Model Output Discussion. 3/12/2022. How cold will it get?

[V for Very Cold]

7 minutes ago, mb018538 said:

For a selfish IMBY point of view, I'll have the ECM 00z. Ta!

It’s a thing of beauty....it’s still 7 days away though...I wonder where FI begins currently?

[radiohead]

Cold all the way to the end of the run, only brief blips of rain turning back to snow in SW areas. At the end of the run it looks like another band of frontal snow is about to push in from the south. 

[Nick F]

So we've got the cold staying entrenched through next week almost nailed, the first hurdle jumped, now it's a case of whether can get some snow away from the usual favoured coastal areas. GFS and UKMO look rather dry away from far north and coasts elsewhere, EC does bring a threat from the southwest from the middle of next week across England and Wales. But it's a great unknown for now.

[iowpompeylee]

Anybody got access to the fax charts? Or can someone stick a link again in as I’m looking for some pop up precipitation in the next few days. If I was a betting man I’d put all my money on the UKMO verifying 

[Mark Smithy]

0z GFS Operational very much on the mild side:

 

One thing that is really noticeable is that the ensemble scatter is no longer occurring on Dec 14th but Dec 17th. So the possible mild breakdown has been pushed further back.

[Gowon]

4 minutes ago, V for Very Cold said:

It’s a thing of beauty....it’s still 7 days away though...I wonder where FI begins currently?

Well, it's all in the future still, so everything is still FI.

[Blessed Weather]

5 minutes ago, iowpompeylee said:

Anybody got access to the fax charts? Or can someone stick a link again in as I’m looking for some pop up precipitation in the next few days. If I was a betting man I’d put all my money on the UKMO verifying 

Scroll down the list on the left:

 

Weather Charts and Data Netweather DataCentre

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Check the latest weather charts and data on Netweather

 

[IDO]

London ens look cold for next 10-days and then scatter in la la land:

So, all-in-all, a seasonal two week spell looks the call, with the few days we have already. There is still a cluster in FI keeping it cold, and it depends on the phasing of the Atlantic lows and the UK trough as to if those colder options remain.

The GFS moved two-steps towards the ECM, with the trigger low from the Asian tPV now showing up around D6-7. That suggests we have better continuity x-model and a likely route post D7. Still not as clean as ECM and GEM.

Lovely GFS 8-day mean:

Very rare of late.

[DJ Fart]

14 minutes ago, V for Very Cold said:

It’s a thing of beauty....it’s still 7 days away though...I wonder where FI begins currently?

Of course it is. Every day there have been eye candy charts knocked out by the models but never getting any nearer, constantly at +168. "Get the cold in first!!". Well, the cold is in and set to stay...now just got to be patient, but it's so frustrating to be looking at the best synoptics for years, and we still struggle to get anything meaningfully snowy from it. 

[irish1]

latest ECM ensembles show good support for cold to last up to 18th. The spike in precip for Southeast Ireland shows risk of low bringing some precip but spread shows how uncertain it is.

[Anthony Burden]

27 minutes ago, Nick F said:

So we've got the cold staying entrenched through next week almost nailed, the first hurdle jumped, now it's a case of whether can get some snow away from the usual favoured coastal areas. GFS and UKMO look rather dry away from far north and coasts elsewhere, EC does bring a threat from the southwest from the middle of next week across England and Wales. But it's a great unknown for now.

Hi Nick,yes the uncertainty continues for the middle of next week in the meantime some very penetrating frosts and also freezing fog could join the agenda.

[ICE COLD]

12 minutes ago, irish1 said:

latest ECM ensembles show good support for cold to last up to 18th. The spike in precip for Southeast Ireland shows risk of low bringing some precip but spread shows how uncertain it is.

Could you post the London ones please ? Or the midlands ? Thank you  

[ItNeverSnowsInWindsor]

Bank!

[Tim Bland]

ECM gets a boom from me! 

[irish1]

6 minutes ago, ICE COLD said:

Could you post the London ones please ? Or the midlands ? Thank you  

London

[Ladyofthestorm]

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. 

[Tim Bland]

ICON looks similar to ECM re the snow event on Weds in the south ..

[mb018538]

51 minutes ago, iowpompeylee said:

Anybody got access to the fax charts? Or can someone stick a link again in as I’m looking for some pop up precipitation in the next few days. If I was a betting man I’d put all my money on the UKMO verifying 

Fax Synoptic Charts From The UK Met Office - Neweather.tv

WWW.NETWEATHER.TV

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Latest Met Office Fax synoptic weather maps

All on here. Not much frontal activity over the UK in the 5 day period, so it's a dry and cold theme for the majority for now.

[Beanz]

11 minutes ago, Tim Bland said:

ECM gets a boom from me! 

Boom for what? It’s a 10 day snow depth chart, it’s bin fodder 

[Portlander]

8 hours ago, DiagonalRedLine said:

Hi Portlander, have used examples of charts on 7th December using a 10 year sample from 2005 to 2015:

You’ll notice there can be variation to the pattern from year to year. However, I think overall would say a typical early Winter chart is one where we get a flow off the Atlantic in general, which most charts above show in some from - usually between the South and West. Flow from the North-West can be fairly common too. The purples (from the Polar Vortex - low upper heights), tending to occupy us close by to our North and North-West around the Greenland area, especially towards Northern Canada. Along with this, Low Pressure systems on average take a South-West to North-East or West to East track through the North-West and North of the UK as they swirl around the upper low heights to our North-West/North.

This might not be the most accurate answer, mind, despite the amount of years experiencing Winters in the UK. (Some with more experience would probably be able to give a better answer), but hope it was of some help.  

Edit: Sorry, should have added welcome to Netweather  

Thanks for your reply. It’s hard to see the excitement without context.

I always think of snow as a distant relative coming to stay… great for a while, but the novelty wears off pretty quickly and you want things to get back to normal

[Liam Burge]

New NOAA outlook has dropped the chance of a tropical system forming from 50% to 30%, however the end of their outlook also suggests a possible rapid strengthening of the low over cold waters.

 

Showers and thunderstorms have increased since last evening near a large non-tropical area of low pressure located over the central subtropical Atlantic about 850 miles east-southeast of Bermuda. However, the system remains embedded within a frontal zone, which is expected to become more pronounced later today as the low begins to move east-northeastward at 20 to 25 mph toward colder waters and interact with a mid-latitude trough. Therefore, while the system could show some subtropical characteristics today, its chances to fully transition to a subtropical or tropical cyclone appear to be decreasing. Nevertheless, significant non-tropical development of this low is expected during the next couple of day

[mfhblue]

Hi All,

I have been around a few years, will probably only post when I have something worth adding to what's already been said.

GFS develops a little feature in the channel on Sunday.  If it does happen it could be very interesting for those in the far south-east...

[nick sussex]

The ECM departs from the consensus upstream by keeping a more amplified trough progression eastwards across the CONUS this culminates in its day 9 and 10 charts which box in the high .

This then adds more forcing into the Atlantic .

The dangers earlier between day 7 and 8 with the ECM are an unfavorable phase point of shortwave heading s/sw which then phases with low heights associated with the Atlantic low .

The ECM relies on the pattern being sufficiently east at that point so the ne momentum associated with the phasing keeps most of the UK in the colder air as the system moves ne into the Low Countries.

Of course with the ECM the rewards are greater for those in the favoured snow areas .

 

Edited December 8, 2022 by nick sussex

[Mike Poole]

Morning all, more good runs this morning.

I think the main uncertainty is about the track of the main low.  It seems certain we have cold air properly in place before it arrives, and also pretty likely that whatever track it takes, cold reasserts itself afterwards.  It seems to me partly because the nature of the low itself is so uncertain, and the situation into which it moves is complex, there is more uncertainty than one might expect with a ‘normal’ system on this kind of path, on its track and timing as it affects the UK.  To give examples from the morning runs:

UKMO (T144) looks like it will miss well to the south, but then splits (T156) and angles NE (T168):

GEM (T168) has a more rounded low, and then it goes south (T192)!

ECM gets a late pull NE as it phases with the low north (T192):

Great dump of snow, but wouldn’t want to be relying on that!

GFS (T144) has the low incoming, then turns into a right royal mess (T168) and then stalls (T192), this one unfortunately does shift the cold by pumping up a southwesterly with the aid of a second low to the southwest:

As we were discussing yesterday, this will take a while to resolve.

Edited December 8, 2022 by Mike Poole

[iowpompeylee]

A little feature Sunday morning on the Fax charts to keep an eye on, For us down south/east May bring some snow flurries. 

Edited December 8, 2022 by iowpompeylee