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doctormog
31 January 2021 11:54:33


The GFS  / GEFS resolution has been discussed many times before.  


The current GEFS is running with the same FV3 core as the latest GFS. IME it is now an excellent model and comparable to ECM ENS. 


With the inclusion of the FV3 dynamical core, GEFS resolution has increased from approximately 33km to 25km, and the number of individual forecasts input into the ensemble has increased from 21 to 31. These changes will allow models to run at a higher resolution of detail and provide better accuracy. Additional upgrades include extending the forecast length from 16 to 35 days, along with improvements to the physics. GEFS attempts to quantify the amount of uncertainty in a forecast by varying the known inputs to multiple forecasts, thereby generating a range of possible outcomes.


https://www.noaa.gov/media-release/noaa-upgrades-global-ensemble-forecast-system


 


Originally Posted by: Brian Gaze 


Yes, I couldn’t remember the resolutions and knew someone else would before I found it. 

Aberdeen
Current conditions (personal WS) 
Brian Gaze
31 January 2021 11:55:58


 


Yes, I couldn’t remember the resolutions and knew someone else would before I found it. 


Originally Posted by: doctormog 


No probs. I'm sure you'll get another chance to find it in a day or two. 


 

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
Gooner
31 January 2021 11:58:05


 


I’m not sure of the exact difference in resolution but I know there is one (others will probably know). I believe the starting input data are the same.


Originally Posted by: doctormog 


Ok, thanks Michael and Brian 

Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


doctormog
31 January 2021 12:00:46


 


No probs. I'm sure you'll get another chance to find it in a day or two. 


 


Originally Posted by: Brian Gaze 


Aberdeen
Current conditions (personal WS) 
Gandalf The White
31 January 2021 12:01:15


 


I’m not sure of the exact difference in resolution but I know there is one (others will probably know). I believe the starting input data are the same.


Originally Posted by: doctormog 


The starting point is indeed the same. The Control and the GEFS are run at a lower resolution - it used to have horizontal grids 4x larger.

Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


doctormog
31 January 2021 12:02:25


 


The starting point is indeed the same. The Control and the GEFS are run at a lower resolution - it used to have horizontal grids 4x larger.


Originally Posted by: Gandalf The White 


 Thanks.

Aberdeen
Current conditions (personal WS) 
Gusty
31 January 2021 12:02:47


 Since 1998 or so, when I first got into this hobby?


(Ensembles. It's what they're for. If the op isn't well supported, as per the 0z ECM in this case, then you note that fact.)


Originally Posted by: Retron 


Thanks. I'll remember that. 

Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
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Global Warming
31 January 2021 12:03:56

P8 of the 06Z GEFS brings a monster snowstorm next weekend. It won't happen of course as it looks very different to most other perturbations. But it is quite an unbelievable run. 60+ hours of continuous snow for some. Quite fun to look at although large areas would be cut off for days if not weeks should that come off 


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-156.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-168.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-174.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-180.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-186.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-192.png


http://modeles16.meteociel.fr/modeles/gens/runs/2021013106/gensfr-8-2-204.png


Looking at the broader picture the GEFS and ECM ENS both show 3-4 days of very cold weather starting next weekend. Beyond that there is lots of scatter. Not worth looking beyond about day 8 at the moment as there is no meaningful picture by that point. The 06Z GEFS have 850's ranging from +8 to -13 for London on 13 Feb. Pointless speculating about the second week of Feb at the moment..

Gusty
31 January 2021 12:05:16

Ignoring today's operational runs it looking pretty much game on for down here then ! 


https://www.wetterzentrale.de/en/show_diagrams.php?model=gfs&lid=ENS&var=2&bw=1&geoid=49909


 

Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
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Rob K
31 January 2021 12:07:31


 


Aviemore currently has 10cm snow cover which it has had for weeks bar the odd day and got to -10c last night with only better to come. What a cold spell up there. 


Originally Posted by: Tim A 


Loch Glascarnoch has been reporting 15-20cm deep snow pretty much all month, whenever I have looked. Is that genuine or are the reports broken?

Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
tallyho_83
31 January 2021 12:08:27
I really don't know what to say about the ECM!? How strange - The operational is a milder run but then again it's ENS mean has shifted colder for instance on the 7th February the ENS AVG MEAN is now -8.2c and on the 8th it's down to -7.7c:

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=06&lid=ENS&bw=1 

An ENS mean of -8c isn't bad but I hope the Op run will trend colder in the 12z model run. However - Compare that to the 00z ENS which showed the ENS AVG MEAN of -6.7c on the 7th and -7.1c on the 8th.
Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
---------------------------------------
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Magical Moon
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Rob K
31 January 2021 12:12:19
I remember someone used to post on here the discussion from the American forecasters (NOAA I think) about which models they were following and which they were discounting. Anyone remember what I mean? It was always written in ALL CAPS in a strange abbreviated telegraphese style.
Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
Retron
31 January 2021 12:12:28


Ignoring today's operational runs it looking pretty much game on for down here then ! 


Originally Posted by: Gusty 


Now, which ops would they be. MetO, GFS(P), GEM?


 

Leysdown, north Kent
mrspatch
31 January 2021 12:14:05
Every year I watch the winter model thread.. Hoping for one time in North East Kent we may get a flake or two. For many years, it seems to coincide with the 6th of February when we are lucky.. It's my middle daughters birthday which is why the date sticks. Would be even nicer this year.. Her 18th and no chance of a party 😢 or even seeing her friends. Fingers crossed as always.
fairweather
31 January 2021 12:15:00

It looks like it might end up as a 5 day wonder but not necessarily. Probably due to the wind strength again no hard frosts and low minimums. That has been a feature of this winter down here with very few frosts or any low temperatures due to the persistent cloud and zero snow cover.

S.Essex, 42m ASL
Global Warming
31 January 2021 12:17:00


 


Loch Glascarnoch has been reporting 15-20cm deep snow pretty much all month, whenever I have looked. Is that genuine or are the reports broken?


Originally Posted by: Rob K 


The SYNOP reports show 12cm at the start of the month. Then it all melted. In the last few days it has been 16-18cm generally. So the numbers have been moving around quite a bit which suggests they are correct.


http://www.ogimet.com/cgi-bin/gsynres?lang=en&ind=03031&ano=2021&mes=1&day=31&hora=12&min=0&ndays=30

bowser
31 January 2021 12:18:12


 


Loch Glascarnoch has been reporting 15-20cm deep snow pretty much all month, whenever I have looked. Is that genuine or are the reports broken?


Originally Posted by: Rob K 


it’s feasible, as said on another thread we’ve been heading to Gartly moor since late December (been 4 times) and I reckon there was 20-25cm on the more exposed bits of the hill last weekend. Most of that snow has barely shifted this last month bar one or two brief mild interludes. Loch Glascarnoch is a bit lower but would be more exposed to snowy precipitation than the eastern glens.

Rob K
31 January 2021 12:20:06
The BBC auto forecast certainly doesn't sound too promising. Not even a single air frost here from now until Feb 13th!
Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
Heavy Weather 2013
31 January 2021 12:22:41

The BBC auto forecast certainly doesn't sound too promising. Not even a single air frost here from now until Feb 13th!

Originally Posted by: Rob K 


I think they use the ECM operational. Not even a blend. At least that’s what I understand so happy to be corrected.

Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
doctormog
31 January 2021 12:29:52
This is definitely a first for this winter and in fact many winters. The ensemble mean on the 06z GEFS suite does not go above -5°C for the entire duration of the run here (until Feb 16th).
Aberdeen
Current conditions (personal WS) 
Steve Murr
31 January 2021 12:45:28

Ive just copied this across if anyone has interest as to why the UKMO is showing what it is

Good Afternoon....

This is a bit more of a macro analysis of the upcoming features.

The overnight run of the GFS / GEFS was pretty similar to the ongoing runs it had been churning out - however UKMO at one extreme was colder much quicker & the ECM was milder much quicker.

This implies they were both some sort of outliers V the EPS & GEFS means.

The ECM at 120 lifts the low out NW creating a S/SE flow where as the UKMO sent is SW clearing through.

The UKMO - ( & only UKMO ) started to shift the placement of the parcels of energy at 72>96- instead of a 'weak' signature of energy over Holland & High energy in that low west of Scotland, the emphasis has strongly swung to the energy over Holland.

As a result of this the 'holland' Low supports the cold air filtering SW through the low countries faster.

The 06z GEFS mean swung a fair way to this but not entirely - this is why they were colder at 144.

The JMA & UKMO at 96 ( 84 for the 12s ) both place emphasis on the holland low



Ally Pally Snowman
31 January 2021 12:45:32

Cold cluster looks stronger


 


 



 


 


 

Bishop's Stortford 85m ASL.
Shropshire
31 January 2021 13:01:20


Cold cluster looks stronger


 


 



 


 


 


Originally Posted by: Ally Pally Snowman 


Yes the 06z out of sync with the pack at various points, suggesting that if it goes well at the key point then the Op is too slow to clear the LP away from the SE - often a GFS fault.

From December 27th 2020, zonality will be banned from mixing with the UK. We appreciate that this may come as a shock to younger people and old Uncle Barty. This ban will last for a minimum of ten days.
CField
31 January 2021 13:06:12

Not every cold snap in 79 was a total nationwide freeze affair.


I remember a short cold snap was ended in the south by snow coming up from NE France turning to rain after 4 hours.The warm front moved north until it stalled over the  North Midlands giving a huge dumping.


Cold up north ,transitional in the south seems to be the theme this winter, infact at times a very 79 feel to it excluding the 2 big cold events.With the approach to spring March northerlies NE winds are sure to become more prevalent  and give the south at least more cold nights with the chance of early visitations of warm conditions. 

Favourite snowstorm
Famous channel low
Dec 31st 1978
Hastings East Sussex
Foot of level snow severe drifting
Next day max temp -4 degrees Celsius

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