Alternate Model Discussion - into 2022

[BlueHedgehog074]

Hi all   After some of the requests we had in the main Model Output Discussion recently, thought I would try and give this short range/slow-paced/alternate Model discussion thread another go.

We did something similar a few years ago: 

and it sounds like something a lot of you would be happy to have. Thus we hope it’ll be a thread that a number will take part in (but don’t worry we won’t make you ). 

It’s a thread focussed on nowcasting and the models up to 5 days ahead (120 hours). Some of you may just be happy with discussing the models up to 3 days ahead, for example, which is perfectly fine. Just up to you really. 

Update 19th December: Due to recent changes to how the Model threads operate, this thread is now open to discuss models of the longer ranges. Just like previously, this thread would still be suitable for those who want a slower paced look at the models, hence the change of name to Slow-Paced Model Discussion (which has now been changed again to the Alternate Model Discussion). Please do continue to use this thread for short range discussion if you like

The main Model thread, which you originally could use here (also had catered for long range Model discussion):

…has now changed to a Hunt For Cold thread (please see link below). More for faster paced model discussion, that’s also more frantic and focuses more on chasing cold charts:

https://www.netweather.tv/forum/topic/96509-model-discussion-hunt-for-cold-christmas-countdown/

Fancy just having a bit of a banter, moan, or ramp about the weather in general (which can still be loosely related to the models)? Please use this thread: 
https://www.netweather.tv/forum/topic/96442-winter-2021-22-moans-and-ramps-thread/
 

Posts in here don’t necessarily have to be in depth or technical, and is a thread that we expect will have a more quieter, balanced, laid back and perhaps a less cold focused feel to it, especially suitable for those who find the main/cold chasing model thread too fast and hair-raising at times. Suitable as well if you want to avoid the roller coaster of emotions that can happen in the other model thread. And the flying teddies!

Please make sure to keep things friendly in here. Rude and nasty behaviour won’t be allowed. For any problems, please either report any offending posts or Private Message one of the team. We’ll come to the rescue as soon as possible (or whenever one of us is available).

Thanks everyone

Edited December 30, 2021 by DiagonalRedLine
Another update to reflect the name change from Slow-Paced to Alternate Model Discussion - DRL

[Dimie10]

Brilliant!! I hope we get some good, educated short term (more chance of being accurate) forecasting here. Thanks 

[johnholmes]

Good idea, hope it catches on DRL.

I'll post in here a bit later as bit busy just now.

just a comment that the closes, so far, to where the very deep low may track is to look at the Met O Fax charts?

this link shows their expected track

UK Met Office Fax Charts - UKMOMSLP Analysis and Prognosis

WWW.WEATHERCHARTS.ORG

---

UK Met Office . . Europe and North Atlantic MSLP analysis and prognosis charts

 

Edited December 3, 2021 by johnholmes

[MattStoke]

Potential transient/hill snow event on Monday. Wouldn't be surprised to see the front's progression slow and snow risk increase a little as we near the time.

[Wingman Blue]

Might stick at the tail end for these parts.  Certainly continuing the cold theme.

[BlueHedgehog074]

A cool and showery day will be in store for many tomorrow as the 12Z GFS shows a keen North-Westerly flow over the UK. Showers, which could merge into some longer spells of precipitation at times, spreading South-East into numerous areas, especially North-Western parts. Cold enough, especially in heavier showers, to be wintry over high ground. Particularly the further North you are.

It’ll be a cold night to follow, with temperatures dipping around and below freezing over some Northern spots. Particularly over high ground. Mostly dry, with clearer spells across many inland areas, which could allow a frost to develop, especially over Northern high ground. Though some showers, still wintry over high ground and perhaps to some lower levels, continuing over parts of Northern and Western Ireland, Wales, Eastern England and some Northern UK coasts

 

A little ridge of High Pressure to the West of the UK on Sunday will edge it’s way Eastwards with a drier day developing for most. Low Pressure over North-Eastern France still close enough for some showers to continue along the far East of the UK, along with a breezy North to North-Easterly flow. Maybe still a few showers down some Western coasts as well. An area of rain then may slip East into Western Ireland from the West into Sunday night. Perhaps introducing some milder conditions there as the flow backs South-Westerly.
 

 

This of which could introduce some sleet and hill snow (possibly getting to some lower levels) throughout Monday as the front runs into some colder air further East (Just as MattStoke covers above with an example from the 06Z GFS run). A fair variety of weather to be had in the next few days it has to be said and may still need to watch out what the possible storm does for Tuesday/Wednesday next week. Though I suspect it’ll become more of a shallower affair and maintain a more Southerly track that a few models have started to show again. A more Northerly track still can’t be ruled out, however

Edited December 3, 2021 by DiagonalRedLine
Adding bit extra

[Stu_London]

Thanks for this thread. I'm sure as and when cold snaps/spells are approaching it will come into its own.

I try to post in here as well as still using the other thread for longer terms thoughts.

looks like a fairly cool showery regime for the next couple of days. Maybe a couple of transient wintry surprises as we are close to marginality with uppers and ground temps at times. 

 

All eyes have been on the atlantic storm for next Wednesday - still lots of uncertainty at 108hr as to how strong it will be and its track. Latest feeling is that the mainland Europe may get the worst of the conditions. 

Likely to have a big effect on how conditions will develop after its gone, so one to keep an eye on for both short and longer term prospects.

 

 

[Wold Topper]

From my very basic understanding early next week looks potentially interesting, it will be a good watch how the models roll this out over the weekend,

[johnholmes]

I still think that the UK Met track, either their model or Fax show the most likely positions for the deep low after this weekend. No GFS this morning and ECMWF has it just nw of the Channel Isles at the same time UK Met have it off eastern Scotland so plenty of difference in just those two models. Like I said I favour UK Met having looked at  300 mb predicted charts. But of course time will tell.

Fortunately it appears to have done most of its deepening before reaching the UK. It may still get named though as everyone is going to be a bit wary after the first named storm with its impacts still being felt for several thousand folk and heaven knows the cost of replacing power lines etc let alone the human cost with 3 deaths.

[johnholmes]

10 minutes ago, johnholmes said:

I still think that the UK Met track, either their model or Fax show the most likely positions for the deep low after this weekend. No GFS this morning and ECMWF has it just nw of the Channel Isles at the same time UK Met have it off eastern Scotland so plenty of difference in just those two models. Like I said I favour UK Met having looked at  300 mb predicted charts. But of course time will tell.

Fortunately it appears to have done most of its deepening before reaching the UK. It may still get named though as everyone is going to be a bit wary after the first named storm with its impacts still being felt for several thousand folk and heaven knows the cost of replacing power lines etc let alone the human cost with 3 deaths.

I tried to post Alex Deakin's post on Facebook but Net Wx blocked it so unable show how he illustrated the degree of uncertainty.

[johnholmes]

5 minutes ago, johnholmes said:

I tried to post Alex Deakin's post on Facebook but Net Wx blocked it so unable show how he illustrated the degree of uncertainty.

 

[johnholmes]

Just now, johnholmes said:

 

Tried the you tube version and this is ok, worth watching

[Stu_London]

11 minutes ago, johnholmes said:

Tried the you tube version and this is ok, worth watching

Very good video forecast - explaining the situation very well. Looks like UKMO have this a bit further north than some of the other models, although as Alex Deakin notes, a fair degree of uncertainty at this point. Does look like the first Atlantic 'bomb' of the season however and sure to have some impacts, most likely to ROI and western parts of the UK.

[knocker]

According to the 06 ecm rain and some snow, perhaps down to relatively low levels north of the Midlands, on the occlusion on Monday whilst at the same time the low is starting to develop in the baroclinic zone away to the soiuth west.

And over the next 24 hours rapid cyc;logenesis takes place as it tracks north east near the left exit of the jet to be 956mb NW of Galway by midday Tuesday

And by midnight wet and windy as the associated front(s) cross the country

 

 

Edited December 4, 2021 by knocker

[Stu_London]

Models seem to be converging around the idea that the storm winds up, gets close to British Isles, then starts to fill and sink south.

Very windy in the west, but I think heavy rain might be the headline maker if frontal systems become slow moving.

Interesting that when modelled in FI - a lot of the output had this storm barrelling through and disrupting the block to the east - now it looks like the theme is that low pressure systems will struggle to get east of the meridian. 

This might allow some influence in our weather from an easterly direction further down the line, however just as likely is that the UK gets stuck in the middle of a Mexican standoff between the Atlantic and the block, with southerlies over the country.

 

[Bradley in Kent]

Good evening all, 

I like the idea of this new thread and I'll be a frequent visitor!

There seems to be a lot more going on than usual and the model inconsistency rather illustrates that. It's all eyes on Tuesday now and there's little point trying to work out evolution past that. It really feels like a crossroads in the evolution of our winter if not this month.

Edited December 4, 2021 by Bradley in Kent

[knocker]

given the likely unsettled weather this week worth another quick look at the mid week low

This morning's updated fax charts which have the low filling and moving into the North Sea east of Aberdeen Tues/Weds

The ecm, having accomplished much of the rapid cyclogenesis in the previous 24 hours near the left exit of the jet, is in the same ball park, if not exactly the same detail. The gfs still keen to having it filling south east over France

According to the ecm calmer on Thursday before another front crosses the country on Friday. Still quite cold with temps below average

Edited December 5, 2021 by knocker

[BlueHedgehog074]

The GFS does seem to be kinda on its own with how far South it’s dropping the stormy Low compared to other models (the GFS 06Z run having it going directly over the channel around 90 hours)

Is probably being a little over optimistic (even though very plausible), considering what the other models show. Does, however, certainly highlight that even 2 days away, the definite track and intensity of this devious cyclone is not fully resolved. 

Even though it would make for some compelling weather for those who like active weather events like that (which I appreciate), on a personal note, am hoping it won’t turn out too wild, despite the strongest of the winds generally likely towards Western UK parts. It’s just when you have to go out or travel in that sort of weather, it’s not so fun at all to be honest

Edited December 5, 2021 by DiagonalRedLine

[Eagle Eye]

Love the idea of this thread can't believe I haven't asked for it before

 

Time to have a look I guess then

ECM still slightly upgrading


Now looking at the height I can tell you that a few lost fisherman won't forget this in a long time, Force 12 winds, nearing Category 2 Hurricane sustained winds if it were born from hot waters

There's so much going on here it's hard to know what to type and I know there's a difference between the wind on land and the wind in the sea, on land it's more impressive but the wind when approaching land is still very impressive
Category 3 wind gusts with the potential for Category 4 wind gusts (although this is not a hurricane for the time of year doesn't allow it I'll be measuring everything to hurricane winds) as it approaches Ireland

Continued high wind gusts, some Category 1 type wind gusts hitting Ireland now

Significantly weakens but now near 140s hitting land 
 (a lot also hitting the west of the UK by now)
TS force winds (sustained) hitting Ireland as we go further on, if this pattern had been heated and in the Atlantic Hurricane season I think we'd be talking about a real monster here


So ECM has some pretty significant wind gusts and sustained winds but it looks like it'll decrease rapidly
That's all I have to say for now 
Xander

[knocker]

The 06 ecm

[Dorsetbred]

3 hours ago, knocker said:

The 06 ecm

It's almost as though the low stalls and just creeps across the Uk, taking it's time to have a look at what its doing..

[knocker]

40 minutes ago, Dorsetbred said:

It's almost as though the low stalls and just creeps across the Uk, taking it's time to have a look at what its doing..

More or less what it does. The rapid cyclogenesis takes place prior to it arriving over Ireland, although there are likely some extremely strong and dangerous winds there for a time and also very windy over parts of the UK mainland. But then it fills quite rapidly as it drifts east

[Mizzle]

58 minutes ago, knocker said:

More or less what it does. The rapid cyclogenesis takes place prior to it arriving over Ireland, although there are likely some extremely strong and dangerous winds there for a time and also very windy over parts of the UK mainland. But then it fills quite rapidly as it drifts east

Hi Knocker, loving your posts and just have a question...what is meant by 'fills'? I've seen a few references to that happening but not sure what it means. TIA.

[knocker]

33 minutes ago, Mizzle said:

Hi Knocker, loving your posts and just have a question...what is meant by 'fills'? I've seen a few references to that happening but not sure what it means. TIA.

Hi Mizzle. in the 24 hours midday Monday > midday Tuesday the low deepens rapidly to be 957mb just went of Ireland. This is about as low  as it gets

And over the next 24 hours it drifts east and the central pressure rises to 975mb, And it will continuing 'filling' until it loses it's identity late Thursday

Edited December 5, 2021 by knocker

[knocker]

The updated fax charts and the ecm take on the wind tomorrow

Some observations on rapid cyclogenesis that might be of interest

http://www.eumetrain.org/satmanu/CMs/RaCy/index.htm