Model Output Discussion - Colder but how cold and for how long?

[Eagle Eye]

5 minutes ago, Tim Bland said:

12z Vs 18z snow over for Thursday. Is this really a great run away from the far north and Scotland ?

Potentially longer lived cold whilst not equalling better snow chances, generally supports a higher chance of snow potential. 

[Lampostwatcher]

2 minutes ago, Tim Bland said:

This run is completely dry for all of Essex next week. Earlier runs had 15cm in your area

Good job its 7 days away

[cold snap]

And it's back on the 18z.

@January Snowstorm.

Snow back into Ireland

[festivalking]

Is that a cold pool developing in the channel at 186. Keen easterly too

[Ice Day]

3 minutes ago, Tim Bland said:

This run is completely dry for all of Essex next week. Earlier runs had 15cm in your area

It's all about getting the cold in Tim.  Come on, you've been here long enough to know that! 

[Zero Visibility]

 

Spot the difference! 

[Richard Fisher]

3 minutes ago, Met4Cast said:

This is a substantial shift in modelling from the 18z so I'd very much like to wait until the ensembles before judging but this extends the blocking far further than the last few runs have managed to. 

In terms of snow detail, honestly couldn't care less at this stage, that will chop, change & new features will pop up seemingly from no where. The low in the middle of next week was always expected to go into France and miss the UK, been saying this for days now.

??? The low will head back north in the next few days. The pros at the Met said there was only a low probability of the low staying in France.

[Chris.R]

All I'm going to say is... 2nd Dec 2023... What happened? what was supposed to happen? Think about that if you're worried about it staying dry

Edited January 11 by Chris.R

[Met4Cast]

1 minute ago, Richard Fisher said:

??? The low will head back north in the next few days. The pros at the Met said there was only a low probability of the low staying in France.

Unfortunately since then it's continued to track southwards across all modelling & ensemble suites. the Met said it was a lower probability (still cannot work out why, these systems generally do trend south) but todays model trends have placed that in the "highest probability" risk. 

Edited January 11 by Met4Cast

[Derecho]

Probably irrelevant at this stage but good to see shallow heights to the north and a disrupting low out west ahead of the cold over the UK. 

Edit: doesn't look like it's coming to anything this time round but trough disruption and shallow highs to our north are what we want to see if northern blocking is to wane...

Edited January 11 by Derecho

[Duane S.]

4 hours ago, Bricriu said:

Just to be clear, are you saying that if QBO was in a westerly phase the Troposphere  impacting  the strat  the way  it is would not be able to happen- that we would not see these splits propagating upwards?

Thats a bit too much A+B=C, as It’s just one ingredient in the cauldron. Other factors combined could still very well override this primary driver. But when the QBO is in its Easterly phase, as well as increasing the probability of SSWs, the atmosphere loses the ability to super charge our own jet stream / vortex in the same way as when we’re in a Westerly phase QBO.

When the QBO is in its westerly phase, it can add energy in, to increase the westerlies in our tropospheric jet stream – leaning towards there being a greater risk of a stronger and persistent jet stream, with associated Atlantic storm systems.

[Tim Bland]

Just now, Ice Day said:

It's all about getting the cold in Tim.  Come on, you've been here long enough to know that! 

Yes, I get it, but the last cold spell in December we got the cold in and the boom charts but no snow. Looking at charts like this just frustrate me. Populated areas of England and wales need a miracle to get snow these days !I want snow , not high heating bills Dagnamit lol 

[Scott Ingham]

The wedge isn’t probably prominent enough on this run but if you look where the black arrow is pointing you can see where the residual elements of inertia have created a wedge. Run it back and forward and you’ll see the trough west of Greenland breaking up and sliding. 
 

This is what could potentially extend our spell. I’d like to see the ensembles move over the next 3 days then it’s game on!

[Premiere Neige]

4 minutes ago, Met4Cast said:

This is a substantial shift in modelling from the 18z so I'd very much like to wait until the ensembles before judging but this extends the blocking far further than the last few runs have managed to. 

In terms of snow detail, honestly couldn't care less at this stage, that will chop, change & new features will pop up seemingly from no where. The low in the middle of next week was always expected to go into France and miss the UK, been saying this for days now.

I'm not even sure why people are getting hung up on the snow charts for 7 days time (not you Met) when it most likely won't turn out like that. Watching the local BBC forecast this evening and the presenter (Paul Hudson) said that snow could not be accurately forecast until 48 hours away....maximum. Will be leaving it until next week before I start taking an interest in what's being modelled in terms of snowfall...

[Mcconnor8]

Just now, Premiere Neige said:

I'm not even sure why people are getting hung up on the snow charts for 7 days time (not you Met) when it most likely won't turn out like that. Watching the local BBC forecast this evening and the presenter (Paul Hudson) said that snow could not be accurately forecast until 48 hours away....maximum. Will be leaving it until next week before I start taking an interest in what's being modelled in terms of snowfall...

This X100

[Mike Poole]

T96 is pushing the edge of the reliable at the moment.  Beyond that, I think we will continue to see this trend to keep the vortex lobes further apart on the 0z runs, and the further evolution after that will continue to change.  Which will be an upgrade in terms of depth of cold, that we can see.  Snow chances will be different because there won’t be a battleground scenario at all next week, is my prediction.  

[matty40s]

9 minutes ago, Rob 79812010 said:

Beeb is up to 11 degrees by 27th. 

Beeb is NOT a model,and the BBC tends to be far behind any model developments as it is based on a French forecasting model....with obvious bias to that lat and longitude. 

[Harveyslugger]

Just now, Mike Poole said:

T96 is pushing the edge of the reliable at the moment.  Beyond that, I think we will continue to see this trend to keep the vortex lobes further apart on the 0z runs, and the further evolution after that will continue to change.  Which will be an upgrade in terms of depth of cold, that we can see.  Snow chances will be different because there won’t be a battleground scenario at all next week, is my prediction.  

That's good.plenty of features will pop up

Edited January 11 by Harveyslugger

[Nath]

Another roller coaster will it wont it be really cold/snowy.  I love the drama but hate the effect on my life expectancy!  I have seen this every year since I joined Netweather.

 

I dont remember a single good freeze up that was modelled 7-10 days out and just happened without drama, setbacks and highs and lows!

 

This one feels like it could be a good freeze up, as the PV is more disturbed than I usually see!

 

I am no expert though even after 15 years of Netweather and reading countless tutorials, I just enjoy rare weather and this amazing forum!

[CoventryWeather]

Too much uncertainty past t96-120, but one thing of note on the GFS 18z is that 10hpa looks split, with a warm core over Scandi.. the ECM has been hinting this again towards the back end of next week...

Interesting mid term.. 

[Scott Ingham]

4 minutes ago, Derecho said:

Probably irrelevant at this stage but good to see shallow heights to the north and a disrupting low out west ahead of the cold over the UK. 

Edit: doesn't look like it's coming to anything this time round but trough disruption and shallow highs to our north are what we want to see if northern blocking is to wane...

Just posted the same thing off the back of a glaam state that is still high this is the possibility before more amplification into Iceland and or Scandi

[Tim Bland]

Warm up by the weekend still there …

[Day_9]

10 minutes ago, Ice Day said:

Absolute scenes at 138

 

In all seriousness, this is quite some upgrade from the GFS

Coming into the reliable now, that SW feature has been consistently modelled on enough runs across all models that it is a viable option on the table - although, at the drop of a hat it could all disappear…….

but that would have been in previous years.  Synoptically this year feels like extremely different, i mean we’ve got a totally shredded Atlantic , cross polar flow, an enormous pool Of bitterly cold air just about to smother us, and what is the vortex doing? “LOLZ”.

so we could witness some memorable events especially given what has been a consistent signal since the autumn.  Forget inter run variables, look at trends in the way of up or downgrades to help determine the most likely outcome in terms of longevity or severity.  
 

precipitation events that so many crave still a fair way off  so ignore snowfall charts (although they are entertaining !!)

 

[Jayfromcardiff]

This is just one model run remember, it's likely to and will most definitely change again numerous times. I still find it strange why the Met Office would be overly confident of the low pressure system not heading South though.

[Mcconnor8]

1 minute ago, Tim Bland said:

Warm up by the weekend still there …

Delayed on this run by a day, and I expect it will keep getting delayed further run by run for a while.

Edited January 11 by Mcconnor8