Winter 2022/23 - Moans, Ramps & Chat

[The Enforcer]

2 minutes ago, Robbie Garrett said:

The one before the NHC feature, right? The jet over iberia should drag them into the iberias. Not towards the UK.

Correct and at T+40 it's nowhere near the UK.

Edited December 6, 2022 by The Enforcer

[The Enforcer]

8 hours ago, The Enforcer said:

Let's assume the next 12z runs show a 'worst-case' scenario of the lowland snow-line being over the north coast of Scotland for 12z Wednesday 14th. Of course, subsequent runs will then move that line around for better or worse, but let's say the average movement is 20 miles south per GFS run, which is not a huge amount. Over the 32 runs between T+192 & T+0 that would be sufficient to push the snowline below the south coast. If using ECM or Meto, it would need to average 40 miles southwards per run over 16 runs between T+192 & T+0, still not a huge amount.

12z ECM duly obliged with a worst-case run, I can see the 18zs (GFS/ICON) have already started the shifting process.

Edited December 6, 2022 by The Enforcer

[The Enforcer]

1 minute ago, IanT said:

Atlantic 2-Day Graphical Tropical Weather Outlook

WWW.NHC.NOAA.GOV

1. Central Subtropical Atlantic: A large area of low pressure located over the central subtropical Atlantic about 800 miles northeast of the northern Leeward Islands continues to produce a broad area of showers and thunderstorms. Environmental conditions appear marginally conducive for development and a subtropical or tropical storm could form in the next couple of days. By Thursday night or Friday, the low will move northeastward over cooler waters and interact with a mid-latitude trough, limiting subtropical or tropical development of the system. Additional information on this low, including warnings, can be found in High Seas Forecasts issued by the National Weather Service. The next Special Tropical Weather Outlook on this system will be issued by 9 PM EST tonight, or earlier, if necessary. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 5 days...medium...50 percent.

Hang on. All this modelling drama over a feature that only has 50% chance of formation?

[Dbarb]

12 minutes ago, The Enforcer said:

Hang on. All this modelling drama over a feature that only has 50% chance of formation?

That's regarding tropical Cyclone formation. A low pressure will form whether it's tropical or not.

Edited December 7, 2022 by Dbarb

[The Enforcer]

I can broadly summarise the various outcomes for early next week that the models have shown at various points:

 

1. Low passes way to South - UK under easterly feed

2. Low passes way to South - UK under northerly feed

3. Low passes way to South - UK under slack feed

4. Low skims the South coast - E feed follows

5. Low skims the South coast - N feed follows

6. Low skims the South coast - slack feed follows

7. Low provides all snow event - E feed follows

8. Low provides all snow event - N feed follows

9. Low provides all snow event - slack feed follows

10. Low provides snow to rain to snow event - E feed follows

11. Low provides snow to rain to snow event - N feed follows

12. Low provides snow to rain to snow event - slack feed follows

13. Low provides snow to rain event - E feed follows

14. Low provides snow to rain event - N feed follows

15. Low provides snow to rain event - slack feed follows

16. Low provides snow to rain event - W feed follows

17. Low provides total rain event - W feed follows

 

In the context of last 'winter' I would settle for any of the first 16 outcomes.

[The Enforcer]

16 minutes ago, RainAllNight said:

Alarm for 2am then? 

Alarm every time an ECM Op run comes out.

[The Enforcer]

It's T+120 time:

 

 

L to R: Fax (still with coastal-only troughs), GFS18z, ECM12z, GEM12z. All different, but all still ok at that timeframe.

[RJBingham]

BBC has us under some nasty battleground sleet Tuesday  

[I remember Atlantic 252]

GFS is absolute pants! not a flake of snow at all, from 0-384

[V for Very Cold]

As much as I love all the pretty charts being posted, I do wish there was more explanation with them... being a novice of just 14 years on here, I do appreciate the help!

[Weather-history]

I wonder how the weather models of today would have coped with Jan-March 1947? 

[LetItSnow!]

28 minutes ago, Weather-history said:

I wonder how the weather models of today would have coped with Jan-March 1947? 

Probably very poorly. I think the majority of people watching would have been reduced to a crumb on the floor from all the stress!

[cyclonic happiness]

1 hour ago, I remember Atlantic 252 said:

GFS is absolute pants! not a flake of snow at all, from 0-384

Well, let's just hope that something pops up in the short term and doesn't do a 2010 on us and leave us with a slight dusting.

I'd at least love to 1" hoar frosts, they look just as good as snow sometimes

[JoeShmoe]

Matt Hugo with by far the most sensible post this am saying that until anything is within 120 hours then just treat it with a very large grain of salt 

even by netweather standards the mood swings every 12 hours have been violent !

[starstream]

1 hour ago, V for Very Cold said:

As much as I love all the pretty charts being posted, I do wish there was more explanation with them... being a novice of just 14 years on here, I do appreciate the help!

Yup, the forums gone downhill a bit with that. It used to be very informative 

[mb018538]

Same applies to a very large number of people on NW! 

[Weatherman_93]

10 hours ago, Dj fart said:

Ha ha! Just clocked who this is! 

All looking like going t1ts up again!

Looks that way. Changing on a daily basis. They wont be happy in the MOD topic!

[The Enforcer]

9 hours ago, Dbarb said:

That's regarding tropical Cyclone formation. A low pressure will form whether it's tropical or not.

Thanks. Reading between the lines, I am understanding that if it is a tropical cyclone, it would be powerful enough to crash through the block, whereas if it is a bog standard low pressure it's going to struggle without a strong Canada PV and Jet stream over Africa and a larger than normal block over Greenland/Iceland/Scandinavia. If the chances are 50%, I don't understand why every run I've seen has it blown up to resemble a hurricane when it appears/lurks to our west.

Edited December 7, 2022 by The Enforcer

[Bald Eagle]

1 hour ago, JoeShmoe said:

Matt Hugo with by far the most sensible post this am saying that until anything is within 120 hours then just treat it with a very large grain of salt 

even by netweather standards the mood swings every 12 hours have been violent !

Thats because he knows what he is talking about

[The Enforcer]

2 hours ago, V for Very Cold said:

As much as I love all the pretty charts being posted, I do wish there was more explanation with them... being a novice of just 14 years on here, I do appreciate the help!

If you're referring to the charts above, I best not say too much as it's above my pay grade, but broadly they all show that in 5 days time that the UK is under a slack polar Arctic/Continental feed and the Azores Low lies out to the west. The forecasting mayhem happens after that.

[The Enforcer]

1 minute ago, irish1 said:

Latest guidance on potential tropical storm in Atlantic, path fairly tight until end.

I note that the one run that ends with the storm to the north-west of the UK, becomes an outlier with an anomalously southern track from very early on.

[Eagle Eye]

31st most trending video on YouTube the Met Office forecast .

We're still at the point where we're looking for prolonged cold being a genuine opportunity that we're taking away from the initial cold, instead looking at the breakdown despite the fact that it's a while away. Just the fact that prolonged cold is a fairly good possibility makes this the best early Winter chance for a long time.

Edited December 7, 2022 by Eagle Eye

[snowblizzard]

8 minutes ago, johnholmes said:

My take using NOAA anomaly charts and ECMWF 10 day outputs

Next issue on tuesday 6 December=

Very little flow light westerly from flow over n Canada which has very marked +ve area centred west of Greenland, (area usually with main upper trough!). contour height s’ern England=534 DM so still fairly cold aloft. Fairly small –ve area over s’ern uk extending sw.

Surface weather staying cold for most areas, synoptic outputs suggest milder air and associated surface features tryinmg to make ne progress. This chart gives no certainty of how far north, not far I would suggest. The 8-14 any ridging has gone to be replaced by a fairly slack westerly  flow with heights in far south about 6+ DM higher at 546 DM. This would suggest that during the 8-14 day period less cold air will be the pattern with that westerly flow.

Using the ECMWF 10 day charts suggests the -5 C isotherm at 850 MB never get further north than N Ireland to the Wash? But the surface flow changes from a SE’ly from the low west of the UK to a slack W’ly. The 500 mb flow  from a fairly slack northerly origin to N of West by the 17th.

Overall the slow change from deep cold N’ly to a less cold westerly in the 8-14 day period from now looks sequential and acceptable in meteorological terms. I would suggest 65-35% for this to be the weather sequence.

Mind you that % suggests it is not a done deal either way so far!

I'll try and add the charts as soon as I can.

Hence, the hints from TV forecaster's that it's likely to become less cold early next week?

[frosty ground]

2 minutes ago, snowblizzard said:

Hence, the hints from TV forecaster's that it's likely to become less cold early next week?

Which TV forecast are showing weather 8 days away? 

[jmp223]

Bitterly braw this morning.  I believe the GFS/ECM etc. are having trouble modelling the impact of the Azores low with the conditions in our current setup.  If the system goes tropical, even although it will be extratropical by the time it interacts with us, surely it would still carry more energy/moist air up towards us than if it was a bog standard low? I believe this may explain a little of the reasoning as to why we see the divergence across the models and runs, accurately modelling the energy of that tropical low, and of course its subsequent direction and potential impacts.

 

I could be talking nonsense as I'm just an enthuasist,  but that's my read on it...wait and see past t+96 for me.

Edited December 7, 2022 by jmp223