Model Output Discussion 17/12/14 17:20>>>· Page 22

Quantum
Advanced Member

20 December 2014 11:47:14

Parallel handles low completely differently to norm. Snow probability and 850s for same time period.

Incidently, isn't it refreshing how much better the parallel (0.5) resolution is to the normal (2.5)? Anyway the ways the models handle the the low are very different and I'm not happy with either, tbh I think the parallel is more realistic although the idea of dropping a NW wave entirely doesn't seem right either, clearly this is going to cause headaches because the further south the low is the more wintry in general. Personally I think the Azores high will be quicker to clear and the low that we do see will be shallower, colder and rather less terrifying in general, while bombogenesis is certainly something that could happen, in practise the low is unlikely to be so vigorous. That said we should not be complacent about the possibility.

Also FYI to the 'weather bomb' bandwagon, this is a REAL (potential) one, the one everyone was yapping about a few days ago didn't count because we were no where near the LP centre and the bombogenesis occured BEFORE it hit the UK.

2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.

Frostbite80
Advanced Member

20 December 2014 11:51:29

#527

Lmao control gives a channel low instead of and east coast storm........more runs needed :/

The Beast from the East
Advanced Member

20 December 2014 12:06:48

#528

Most of the GFS ens now flatten the pattern. Perhaps a new trend with ECM following tonight. Still time for one last swing back to cold, but I think we need to prepare ourselves (bottle of gin and blunt razor at the ready)

"We have some alternative facts for you"
Kelly-Ann Conway - special adviser to the President

Jonesy
Advanced Member

20 December 2014 12:21:14

#529

..oh and a 50% symbol

Diagramme GEFS

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

Houston, we have a problem

Medway Towns (Kent)
The Weather will do what it wants, when it wants, no matter what data is thrown at it !

Andy Woodcock
Advanced Member

20 December 2014 12:23:13

#530

The 06z GFS is desperate and I mean desperate with all charts beyond 144 being as bad as it gets with massive heights to our south stretching from the Azores to the Med and down to the Equator!

The new year period couldn't be any milder with those Synoptics.

The MetO are not predicting such a mild outcome yet and I hope the update doesn't bring one.

At the moment the Weather Gods are having a bloody good laugh at the expense of TWO members.

Andy

Andy Woodcock
Penrith
Cumbria

Altitude 535 feet

"Why are the British so worried about climate change? Any change to their climate can only be an improvement" John Daley 2001

Brian Gaze
Administration

20 December 2014 12:39:29

#531

GEFS6z picking up a cluster of runs around 29/12 which probably isn't far off the ECM. Snow row reflects this too:

http://www.theweatheroutlook.com/twodata/datmdlout.aspx

Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

Brian Gaze
Administration

20 December 2014 12:41:46

#532

Incidently, isn't it refreshing how much better the parallel (0.5) resolution is to the normal (2.5)?

Originally Posted by: Quantum

That's just the output data sets and has nothing to do with the underlying model. TBH it's only relevant for local forecasts out to about 48 and irrelevant for chart plots.

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

Quantum
Advanced Member

20 December 2014 13:02:58

#533

That's just the output data sets and has nothing to do with the underlying model. TBH it's only relevant for local forecasts out to about 48 and irrelevant for chart plots.

Originally Posted by: Brian Gaze

So do they use interpolation or has the data resolution always been the same as the parallel?

Anyway even if its objectively no more useful than the normal resolution, its certainly more aesthetically pleasing which is something I do care about (probably too much).

2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.

some faraway beach
Advanced Member

20 December 2014 13:09:07

#534

Re the ECM ensemble posted by Retron which shows mean max temps of 3C after Christmas and going into the New Year.

Again, very interesting. Its impossible to deny the risk of something colder is still there from around 28-29th. But all the while the Op says no, and all the while the cold stays well out in FI, it is also worth paying attention to the operational output and keep checking on what the experts at the Met O say will transpire.

Originally Posted by: Whether Idle

The ECM op finishes bang on the ensemble mean.

Edited by user 20 December 2014 13:11:27 | Reason: Not specified

2 miles west of Taunton, 32 m asl, where "milder air moving in from the west" becomes SNOWMAGEDDON.
Well, two or three times a decade it does, anyway.

Quantum
Advanced Member

20 December 2014 13:11:14

#535

The ECM op finishes bang on the ensemble mean.

Originally Posted by: some faraway beach

Tbf the ECM op really doesn't end badly at all! Indeed we have a wave from the NW threatening a reload and the -6C isotherm in the midlands.

2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.

Saint Snow
Advanced Member

20 December 2014 14:12:17

#536

http://www.meteociel.fr/modeles/gefs.php?carte=1

Originally Posted by: RobN

Thanks, Rob (missed your post previously!)

Martin
Home: St Helens (26m asl) Work: Manchester (75m asl)
A TWO addict since 14/12/01
"How can wealth persuade poverty to use its political freedom to keep wealth in power? Here lies the whole art of Conservative politics."
Aneurin Bevan

Brian Gaze
Administration

20 December 2014 14:13:41

#537

So do they use interpolation or has the data resolution always been the same as the parallel?

Anyway even if its objectively no more useful than the normal resolution, its certainly more aesthetically pleasing which is something I do care about (probably too much).

Originally Posted by: Quantum

I rewrote the download routine for the new GFS so TWO can switch between the 0.25, 0.5 and 1.0 data sets at will without recompiling. These show 0.25, 0,50 and 1.0:

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

Quantum
Advanced Member

20 December 2014 14:29:17

#538

I rewrote the download routine for the new GFS so TWO can switch between the 0.25, 0.5 and 1.0 data sets at will without recompiling. These show 0.25, 0,50 and 1.0:

Originally Posted by: Brian Gaze

That's really significant, and I definitely prefer the 0.25 one. I was wondering what 0p50 1p00 were, I guess then they are just inferior versions of 0p25. Tbh I'm always going to use 0p25, even when I use other data sets for the same chart with different resolutions.

2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.

Brian Gaze
Administration

20 December 2014 15:13:02

#539

That's really significant, and I definitely prefer the 0.25 one. I was wondering what 0p50 1p00 were, I guess then they are just inferior versions of 0p25. Tbh I'm always going to use 0p25, even when I use other data sets for the same chart with different resolutions.

Originally Posted by: Quantum

Yes, they're all generated from the same model run. When you double the horizontal resolution of the output data you effectively quadruple the size of the dataset. As gribs get finer and finer the need for mesocales probably diminishes, but so does the need to be more selective in what you're picking etc.

Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

Whether Idle
Advanced Member

20 December 2014 15:42:03

#540

Re the ECM ensemble posted by Retron which shows mean max temps of 3C after Christmas and going into the New Year.

The ECM op finishes bang on the ensemble mean.

Originally Posted by: some faraway beach

I was referring to the section where the Op is a mild outlier, 27-29 Dec.

Dover, 5m asl. Half a mile from the south coast.

nsrobins
Advanced Member

20 December 2014 15:42:31

#541

Yes, they're all generated from the same model run. When you double the horizontal resolution of the output data you effectively quadruple the size of the dataset. As gribs get finer and finer the need for mesocales probably diminishes, but so does the need to be more selective in what you're picking etc.

Originally Posted by: Brian Gaze

Great work Brian. But the question is, when is it going to snow?