Model output discussion - winter proper underway

[Summer Sun]

The 00z GFS ens shows a rapid rise on the 850s we go from around -5 on Sunday to +6 on Tuesday we then remain milder than average before a steady drop down from around the 23rd but still a touch above average

[mb018538]

7 minutes ago, ArHu3 said:

 

And as icing on top the stratosphere is picking up 

 

(the forum software changes to the wrong picture, trust me it's bad) 

Picking up perhaps - but still weak compared to the normal values for this time of the year. All very interesting!

[jvenge]

2 minutes ago, mb018538 said:

Picking up perhaps - but still weak compared to the normal values for this time of the year. All very interesting!

Always best not to confuse a mean with normal. That is quite within a "normal" (or shall we say "typical") range. 

[stodge]

17 minutes ago, Summer Sun said:

The 00z GFS ens shows a rapid rise on the 850s we go from around -5 on Sunday to +6 on Tuesday we then remain milder than average before a steady drop down from around the 23rd but still a touch above average

I have to say I was surprised how anticyclonic the GFS 00Z OP and Control were going into next week.

To be a bit IMBY-ist (living in lowland East London), there looks to be a strong rise of pressure from Monday.

The Control for next Wednesday:

OP at the same point:

You can bin 850s at this time of year under anticyclonic conditions as an indicator. I suspect the SE (and indeed much of the south) might hang on to colder, clearer conditions with morning frost and fog and day time numbers struggling - it's almost exactly mid winter in terms of day length so there's not a lot of daylight for the Sun to burn off the frost and fog.

Rather than look to the east in vain it may be the direction to look is south with rising pressure and while frost and fog isn't what many or indeed most want for Christmas, it would be cold for many and I think looking through the Ensembles it's not an option to be ignored.

[frosty ground]

So we find ourselves back to where we was a few weeks ago when the models then as now started to show a westerly regime and some show some pretty mild weather, of course this is leading to a few posters to once again start worrying about the next 4 weeks, soon to be 6 weeks then Winter will be over ETC. I suspect we will see a repeat of what we have just had.

Snow a possibility for some Wednesday night after a brief warm up during wednesday and then another northerly shot there after.

[Frosty.]

28 minutes ago, Summer Sun said:

The 00z GFS ens shows a rapid rise on the 850s we go from around -5 on Sunday to +6 on Tuesday we then remain milder than average before a steady drop down from around the 23rd but still a touch above average

Again, no surprise there, disappointment yes, surprise no..the GEFS mean has been showing this for some time but it kind of got ignored during the cold frenzy.....anyway, ive  enjoyed the BIG FREEZE..as the media very generously described it!

[carinthian]

11 minutes ago, frosty ground said:

So we find ourselves back to where we was a few weeks ago when the models then as now started to show a westerly regime and some show some pretty mild weather, of course this is leading to a few posters to once again start worrying about the next 4 weeks, soon to be 6 weeks then Winter will be over ETC. I suspect we will see a repeat of what we have just had.

Snow a possibility for some Wednesday night after a brief warm up during wednesday and then another northerly shot there after.

Even at day 10 the Atlantic zonal jet fails to make significant in roads into the British Isles. Yes, most models going for a milder phase but the outcome for type and how mild still open to doubt in my thinking anyway.

C

Edited December 12, 2017 by carinthian

[Chesil View]

Just now, Frosty. said:

Again, no surprise there, disappointment yes, surprise no..the GEFS mean has been showing this for some time but it kind of got ignored during the cold frenzy.....anyway, ive  enjoyed the BIG FREEZE..as the media very generously described it!

Yes always makes me laugh when the media have to turn a five day outbreak of normal winter weather into The big freeze.

[ArHu3]

41 minutes ago, mb018538 said:

Picking up perhaps - but still weak compared to the normal values for this time of the year. All very interesting!

I don't know what you see but it almost hits 2sd

@jvenge

Edited December 12, 2017 by ArHu3

[TEITS]

1 hour ago, terrier said:

So the model output overnight doesn’t look great. But haven’t people been reading the updates from GP Tamara etc. We are going to see wild swings in the output. We were always due a milder faze upto xmas week. Which is what the models are now starting to show. But flipping heck it’s only the 12th of Dec we have another 3 months of winter to go. And the phrase straw clutch is been banded about with the output. Unbelievable Jeff. 

In my opinion we haven't been seeing wild swings in the output in recent days. Actually the models have been consistent in bringing us a return to milder SW,lys.

Personally I think members should forget about the predicted Scandi HP and focus on just what the models are currently predicting. The reason I say this is because even towards the latter stages of the GFS we couldn't be further away from an E,ly via a Scandi HP if we tried. If anything any future cold spells in distant F.I are more likely to come from a NW/N,ly.

[lassie23]

11 minutes ago, Frosty. said:

Again, no surprise there, disappointment yes, surprise no..the GEFS mean has been showing this for some time but it kind of got ignored during the cold frenzy.....anyway, ive  enjoyed the BIG FREEZE..as the media very generously described it!

Yes they like to hype the weather don't they A mild stormy end to december would tie in nicely with iapennell's long range forecast

Edited December 12, 2017 by lassie23

[mb018538]

2 minutes ago, ArHu3 said:

I don't know what you see but it almost hits 2sd

@jvenge

That was my thoughts too....surely 2 standard deviations from the mean would be classed as significant?!

 

[karyo]

2 minutes ago, lassie23 said:

Yes they like to hype the weather don't they A mild stormy end to december would tie in nicely with ianpenell's long range forecast

Is there a thread for it on net weather? 

[Scandinavian High.]

As Tamara said a few days keep an eye out to north east and john hammered states in is blog mild weather could not last very long ..

[BLAST FROM THE PAST]

19 minutes ago, carinthian said:

Even at day 10 the Atlantic zonal jet fails to make significant in roads into the British Isles. Yes, most models going for a milder phase but the outcome for type and how mild still open to doubt in my thinking anyway.

C

Totally agree.  We are really cold at the moment, renewed cold shot come weekend.  I strongly suspect we will start to see different solutions developing during the week.  Yes westerly/Atlantic influence is likely to come but how it comes and how long before more cold interaction?  It’s been a pretty decent start to winter and more cold interest still to come before one needs to think about ‘westerly’ incursions.

Let’s give it a chance at least to play out.....as this winter imo will have several chances of real wintry weather

BFTP

Edited December 12, 2017 by BLAST FROM THE PAST

[BLAST FROM THE PAST]

13 minutes ago, karyo said:

Is there a thread for it on net weather? 

BFTP

[jvenge]

44 minutes ago, ArHu3 said:

I don't know what you see but it almost hits 2sd

@jvenge

Almost, briefly, almost ;-)

You don't arrive at a mean value by "normal" conditions tracking the mean. So, it is on the edge of a standard deviation and two standard deviations briefly. Standard deviation, by its name, suggests it is quite, well, standard? So, while it stays within a standard deviation, on either side, I'd suggest that's quite normal and average for an observation/forecast.

 

 

Edited December 12, 2017 by jvenge

[West is Best]

In the aftermath of widespread snow, the coldest day in 7 years and the coldest night of the year, are we in danger of treating Wednesday night / Thursday slightly casually?

 

I still think further ahead the scatter is HUGE. When that happens it means (to me) that upstream signals are not clear cut and a number of permutations are possible. All to play for still and I wouldn't be surprised to see some cold operationals appear over the next few days:

Scatter gun:

 

[ArHu3]

Gfs 6z is coming with quite a big change from 168h, well things can only get better, right ?

Edited December 12, 2017 by ArHu3

[Interitus]

7 minutes ago, jvenge said:

Almost, briefly, almost ;-)

You don't arrive at a mean value by "normal" conditions tracking the mean. So, it is on the edge of a standard deviation and two standard deviations briefly. Standard deviation, by its name, suggests it is quite, well, standard? So, while it stays within a standard deviation, on either side, I'd suggest that's quite normal and average for an observation.

Depends on the probability distribution, but assuming a normal distribution, only roughly 2.5% of events would lie beyond 2 sd - in this case 2.5% of daily zonal wind speeds would be lower than the forecast on those days.

[jvenge]

4 minutes ago, Interitus said:

Depends on the probability distribution, but assuming a normal distribution, only roughly 2.5% of events would lie beyond 2 sd - in this case 2.5% of daily zonal wind speeds would be lower than the forecast on those days.

Quite, but it isn't actually showing in 2sd, just close to, and briefly, before moving back into a standard deviation. I actually think it is quite encouraging for the time of year :-)

I generally have an issue when people who confuse mean and normal and thought I'd rant a bit while the forum is quiet. 

Edited December 12, 2017 by jvenge

[feb1991blizzard]

1 minute ago, ArHu3 said:

Gfs 6z is coming with quite a big change from 168h, well things can only get better, right ?

Doesn't look like it to me, yes there is a bigger dig further south of the Atlantic trough at 180, because this is still positively tilted, I cant see it making that much difference to the second half of the run apart from a tiny bit more amplification, if it had a negative tilt on it pushing WAA towards Greenland, we would be in business.

[Rocheydub]

I’d advise those that are frustrated by the medium and FI charts to do what I do annually. Take a break from model watching for a few days. Trust me, it’s good for the soul. More often than not, something more palatable shows up when you return... I’ve just never had to do it so early in the season before! My snowless cold spell/slider has seen to that! I’ll return in a few days! 

[Chesil View]

9 hours ago, Paul_1978 said:

Not in so many words! 

See the Model Tweets thread. 

Hi Paul I was not going on the model tweets but a members personal communication with Fergie.

[I remember Atlantic 252]

slug needs to be further north, but potentially cold, frosty foggy in the south, warm in NW, esp Scotland

Edited December 12, 2017 by I remember Atlantic 252