Model Output Discussions 12z 01/09/2016

[johnholmes]

To see how variable the models are just compare the Sat 240h and that today, one a cold option the other a milder idea. Compare each run with its predecessor for a realistic comparison, then compare it to the other longer term models and see how, if, when the begin to move towards similar charts and the time scale. It is rare this happens before 168h sometimes as close as 72h. That does include rather infamous cases where deep eastern cold was being predicted by various models right down to 72h.

It is fun and also absorbing to watch the count down but not good for ones blood pressure if it s taken too seriously. For all its faults the longer term outlook, 6-30 days, by UK Met is about our best bet for what may happen up to a month ahead. But is really good if we can appear to out do them.

[bobbydog]

7 minutes ago, johnholmes said:

Come on folks it really is going to seem an incredibly long winter no matter if you are a cold or mild supporter if every run is going to micro analysed for deep cold. That  just will not happen, never has never will. Check the old charts for 1946-7 or 1962-63. Neither winter really began before Christmas. Can we have some realistic analysis of pre 240h and how the UK as a whole looks to be with regard to weather please?

Rather blocked for a week or possibly two, beyond that who knows. I certainly do not.And the first week of November is hardly a time to get lying snow for more than a few hours anywhere on low ground south of the Border, or am I totally wrong?

A point well made John but I think most of us are looking at the longer term bigger picture rather than micro analysing details. i can't speak for everyone but I'm personally not expecting anything spectacular in November. I would rather see the hemispheric profile develop favourably for when winter actually arrives! 

[Cheshire Freeze]

1 minute ago, bobbydog said:

A point well made John but I think most of us are looking at the longer term bigger picture rather than micro analysing details. i can't speak for everyone but I'm personally not expecting anything spectacular in November. I would rather see the hemispheric profile develop favourably for when winter actually arrives! 

I think the groundwork has already been done for the early winter pattern (at least). As I said, I don't think I've seen an archive chart yet where November didn't feature a strengthening trop vortex and at least some mobility.

[andymusic]

defo looking flatter and real cold being blocked right now but possible colder weather remains around the date 7th Nov - bit worrying comment from good old Joe B from across the pond - "North America in for an early winter" and we know what happens if the Eastern seaboard starts cranking up their winter, the jet stream may get it's act together over the Atlantic - but like others have said we may need a period of zonal mobility before we get to the real cold once we are immersed in the actual winter months

[bobbydog]

3 minutes ago, CreweCold said:

I think the groundwork has already been done for the early winter pattern (at least). As I said, I don't think I've seen an archive chart yet where November didn't feature a strengthening trop vortex and at least some mobility.

I made a similar point earlier in the thread. If the damage (to the vortex) is done now, when it inevitably does crank up, it's much more likely to throw some of its cold our way.

[Cheshire Freeze]

3 minutes ago, bobbydog said:

I made a similar point earlier in the thread. If the damage (to the vortex) is done now, when it inevitably does crank up, it's much more likely to throw some of its cold our way.

It'd be interesting to see the pressure anomaly charts in a week or so for the autumn to date. I suspect that we're bang on the historical analogue for a post strong Nino into la Nina autumn. This is interesting because the corresponding winter pattern is anomalous Greenland-Iceland heights and a resultant cold UK. 

[Frosty.]

The Gem 12z is an upgrade in comparison to 24 hours ago, it looks increasingly unsettled by thurs / fri and progressively colder by next weekend into the first part of week 2 with strengthening Nly / NEly winds and cold enough for snow on northern hills...By T+240 the pattern briefly flattens out but upstream there are signs of further cold shots from the NW. normally we would be stuck with a sw / ne aligned jet with a super strong PV but not this autumn and to me it looks like chilly weather is on the way and it could be feeling wintry at times.

Edited October 30, 2016 by Frosty.

[Captain Shortwave]

Whilst the pattern does seem to flatten a touch into week 2, I can't see any sign of a true zonal signal emerging with the Azores high sitting west of the UK with a flow north of west dominating. GEFs below....

      

 

Temperatures do rise a little to near normal values, this could more than likely be the true signal being masked by the more mobile members. The first half of November does look below normal temperature wise going by the model output, even when adding the increased signal for something more mobile developing. So rain or showers at times, these wintry on the hills and possibly to low levels in the north at times, night frosts should become increasingly widespread too.

Edited October 30, 2016 by Captain Shortwave

[feb1991blizzard]

2 minutes ago, CreweCold said:

It'd be interesting to see the pressure anomaly charts in a week or so for the autumn to date. I suspect that we're bang on the historical analogue for a post strong Nino into la Nina autumn. This is interesting because the corresponding winter pattern is anomalous Greenland-Iceland heights and a resultant cold UK. 

We are, and yes the winters that follow are generally cold, ive seen the analogues, they average out at above average heights over Iceland and winters tend to be front loaded, however, if you look at the individual years they vary between Greeny highs and scandi highs, theres also variations between recent ones and ones 80 years ago, the latter tending to be colder, that's what I can remember anyway.

[Cheshire Freeze]

Just now, feb1991blizzard said:

We are, and yes the winters that follow are generally cold, ive seen the analogues, they average out at above average heights over Iceland and winters tend to be front loaded, however, if you look at the individual years they vary between Greeny highs and scandi highs, theres also variations between recent ones and ones 80 years ago, the latter tending to be colder, that's what I can remember anyway.

Historically, until the 1960s I think, they tended to be quite severe. Then this flipped...with 2008 possibly being another flip point and reverting to the pre 1960s patterns. I guess this year will be a good bell weather to test this theory out.

[Mucka]

41 minutes ago, johnholmes said:

Come on folks it really is going to seem an incredibly long winter no matter if you are a cold or mild supporter if every run is going to micro analysed for deep cold. That  just will not happen, never has never will. Check the old charts for 1946-7 or 1962-63. Neither winter really began before Christmas. Can we have some realistic analysis of pre 240h and how the UK as a whole looks to be with regard to weather please?

Rather blocked for a week or possibly two, beyond that who knows. I certainly do not.And the first week of November is hardly a time to get lying snow for more than a few hours anywhere on low ground south of the Border, or am I totally wrong?

You are totally wrong in that no posts have unrealistically micro analyzed charts for deep cold and lying snow or that deep cold and lying snow never happen before well into December.

Other than that I thought you were spot on.

Edited October 30, 2016 by Mucka

[Scandinavian High.]

Colder spell on the way with some cold rain and some wintery showers on the hills nights  will be cold with some autumn frosts too later in the period it stays cold no mild stormy weather on the horizon yet 

[knocker]

This evening's GEFS 6-10 anomaly is pretty much how you would expect to see it having looked at the det. run. Ridging mid Atlantic with a positively tilted trough centred over the UK orientated NE-SW so supporting the forecast of some somewhat inclement and cool days. Also to note the Canadian vortex is tending to phase with the Aleutian low and the whole pattern is certainly introducing some warm air into the north of N. America and to a lesser extent the western Atlantic. A quick glance at the 10-15 shows Mid Atlantic ridge still and the neutrally tilted to the east but best left until a chance to look at NOAA and the ecm

 

 

Edited October 30, 2016 by knocker

[Summer Sun]

The 12z ensembles give Inverness the best chance of snow

Further south we see more cold runs than mild runs to the 8th beyond its a bit of a split

[Ali1977]

Great 144 chart from the ECM, cold is incoming from the NE and seems to have more chance of getting in compared to the GFS . 

-16c uppers in Scandy is pretty impressive so early in Nov.

Edited October 30, 2016 by Ali1977

[SMU]

Yes

looking at the UK 144 & 168 chart

sleet & snow showers possible over the higher ground on bonfire evening of the NE

At 168 I still think the eastward progression of the atlantic looks over cooked -

The word 'Slider' may be in the discussion points tomorrow!

S

 

 

 

Edited October 30, 2016 by Steve Murr

[Matthew.]

The ECM 12z has the Low across the UK on Friday ending the higher pressure spell after weeks and then drags cold air through as the Low moves east. Exciting upper air temps for next Sunday. 

[Mucka]

4 minutes ago, Steve Murr said:

Yes

looking at the UK 144 & 168 chart

sleet & snow showers possible over the higher ground on bonfire evening of the NE

At 168 I still think the eastward progression of the atlantic looks over cooked -

The word 'Slider' may be in the discussion points tomorrow!

S

 

 

 

144 comparison shows ECM siding more with GFS than UKMO on that front but UKMO has modeled the North Atlantic sector very well so we will have to wait and see if it pans out that way again tomorrow and if you are onto something.

Edited October 30, 2016 by Mucka

[Frosty.]

At T+192 the Ecm 12z shows an atlantic depression from the NW crashing in towards and then over the uk subsequently but it's not mild.

Edited October 30, 2016 by Frosty.

[SMU]

Not quite frosty - More like the labrador low...

[Matthew.]

6 minutes ago, Frosty. said:

At T+192 the Ecm 12z shows the atlantic crashing in

It wouldn't surprise me Frosty if that Low  has a similar pattern to the one modelled for Friday with heights maybe building back in the Atlantic. We see tomorrow

Edited October 30, 2016 by Matthew Wilson

[Paul]

Interesting blog from Nick:

Colder & More Seasonal Feel Early November?

[January Snowstorm]

There's a trend in tonight's charts that any atlantic onslaught will be short lived. Heights to our North are re-establishing  by day 8 or 9.

The Met and Ian have called this blocking very well. After years of watching I value his words more than any model.

Put simply I would rather have the met on board than cross model support. They also called the 2010 event well in advance

 

[Frosty.]

Well the Ecm 12z becomes very unsettled but it doesn't look mild at all, in fact it would feel chilly.

[swfc]

ecm altho at day ten is not the atlantic as such making a normal west to east movement ete.the nhp yet again shows waa going up from the eastern seaboard and yet again pressure rising up threw the atlantic.after 40 years of model watching ive not seen seen an oct and running into nov like this!!.