theweatheroutlook

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Ally Pally Snowman
27 November 2023 08:47:22
ECM ensembles a little colder than yesterday's 12z. Certainly colder than the GEFS. 

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=ecm&var=2&run=00&lid=ENS&bw=1 
 
Bishop's Stortford 85m ASL.
Saint Snow
27 November 2023 09:33:15
It's the hope what kills ya!

A chilly blip, then likely back to mild (or at least uncold) dross.

 

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
Gandalf The White
27 November 2023 09:44:13

It's the hope what kills ya!

A chilly blip, then likely back to mild (or at least uncold) dross.

 

Originally Posted by: Saint Snow 



I assume you’re looking at FI on GFS: reminds me of the children’s party game of pin the tail on the donkey.

GFS is so far out of line with what the MetOffice is saying that I’m disregarding the output beyond a week.
Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Timmytour
27 November 2023 09:49:51

I assume you’re looking at FI on GFS: reminds me of the children’s party game of pin the tail on the donkey.

GFS is so far out of line with what the MetOffice is saying that I’m disregarding the output beyond a week.

Originally Posted by: Gandalf The White 



I believe a week ago when the GFS was showing cold runs it was way out with what the Met Office was saying....
Broxbourne, Herts 133ft ASL
David M Porter
27 November 2023 09:50:00

I assume you’re looking at FI on GFS: reminds me of the children’s party game of pin the tail on the donkey.

GFS is so far out of line with what the MetOffice is saying that I’m disregarding the output beyond a week.

Originally Posted by: Gandalf The White 



I think that's a very sensible thing to do at the moment, Peter. 👍

The only things that concerns me ever so slightly is that IIRC, GFS was the first model or at any rate one of the first to pick up on this week's cold snap. I only hope that it isn't as accurate this time with what it is showing for later next week and beyond, but we shall see.
Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
+1
squish
27 November 2023 09:52:35
06z ICON and 06z gfs both further south or missing for Thursday 
D.E.W on Dartmoor. 300m asl
ozone_aurora
27 November 2023 09:56:30
Can anyone explain me what exactly F1 means in model output forecast, I mean how many model forecast days is it from say now (or to put it another way what date would it be of it say, from 10th of the month)?

All I can see from the charts is hours forecast.

Anyway, to go back to previous post I too disregard the output beyond 7 days; these are just too unreliable.
Saint Snow
27 November 2023 10:12:24

Can anyone explain me what exactly F1 means in model output forecast, I mean how many model forecast days is it from say now (or to put it another way what date would it be of it say, from 10th of the month)?

All I can see from the charts is hours forecast.

Anyway, to go back to previous post I too disregard the output beyond 7 days; these are just too unreliable.

Originally Posted by: ozone_aurora 




Firstly, it's 'FI'. Stands for 'Fantasy Island'. Fantasy Island was a American TV show from yesteryear where guests arrived on the island to live out their fantasy (no, not those types of fantasy 😀)

The use on TWO came about many years ago when, during a run of really poor winters, a GFS run would tease with great output for the far reaches of the run (as in, "the GFS 6z is showing a huge Scandy high at t+324 bringing in 850's around the -15c mark, but it's all just Fantasy Island stuff"). The phrase stuck (I wonder if any of our long-standing members remember who first coined it)

There was no hard and fast rule for the time period. 

It's evolved to also mean the very appropriate point at which a model run's output becomes unreliable (again no set time period)

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
+2
scillydave
27 November 2023 10:14:28

Can anyone explain me what exactly F1 means in model output forecast, I mean how many model forecast days is it from say now (or to put it another way what date would it be of it say, from 10th of the month)?

All I can see from the charts is hours forecast.

Anyway, to go back to previous post I too disregard the output beyond 7 days; these are just too unreliable.

Originally Posted by: ozone_aurora 



FI = Fantasy Island.  A popular piece of TWO slang for any model output that's considered beyond the reliable range (which changes with model output certainty i.e. when models or an individual model's runs are all aligned).
Currently living at roughly 65m asl North of Cowbridge in the Vale of Glamorgan.

Formerly of, Birdlip, highest village in the Cotswolds and snow heaven in winter; Hawkinge in Kent - roof of the South downs and Isles of Scilly, paradise in the UK.
tierradelfuego
27 November 2023 10:32:56
Can't add much to the above two responses other than to maybe give an actual example from now, for some context around timeframe(s).

Looking at the GEFS suite today at 00z for Reading, the 850s and 2m's are pretty aligned out to about the 4th Dec with smallish deviation on or around the 30th Nov.

When you look at the MLSP pressure though, even 3 days away on the 30th Nov there is over 30 mB difference in the suite, which is a pretty large variation. To be fair after the 30th, it does come back together until the 4th.

IMHO you'd be hard pushed to have any confidence after the 30th and you might say that that as of now FI starts from the 30th, others would say the 4th... there's no hard and fast rule. You'd probably look at the 6z and then the 12z suite to determine it as it evolves.
Bucklebury
West Berkshire Downs AONB
135m ASL

VP2 with daytime FARS
Rainfall collector separated at ground level
Anemometer separated above roof level
WeatherLink Live (Byles Green Weather)
nsrobins
27 November 2023 10:38:12

The phrase stuck (I wonder if any of our long-standing members remember who first coined it)

Originally Posted by: Saint Snow 


I don't think anyone would be especially keen to take credit for it 😉
There is still twittering in the twatersphere about a 'freezing' easterly on Friday piling in snow showers. Perhaps this is to make up for the likely 'miss' of the low to our south (how GFS likes to overdo low pressures), but I just can't see how uppers of no less than -7 across a relatively warm N Sea will deliver this early in the season. Wintry showers possible, but widespread convective snowfall would be very surprising.
Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO
Rob K
27 November 2023 10:47:24

Can anyone explain me what exactly F1 means in model output forecast, I mean how many model forecast days is it from say now (or to put it another way what date would it be of it say, from 10th of the month)?

All I can see from the charts is hours forecast.

Anyway, to go back to previous post I too disregard the output beyond 7 days; these are just too unreliable.

Originally Posted by: ozone_aurora 



Fantasy Island has a uniquely flexible definition.
When heavy snow is forecast, "FI" begins at T +6 hours, if not before.
If a gigantic Euro high stretching from the Azores to Moscow is showing on the output at 300 hours then FI begins at approximately T +468 hours.
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
+3
Ally Pally Snowman
27 November 2023 10:49:36
Well in FI we get an easterly from the GFS 6z.
Better run from the GFS snow could pop up at any point from about Thursday for a week. Always borderline but that's normally the way.
 
Bishop's Stortford 85m ASL.
ballamar
27 November 2023 10:50:19
GFS op run churns out massive continental high with ensuing cold continental winds
Gusty
27 November 2023 10:56:42

GFS op run churns out massive continental high with ensuing cold continental winds

Originally Posted by: ballamar 



A very significant run that one IMO.
Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
https://www.facebook.com/stevewall69/ 



+1
ballamar
27 November 2023 11:01:30

A very significant run that one IMO.

Originally Posted by: Gusty 



be interesting to see the full ENS 
doctormog
27 November 2023 11:14:19

be interesting to see the full ENS 

Originally Posted by: ballamar 



Hopefully it's an outlier as days of damp cold drizzly muck are grim, especially at this time of the year.
Aberdeen
Current conditions (personal WS) 
Retron
27 November 2023 11:17:44
I've been keeping an eye on the ML ECMWF output (glorified pattern matching) - it has been verifying above the traditional models lately.

This morning's effort shows disrupting lows to the west and the block holding firm, indeed by day 10 there's an extension of the Siberian high over Scandinavia and a discrete high over Iceland... pretty much the holy grail if it's an easterly you're after.

As a fan of the latter, and a CompSci guy myself, I'll be very interested to see how this plays out.

https://charts.ecmwf.int/products/graphcast_medium-mslp-wind850?base_time=202311270000&projection=opencharts_europe&valid_time=202312070000 
Leysdown, north Kent
Retron
27 November 2023 11:19:36

be interesting to see the full ENS 

Originally Posted by: ballamar 


It's time for one of my regular winter-season reminders, I think - remember, the ECM ensemble output is available, in full, for any location in the UK, from 8 AM every morning.

Today's op run was on the cold side down here, but not an outlier. 3C maxes though aren't quite enough for anything interesting...

https://charts.ecmwf.int/products/opencharts_meteogram?base_time=202311270000&epsgram=classical_10d&lat=51.3973&lon=0.921564&station_name=Leysdown-on-Sea 
Leysdown, north Kent
White Meadows
27 November 2023 11:24:59
Latest Met office contingency planners 3 month update is out this morning, and they are going for a slight chance of milder than colder overall. Also more chance of cold impacting later in winter, as one would expect with the El Niño profile.

link here: 

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/business/public-sector/civil-contingency/3moutlook_djf-v1.pdf 

Discuss…
Taylor1740
27 November 2023 11:25:48

GFS op run churns out massive continental high with ensuing cold continental winds

Originally Posted by: ballamar 


yes can see a battleground scenario developing likely with the UK on the mild Atlantic side, however it's a long way off so not a done-deal yet.
NW Leeds - 150m amsl
Rob K
27 November 2023 11:28:49

be interesting to see the full ENS 

Originally Posted by: ballamar 


Not much support for the Scandi high option. P11 and P30 look the best of the bunch.
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
CField
27 November 2023 11:33:59
Lots of potential still at 384hrs 06z gfs to me...need purples to our north east....a January 85 would be nice for the South East....the ice on the  Hastings Old Town boating lake by the seafront was a foot deep
Favourite snowstorm
Famous channel low
Dec 31st 1978
Hastings East Sussex
Foot of level snow severe drifting
Next day max temp -4 degrees Celsius
some faraway beach
27 November 2023 11:36:04

I've been keeping an eye on the ML ECMWF output (glorified pattern matching) - it has been verifying above the traditional models lately.

This morning's effort shows disrupting lows to the west and the block holding firm, indeed by day 10 there's an extension of the Siberian high over Scandinavia and a discrete high over Iceland... pretty much the holy grail if it's an easterly you're after.

As a fan of the latter, and a CompSci guy myself, I'll be very interested to see how this plays out.

https://charts.ecmwf.int/products/graphcast_medium-mslp-wind850?base_time=202311270000&projection=opencharts_europe&valid_time=202312070000 

Originally Posted by: Retron 



That would tie in with the fact that until the last few days TWO's list of analogue years had the top-matching year at around the eight or nine thousand mark, i.e., a decent match. So it's not surprising that the machine-learning output has been performing well.

The problem is that the top-rated year is now hovering well over 10,000, i.e., a poor match. That's sod's law, of course, with the machine churning out a chart like the one you've linked to. (As it happens, the top-rated analogue this morning is 1981, which explains how that chart came about; but the index value is a whopping 10268, i.e, not much of an analogue at all.)
2 miles west of Taunton, 32 m asl, where "milder air moving in from the west" becomes SNOWMAGEDDON.
Well, two or three times a decade it does, anyway.
fairweather
27 November 2023 12:12:38

Fantasy Island has a uniquely flexible definition.
When heavy snow is forecast, "FI" begins at T +6 hours, if not before.
If a gigantic Euro high stretching from the Azores to Moscow is showing on the output at 300 hours then FI begins at approximately T +468 hours.

Originally Posted by: Rob K 


So true! I think the general rule would be don't expect anything outside of a week to be accurate for weather but perhaps more accurate for direction of trends.
S.Essex, 42m ASL

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