theweatheroutlook

Karl Guille
01 February 2023 20:40:40
Low pressure over the northern med (ideally France / Italy region) is a pre-requiste for cold air to advect westwards into France / UK.  Currently looks unlikely that a proper injection of cold will ensue from the current set up (given lack of current other model support for GFS option) but still time for change in the next 24/48 hours. This has always represented the best chance of an 'ice day' IMBY!
St. Sampson
Guernsey
idot
  • idot
  • Advanced Member
01 February 2023 20:46:28
Originally Posted by: Rob K 

Even if this one fails (as is likely) there is still plenty of winter left.



except that in 4 weeks time it will probably warm enough to sit outside in a t-shirt and that in two weeks time the sun will be too strong for any long lived snow event that we all want. 

It seems the window is so brief in these modern winters

😁😟🐍
https://twitter.com/JohnathanSizz 

 
Gandalf The White
01 February 2023 21:10:10
Originally Posted by: idot 

except that in 4 weeks time it will probably warm enough to sit outside in a t-shirt and that in two weeks time the sun will be too strong for any long lived snow event that we all want. 

It seems the window is so brief in these modern winters

😁😟🐍



The strength of the sun in the last week of February is the same as it is in mid-October. I think t-shirts outside are exceedingly rare on a cool October day.
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


+2
Chunky Pea
01 February 2023 21:58:59
Originally Posted by: idot 

except that in 4 weeks time it will probably warm enough to sit outside in a t-shirt

😁😟🐍


providing there is no wind! Reached a well above average 10c here today but that wind made it feel more like -10c. 🥶
Current Conditions
https://t.ly/MEYqg 

"You don't have to know anything to have an opinion"
--Roger P, 12/Oct/2022
+1
Quantum
01 February 2023 21:59:02
Lobe looking broadly the same at T+72h on the GFS18Z.

Nothing major expected in terms of upgrade or downgrade.

EDIT: Lobe at T+96h is stronger. Expecting a substantial downgrade :(

EDIT2: Subtantial looking like the wrong word! The weaker lobe doesn't seem to have made much impact suprisingly. Still, its alot weaker than the ECM12z e.c.t. anyway.


 
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
Quantum
01 February 2023 22:08:22
OK comparing T+132h between GFS18Z and GFS12Z, the pattern doesn't look much worse (if at all worse on the 18Z) although the high is a bit further south. The lobe being a bit stronger is clearly still having an impact (in a negitive way). Since the 6Z the lobe has trended stronger on the GFS, this is not great if this trend continues.
 
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
Quantum
01 February 2023 22:12:57
Worth noting that the slight trend to strengthen the iceland lobe on the GFS is still a gulf away from the other models.

ICON 18Z has a central 500hpa height of around 500dm at T+72h
GFS 12Z doesn't have a central height because there is no closed circulation, but in roughly the same spot the height is 510dm
The GFS6Z at the same time was maybe 511dm or 512dm.




 
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
crazysaint
01 February 2023 22:26:25
GFS really not letting go of it's path currently
Wickham, Fareham, Hants
+1
squish
01 February 2023 22:32:05
But of a pub run ! 
D.E.W on Dartmoor. 300m asl
+1
ballamar
01 February 2023 22:32:49
Thinking the op will be one of the coldest options!
squish
01 February 2023 22:34:51
Sub -14c 850s across the south !!
D.E.W on Dartmoor. 300m asl
+1
Quantum
01 February 2023 22:36:45
So GEM18Z does exist out to T+84h, the crucial time is now T+72h when the lobe forms so we can compare GEM12Z with GEM18Z.

So the verdict?
The lobe is ALOT weaker on the GEM18Z compared to the 12Z. Take a look at T+78h. Look a little NE of where the surface low is (995hpa on the 18Z) and you can see the 18Z is consistently 3-6dm higher!

This is big. GEM has flipped sides!!!!!


IMAGE. Members enable at bottom of page

IMAGE. Members enable at bottom of page
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
Quantum
01 February 2023 22:45:12
Gah this isn't so straight forward.

GEM18Z has swung massively towards the GFS solution, but ARPEGE has gone the other way. The lobe is stronger on the ARPEGE. Summary of the 18Zs so far.

GFS: Modest downgrade (saved by a lucky surface pattern)
GEM: Big upgrade
ARPGEGE: Downgrade
ICON: No substantial change (still terrible though)

 
Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
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.
MRayner
01 February 2023 22:47:02
The difference at 140 between ECM and gfs is certainly an eye opener, one is going to be spectacularly wrong I feel ! Odds on it’s the GFS as it’s the 🥶version . 
Location Whisky 🥃 country, Cragganmore ,Moray, 440 AMSL
squish
01 February 2023 22:51:18
18z gefs a slight upgrade at +144 as a whole (synoptically)

 
D.E.W on Dartmoor. 300m asl
ballamar
01 February 2023 23:00:45
Early GEFS quite strong on agreeing a plunge in temps (London) from 7th/8th 
Karl Guille
01 February 2023 23:17:01
Some rather eye watering ensembles on the 18z GFS for us snow starved Channel Islanders!!
https://modeles16.meteociel.fr/modeles/gensp/runs/2023020118/graphe3_00000_220_245___.gif 
 
St. Sampson
Guernsey
idot
  • idot
  • Advanced Member
01 February 2023 23:24:08
Originally Posted by: Karl Guille 

Some rather eye watering ensembles on the 18z GFS for us snow starved Channel Islanders!!
https://modeles16.meteociel.fr/modeles/gensp/runs/2023020118/graphe3_00000_220_245___.gif 
 



Confidence.😁😎👿
 
https://twitter.com/JohnathanSizz 

 
tallyho_83
01 February 2023 23:39:40
I'll take P08 from the 18z run please at +228: (-16c 850's!)

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Home Location - Kellands Lane, Okehampton, Devon (200m ASL)
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Sean Moon
Magical Moon
www.magical-moon.com


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