Model thread discussion - cold spell looming

[Blessed Weather]

Just a gentle reminder that this is the Model Output Discussion thread please. Other threads are available for other discussions:

Winter 2020/21 chat, ramps, moans and banter

Regional Discussions

February Cold Spell Discussions

Met Office Further Outlook

Thank you.

[MJB]

5 minutes ago, Tim Bland said:

That’s yesterday’s 12z I don’t think 18z or 00z has any snow? Icon also backed away from throwing out that shortwave at the weekend.

some very respected meteorologists on Twitter are saying models always underestimate the strength of the block and the cold will hold firm. I’m not so sure. I can’t   Recall a time that all models were wrong at fairly short notice?   Some are hanging on every word of Carol Kirkwood this morning ...I can tell you 100% she is reading the script of last nights ECM.. they will switch to the new ECM run later .

yes apologies 

[MJB]

Then lets get this in and have some sort of snowy breakdown

That's a hammering for some 

[blizzard81]

6 minutes ago, Tim Bland said:

That’s yesterday’s 12z I don’t think 18z or 00z has any snow? Icon also backed away from throwing out that shortwave at the weekend.

some very respected meteorologists on Twitter are saying models always underestimate the strength of the block and the cold will hold firm. I’m not so sure. I can’t   Recall a time that all models were wrong at fairly short notice?   Some are hanging on every word of Carol Kirkwood this morning ...I can tell you 100% she is reading the script of last nights ECM.. they will switch to the new ECM run later .

The argument that models underestimate cold blocks does have some truth to it. On the flip side, I recall many times when the models sweep them aside and prove 100% correct. The trend yesterday was to almost cancel out a 'true' beast visiting our shores in around 7 days but kept us in a cold 'holding' pattern. This morning unfortunately they have stepped back further and taken away the cold holding pattern. Need to see what the other runs show as the day progresses before totally giving up the ghost. 

[Tim Bland]

Here’s some good news...

[ptow]

1 hour ago, markw2680 said:

Come on people you can’t write off the cold coming back with a vengeance just yet, it’s Tuesday morning unless I’m mistaken? And yet we are saying it’s all over for the weekend! That’s 4-5 days away, a lot can change in the next day or two.

I expect the milder air to try and push in over the weekend but will probably only make it into the west before slowly the cold in the east will beat it back again. At least there’s a chance of snow coming in from the west

You are right a lot can change. On friday I was expecting 4 ice days and 5+cm of snow. Reality - 1 ice day and a dusting

[Tim Bland]

8 minutes ago, MJB said:

Then lets get this in and have some sort of snowy breakdown

That's a hammering for some 

Looks at the accumulation charts it’s currently a slushy 1cm that lasts about an hour and only the north west Amd Scotland that sees anything significant ..I doubt Scotland will notice another 5cm on top of what they have let’s hope it adjusts south and changes the angle of attack so it doesn’t brush the cold away so quick and gives snow for more than an hour before rain 

[MJB]

1 minute ago, Tim Bland said:

Looks at the accumulation charts it’s currently a slushy 1cm that lasts about an hour and only the north west Amd Scotland that sees anything significant ..I doubt Scotland will notice another 5cm on top of what they have let’s hope it adjusts south and changes the angle of attack so it doesn’t brush the cold away so quick and gives snow for more than an hour before rain 

It's potential which is an awful lot more than what is showing the charts for me currently lol ............I see the Beeb are still banging on about the cold winning , so what are they looking at ? Are they just a day behind ? 

[Battleground Snow]

Don't worry the icon has got this.

Does anyone remember the last time it modelled an intense high over Scandinavia and a piece of the vortex trying to come underneath better than all the others?

[sheikhy]

3 minutes ago, Battleground Snow said:

Don't worry the icon has got this.

Does anyone remember the last time it modelled an intense high over Scandinavia and a piece of the vortex trying to come underneath better than all the others?

Imagine if gfs goes the other way on the 06z

[Battleground Snow]

1 minute ago, sheikhy said:

Imagine if gfs goes the other way on the 06z

Haha, i'd give it a less than 10% chance, but never know!

[Don]

Well, looks like that could be it folks!  The MJO no longer looks to be very effective either, so I think once this cold spell (which I think has been the most disappointing I have ever known!!) is over, the rest of February may not be up to much.  Perhaps time to look forward to spring?!

[Severe Siberian icy blast]

19 minutes ago, Tim Bland said:

Here’s some good news...

Tbh I fully expect the cold air to win, the signals had a wobble on the models we use recently, but this mornings 0z is the strongest yet how many times have the over night runs done this? 

Also the last weather on BBC1 with carrol, with new graphics as it changed from the one before it, did a rare and extended look into next wk where she says they are expecting the cold air to run, that was with the over night runs on her graphics, 

I expect a shuttle shift over the next day or 2, a milder day or 2 yes, but with cold air fighting back 

[Scandinavian High.]

Still think this not done I expect cold to hang on ..

[AWD]

24 minutes ago, Tim Bland said:

Here’s some good news...

To be fair, taking that chart at absolute face value, an anomaly like that shown won't translate to overly cold surface conditions given the time of year the chart is for (lengthening days, strengthening sun etc etc).  You would need the darker blues, as shown over Eastern Europe, to be overhead for something more worthwhile.

Admittedly, I'm taking it at face value though (not what anomaly charts are really for) and it obviously can be improved or watered down with regards to cold conditions.

[Griff]

1 minute ago, Griff said:

 

Blocking does seem very likely, if not inevitable, just the position is in question... 

[mushymanrob]

Coldies might like this...... the anomaly charts do not support the rapid breakdown some op runs are currently suggesting. And Atlantic breakdown doesnt look likely until later next week, if at all...might be fun watching them try though, the west could get a dumping.. But this chart suggests high pressure holds on until at least after next wednesday. So expect a cold, mainly dry, raw feel to the weather in the stronger breezes. But this chart is not a mild one and the extended chart isnt much different.

With a strong block to our North, a re-load of the Beasterly is certainly a possibility, albeit low atm.



 

[Polar Maritime]

Battleground snowfall into the weekend with some big totals in places if the UKV extended is correct, To early for me to call whether the warmer air will win out atm, But for now the cold air is firmly on place..

 

Edited February 9, 2021 by Polar Maritime

[Don]

Just now, Griff said:

Blocking does seem very likely, if not inevitable, just the position is in question... 

It’s a pity the shorter range models have shifted towards a milder outlook!

[Guest]

1 minute ago, Polar Maritime said:

Battleground snowfall into the weekend with some big totals in places if the UKV is correct, To early for me to call whether the warmer air will win out atm..

 

Still so much to be pinned down, yesterday it showed the south west getting a dumping, unsurprisingly its all rain this morning...

[Polar Maritime]

7 minutes ago, Alderc said:

Still so much to be pinned down, yesterday it showed the south west getting a dumping, unsurprisingly its all rain this morning...

Looking at yesterday's UKV at today's timeslot and current radar..

Edited February 9, 2021 by Polar Maritime

[Notty]

Little bit of a push-back West from the cold

GFS Op 06z -v- 00z

Not for long though ...

That's it - I've had enough - bring on the Spanish plumes, roll on spring

Edited February 9, 2021 by Notty
Added last chart and comment

[johnholmes]

The 500 mb outlook 

Tuesday 9 feb

Ec-gfs and both fairly similar to one another;no trough-ridge in far w=general w’ly over pacific, still major trough now less w-e more nw-se with strongish flow beneath it turning sw’ly into uk and ridge off n’ern Scandinavia, little flow on ec into Europe, more on gfs with both showing marked troughing way east into med

Noaa 6-10 some sign of trough-ridge far w but not the ‘classic’ form; strong flow from this area n of w over much America beneath main trough s of Greenland, still w-e orientation but less so than last few days, strong flow turn ssw to marked ridge out of Scandinavia to Greenland with 150 dm +ve in this then on into far east Europe down to med, so similar in eastern half for last 3 days or so. A degree of similarity with ec-gfs in this. 8-14 has flattish flow across all chart until the ridge as detailed in 6-10 with slightly more flow into s’ern Europe beneath this than 6-10 showed.

Overall, blocking holding but perhaps too far away from uk to really hold up atlantic enchroaching slowly into uk.

This is shown on ECMWF charts, slow process but by 15/16 Feb both upper and surface flow is shown to be s of w and with 850 temperatures easing up across all of country. Even +ve values shown on colour charts by 10 days from now.

Little indication to me that this is not going to happen. Is it a temporary spell of milder air or a more polonged spell? I suspect it is more than a blip. Beyond 14 days, not my area

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

 

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

I see mushy has posted above, it would seem our views diverge a shade!

Just a comment about the showers coming in off the N Sea during this cold spell. None of the skew-t diagrams, sveral days prior to the first showers, nor during the last 48 hours have shown cloud tops above 8-at times 12,000 ft. The air aloft has not been as cold as say on previous cases when bands/showers have affected eastern and central hours. Thus the intensity of many of the showers has not been very high. Obviously in a few locations the frequency tended to make up for this. I have not noticed any posts about 'thunder-snow' another indication that the instability has not been very marked.

 

[Battleground Snow]

Better WAA going up on this run, probably not going to be enough, but nice to see, FI is definitely at 72-96

ECM and ukmo and show the breakdown at 120, so there is still a small chance they are getting this wrong.

[I remember Atlantic 252]

Assume it won't make it over mountains, or another 12 March 2006 horror