theweatheroutlook

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Brian Gaze
30 January 2025 11:47:53
Will February bring an "old school" easterly? Onwards with the model discussion...
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
+2
ballamar
30 January 2025 12:26:49
Whether it could classify as old school is another question - looks like the chance of a continental feed is definitely higher than usual. Ideally lower pressure to the south would be a bonus and there are some signs of this. For now drier weather is on the cards - very cold easterly possible….longevity and tilt dependent!
The Beast from the East
30 January 2025 12:52:47

Will February bring an "old school" easterly? Onwards with the model discussion...

Originally Posted by: Brian Gaze 


Too many obstacles to overcome to even get close 
At least some faux cold and if we get lucky a battleground snow event. But the northern arm of the jet is just too strong these days. 30 years ago, definitely, sadly today we need an SSW to kill the jet first
Purley, Surrey, 70m ASL

"We have some alternative facts for you"

Kelly-Ann Conway - former special adviser to the President
MRazzell
30 January 2025 13:12:32
Looking quite chilly on the GFS in a weeks time ("mild" if you're in West Yorkshire...). Rainfall levels nice and low too excluding the far NW, Central Highlands and NI. Jet stream still flapping about and struggling to make up its mind but certainly doesnt look as strong as it has been recently. Could be a decent spell of weather coming up, wouldnt take much for it to turn exciting.
Far north of East Sussex. +150m asl.
Rob K
30 January 2025 14:06:15
GFS 6Z shows a proper battle between a strong jet and a big block, resulting in a bit of a stalemate - chilly but mostly boring. Wouldn't take much to allow something more interesting.

ECM seems more progressive.
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
Gandalf The White
30 January 2025 14:30:08

GFS 6Z shows a proper battle between a strong jet and a big block, resulting in a bit of a stalemate - chilly but mostly boring. Wouldn't take much to allow something more interesting.

ECM seems more progressive.

Originally Posted by: Rob K 


Over the years that’s not an unusual scenario. I can remember not infrequent occasions when the ‘battleground’ was over the southern North Sea or Denmark, leaving us on the mild side of the zone.
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Quantum
30 January 2025 14:33:07
It definitely looks like a blocked pattern, that's the certain bit. The uncertain bit is, does the block align (eventually) in the right way to do anything interesting for us.
But it is blocked. And its come a little earlier than the MJO would have suggested. I see three bursts of deep WAA prior to 192h, which strengthens the deep high each time.
Things certainly seem to be looking good by the end of the first week of February. Remember, the easterly might not be the 'one', often you need a faux cold scandi high prior to retrogression to greenland before the real cold gets in.
Still February looks like it has a good shot of being a cool month at the very least.
2024/2025 Snow days (850hpa temp):10 days with snow/sleet falling
18/11 (-6), 19/11 (-6), 23/11 (-2), 22/12 (-5), 04/01 (-5), 05/01 (0),14/02 (0), 15/02 (0)12/03 (-6), 13/03 (-6),
2023/2024 8 days 29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)
2022/2023 7 days 18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)
2021/2022 12 days
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)
+1
DPower
30 January 2025 15:34:26
Absolutely pathetic over on the other forum, bloody teleconnection numb nuts can not read NWP let alone teleconnections. Met4cast last year was wetting his panties with excitement with what the huge +AAM was showing yet two days later it completely imploded. Then a year later and its "there will be no high latitude blocking, no easterly, no SSW or splitting of the vortex". Why, because the teleconnections do not allow it. Bloody Insanity. 
Moving on and of course I could be wrong but it looks like the models to me are starting to firm up on the orientation and location of the massive high (that should not exist). Just hoping we get to pull in some colder uppers and the chance of a convective easterly. February could  be a very interesting month especially if the strat charts are anyway near correct.
Quantum
30 January 2025 16:15:51

Absolutely pathetic over on the other forum, bloody teleconnection numb nuts can not read NWP let alone teleconnections. Met4cast last year was wetting his panties with excitement with what the huge +AAM was showing yet two days later it completely imploded. Then a year later and its "there will be no high latitude blocking, no easterly, no SSW or splitting of the vortex". Why, because the teleconnections do not allow it. Bloody Insanity. 
Moving on and of course I could be wrong but it looks like the models to me are starting to firm up on the orientation and location of the massive high (that should not exist). Just hoping we get to pull in some colder uppers and the chance of a convective easterly. February could  be a very interesting month especially if the strat charts are anyway near correct.

Originally Posted by: DPower 


I always think SSWs are overrated anyway. The troposphere and the stratosphere are really not that well coupled at all; the tropopause is this massive wall of stability that really stops much interaction between the two. Its why I prefer to focus on the upper trop.
2024/2025 Snow days (850hpa temp):10 days with snow/sleet falling
18/11 (-6), 19/11 (-6), 23/11 (-2), 22/12 (-5), 04/01 (-5), 05/01 (0),14/02 (0), 15/02 (0)12/03 (-6), 13/03 (-6),
2023/2024 8 days 29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)
2022/2023 7 days 18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)
2021/2022 12 days
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)
+1
Rob K
30 January 2025 17:18:17
12Z GFS shows the Atlantic pushing the block aside more easily than the 6Z, but ironically the air (at 850mb at least) is colder from the west than it was from the east anyway! A sign of the times, cold America, warm Europe. In another few years might we be looking at westerlies being the source of our snowfall?
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
ballamar
30 January 2025 17:28:39

12Z GFS shows the Atlantic pushing the block aside more easily than the 6Z, but ironically the air (at 850mb at least) is colder from the west than it was from the east anyway! A sign of the times, cold America, warm Europe. In another few years might we be looking at westerlies being the source of our snowfall?

Originally Posted by: Rob K 


Dynamics of snow from the west is much different than from the east though
Rob K
30 January 2025 17:47:41

Dynamics of snow from the west is much different than from the east though

Originally Posted by: ballamar 


Yes obviously there is much more boundary layer modification. Still a bit depressing when we have deeper cold coming across 3000 miles of Atlantic than we can get from Scandinavia!
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
Brian Gaze
30 January 2025 17:58:41

I always think SSWs are overrated anyway. 

Originally Posted by: Quantum 



I agree. 

We're now at the time of the year when the classic "raw" easterly can develop. However, we're also approaching the point where daytime temperatures can increase noticeably due to the strengthening sun. 
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
+1
Jiries
30 January 2025 18:17:01

Yes obviously there is much more boundary layer modification. Still a bit depressing when we have deeper cold coming across 3000 miles of Atlantic than we can get from Scandinavia!

Rob K wrote:


It happened in 1996 when New York was -26C and this cold air travelled to here giving us -2c maxes from the west but snowfall was poor quality and wasn't much fallen as preicps band was broken to pieces instead of winter storm type to give us deep snow cover.
Brian Gaze
30 January 2025 18:18:39

It happened in 1996 when New York was -26C and this cold air travelled to here giving us -2c maxes from the west but snowfall was poor quality and wasn't much fallen as preicps band was broken to pieces instead of winter storm type to give us deep snow cover.

Originally Posted by: Jiries 



The famous white Christmas in 1999 was the result of an Atlantic flow.
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
30 January 2025 18:58:03

The famous white Christmas in 1999 was the result of an Atlantic flow.

Originally Posted by: Brian Gaze 


Have you noticed how you need an anticyclonic flow to get truly deep cold from the US? If you have a slight 'sad face' shape in the contours you can quite easily get -12C uppers to the UK on a pure westerly, yet if you have 'smiley face' shaped contours, you struggle to get below -5C even with a direct flow. My guess is that even very modest descent from anticyclonic flow inhibits bouyant mixing and prevents the maritime boundary layer from mixing with the deep cold above.

So when watching those model outputs, look for 'sad face' shapes in the contours and see how easily they bring deep cold across the atlantic!
2024/2025 Snow days (850hpa temp):10 days with snow/sleet falling
18/11 (-6), 19/11 (-6), 23/11 (-2), 22/12 (-5), 04/01 (-5), 05/01 (0),14/02 (0), 15/02 (0)12/03 (-6), 13/03 (-6),
2023/2024 8 days 29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)
2022/2023 7 days 18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)
2021/2022 12 days
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)
+1
nsrobins
30 January 2025 20:01:33
NWP teasing and tempting, a stubborn block v a rampant PV and all the time the clock is ticking.
I might eat my words but this could be another winter that fizzles away.
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
ballamar
30 January 2025 21:13:29

NWP teasing and tempting, a stubborn block v a rampant PV and all the time the clock is ticking.
I might eat my words but this could be another winter that fizzles away.

Originally Posted by: nsrobins 


They have to keep up their site visits somehow! The strat temp forecasts and all the WAA should in theory keep the high robust with enough to keep us under influence
Jiries
30 January 2025 21:17:41

Have you noticed how you need an anticyclonic flow to get truly deep cold from the US? If you have a slight 'sad face' shape in the contours you can quite easily get -12C uppers to the UK on a pure westerly, yet if you have 'smiley face' shaped contours, you struggle to get below -5C even with a direct flow. My guess is that even very modest descent from anticyclonic flow inhibits bouyant mixing and prevents the maritime boundary layer from mixing with the deep cold above.

So when watching those model outputs, look for 'sad face' shapes in the contours and see how easily they bring deep cold across the atlantic!

Originally Posted by: Quantum 


It like when a plane travel from New York to London they go NE then E then SE to UK so you refering the isobars to be same lines that allow the cold air to travel as per the plane route and hit here than straight line which will warm up quicker.  I was in Los Angeles and Toronto during 1999 Xmas and was standard winter there and mostly sunny in LA.  Cold and snow from Greenland isobar route are also excellent for here due to Cheshire Gap firing up.
phlippy67
30 January 2025 22:00:35
Conditions will have to change drastically in the Baltic region to get any proper cold from an easterly block, if it happens, as a lot of it has been above freezing and raining recently with little if any snow on the ground in the southern half. I have friends in Finland and they're saying it's like spring with mild, damp conditions for the past few days and even if we do get an easterly flow it's got a relatively warm North Sea to cross so i wouldn't expect any more than a nagging chilly breeze with possibly some wintry ppn away from the coast...unfortunately it's not the 80s anymore.
Brian Gaze
30 January 2025 22:45:14

Have you noticed how you need an anticyclonic flow to get truly deep cold from the US? If you have a slight 'sad face' shape in the contours you can quite easily get -12C uppers to the UK on a pure westerly, yet if you have 'smiley face' shaped contours, you struggle to get below -5C even with a direct flow. My guess is that even very modest descent from anticyclonic flow inhibits bouyant mixing and prevents the maritime boundary layer from mixing with the deep cold above.

So when watching those model outputs, look for 'sad face' shapes in the contours and see how easily they bring deep cold across the atlantic!

Originally Posted by: Quantum 



I've not noticed it, but your logic make sense. Also, I like your smiley (cyc) and sad face (anticyc) analogy - that's really excellent, although it would be nice if it was the other way round!
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
+1
Quantum
30 January 2025 23:21:41

I've not noticed it, but your logic make sense. Also, I like your smiley (cyc) and sad face (anticyc) analogy - that's really excellent, although it would be nice if it was the other way round!

Originally Posted by: Brian Gaze 


I suppose it works for mildies!

I've noticed it on model outputs mostly, but when the anticyclonic flow is really pronounced such as an almost southerly becoming almost northerly in the flow the uppers barely seem to get modified by the atlantic at all. Of course if you are after snow this is all rather counterintuitive, as synoptic scale stability is not conductive to showers; its quite possibly the showers that are doing all the mixing.

I suppose the ideal scenario for western based snow is just enough CIN (convective inhibition on a synoptic scale) to keep shower activity low across the entire atlantic until the friction from the land overcomes it and convection bursts into being over the UK. We see this kind of scenario sometimes in very cold anticyclonic easterlies or south easterlies. The uppers are something like -13C while the pressure is 1030hpa or something; no showers form over the North sea because the air is just too stable, but the friction over land is just enough to set off the showers. This kind of convective snow looks rather wierd because its rather continuous with the strongest precip pockets over the pennines rather than the coast. 2018 is a good example of this effect in action; I suppose come to think of it it also explains how the uppers got so cold with weak modification.
2024/2025 Snow days (850hpa temp):10 days with snow/sleet falling
18/11 (-6), 19/11 (-6), 23/11 (-2), 22/12 (-5), 04/01 (-5), 05/01 (0),14/02 (0), 15/02 (0)12/03 (-6), 13/03 (-6),
2023/2024 8 days 29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)
2022/2023 7 days 18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)
2021/2022 12 days
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)
Ally Pally Snowman
31 January 2025 05:39:33
Looks like the story of January continues into February - cold but bland. 
Bishop's Stortford 85m ASL.
+2
DPower
31 January 2025 07:24:19

I always think SSWs are overrated anyway. The troposphere and the stratosphere are really not that well coupled at all; the tropopause is this massive wall of stability that really stops much interaction between the two. Its why I prefer to focus on the upper trop.

Originally Posted by: Quantum 


The troposphere is far from stable. In fact it would be fair to describe it as completely chaotic.
Quantum
31 January 2025 08:30:40

The troposphere is far from stable. In fact it would be fair to describe it as completely chaotic.

Originally Posted by: DPower 


The tropopause not the troposphere. The tropopause is the interface between the troposphere and the stratosphere. It is characturised by a massive increase in stability
2024/2025 Snow days (850hpa temp):10 days with snow/sleet falling
18/11 (-6), 19/11 (-6), 23/11 (-2), 22/12 (-5), 04/01 (-5), 05/01 (0),14/02 (0), 15/02 (0)12/03 (-6), 13/03 (-6),
2023/2024 8 days 29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)
2022/2023 7 days 18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)
2021/2022 12 days
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)

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