Model output discussion - late November

[Jordan S]

Didn't post for over a day  I've covered the next few days recently but looking further ahead Before any *potential* for snow and or any significant cold we may have to keep an eye up wind for nasty low pressure systems possibly developing in this long fetch west/northwest flow shown for late next week across the UK..

Gem..

Sunday 8th 6am chart.. 

8th midday chart.. 

8th 6pm chart.. 

A very vigorous area of low pressure moving from west /northwest to east/southeast across the UK bringing widespread very strong gusts of wind to many areas.

This shown to be accompanied by significant rainfall. 

Gem rainfall..

Midnight 8th..

GFS..

Although a day later its a Similar scenario a vigorous low slipping southeast of the UK with very strong winds for many areas. 

Monday 9th..

Ecmwf..

Ecmwf shows this low too as a significant feature but has it diving Southeast over the uk a little sooner with very windy conditions and heavy rain but mild for a time as it comes in, then the Ecmwf shows something different to the others with colder air behind as a cold northerly begins to push down courtesy of higher pressure ridging north to the west of the UK. 

8th..

9th..

10th..

Now If we put the average output from the Gfs, Gem and Ecmwf combined then this is the pattern shown..

Friday 6th..

Sunday 8th..

Tuesday 10th..

This too does show that nasty low although not to the Gem extent but bringing a very strong northwesterly wind across the country for around or on the 8th, after that it shows a continuation of the unsettled theme upto day 10 although not particularly mild with winds tending to be westerly or northwesterly more frequent spells of rain and hill snow for the north at times if this pattern happens. 

I Woudn't usually focus on something this specific at this time frame and you won't see me do it too often, ofcourse this may be dropped in the next couple of days but this system has shown in recent model runs from various computer models and I've taken more notice especially because the average output is showing a similar theme with the pattern modelled being conducive for stormy weather.

Now of course this particular low/storm is not to be taken as likely at this stage the details will change as one would expect especially as this is over a week away if indeed anything similar to these charts does happen. I'm more Highlighting the potential for a stormy period perhaps unfolding days 5-10 which could culminate in something similar to above which woundn't be a suprise but perhaps a shock given the lack of any storms this autumn. 

Edited December 1, 2019 by jordan smith

[Cheshire Freeze]

1 minute ago, inghams85 said:

It's 10 past 12 and I can't be assed to show you but I can explain. We've just had a record breaking displacement event moving the core of the strat away from Greenland to Scandinavia leaving a vacuum for high pressure in the Greenland locale. Without AAM support this would at the very least support a strong topper scenario. However we have AAM support and an upcoming MJO orbit which at the same time lends to an idea of height rises in the North West. All these factors together and breaking the science down simply implies the ecm scenario is extremely plausible. I'd put it at 60-70% minimum. The gfs outcome has no scientific background support its just throwing out a random couple of runs from its clusters. You are basing on the ecm being wrong because of previous let downs and patterns models take. If I'm wrong about this this is now your turn to explain why I'm wrong and your not?? 

Read above.

Why do I feel you're throwing around terms at me that you have no idea about?

You'll never see any strat expert worth their salt go as high as 60-70% minimum certainty over a trop pattern after only a displacement event.

[inghams85]

1 minute ago, CreweCold said:

Read above.

Why do I feel you're throwing around terms at me that you have no idea about?

You'll never see any strat expert worth their salt go as high as 60-70% minimum certainty over a trop pattern after only a displacement event.

I've read it your saying the middle of the month a week after me. It's a reflective displacement event. Trop responses are very quick in this scenario. They always are in this type of displacement especially so pronounced. Where's your reasoning other than to say you think there's tentative signals from the strat. Fire your tropics knowledge at me for a start. You are a poster that relies on past experience with models but you can't do the climate is an ever changing animal

[Cheshire Freeze]

8 minutes ago, inghams85 said:

I've read it your saying the middle of the month a week after me. It's a reflective displacement event. Trop responses are very quick in this scenario. They always are in this type of displacement especially so pronounced. Where's your reasoning other than to say you think there's tentative signals from the strat. Fire your tropics knowledge at me for a start. You are a poster that relies on past experience with models but you can't do the climate is an ever changing animal

You're assuming that a+b=c in meteorology but in truth there is no formula that exists like that. At least not one that we know of. Otherwise we'd be able to get predictions 100% nailed on. 

We've had promising signals for the past few years but all have come to nothing bar the major SSW of Feb 2018. 

Could it be that what we thought we understand was just a false dawn? Or that other variables are more important? 

Either way, even if you're relying on the tropics approach to forecast future weather, you are still at the mercy of the NWP to extrapolate your reasoning from...

Edited December 1, 2019 by CreweCold

[inghams85]

Just now, CreweCold said:

You're assuming that a+b=c in meteorology but in truth there is no formula that exists like that. At least not one that we know of. Otherwise we'd be able to get predictions 100% nailed on. 

We've had promising signals for the past few years but all have come to nothing bar the major SSW of Feb 2018. 

Could it be that what we thought we understand was just a false dawn? Or that other variables are more important? 

All I'm saying is based on what we know the ecm output is miles miles more plausible than the gfs. I never said it was nailed on that's why I said 60-70% but there is 100% no reason to be pessimistic at this stage when the colder option is more likely 

[Cheshire Freeze]

2 minutes ago, inghams85 said:

All I'm saying is based on what we know the ecm output is miles miles more plausible than the gfs. I never said it was nailed on that's why I said 60-70% but there is 100% no reason to be pessimistic at this stage when the colder option is more likely 

Damn, I must have got really lucky then with my previous assertions. What's the betting I land with my prediction that you class as a 30-40% chance?

[inghams85]

1 minute ago, CreweCold said:

Damn, I must have got really lucky then with my previous assertions. What's the betting I land with my prediction that you class as a 30-40% chance?

What previous assertions are these then? 

Edited December 1, 2019 by inghams85

[Cheshire Freeze]

4 minutes ago, inghams85 said:

What previous assertions are these then? 

Think I've fooked up once in 5 years- last year when I called a very cold January due to the SSW.

17/18 I said we'd need a SSW to break the vortex down before we saw cold- much to the disdain of people in this forum. Yet what happened. Pretty sure @feb1991blizzard can vouch for me...

Then there was 16/17 when the Metoffice were going cold and I refuted it. 

I HATE hubris, but if you're going to push me to it...

Edited December 1, 2019 by CreweCold

[inghams85]

2 minutes ago, CreweCold said:

Think I've fooked up once in 5 years- last year when I called a very cold January due to the SSW.

17/18 I said we'd need a SSW to break the vortex down before we saw cold- much to the disdain of people in this forum. Yet what happened. Pretty sure @feb1991blizzard can vouch for me...

Then there was 16/17 when the Metoffice were going cold and I refuted it. 

I HATE hubris, but if you're going to push me to it...

I think I'll get you a job with the met office if you've messed up once in 5 years...... Oh dear! 

[Cheshire Freeze]

Just now, inghams85 said:

I think I'll get you a job with the met office if you've messed up once in 5 years...... Oh dear! 

The forums are free to look back upon...

 

Edited December 1, 2019 by CreweCold

[inghams85]

Just now, CreweCold said:

The forums are free to look back upon...

 

Let's see how it pans out shall we. Until then I'd like to hear your scientific reasoning behind your opinion. Nothing more nothing less

[Cheshire Freeze]

1 minute ago, inghams85 said:

Let's see how it pans out shall we. Until then I'd like to hear your scientific reasoning behind your opinion. Nothing more nothing less

[inghams85]

Just now, CreweCold said:

Thought as much. Your a good member of this group but try to back up what you say mate

[pinball wizard]

Calm down chaps it's only the weather 

[icykev]

Key evolution I believe. Heights must be noted to eastern seaboard. Can we get a break at this time period.

Looks possible with current pattern.

[edo]

Some great weather debate tonight 

[inghams85]

11 minutes ago, edo said:

Some great weather debate tonight 

Hahahaha is that aimed partly at me lol

[knocker]

Outlook - Mainly dry and cold for England and Wales, less so for N. Ireland and Scotland

The North Atlantic 500mb and surface analysis for midnight

After a frosty start to the day, with the odd fog patch which may be slow to clear, it should be a sunny and cold day for all as the high cell nudges east over the UK, with just the odd shower along northern and eastern coasts

Tonight will be clear with quite a widespread frost south of the border with a number of fog patches, But there is a lot going on out in the Atlantic and a frontal system is driven around the northern perimeter of the high to bring cloud and rain into northern Scotland from midnight

Monday will be sunny and cold with light winds for most but windy with rain over northern Scotland courtesy of the aforementioned frontal system(s) And as can be seen developments continue apace in the west

The rain should clear Scotland Monday night, albeit still windy, so Tuesday a sunny and dry day for all once the early frost and fog has cleared. But a lot of pressure is being exerted on the ridge from the two energy flows to the west

The analysis to the NW and W on Wednesday is complex to say the least with a lot of cyclogenisis going on as the ridge comes under increasing pressure. Resulting in a weakening cold front tracking south east down the country with patchy rain in the north and quite windy whilst further south remains dry and cold.

By Thursday the ridge is barely hanging on in the far south as it becomes very windy in the north as warmer air sweeps in from the south west along with a frontal system that brings rain to N. Ireland and Scotland, heavy in the north west

 

Edited December 1, 2019 by knocker

[knocker]

After a brief ridge on Saturday the gfs develops quite an intense low resulting in heavy rain and strong winds in the north. Obviously at this range just a watching brief but the environment is primed for cyclogenisis so not that unreasonable

[SLEETY]

The longer range charts  currently have    an uncanny look about December  1981 about them,the year I was old enough to be iinterested in the weather.

Of course at that timescale it  could change to a less cold outlook,or even colder outlook.

The uppers never got below minus 5 here that month but their were some serious snowfalls here despite that.

The models  do tend to over amplify in far out land I have noticed,so need to see these charts in the semi- reliable before getting overly excited yet..

[That ECM]

T240 gefs. I think the mean on this occasion is ok as guide.

[knocker]

The ext GEF mean anomaly does not develop any meaningful ridging into Greenland and thus has a single westerly flow over the UK perhaps tending to WNW, With some amplification over N. America and the source of the air temps a tad below average in the likely unsettled weather. The usual caveats apply on the day to day variations regarding the movement of surface lows and any airmass phasing

Edited December 1, 2019 by knocker

[feb1991blizzard]

13 minutes ago, knocker said:

The ext GEF mean anomaly does not develop any meaningful ridging into Greenland

Yes the last few runs have been a lot flatter, Interesting to find out whether the EPS follow suite.

[That ECM]

47 minutes ago, feb1991blizzard said:

Yes the last few runs have been a lot flatter, Interesting to find out whether the EPS follow suite.

T192 gfs and ecm. Fi begins at t120-t144. 

 

Edit t240  ecm may answer your question.

Edited December 1, 2019 by That ECM

[Jordan S]

A Frosty start to the day for northern areas with wintry showers for northern and Eastern coastal areas of Scotland and Northern Ireland these will continue but for the far south it is a fairly cloudy start this is associated with the remnants of yesterday's low which has kept things frost free here to begin the day, there has also been some rain, sleet and snow showers for parts of northeast England overnight some quite heavy too which have come a fair way inland, these will turn lighter and fewer here.. a few light showers for central areas too Through the morning but these fade and many areas stay dry the cloud should break for the far south during the morning.. during the afternoon into this evening a line of showery rain may effect east anglia and the southeast giving a millimetre or two.

Feeling cold today for all with some parts of Scotland remaining around freezing all day. 

Hirlam..

Any left over showery rain for east anglia and southeast England fades away overnight with a frost quickly forming in the north then the south later on but some mostly light and patchy rain likely for northern Scotland later in the night. 

Edited December 1, 2019 by jordan smith