismissing the run because it's not what we want to see 

Think people are dismissing the fact it blows up at low for no reason.. that won’t happen.

[jimbo36]

Well if all the models are still showing this in 48 hours, then i'll have to set up a stormporn forum page and the first 100 members get a free box of tissues

[sheikhy]

2 minutes ago, Man Without Beard said:

The 4 GFS runs from today for Sunday. If you haven't been following the runs, you'd be hard pressed to rank them from coldest to mildest, and you'd probably get it wrong. And you probably won't know that one of them is rain for the south, and another is borderline.

That's how tricky it is to forecast this coming weekend.

          

Have you noticed something mate!!the apparently rubbish runs from the 06z and 18z have more waa going north into europe and norway!!a coincidence?!

[Mucka]

I wouldn't discount that low deepening and moving N as there would be huge temp gradient between the air it drew in on its southern flank from the SW and the air it would pull in on its northern flank from the NE

 

Note: Not discounting is not the same as think will happen.

Edited February 1, 2021 by Mucka

[radiohead]

2 minutes ago, D.V.R said:

Guys.. can we stop dismissing the run because it's not what we want to see 

Depends on who is seeing it though! It delivers very heavy snowfall in strong winds, severe blizzard conditions, for some areas.

 

[kold weather]

Just now, D.V.R said:

Guys.. can we stop dismissing the run because it's not what we want to see 

I'm close to dismissing it because its creating a 980mbs dartboard low when no other model is even within the ballpark...ECM about 1000mbs, GEM 1000, UKMO 1000mbs, GFS 980mbs. Odd one out much?

And also because we fully well know what the GFS is like when it comes to overegging LPs.

Now I'm far from dismissing the possibility of the low ending up too far north...however a stronger low by default is going to end up further north due to the center of the fujiwara point being further east and closer to the larger low, which causes it to tuck much tighter into the UK than on the likes of the ECM and UKMO for example.

IMO much like the 12z ECM was, its an extreme solution that IMO has little chance of coming off like that. A weaker 995mbs low in that position. Possible, though it would be less likely to get anywhere near that far north.

 

[Rocheydub]

3 minutes ago, jamesgold said:

That looks a lot cleaner than the OP doesn’t it?

Means at that range always look "cleaner".

[nick sussex]

It’s weird I’m worried about  that limpet shortwave , others are worried about the Iberian Low .

We’re all in a frenzy of worry ! 

I should change my handle to the  NW shaman channeling the cold and snow hopes of UK coldies aswell as all the angst ! 

 

[Allseasons-Si]

4 minutes ago, Man Without Beard said:

The 4 GFS runs from today for Sunday. If you haven't been following the runs, you'd be hard pressed to rank them from coldest to mildest, and you'd probably get it wrong. And you probably won't know that one of them is rain for the south, and another is borderline.

That's how tricky it is to forecast this coming weekend.

          

Second one is rain for the south as i can tell from the thicknesses?

[Cloud 10]

GFS para. starting to dribble out now.

I'm liking these double pub runs.

[weirpig]

Control  similarish to the opp   

[Jason M]

Well the pub run sends the beast off with its tail between its legs. Only one run but can't completely discount it as all the ingredients are there for the low to rapidly deepen and come further north.