Model Output Discussion - cold spell to end Autumn

[bluearmy]

No agreement on the esb and Newfoundland between any of the big four by day 5/6...............

[damianslaw]

Key features on all the models are -

Strong arctic heights

Long wave deep trough over NE Canada and E/NE USA, sending warm air advection up west side of Greenland, which is killing the development of the PV - Stretched volatile disorganised PV is the result

Strong N Pacific ridge

Displaced Azores high

All these combined setting up a pattern ripe for a possible lengthy colder period than average. The main determinant will be the position and depth of the long wave trough trough over the eastern seaboard and its interaction with the jetstream. The models continue to suggest a split jet, which conversely will help aid height development to our NE - this is key, as it forces energy SE, hence we see a trough dropping through central europe, with the UK locked on the colder side of the polar jet. Further shortwave activity from the main parent trough over the eastern seaboard will track on similiar path i.e. SE, ensuring the azores high remains displaced, and crucially longer term could help aid stronger height development to the NE - we are then not in slider territory but undercut territory - anyway getting ahead of myself here.

We have started winter on an exceptionally interesting note synoptic wise, whilst we do have a zonal flow of sorts, its far from the norm we usually see at this time of year. 

Edited December 3, 2017 by damianslaw

[Ice Day]

Looking very good at 144.  Does look an improvement vs the 00z at this stage

 

Edited December 3, 2017 by Ice Day

[captaincroc]

Boom! This is what I have wanted to see this morning, clearer heights to the north and only way is under for the lows. Will keep cold air in longer too.  Have to go our now but can't believe this chart (yes it can change haha) at 144 hours.

 

[Weathizard]

Up goes the wedge! Looks like a nice 6z, northern and NW users must be rubbing your hands in glee

[feb1991blizzard]

This run is more amplified and will lead to a cold and snowy run but not sure what its worth ref - BA's post, cant really choose a path for D7 onwards if you cant get agreement at D5.

[clark3r]

That looks very cold to my eyes

[Iceberg]

Energy under the high and not over it. Not sure whether this will be good or bad re snow but it’s certainly a big Change. 

It kind of supports the ec eps with greater North Atlantic blocking as a viable possible candidate. 

[Duane S.]

12 hours ago, Broadmayne blizzard said:

Tell me about it Karlos I,m still having counselling for that particular sNOw event..

*shudder*. The mother of all snow shields that was. 

 

[terrier]

Well to my untrained eyes the ukmo looks out of kilter this morning. The gfs06z looks bitterly cold with snow chances a plenty. Ecm also looks favourable for snow showers. So I think we will see a much better ukmo later. Hopefully anyway. 

[snowbunting]

1 minute ago, Weathizard said:

Up goes the wedge! Looks like a nice 6z, northern and NW users must be rubbing your hands in glee

Me.. rubbing me hands in Glee... lol.

Minor changes for us in the North as the area of low exits the Uk bring gales or severe gales. Not convinced about the timing of the arrival of the snow on thursday... I think it will be earlier on thursday not later.  

Fully expecting cold weather to bring blizzards and drifting snow to us in the North. 

 

 

 

 

[Mucka]

If the undercut happens it seems very unlikely the low would not eject E/SE rather than just sink S so I would take this run with an extra pinch of salt after 144

Or maybe that is just wishful thinking as I am heading to the Canary Islands 

[That ECM]

1 minute ago, Mucka said:

If the undercut happens it seems very unlikely the low would not eject E/SE rather than just sink S so I would take this run with an extra pinch of salt after 144

Or maybe that is just wishful thinking as I am heading to the Canary Islands 

And I'm off to Lapland and the 850's are better in Bournemouth than there, so it's probably nailed it!!

[feb1991blizzard]

2 minutes ago, Mucka said:

If the undercut happens it seems very unlikely the low would not eject E/SE rather than just sink S so I would take this run with an extra pinch of salt after 144

Or maybe that is just wishful thinking as I am heading to the Canary Islands 

I take it then you actually don't want precipitation over there then.

[Mucka]

5 minutes ago, feb1991blizzard said:

I take it then you actually don't want precipitation over there then.

I will be crying in my cornflakes mate.

I haven't been away for a few years so it would be typical for it be cold and snowy here and miss it because I am chasing the sun - but then still get rain in Lanzarote!

Give me cold and snow or warm and sunshine, anything but cold wet and windy, our typical winter fare.

 

Edited December 3, 2017 by Mucka

[Iceberg]

19 minutes ago, Iceberg said:

Energy under the high and not over it. Not sure whether this will be good or bad re snow but it’s certainly a big Change. 

It kind of supports the ec eps with greater North Atlantic blocking as a viable possible candidate. 

And gfs demonstrates why the energy going under might be both good and bad. The angle of the jet needs to dive, for that we need the energy over the top, but we also need heights to build above so that a channel forms for the energy. 

Gfs 06z does neither we get very little snow and then a flat jet in the medium timeframe. 

[Frosty.]

The 6z shows a bitterly cold arctic blast later in the week, feeling sub-zero in the wind and plenty of snow showers with frosts and ice..that will do for me for now ta..in fact, some ice days too on fri, sat & sun!..Boom

Edited December 3, 2017 by Frosty.

[Methuselah]

5 minutes ago, Frosty. said:

The 6z shows a bitterly cold arctic blast later in the week, feeling sub-zero in the wind and plenty of snow showers with frosts and ice..that will do for me for now ta..in fact, some ice days too!..Boom

But I do think that a lot of model-related heartache would be avoided if Admin would swear-filter the word 'accumulation'...and maybe change it to 'puddle'?

[Sky Full]

I have come to the conclusion that even looking at the charts more than a few days ahead is seriously damaging to my mental health - perhaps they should come with health warnings: vivid images showing the result of over-reliance on the long term output; perhaps pictures of bruised and aching heads from too much banging against a wall  , or double-crossed eyes from too many early morning views of the latest runs , for example.   Anyway, I am determined to avoid long term charts in favour of the (hopefully) reliable next few days.....

Here are the main models showing the 8th December - only +120hours so surely nothing can go wrong at this distance??

UKMO   

ECM      

GFS      

GEM     

To my eyes these four models seem to be in broad agreement at +120h that we will all be enjoying a stong N/NW airflow bringing cold conditions and the possibility of snow showers for many.  Who gets them may have to wait for the day to unfold but my sanity depends on these charts being reliable....   After this date the models begin to disagree on how our weather will develop from 5-10 days hence and I for one am not going to risk a straitjacket by paying them any more attention for the time being, thank you very much.  

[Nick123]

Hi guys I've been stalking this forum for weeks now and I have to say what a roller coaster the past few weeks have been. What's your opinions on end of next week? Cold blip or something more exciting? 

[JamesL]

Gfs 6z looks like a rinse and repeat. Seems the cold always appears just before a weekend

[bobbydog]

and here comes the reload later on-

@Mucka you could be stranded in lanzarote for weeks..... 

[Frosty.]

The problem on here is constant worrying about breakdowns instead of enjoying the cold and snow when its on the way or actually here..Just make the most of what we get. Beyond next weekend is unreliable but the arctic blast looks nailed..hope for reloads into the following week!

[bluearmy]

The eps clusters go awol after day 10 with them having nothing other than one cluster - given that this doesn't tie in too closely with the ens mean I doubt that's correct !

prior to this, the largest cluster up to day 7 is the op one at almost 50% which then becomes the smallest cluster at day 8! Enough said...........

[MKN]

So from the massive blizzards shown on Friday things look to be back to reality with a decent Northerly instead for days 4 to 7. Snowfall i think is likely to be restricted to those areas that usually do well with elsewhere joining in on occasion. Low lying snow is probably unlikely for many though unless we see something organised form. Looking at d8 onwards a westerly influence is probably the most likely and a return to more average temperatures.