The Weather Outlook

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doctormog
26 November 2024 16:37:07

Yes GEFS shows barely a single member dropping below -5c 850 temps up to mid-December which suggests a very strong zonal pattern becoming established, therefore it would be difficult to see a cold spell pre-xmas occurring.

Originally Posted by: Taylor1740 

I assume you were discussing the 06z GEFS suite. If so, you must have been reading them incorrectly as 15 members dipped below -5°C for t850hPa for London.

(For this location all but one member went below -5).  


ballamar
26 November 2024 16:39:17
Interesting build of HP on the GFS op run - hopefully its an emerging signal
Quantum
26 November 2024 18:49:01
The models seem to have a nice pattern at the surface but pretty boring at the 500hpa level in the next week or so.

Until we get higher heights in the north I can't see much arising.


25/26 (850hpa temp) 11 days snow/sleet falling

18/11 (-4) 19/11 (-6) 20/11 (-6) 01/01 (-7) 04/01 (-10) 10/01 (-7) 11/01 (-3) 30/01 (-1) 13/02 (-6) 15/02 (-4) 18/02 (-6)

24/25 10d

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)

23/24 8d

29/11 (-6) 30/11 (-6) 02/12 (-5) 03/12 (-5) 04/12 (-3) 16/01 (-3) 18/01 (-8)08/02 (-5)

22/23 7d

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

21/22 12d

Brian Gaze
27 November 2024 08:16:52
I've had to remove OT posts again. Please stay focused on the model output.
Brian Gaze

Berkhamsted

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Brian Gaze
27 November 2024 08:22:20
Still some interest at the moment. No indications of a winter wonderland, at least not in the southern half of the UK. However, a flat southwesterly doesn't seem to be locking in yet either. It very well may do as we head through next month, but let's wait and see.

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Brian Gaze

Berkhamsted

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DEW
  • DEW
  • Advanced Member
27 November 2024 08:46:20
WX temp charts start with a very warm (for them) Russia, only just above freezing, and Europe as a whole a little above norm. In week 2 it becomes colder in Russia, and this time instead of a breakout to the S or SE, the main thrust is across the Baltic to Norway, with colder patches appearing over mountainous areas in C Europe. Not much change for Britain, and any real warmth is in S Spain. Pptn pattern as yesterday, week 1 wet for Atlantic coasts, less so over continental Europe; week 2 heavy rain developing in a band Britain - France - Balkans and notably Greece.

GFS Op - the 'legacy' from storm Bert referred to in previous reviews has greatly intensified and is now storm Connal in it own right, 1000mb German Bight by midnight but moving on quickly. As before, pressure rises behind it, but the HP in today's forecast then moves further east (now 1035mb Ukraine Sun 1st) allowing troughs to affect more of Britain than just the western coasts  and ushering in a mobile spell of weather - 1005mb generally for Britain with N-lies Mon 2nd, 990 mb Irish Sea Wed 4th, 975mb Hebrides Fri 6th. the last of these develops into an elongated trough from the N Sea down to Italy persisting with NW-lies for Britain until Fri 13th. At the end the Azores HP appears to be making an approach to the SW.

ECM - like GFS to Mon 2nd, but then leaves out LP Wed 4th, and that on Fri 6th does not develop to the SE, continuing HP more generally over Europe setting up a spell of zonal weather with W-lies not NW-lies.

GEM - closer to ECM; indeed more HP-dominated, the HP cell appears Wed 4th close to/over Britain, only just about breaking down Fri 6th with deep LP well to the N near Iceland

GEFS - mild and mostly dry to Mon 2nd, then back to norm  (indeed a brief sharp dip for Scotland)with rain setting in for many runs. Poor agreement for ens members after this date - mean temp is slightly below norm but by Wed 11th this is in the middle of a +/-10C range


War is God's way of teaching Americans geography - Ambrose Bierce

Chichester 12m asl

Brian Gaze
27 November 2024 09:22:53
ECM also not without interest later on.

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Brian Gaze

Berkhamsted

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CField
27 November 2024 09:31:40

Still some interest at the moment. No indications of a winter wonderland, at least not in the southern half of the UK. However, a flat southwesterly doesn't seem to be locking in yet either. It very well may do as we head through next month, but let's wait and see.

UserPostedImage

Originally Posted by: Brian Gaze 

All feels very 2017 to me....


Favourite snowstorm

Famous channel low

Dec 31st 1978

Hastings East Sussex

Foot of level snow severe drifting

Next day max temp -4 degrees Celsius

Chunky Pea
27 November 2024 10:12:04
Only thing of interest in the output I can see is how cold the near Arctic remains throughout. Cold spilling out of US later doesn't really want to trigger much, though given how volatile that situation can be, it could be a case of the models picking out any potential at the last momemt. 


Patrick,

East Galway, Ireland.

ballamar
27 November 2024 10:47:41
Cold zonality fans might be getting excited - nothing too cold yet on the Op run but something to watch
The Beast from the East
27 November 2024 10:55:46

All feels very 2017 to me....

Originally Posted by: CField 

Remind us? 

Obviously we had the Beast in Feb 2018 but I cant remember anything special before 


Purley, Surrey, 70m ASL

"We have some alternative facts for you"

Kelly-Ann Conway - former special adviser to the President

Ally Pally Snowman
27 November 2024 11:17:21
The GFS 6Z is a little better with a wedge of heights to our north but it's 300h . Waiting for something interesting is becoming the norm though. 
Bishop's Stortford 85m ASL.
Brian Gaze
27 November 2024 11:21:21

Remind us? 

Obviously we had the Beast in Feb 2018 but I cant remember anything special before 

Originally Posted by: The Beast from the East 

We had 14cm of snow on 10th December 2017. Some pics here:

https://www.theweatheroutlook.com/weather-news/4102/berkhamsted-snow-gallery 

 


Brian Gaze

Berkhamsted

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Saint Snow
27 November 2024 11:35:39

We had 14cm of snow on 10th December 2017. Some pics here:

https://www.theweatheroutlook.com/weather-news/4102/berkhamsted-snow-gallery 

 

Originally Posted by: Brian Gaze 

We didn't (we got a slushy dusting on the 12th, which didn't last long)

PV is trying to form, but struggling to become that horrible, singular blob due to areas of HP popping up over the Arctic, which is a small positive, I guess.

Otherwise, once again, the ridging AH (eastwards/north-eastwards) is our enemy. 

That blob of HP that forms to our NE in GFS's latest FI looks 'topple-y'


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

ballamar
27 November 2024 11:36:45
Even if it’s later in the run blocking in Dec is nice to see - every trend has to start somewhere!
Hippydave
27 November 2024 12:43:51

Cold zonality fans might be getting excited - nothing too cold yet on the Op run but something to watch

Originally Posted by: ballamar 

Was thinking something along those lines when I looked at the GFS 6z, although I did mentally add 'or as we like to call it here in the far SE, zonality'. 😜 I imagine on the ground it'd range from cool and damp to cold and damp for most of the time, although as usual hillier areas further north would potentially see snowfall.

In any case it's an interesting run purely because the cool/chilly air dominates with only brief milder slices rather than the more typical mild stuff with brief lee northerlies affecting Scotland/Northern England. 


Home: Tunbridge Wells

Work: Tonbridge

fairweather
27 November 2024 12:47:01
Yes, in recent years cold trends seem to start in the 7-10 day window, sometimes less, irrespective if what the longer term output was.
S.Essex, 42m ASL
Brian Gaze
27 November 2024 12:47:16
The ECM ENS probability charts are quite informative IMO. This shows the % chance of 5mm or more rain falling on t+11 days. Based on this, there's a strong signal for a westerly based pattern.   

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Brian Gaze

Berkhamsted

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

Gandalf The White
27 November 2024 15:31:17

The ECM ENS probability charts are quite informative IMO. This shows the % chance of 5mm or more rain falling on t+11 days. Based on this, there's a strong signal for a westerly based pattern.   

UserPostedImage

Originally Posted by: Brian Gaze 

The amount of rain shown over the Channel and northern France suggests there won’t be a block of high pressure sitting there, so perhaps it will be proper zonality and not the version that gets displaced north.


Location: South Cambridgeshire

130 metres ASL

52.0N 0.1E



David M Porter
27 November 2024 17:03:39

Remind us? 

Obviously we had the Beast in Feb 2018 but I cant remember anything special before 

Originally Posted by: The Beast from the East 

We had a week of pretty frequent snow showers here in mid-January 2018 during a spell of cold zonality, about 6 weeks before the Beast struck. The snow we had from the west in January gave quite a covering here for a number of days.


Lenzie, Glasgow

"A body of men holding themselves accountable to nobody ought not to be trusted by anybody." – Thomas Paine

CField
27 November 2024 17:50:43

Remind us? 

Obviously we had the Beast in Feb 2018 but I cant remember anything special before 

Originally Posted by: The Beast from the East 

Had a lot of wet hill snow events followed by hard frosts in December 2017....lot of cold rain too in Kent...and the 2018 event followed .....this winter is showing a lot of potential at present....Still got to keep an eye on heights to the SW though....


Favourite snowstorm

Famous channel low

Dec 31st 1978

Hastings East Sussex

Foot of level snow severe drifting

Next day max temp -4 degrees Celsius

nsrobins
28 November 2024 06:38:12
After my weekly ‘model mood smoothing’ look at the NWP I can’t see much going on other than a generally westerly pattern into December. I see there’s a fair amount of GLAAMING and torquing and fishy stuff being discussed on various sites but the baseline output doesn’t offer much for the coldies for the foreseeable. With a strong Atlantic jet and the cold plunge across the NE of the US next week we’re likely to see more wind and rain than cold and frosty.


Neil

Fareham, Hampshire 28m ASL (near estuary)

Stormchaser, Member TORRO

Retron
28 November 2024 06:46:33

After my weekly ‘model mood smoothing’ look at the NWP I can’t see much going on other than a generally westerly pattern into December. I see there’s a fair amount of GLAAMING and torquing and fishy stuff being discussed on various sites but the baseline output doesn’t offer much for the coldies for the foreseeable. With a strong Atlantic jet and the cold plunge across the NE of the US next week we’re likely to see more wind and rain than cold and frosty.

Originally Posted by: nsrobins 

The funny thing is that the recent cold spell (with snow for some) popped up at relatively short notice, and wasn't predicted by those who dwell in teleconnections. I remain sceptical of their worth, and just see them as an alternative way of viewing the pressure and rainfall charts.

The London GEFS retains its usual winter sine-wave look (with the waves out of period at the end, causing a mess) and there are very few runs touching -10. It does seem shifted down a bit towards the end (instead of the usual +5 to -5 spread, it's more like +5 to -7), but at the moment it's all looking rather zonal.

EDIT: And there'll be no help from the stratosphere either, the vortex is much stronger than usual for the time of year, and even by January it'll only be back to around normal.

https://charts.ecmwf.int/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202411270000 


Leysdown, north Kent
Crepuscular Ray
28 November 2024 08:17:04
Just going purely on the 00Z surface charts, the first half of December looks like a rollercoaster ride of deep Lows and Ridges. A few cold shots from the NW and a few mild wafts from the SW.

Could be worse......could be better 🤔


Jerry

Edinburgh, in the frost hollow below Blackford Hill

DEW
  • DEW
  • Advanced Member
28 November 2024 08:37:44
WX charts show current week's temps for W Europe near norm, and those further east well above though below freezing in absolute terms. In week 2 the cold air in the east firms up but only makes moderate progress westwards though the freezing areas over mountainous areas (Alps, Carpathians) expand. Pptn map much like yesterday - week 1 for Atlantic coastal countries and a local wet spot in Greece; week 2 wet in most areas between a very dry Spain and, ditto, Russia (and especially wet/snowy for Iceland, N Scotland and Alps.)

GFS Op 0z - current HP soon off to E Europe allowing a broad trough to dip down from the north Mon 2nd, followed by a more-or-less zonal set-up , i.e. westerlies with an uncertain balance between LP to the north and HP to the south, an LP embedded in the flow Sat 7th 995mb introducing more unsettled weather as it crosses England. The zonal conditions are completely disrupted by very deep LP 935mb S Iceland Thu 12th quickly running down to the N Sea 975mb with storm force N-lies.

ECM - similar to GFS but zonal flow more disrupted by LP; an extra trough Fri 6th, and the LP after that is over Scotland 995mb on Sun rather than Sat.

GEM - differs from both the above after Wed 4th as HP develops in northern N Sea and persists until at least Sat 7th with strong S/SW-lies for western areas

GEFS - mild and mainly dry to Mon 2nd when temps dip for a couple of days before ens members increasingly disagree. Mean temps a degree or two above norm around Fri 6th and similarly below around Tue 10th within an envelope of +/-5C. Rain likely around Sat 7th, not much at other times. 


War is God's way of teaching Americans geography - Ambrose Bierce

Chichester 12m asl

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