Ladyofthestorm
-
Posts
646 -
Joined
-
Last visited
-
Days Won
1
Content Type
Forums
Blogs
Gallery
Events
Learn About Weather and Meteorology
Community guides
Posts posted by Ladyofthestorm
-
-
It's not truly zonal long term either.
The PV looks still very fragmented, ragged and fragile and I know that we are needing to look east and not west for weather in January.
We have had a continuing wintry theme here in December. One mild day and that's been it! And we live right on the cusp of the Atlantic influence.
-
5
-
-
10 minutes ago, Cymro said:
You are a brave man! 100% at your peril!
Agreed, I think the GFS is closer in resolution than the EC.
-
3
-
-
- Popular Post
The teleconnections are not exactly screaming mild Atlantic either. AO staying neg and the NAO negative to neutral. Not exactly the Atlantic flip.
Yes chances of a white Christmas for the south of UK is very slim , but further north every possibility .
Looking ahead anplication of that problematic deep low, but look how it backtracks and moves west over the Atlantic.
So no clues. As yet. The ensembles are still anyone's guess even mid term.
Certainly don't put away the sledges just yet.
-
13
-
47 minutes ago, MattH said:
Morning.
This is, without question, as I think Mike Poole mentioned a little earlier, one of the most difficult and volatile periods in model data for some considerable time, believe me it is making it extremely difficult for forecasters with regards to 'fine tuning' the details for the Christmas Weekend, but even now that remains near impossible to do, given the ongoing oscillations with the model data for this weekend and into early next week.
This is, once again, highlighted perfectly by the comparison with the GEFS which lower 850mb temperatures from the N through Christmas Eve and into Christmas Day, yet the ECMWF is still holding a more developed low over the British Isles with higher 850mb temperatures - Quite remarkable and tiring to say the least. As I mentioned a few days ago, there is no 'quick fix' here and it is still a case of waiting for NWP to sort this whole mess out, but with clearly much shorter lead times than would otherwise be the case for any sort of detail. Overall, I haven't changed my stance on the colder air getting into Scotland by the 22nd/23rd with reasonable confidence, then filtering southwards through Christmas Eve and into Christmas Day, perhaps with the exception of the far south.
There also remains a risk that somewhere, through central areas, depending on how Friday's low evolves and tracks eastwards through central areas then a significant snowfall event remains possible before the low clears into Christmas Eve, something to keep an eye out for too.
Where we go from there is equally uncertain - The 00Z GFS highlights yet another extreme evolution with significant winter synoptics through late Dec and into the New Year period, all very possible, but, equally, there remains a number of solutions that provide greater emphasis on a more unsettled, zonal pattern becoming established as well, this is less-likely, IMO for the reasons below, but certainly has to be considered.
The long-predicted next passage of the MJO is underway, most recent OLR anoms showing it is now approaching the Maritimes (phases 4-5) and we continue to see some interesting AAM plots making an appearance now as well...
If we use the regression plots as a guide, then compared with phases 3 and 4, phases 5-6 creates quite a significant change to the N Hem profile, as exampled above. Obviously, and as usual, there are other factors to consider and there is not an A+B=C outcome here...but...it increases confidence that the MJO and resultant AAM changes will, IMO, give yet another boost to blocking patterns looking ahead and but the brakes on any sort of arrival of the usual winter-time pattern that is a dominante +ve NAO regime. It is also interesting to note that the overnight EC Monthly AAM plot has shifted quite significantly higher as well than recent runs (see below) while we continue to some very interesting frictional torque plots, while we also now see tendency increasing, and with the GWO heading over towards phase 4, which I mentioned was likely in a post few days back...Plots below highlight all of this.
At the moment there remains little evidence for any significant downwelling or influences from the strat on the trop either for at least 2 weeks, if you ask me. As I mentioned the other day mind it would be extremely rare (near impossible!?) to go a whole winter without some sort of connection at some point. However, as previously discussed this up-coming MJO passage could be arriving at the right time, not to only reinforce tropospheric blocking, but to potentially aid in the development of an SSW as well, but that is even more problematic. Some model data suggests that another significant MJO could occur through late January as well, so I'm still in the 'camp' that an SSW will eventually happen this winter, but, as ever, time will tell on that one.
Overall, the short-term term remains very problematic - The overall suggestion for Christmas would be the further north you are, the greater risk that it'll be a cold and seasonal one, than compared with further south. Where we go from there, between Christmas and into the New Year is equally troublesome as I fully expect further amplification to the pattern and, of which, will continue to bring about some further very interesting, but also conflicting NWP data. As usual in an amplified pattern wherever there is a significant ridge, there is always a trough, etc.
Fascinating watch and output as early winter progresses, but definitely a case of not getting caught up on each model run, more-so than ever is this currently a perfect example of that and we shall see where we go from there.
Best wishes for Christmas.
Matt.
Hi Matt
So the Greenie High later on the runs is just one possible scenario and the ECM hasn't picked up on the decoupled Stratospheric / Tropospheric conditions,?
Usually GFS is good at picking up the blocking trends and given conditions right now in the arctic it wouldn't surprise me.
-
1
-
-
I'm reading a significant amount of mild ramping .
We have just had our coldest early part of December since 2010 and I do not see anything in any charts that suggests Atlantic driven weather for the rest of it.
Yes mild incursion, but it is brief.
Christmas day away from South of England and Wales looks potentially a white one,
Indeed the GFS is beginning to come into a more reliable timeframe now
A clear -10 850pha across Scotland and Northern England from a Greenie High. I would expect snow showers from this immediately away from coasts and to higher ground as a minimum.
The ECM follows similar trends, maybe not as dramatic but nonethe less same idea and origin.
Now look at the ensembles for my area , yes we are in the north but we are right under the influence of the gulf and Jetstream...... And it gone on holiday.
If anything the GFs and GEFS want to head back to the factory reset button of mild Atlantic late in the runs. However look at these . Mild outliers in F1 well above the mean and lots of runs much colder!
Last time I saw a run like that for actual Christmas day was 1995! No thankyou , we had cold turkey because of a powercut due to ice and -24c in Braemar.
That leads me onto the teleconnections
The AO and NAO heading very slowly back to neutral.
That is not the same thing as positive. And certain no medium term indication of a return to milder Atlantic driven weather other than for Monday.
That negative AO for December is quite incredible. It's going to take a while, if at all for the polar Vortex to recover.
Any recovery doesn't last long. I've not idea what the prospects are for a SSW but look at the highs constantly chipping away at it... Big wavy wobbly unstable , weakened.
So I'm not convinced it isn't all over , indeed we aren't playing football, so let's just watch these fascinating charts and runs play out.
The game has just literally started. Interesting times are afoot!
-
3
-
-
24 minutes ago, TSNWK said:
So primed to drop a Cross polar flow over us.. if we can just keep on building those mid Atlantic heights..annoying as it looks feasible but you kinda now the outcome with other models and previous runs. But we still crack on.
That looks one heck of a fragmented polar vortex with arctic heights not far from the pole. I would need more persuading of a significant return to Atlantic driven storms.
-
1
-
-
Looking at the ensembles this morning for my area and the NAO/AO ensembles yesterday and the blocking plots from NOAA I suspect that any thaw for us will be short-lived. We have a milder spell next week... Briefly , then another reload just literally before Christmas. Longer range, the devil is in the detail, could be a cold dry ( I think that's a GEFS outlier ( blue line post 7 days) with cold 850s but 1040 mb or snowier out all the rest of the models. What I did note is that there is definitely less uncertainty in the models longer term , and less spread of the individual runs in Fl, that we should watch as that's an indication of non Atlantic driven based weather.
Also note the very bedraggled polar vortex.. we don't need a SSW for colder weather doors to open. Certainly we can see our Atlantic doors are not wide open.
It's been the coldest December easily since 2010. The trend is your friend and I think it has alot on common with 2010. So definitely see how this pans out.
-
4
-
-
Not convinced that mild will be anything other than transient ( maybe a green Christmas). The AO and NAO are staying strongly negative and slightly negative to neutral respectively on the GFS runs. That huge area of high pressure isn't going to just disappear overnight. Looks like it might migrate west.
-
1
-
-
Seeing many perps pick up and what I thought too.
GFS post 180 hrs is struggling to keep the colder air seen on both the 18z and 0z . However this model in particular is really bad for putting Hannah t back to Westerly based configuration when things become uncertain.
Looking more closely at the ensembles, it's suggesting the GFS operational is indeed running at the milder side of the runs.
I suspect a huge backtrack by Saturday and us locked in cold until next week.
-
5
-
-
I won my bet at 1155 pm last night against my hubby that the road would be white by end of Wednesday. £40 is mine. Such a sour grape loser as he was so cocky that he would win it Banking on a warm road surface. Lol He didn't bank on Graupal falling from the heavens in a single snow shower.
But anyway, GFS is Fl hrs is heading back to mild stuff, as 18 z and 0Z as already noted as happened before ignore that, it has a tendancy to drop colder signals and intiate a milder westerly signal as a bias.
So before everyone throws the sleighs and snow shovels back in the cupboard hold your nerve.
The signals for medium range Nly and Greenie blocking as still very strong.
-
4
-
-
14.5 C in morning
18 C after the wood burning stove is lit in the evening
-
10 minutes ago, Purga said:
That's scuppered it then!
The cardinal rule is not to tell family and friends - guaranteed to usher in the mild muck
Nah don't believe in sods law.
For info the NAO ensemble looks to stay negative for the next two weeks.
Just like 2010!
A repeat performance anyone?
-
8
-
-
- Popular Post
4 minutes ago, Cambrian said:I was looking again at the 12z GFS op at day 10, getting flashbacks…
Then the 18z op at day 10 came out, still flashbacks…
Scratching my head wondering in which movie I’d seen this scene before, but still not entirely sure, until….
Yep, same film
And here my hubby took the total Mick out of me this evening and said that he looks forward to the day after tomorrow weather!
PS I have a £40 bet with him that snow will be lying on the road by Wednesday!
-
10
-
So synoptics and models ponit towards a lengthy cold and potentially snowy situation.
I can't see that Greenie high relinquishing it's grip before the third week.
-
1
-
-
9 minutes ago, CreweCold said:
There’s a fair bit of moderation going on due to the fact SSTs around the UK are still fairly warm. That should aid shower activity and small organised feature formation though.
I did ponder on the thought would that produce that phenomena lake snow affect as there is alot of moisture hitting some verty cold dry air . Especially so later on.
One to watch I think.
-
1
-
-
7 minutes ago, Nick F said:
Exactly that ... worry about getting the cold first, once that's ok, the snow will come. It shows precip / showers being generated over sea as the cold air crosses the relatively warmer SSTs, showers would likely blow inland too. And you can't realistically expect a model, even high res, to pick up features that may bring more organised snowfall at that range.
I'm.trying to remember who told us to get the cold in first ... Chino maybe ?
-
1
-
-
Is this the beginning of a PV split without a significant SSW?
-
3
-
-
Definitely a long game on this one for cold lovers. Still very strong signals for settling down beginning of December. What happens after that is anyone's guess. The scenario of that high pressure over Atlantic ridging up to Greenland and letting the Nly gates open is plausible like we saw in the GFS yesterday. Watch for that scenario returning at 240hrs!
It's done it before.
-
4
-
-
52 minutes ago, Weather-history said:
The updated Bonacina analysis gives 7 of the 1990s winters as "little" snow. Baffles me how anyone (not naming names) can continually suggest that the winters of the 1990s were generally very snowy unless you are comparing it against a period that had even less snow, but there were long periods that had hardly any snow during the 1990s.
Bonacina UK Snowfall History and Events 1875-2021 (Bonacina/O'Hara)
DURHAMUKWEATHER.COMUK Snowfall History/Statistics catalog developed by Leo Bonacina. This summary of UK snow has been augmented by me with information from additional sources and brought up to date (the original only...Hmmm agree with you on that.. with exception December 1993 and 1995,
-
1
-
-
Ian Simpsons analysis of the current synoptic setup and the analogue years of 2001 and 2005 give me much hope.
Later parts of December 2001 was particularly chilly affair with the north of Scotland having a rare white Christmas. The cold spell lasted for nearly 3 weeks and well into January .
Winter of 2005 was relatively mild little snow but very windy... Until late February when the north finally opened up and we got a proper dumping of snow.
-
1
-
-
9 hours ago, RainAllNight said:
Although I can't answer this question, I have found that the combination of these two tools seems really awesome for trying to understand this stuff!
Surface Pressure Charts - Met Office
earth :: a global map of wind, weather, and ocean conditions (nullschool.net)
Thankyou. Looks like a very strong jet.but a very wobbly one. I think it will cast a few surprises . Going to be an interesting winter!
-
1
-
-
On 01/10/2022 at 19:35, BLAST FROM THE PAST said:
Nasty little feature developing for the 5th. Heavy rain but potential very strong winds for the South
BFTP
I'm still trying to fathom exactly what it is?
I can't see any clue other than a very strong jet stream.
-
I'm surprised winter 2017 to 2018 hasn't been mentioned.
The only winter we had here on the Outer Hebrides to have snow lying on ground every month.
November to May.
Not sure what year to compare it by but the trend was ridging high pressure in the Atlantic riding up towards Greenland letting Nly air flood south. Seen something similar this year.
-
22 hours ago, Uncertainy said:
I’ll miss this La Niña when it’s gone!
Mean temps still below average after day 10, according to the GEFS of course…
This is turning out to be an ‘unusually normal’ September, with the unrelenting heat of recent months (and Septembers) notably absent. The continued attempts at ridging in the mid / N Atlantic are notable to this observer as signposts for the coming months as they reflect a) the continued Nina base state and b) the anomalous warm SSTs in the that same region.
What’s also fascinating is the consistency of this signal in the medium range: check out the day 12 GEM mean
Now compare that with the NAEFS
If the EPS completes the set later on then we could end up a with a CET below 15 which would be Remarkable considering the warm and humid opening to the month.
It's not going anytime soon!
-
1
-
Model Output Discussion - Christmas week and beyond
in Forecast Model Discussion
Posted
The polar vortex looks at best uncomfortably unstable. It's coldest parts always wanting to split . It looks ragged and happy to spill contents.
Watch the significant cold to the East
It's not exactly screaming mild, wet and stormy for our Atlantic shores either.
Maybe some cold PM air from NW, transient bringing wintry showers to Scotland.
Not convinced the mild conditions will last long.