FI Charts (T120+ onwards) Winter 2018 **READ MOD NOTE IN FIRST POST**

pistolpetes11

For me I got my most significant snowfall in 7 years , and it would appear to be the same for a few more on the east coast or eastern side of the Country so I find it interesting as to which model got this correct

nacho libre

Take that mr vortex!

sryanbruen

Classic GFS FI with a beasterly in the mix.





EDIT: Dammit Nacho, you bet me to it!

gabeeg

His was animated too. For shame.

That didn't take long though. Seems like it was only last night that I asked you about when you thought it might manifest in the models

sryanbruen

gabeeg wrote: »

His was animated too. For shame.

That didn't take long though. Seems like it was only last night that I asked you about when you thought it might manifest in the models

Yes, it's going for around the time I told you, just that remember this is FI. Even with a bit of support, take it with a large pinch of salt .

gabeeg

Nonsense. I've taken the week off work in anticipation.

So don't let me down

sryanbruen

nacho libre wrote: »

""This would *not* fit the criteria of a mid-winter SSW defined in Charlton and Polvani (2007). They specify events in which the zonal winds stays easterly for more than 10 consecutive days as final warmings.""

What a load of baloney, where did you read that?

Let's not forget that last year's SW was considered a SSW for a short while - and it being the weakest on record but then was changed to just a significant warming than a SSW. The winds were reversed only for about a day and just at -0.1m/s :pac:. We all know how much of a disappointment that was in the end.

sryanbruen

Plenty of beautiful charts to gaze a look at in the GFS 12z ensembles! I won't spam the thread with them but here's the control run just as a base line .

BLIZZARD7

A thing of beauty - If we manage to get a very quick trop response I can see us under a continental flow by day 9 or 10. Expect the model runs to move forward with this at pace if it's going to come off - some great chart viewing to be had for the foreseeable I suspect.

Ardrageen

With everyone looking to the skies for snow, is there is a chance that this wind event could sneak up on us unawares next Tuesday?






Once again its a bin night for me, Storm Eleanor, Fionn and Georgina have all arrived on my bin night :mad:

patneve2

Hopefully the record snowfall that hit Western Russia a few days ago (heaviest in 100 years) will further aid the development of a Scandi-Russian High..

nacho libre

patneve2 wrote: »

Hopefully the record snowfall that hit Western Russia a few days ago (heaviest in 100 years) will further aid the development of a Scandi-Russian High..

.. and hopefully we get a record snowfall too.

Iancar29

6 Days out but certainly looks more interesting than what we've had! A small and delicate system so no doubt it will change alot.

BLIZZARD7

Atlantic running into major resistance from the block to our North east by day 7 on the GFS 12z - This is trending the right way -

JCX BXC

Strange how the GFS thinks it'll be snowing at sea and 6c concurrently.

Rebelbrowser

Cant post charts but lovely Easterly on this morning's GFS in FI

Elmer Blooker

Rebelbrowser wrote: »

Cant post charts but lovely Easterly on this morning's GFS in FI

....... and the ECM showing nice northern blocking. I'm surprised that some of the early risers haven't already posted this chart as we have been waiting for the ECM to get on board!

George Sunsnow

Fascinating that these outcomes are being modeled from current at the time of running the programme observed data and before any strat warming which hasn’t happened yet

They don’t as far as I’m aware get modified with the effects of a potential SW,why should they
You can’t enter unknown variables now for an event that is being only modeled in the stratosphere
They’re entirely concerned with the troposphere
How can you without skewing the results into something way wrong enter data from what may but has not yet affected our troposphere or indeed whose eventual effects are not exact
It seems to me to be a useless exercise because all you’ll have after it is complete fantasy

If anyone has any information to the contrary,please post it here

The flip side of that question is that FI must be more untrustworthy now than usual if outcomes in FI have yet to be majorly affected by things up north that haven’t happened yet

Rebelbrowser

George Sunsnow wrote: »

Fascinating that these outcomes are being modeled from current at the time of running the programme observed data and before any strat warming which hasn’t happened yet

They don’t as far as I’m aware get modified with the effects of a potential SW,why should they
You can’t enter unknown variables now for an event that is being only modeled in the stratosphere
They’re entirely concerned with the troposphere
How can you without skewing the results into something way wrong enter data from what may but has not yet affected our troposphere or indeed whose eventual effects are not exact
It seems to me to be a useless exercise because all you’ll have after it is complete fantasy

If anyone has any information to the contrary,please post it here

The flip side of that question is that FI must be more untrustworthy now than usual if outcomes in FI have yet to be majorly affected by things up north that haven’t happened yet

Wondered that myself. Can the SSW be having some effect already?

pistolpetes11

Exactly , people need to be prepared for the swings and roundabouts, day 10 showing up now should be treated as completely madness FI until they reach 72 hours out because there going to chop and change like crazy .

Don’t follow every run as gospel as the only thing you will be fit for at the end of it is some Valium !

George Sunsnow wrote: »

Fascinating that these outcomes are being modeled from current at the time of running the programme observed data and before any strat warming which hasn’t happened yet

They don’t as far as I’m aware get modified with the effects of a potential SW,why should they
You can’t enter unknown variables now for an event that is being only modeled in the stratosphere
They’re entirely concerned with the troposphere
How can you without skewing the results into something way wrong enter data from what may but has not yet affected our troposphere or indeed whose eventual effects are not exact
It seems to me to be a useless exercise because all you’ll have after it is complete fantasy

If anyone has any information to the contrary,please post it here

The flip side of that question is that FI must be more untrustworthy now than usual if outcomes in FI have yet to be majorly affected by things up north that haven’t happened yet

George Sunsnow

Rebelbrowser wrote: »

Wondered that myself. Can the SSW be having some effect already?

I don’t see how
Unless nwp’s have a bias correction for it in their troposphere modeling and I don’t see how entering an unknown (a guess essentially) into trop models like we look at in this thread would do anything other than skew the entire modeling process including the reliable

That’s why I suspect met people are mentioning it a lot but only speculating on potential
It’s also a reason to completely discount FI for now other than *if* current conditions trend FI to blocking and easterlies ,imagine what effect an actual SW would do to this
Enhance and bed it down would be my guess
But for sure what’s appearing now in 2 weeks time is even more uncertain than ever

George Sunsnow

pistolpetes11 wrote: »

Exactly , people need to be prepared for the swings and roundabouts, day 10 showing up now should be treated as completely madness FI until they reach 72 hours out because there going to chop and change like crazy .

Don’t follow every run as gospel as the only thing you will be fit for at the end of it is some Valium !

It’s Shouldnt chop and change more than usual until the SW takes affect on nwp’s starting data
So nothing for a week or two at least I’d imagine
Meantime output beyond a week very very suspect

Gaoth Laidir

Models don't only forecasts the troposphere but go right up through the stratosphere and even into the mesosphere. The ECMWF, for example, goes up to 1 hPa. To say that they can't model what happens below that is wrong.

BLIZZARD7

Gaoth Laidir wrote: »

Models don't only forecasts the troposphere but go right up through the stratosphere and even into the mesosphere. The ECMWF, for example, goes up to 1 hPa. To say that they can't model what happens below that is wrong.

Indeed they model many different layers and have built in interactions between the troposphere and stratosphere etc, they will and most likely are already (GFS FI for last few runs) showing a response to the SSW.

The ECM 00z run throwing heights into Greenland is also possibly the start of the trop response given it's expected to have a quick response this time around. I would agree that the models after +120hrs will be quite useless though as they generally aren't sure of how to deal with a disintegrating polar vortex from at long range. They will only get a proper handle on this when they known for sure the extent of the warmings.

Having said that, there will probably be some extreme scenarios showing up on op runs in next few days (think 1947 style) but won't be worth taking much note of until the warmings have actually happened (only a few days til zonal wind reversal now).

George Sunsnow

Gaoth Laidir wrote: »

Models don't only forecasts the troposphere but go right up through the stratosphere and even into the mesosphere. The ECMWF, for example, goes up to 1 hPa. To say that they can't model what happens below that is wrong.

To say they can’t model from what isn’t there to be fed in as it hasn’t happened yet is right though and is what I was saying...
Sigh :rolleyes:

BLIZZARD7

George Sunsnow wrote: »

To say they can’t model from what isn’t there to be fed in as it hasn’t happened yet is right though and is what I was saying...
Sigh :rolleyes:

They do model the outcomes based directly on what happens before though and in this case the strat warming and zonal wind reversal are forecast to happen over the weekend. So yeah the ssw is not fed in at the very start but the variables that will cause the ssw in the strat are fed in at the start.

Iancar29

George Sunsnow wrote: »

To say they can’t model from what isn’t there to be fed in as it hasn’t happened yet is right though and is what I was saying...
Sigh :rolleyes:

I'd disagree, thats like saying they can't model a low pressure system forming before a jet stream buckles to set the field for the formation of said low pressure.

The physics and mathematical models are there to predict what will happen in the future from the initial conditions. They don't wait on a certain event to occur before predicting the next set of conditions. Yes the resolution isn't there to get the details right of something that is happening so high up in the atmosphere, but it is all part of the T-0 data.

George Sunsnow

BLIZZARD7 wrote: »

They do model the outcomes based directly on what happens before though and in this case the strat warming and zonal wind reversal are forecast to happen over the weekend. So yeah the ssw is not fed in at the very start but the variables that will cause the ssw in the strat are fed in at the start.

I could not look at it that way because chaos means beyond day 5 or 6 in our 850 or 500 mb charts are unreliable
We seem to have had reasonable agreement between gfs and ecmwf on this forthcoming strat warming though
Less chaos up there it seems,I’ll leave Syran to give the dissertation on why that is

sryanbruen

Rebelbrowser wrote: »

Wondered that myself. Can the SSW be having some effect already?

Whilst I am skeptical of how fast the models seem to be responding to the SSW - just after a few days of it taking place, the only example from history we can go off of was January 1985 which had a fast tropospheric response in the space of less than 2 weeks. I can only say this for us because Europe was pretty much in the freezer whilst the SSW then was going on and Ireland was on the edge of it 'til the second or third week of the month. In the end, the IMT was 2.3c which was -3.2c below the 1981-2010 average.

I'll continue to update on SSW in the Winter discussion thread.

George Sunsnow

Iancar29 wrote: »

The physics and mathematical models are there to predict what will happen in the future from the initial conditions. They don't wait on a certain event to occur before predicting the next set of conditions. Yes the resolution isn't there to get the details right of something that is happening so high up in the atmosphere, but it is all part of the T-0 data.

That’s another way of putting it that what’s happening now is used to predict the future weather (obviously) and in effect saying that what’s happening in the strat now is being played forward into a theory of what the weather on the ground will be ie that the two are being analyzed in tandem
I asked that earlier
If that’s the case (and tbh I’m leaning towards thinking it is) then we’re back at pistol Pete’s advice earlier of avoiding FI altogether for a while if you are of a nervous disposition as it will be even more all over the shop than usual