Model output discussion - Winter has arrived and the hunt for cold is on

[Northern Sky]

5 minutes ago, Djdazzle said:

I am staggered that so many people are surprised by today’s output. Why do people, some of who have been on here for years, expect cold charts in FI to come to fruition? We have had cross model support at T96 in the past, and it’s still gone wrong. It was literally a 1% chance that last night’s runs would actually happen.

 

Yes it's the same every year. Very occasionally we get cold that appears in FI and gets more or less counted down but that is maybe one time in twenty or less. The fact is the models are simply not accurate at a range of anything above 96hrs and even then as you say they can be wrong.

The best advice is when the models show different scenarios is always believe the one that is the worst for cold. It's fun chasing the cold as long as you don't have unrealistic expectations. Most of the time our Winters are pretty mild, that's just how it is, like it or not.

[LRD]

10 minutes ago, Ali1977 said:

From yesterday to this, the only positive I can think of is that if the charts were so wrong yesterday, why are they correct today.  Sadly they are correct more often or not when it doesn’t scream “big freeze”

The modelling to the north and NW is so fundamentally different from yesterday to today you have to wonder what particular difference has been picked up in the Greenland area that wasn't yesterday or the day before. After some years of good forecasting progress, the models seem to have plateaued in performance. Science will have to keep on working to get them to the next level when predicting a week or more out

[Jordan S]

A strong jetstream for the weekend and in particular next week according to the Gfs.. 

This area of the jet stream for tuesday allowing rapid development of a low pressure system as it moves across the UK.

Rainfall..

Wind gust speeds.

 red (40+mph)

pinkish (60mph)

white/grey (70+mph) 

no certainty on this ofcourse at this range but a strong jetstream with the risk of stormy conditions have been hinted for several days now by the GFS. As shown by others a fair few models going with a similar scenario. 

The rainfall accumulation for the next ten days show Western Scotland having a lot for this period, making up for the very dry autumn if this is correct. 

Edited December 4, 2019 by jordan smith

[swfc]

Thanks Jordan,great graphics

[Ali1977]

The mean is not as bad as the Op on the ECM at 240, Germany is a good place to look ref the difference. Jet stream still into Southern France too.

The PV however, that looks pretty meaty in the wrong area for coldies!! 

Edited December 4, 2019 by Ali1977

[Allseasons-Si]

Right!!!

think of this as a roller coaster yes,the models have there upgrades and downgrades it happens all the time,at the moment the roller coaster car/s are at the bottom of a dip on that roller coaster,these cars will steadily ascend up the roller coaster through tonight and then we get that thrill and buzz again tomorrow

as i said yesterday and prob the day before and i will repeat it again that the Azures hp cell is still forecast to be displaced to our west allowing further troughs to get into the mid lats 

the theme is still the same and the models will not resolve this yet at several days out so chill and lets see what happens

lastly the ecm ens still look cold to me and have not changed that much since yesterday

so sit tight peeps it only 4th Dec not 4th March

laters.

[booferking]

1 minute ago, Allseasons-si said:

Right!!!

think of this as a roller coaster yes,the models have there upgrades and downgrades it happens all the time,at the moment the roller coaster car/s are at the bottom of a dip on that roller coaster,these cars will steadily ascend up the roller coaster through tonight and then we get that thrill and buzz again tomorrow

as i said yesterday and prob the day before and i will repeat it again that the Azures hp cell is still forecast to be displaced to our west allowing further troughs to get into the mid lats 

the theme is still the same and the models will not resolve this yet at several days out so chill and lets see what happens

lastly the ecm ens still look cold to me and have not changed that much since yesterday

so sit tight peeps it only 4th Dec not 4th March

laters.

That's this morning's ens is it not?

[Allseasons-Si]

1 minute ago, booferking said:

That's this morning's ens is it not?

Oops!!! yes,sorry

the latest

^i still stand on what i said above though.

 

[Weathizard]

21 minutes ago, Ali1977 said:

The mean is not as bad as the Op on the ECM at 240, Germany is a good place to look ref the difference. Jet stream still into Southern France too.

The PV however, that looks pretty meaty in the wrong area for coldies!! 

Looks like the OP represents the biggest clusters quite well to be fair especially at such long range.

[MATTWOLVES 3]

I can't understand the notion of if it's in FI it won't come off!! All cold spells whether past or present have to start in fi, they can't just turn up overnight! Today may have been a bad day at the office, but it's not a year in the sin bin! Expext upgrades and downgrades galore over the next few days. The ECM mean maybe less positive than earlier, but there remains quite alot of spread!! Colder options very much still on the table. 

[Paul]

2 minutes ago, Mattwolves said:

I can't understand the notion of if it's in FI it won't come off!! All cold spells whether past or present have to start in fi, they can't just turn up overnight! Today may have been a bad day at the office, but it's not a year in the sin bin! Expext upgrades and downgrades galore over the next few days. The ECM mean maybe less positive than earlier, but there remains quite alot of spread!! Colder options very much still on the table. 

The notion is pretty simple. Any outcome shown in FI is less likely to come off. That's why those who hang their hats on what it's showing end up being disappointed more often than not.

[swfc]

16 minutes ago, Mattwolves said:

I can't understand the notion of if it's in FI it won't come off!! All cold spells whether past or present have to start in fi, they can't just turn up overnight! Today may have been a bad day at the office, but it's not a year in the sin bin! Expext upgrades and downgrades galore over the next few days. The ECM mean maybe less positive than earlier, but there remains quite alot of spread!! Colder options very much still on the table. 

You just blown my mind there lol.is that a paradox regarding fi? If there is fi then it must be zero hrs .where does it start???

[swfc]

14 minutes ago, Paul said:

The notion is pretty simple. Any outcome shown in FI is less likely to come off. That's why those who hang their hats on what it's showing end up being disappointed more often than not.

Where is fi Paul? Not a trick question but any spell of weather has to develop.

[syed2878]

hardly surprising UK met model didn’t buy into the cold spell next week writing has been on the wall Exeter also backed away from the long range for end of December from cold and dry too windy and wet with optic in temperatures. this was the reason I wasn’t getting excited by the GFS and to an extent ECM output over the last few days until you KMO is on board with any cold snaps or spell I don’t get excited. .

[Fairweather Teessider]

6 minutes ago, syed2878 said:

hardly surprising UK met model didn’t buy into the cold spell next week writing has been on the wall Exeter also backed away from the long range for end of December from cold and dry too windy and wet with optic in temperatures. this was the reason I wasn’t getting excited by the GFS and to an extent ECM output over the last few days until you KMO is on board with any cold snaps or spell I don’t get excited. .

What?

[tight isobar]

11 minutes ago, syed2878 said:

hardly surprising UK met model didn’t buy into the cold spell next week writing has been on the wall Exeter also backed away from the long range for end of December from cold and dry too windy and wet with optic in temperatures. this was the reason I wasn’t getting excited by the GFS and to an extent ECM output over the last few days until you KMO is on board with any cold snaps or spell I don’t get excited. .

....and the forementioned 'forecast'.. is open for both 're-Analysis/change in structures..

Believe me.

I'll chuck some formats and deciphering Analysis myself later also..

I'm somewhat stunned by the pulling of teeth and doom tbh.

And I hope I can shed some light on that firm belief!!

We are @wobble- gate as things stand..and a stark contrast awaits...imo.

We'll leave that here.....'>for now<.

Edited December 4, 2019 by tight isobar

[The Real Snowman]

3 minutes ago, Fairweather Teessider said:

What?

Basically if the UKMO isn’t onboard then don’t get too excited. Many of us did, many of us dared to dream but alas many of us are disappointed. As much as I’d have been interested to see how the news would report the ‘snowcane’ and indeed how the pattern would evolve subsequently without the UKMO buying into the notion of the cold spell being suggested by the other models it was always a risk to  get too excited. Lesson learnt (again) (until next time). This model watching is worse than crack. 

[Allseasons-Si]

12 minutes ago, syed2878 said:

hardly surprising UK met model didn’t buy into the cold spell next week writing has been on the wall Exeter also backed away from the long range for end of December from cold and dry too windy and wet with optic in temperatures. this was the reason I wasn’t getting excited by the GFS and to an extent ECM output over the last few days until you KMO is on board with any cold snaps or spell I don’t get excited. .

The UKMO is not in range of the cold synoptic and besides,it's not happened yet.

[ArHu3]

I haven't seen such unity between the ensemble members so far for a long time, look at how little scatter there is in the wind direction (windrichting), usually it's all over the place by day 7-8

[Catacol]

1 hour ago, feb1991blizzard said:

Catacol is just posting now - hopefully with a better update on some more tropical forcing for the second half of December.

Blimey - you got a webcam in my sitting room?! Hehe - I was just toying with taking up Mr Frosts promise of him eating a sledge if all of us don’t see a snowflake this year. Some in this forum have no idea how lucky they are not to live in Somerset......

Next week will certainly be interesting, just to see the impacts of the Pacific jet extension on the back of +EAMT and witness its ability to spike the pattern around the hemisphere. The truth of the end of next week is too far off to bin entirely as a cold snap because the magnitude of the wave breaking that will accompany the jet surge is open to interpretation and I would imagine the models will struggle to get a precise handle on how that surge will pan out. Bear in mind it hasn’t even reached the west coast of the US yet.

The bigger question really is what happens when that surge passes. I posted optimistically that a block might form with sufficient longevity to carry through to later in December. But I don’t think in truth this is the most likely outcome. The MJO is not positioned favourably yet, and from pirated tweets I’ve seen today it would appear any rise in GLAAM has slowed to a neutral crawl. In blunt terms this means that support for sub tropical high pressure will increase, and in turn that means less support for a -NAO pattern. This was my gut feeling going into December - the spike in torque adds some spice to the short term, but it doesn’t change the overall direction in the first half to two thirds of the month.

Much still hangs on the extent to which tropical convection can emerge from phase 6 and get to the maritimes, the strength of that convection and the condition of the vortex in the context of QBO progression. I am an avid reader - comes with my profession - and I can tell you that opinions on this are divided across the net. I painted two distinct pathways for winter in my forecast because the junction represented by the potential pathways at the end of December was pretty clear, but genuinely I think the direction of travel at that point hangs in the balance. The snowper in me wants the amplified, Nino attractor pathway smoothed by a transition to an eQBO and a vortex in collapse; the realist in me also sees the distinct possibility of vortex recovery, delayed QBO transition and an MJO struggling for effect in the context of a standing wave in MJO phase 2 that helps prevent helpful impacts in the extra tropics - helpful if you want cold that is. A kind of half way house blend is obviously a compromise solution.

Don’t need charts tonight. For now enjoy a rollercoaster ride into next week and NWP output that I suspect will catch the eye again before the impacts of jet resurgence fades, and in the meantime perhaps we can get some evidence emerge as to how the run in to Xmas may develop vv the tropical signal and vortex as drivers. It’s only Dec 4. Plenty of time for multiple rollercoaster rides....

[Allseasons-Si]

Thanks for that update Catacol all be it a sober on the fence one.

 

[booferking]

Well well well jet a lot further South 120hr and that troublesome low running along the base of it.

Edited December 4, 2019 by booferking

[Allseasons-Si]

Icon 120 sure doesn't blow up that low in the Atlantic,what ramifications would this have later on?

 

[damianslaw]

I'm refraining from commenting on the models at the moment, as we about to enter a very turbulent time, and fully expect sudden short term development to scupper the medium output - reliable timeframe in terms of detail 96hrs tops..

[blizzard81]

Ok, I think we all need a silver lining tonight and this is the best I could come up with. First chart is ecm debilt ens from this morning days 12 to 15. Second chart is the updated ecm debilt from tonight's 12z run for the same days. You can clearly see colder clustering on tonight's run. Chins up!