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Model output discussion - Post SSW - Will it turn cold?


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/

Thank you!

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Cold - Yes Instability - Yes Prolonged - Yes I just wet myself - Yes!

I quite often agree with your sort of sentiment, as I'm one who opts to look at the most likely solution to fit the signals rather than the preferred one But, equally impartially and with intended

Sorry, I just thought I’d walked into the moans threa.. oh wait. <passes around a big bag of grips> No sooner do we get a cold spell within sight it astonishes me that time and time again some p

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Just now, CreweCold said:

I've seen model ensemble suites flip inside 96 hours...we're far from safe on this one!

Yup! Though I think this one is unique because:

a) There is so much agreement with the weather models
b) We know a record SSW event is encouraging such synoptics

As of now I'm 80-90% sure which is higher then any other forecast deep cold spell (been observing since 2007)

If we have the same level of agreement this time tomorrow evening then it will be a case of how long the cold spell lasts, not if it will arrive.

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6 minutes ago, East_England_Stormchaser91 said:

There's no doubt about it. Imminent power failures for many and utter chaos will pursue if this 18z does happen. 

Whats even worse, people like myself have never experienced a true proper blizzard not seen since the likes of 87,91,63 or 78! 

I pray for everyone to stay safe and get stocked up with essentials. I'm trying not to get carried away here, but this really might be the big event that's been so long overdue. The even more frightening prospect, is that this thing is being actually upgraded run by run. 

Last proper blizzard down this way was Jan 82, but we survived. Jan 87 extreme cold and very snowy and there was much drifting but it wasn't until after the snow had stopped that the wind picked up enough to cause drifting. Feb 91 was very cold and very snowy but no drifting that I remember.

The charts we are seeing now remind me most of Feb 91. 

If an 18z GFS style blizzard should occur there would be plenty of warning and authorities would be as prepared as possible. I'm sure people would panic and certain sections of the media would whip people into a frenzy - yes Daily Express I'm looking at you! But people would adapt and pull together and whilst there would undoubtedly be hardship and difficulties we would be ok in the end.

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I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

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1 minute ago, Sam Mithell said:

Well what a fantastic set of charts ,being an amatuer i see people mentioning southern england are in for it , Anyone think eastern scotland looking at alot of snow out of this ?

If any of these runs we're seeing come to fruition then the simple answer is YES.

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1 minute ago, Quicksilver1989 said:

Yup! Though I think this one is unique because:

a) There is so much agreement with the weather models
b) We know a record SSW event is encouraging such synoptics

As of now I'm 80-90% sure which is higher then any other forecast deep cold spell (been observing since 2007)

If we have the same level of agreement this time tomorrow evening then it will be a case of how long the cold spell lasts, not if it will arrive.

I think we are already at the point where a cold spell will happen, regardless of the type. The only question is how deep and snowy it goes.

18z control run is *better* than the op...

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1 minute ago, Raythan said:

I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

I can't remember exactly but I think with 2010 the models were like a dog with a bone that couldn't let go for a week or so leading up to it, very similar to how they are now.

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1 minute ago, Raythan said:

I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

2010 was modelled incredibly well, you were able to count down from 240hrs with only minor wobbles.  Not sure about 2009 and 2013 though.

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At  way out at 177 hours, on the southeast coast, the warmest GEFS 850mb temperature is -11.3. All other 19 members plus the op and control are colder than that, most significantly colder. Absolutely bonkers.

Edited by radiohead
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1 minute ago, Raythan said:

I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

2010 was rock solid from the start. Intial thrust was overdone but other than that no drama. Indeed as time went by the models improved as they sniffed another block forming. Something to watch as we have had several bursts of strat warming.

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12 minutes ago, Southender said:

So what day this week can we be confident of these cobra runs actually coming off? Fri/Sat or are the building blocks in earlier than that?

Easterly flow is of high confidence. But the cold cone is still wide think like a hurricane graph and how those are shown.

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1 minute ago, Raythan said:

I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

Just thinking exactly the same. I think 2010 was forecast well in advance by the Met Office etc and smoothly evolved. Let’s  hope this is doing the same!!! 

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2 minutes ago, Raythan said:

I’d love to know how these major cold spells were modeled , I mean was the signal that strong there were only minor ‘wobbles’ , how did 2010 go ? Drama or just solid with upgrades ? From what I read the met seen 2010 far out ?

Interesting question, I think a thread should be created so we can look back for future reference. It'd be a great way to remind ourselves how notable weather patterns evolve in the model output. :)

PS sorry mods if its off topic, I know its busy in here tonight.

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1 minute ago, kold weather said:

2010 was rock solid from the start. Intial thrust was overdone but other than that no drama. Indeed as time went by the models improved as they sniffed another block forming. Something to watch as we have had several bursts of strat warming.

I think the main worry here has to be that the modelling picks up a new signal which interferes with the QTR response of the SSW. By this I mean that the ongoing effects of the reversal may actually hinder what is already a pretty perfect set up. I believe that this has been highlighted as a risk factor before. If the modelling is overlooking strat effects that are yet to be filtered into the modelling then this is a potential issue. 

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Just a nagging doubt, the coldest weather is over a week away, we saw on a couple of ecm runs three exists the possibility of the coldest air going south.  Is it likely the models will show today's charts again and again for 7 days.   I know an easterly is nailed on, but at 7 days there is surely still doubt about the severity? 

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1 minute ago, SN0WM4N said:

cold cone

That’s brilliant , wonder if the more knowledgeable peeps on here would dare do a crayon job and draw a cold cone for possible projection 

 

2 minutes ago, SN0WM4N said:

hurricane graph

 

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7 minutes ago, CreweCold said:

I think the main worry here has to be that the modelling picks up a new signal which interferes with the QTR response of the SSW. By this I mean that the ongoing effects of the reversal may actually hinder what is already a pretty perfect set up. I believe that this has been highlighted as a risk factor before. If the modelling is overlooking strat effects that are yet to be filtered into the modelling then this is a potential issue. 

I think that's a very fair point.  The SSW has had a significant and violent impact on the entire northern hemisphere weather patterns, so maybe there's more that aren't yet visible to the models.  However, I think if we can get through tomorrow with only minor changes we can be fairly confident that the models are converging on the correct solution.  As I said earlier though, 72 hours for an easterly is what I'm working to before the family get told!

Edited by Ice Day
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1 minute ago, CreweCold said:

I think the main worry here has to be that the modelling picks up a new signal which interferes with the QTR response of the SSW. By this I mean that the ongoing effects of the reversal may actually hinder what is already a pretty perfect set up. I believe that this has been highlighted as a risk factor before. If the modelling is overlooking strat effects that are yet to be filtered into the modelling then this is a potential issue. 

yep apart from the shortwave shown on 3 ensembles which comes west from Belarus/poland and then north west through our block allowing attacks from the south west.

the only other thing I can think of is the SSW is still under modelled and block shoots to Greenland and further before the cold comes in but seeing we haven't really seen that on any model yet I think it is very small chance

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16 minutes ago, CreweCold said:

Funny you should mention that (in jest) because my theory is that the ice ages started with events in the mid latitudes i.e greater outpouring of cold instances from the higher latitudes. Suppose that is for another thread though!

Crewe ...

How about coming into my spider's den over on the other forum.... :nonono:

Seriously though the bitter cold winters of 1695-7  are believed to have very similar synoptics, and occurred at the very bottom of Maunder Minimum sun spot period. The difference was that they started in January.

I once saw a 'probable' pattern for the atmospheric pattern that someone constructed of  the time, and from the data  available,  and it looked just like T200 - T300 on todays GFS run.

Truly amazong run! 

Midlands Ice Age

:nonono::cold::D

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Just now, Ice Day said:

I think that's a very fair point.  The SSW has had a significant nnd violent impact on the entire northern hemisphere weather patterns, so maybe there's more that aren't yet visible to the models.  However, I think if we can get through tomorrow with only minor changes we can be fairly confident that the models are converging on the correct solution.  As I said earlier though, 72 hours for an easterly is what I'm working to before the family get told!

Agreed.

I always see the models struggle so much when it comes to eastern dominated weather patterns. The constant western data just meddles with it.

Its always wanting to go back to the Atlantic and after a while, after some days of data, it finally comes true (I see this on all models every year)

I personally think it holds true with any shortwaves and any return to the Atlantic, It takes a few runs to get that going again

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