Model Output Discussion - Into November 2019

[feb1991blizzard]

1 minute ago, MattStoke said:

Winter starts and, as if by magic, the northern blocking, that has ruined the past several months but would have brought significant cold and snow in winter time, disappears.

True but the only thing i would say is it is not by magic, its because of the polar night, it creates a strong temperature gradient between the pole and the low latitudes which fuels a strong jet.

[northwestsnow]

16 minutes ago, weirpig said:

Looks a mobile first half of December 

It is looking incresingly like a mobile spell of weather is going to be unavoidable...

The EC mean is pointing that way too.

I'm far from convinced in seasonal modelling so i would say a quieter few days this week, moreso further north,followed by an unsettled phase lasting minimum of 10days is a decent shout,as it stands.

Edited November 19, 2019 by northwestsnow

[weirpig]

1 minute ago, northwestsnow said:

It is looking incresingly like a mobile spell of weather is going to be unavoidable...

The EC mean is pointing that way too.

I'm far from convinced in seasonal modelling so i would say a quiter few days this week, moreso further north,followed by an unsettled phase lasting minimum of 10days is a decent shout,as it stands.

Yep I'll go along with that  maybe a couple of wind storms  which has actually been quite sparse this autumn    still too early imo  for most who crave the white stuff 

[northwestsnow]

Just now, weirpig said:

Yep I'll go along with that  maybe a couple of wind storms  which has actually been quite sparse this autumn    still too early imo  for most who crave the white stuff 

Yes, i'm not convinced of anything as far as December is concerned, still too early.

My fear is heights getting entrenched across S Europe if i were to be honest,and its probably the favourite ..

We do know the zonal winds are forecast to drop off for a while so perhaps there is scope for the MJO to play a part.

 

[Ali1977]

Another cold shot showing later in Nov, 850s not updating but I imagine cold enough for Winfrey showers , especially northern high ground 

[knocker]

The North Atlantic 500mb and surface analysis for midnight and the Camborne sounding which illustrates the frontal cloud arriving above the dry zone

Quite a severe ground and air frost in many areas accompanied by thick fog, mainly concentrated in east Wales and central and eastern parts of England Which will be slow to clear.After it does much of England and Scotland will be sunny. But as can be seen cloud and rain are on the way, courtesy of the slow moving occlusion, and will effect N. Ireland and the far west through the day

Tonight still some patchy fog and frost around in the east but cloud and sporadic rain has encroached more areas in the west so no frost

Tomorrow much the same picture with eastern areas remaining dry, perhaps with more cloud, with the patchy rain continuing in the west,  But the wind is picking up as the trough becomes negatively tilted as it is squeezed by the energy hitting the block

The squeeze continues through Thursday and heavier rain will effect N. Ireland, Wales and the south west from the occlusion associated with a now quite complex area of low pressure. Showers may also effect the north east coast of Scotland in what is now quite strong south easterly wind

By Friday a complex wave has developed in the south east quadrant of the trough and this will bring some heavy rain to the south west although it is warming up a tad

The low creeps north east through Friday night and Saturday and the associated occlusion will bring rain to much of the country

 

Edited November 19, 2019 by knocker

[knocker]

According to the gfs continuing unsettled and windy through the beginning of next wek and then it goes on to develop the Euro trough so without seeing the GEFs I'll leave it at t168

[knocker]

To some extent the ext GEFS supports this with defamation of the vortex courtesy of a ridge extending into the Arctic and thus a trough aligned south to the north of the UK, albeit retaining the extension to northern Canada adjacent to the Greenland ridge So still a strong westerly upper flow south of this across the Atlantic portending unsettled with temps around average

[knocker]

A quick glance at the EC weekly update for the period 10th December -01st January

Salient points

The first week split vortex with the main lobe northern Canada and trough to the north west of the UK; Strong westerly upper flow with temp a tad above average

Second week no significant change but perhaps temp nearer average

The third week some retrogression of the trough with the Azores high sniffing the coffee and temps a tad above average

 

 

 

 

[Ali1977]

20 minutes ago, knocker said:

A quick glance at the EC weekly update for the period 10th December -01st January

Salient points

The first week split vortex with the main lobe northern Canada and trough to the north west of the UK; Strong westerly upper flow with temp a tad above average

Second week no significant change but perhaps temp nearer average

The third week some retrogression of the trough with the Azores high sniffing the coffee and temps a tad above average

 

 

 

 

I’m hoping this makes the Azores high choke on the coffee, not sniff it. It’ll be I retesting to see if the long range updates start hinting at possible effects (not guaranteed) of a warm up in the Strat. 

[mb018538]

Nice to see the main lump of the vortex isn't in its usual spot to our NW. All eyes on the warming event now, looks like staying unsettled in our neck of the woods for quite a while longer yet.

[Jordan S]

Morning. 

Using the Gfs and Gem mainly for this update.. So a snapshot below 3 timestamps.. 

GFS for Friday..

Sunday 24th..

Tuesday 26th..

Friday 29th..

Finally 1st December unreliable time frame but shows a classic vigorous low pressure system pushing quickly northeast across the north Atlantic grazing Scotland and sending an active cold front towards the UK with gales for the far northwest of Scotland and Northern Ireland..

An impressive Wind gust chart..

Now the Gem..

Friday 22nd..

Sunday 24th..

Sunday evening..

Tuesday 26th..

Friday 29th..

If we blend Ecmwf the Gem and Gfs average output together this is the synoptics shown.. 

Monday 25th..

Friday 29th..

Good agreement for southerly tracking low pressure systems bringing plenty of rain with a risk.. only a risk at this stage of a particular spell of very strong winds for more southern areas towards the end of the month but uncertainty as expected.. Higher pressure towards Greenland and a displaced Azores high keep the unsettled conditions locked further south than would typically be expected. 

So Gfs for the next few days out to around a week in more detail.. 

Continuing drier than recently for most parts of the UK the exception being the far southwest of England and Wales with rain effecting here and perhaps fringing into Scotland later today for a time with a frontal system stalled out to the far west this is expected to push back further west into Ireland by tomorrow evening as high pressure over the continent exerts more influence.. What this does is strengthen southerly winds.. 

This evening and tomorrow..

Thursday winds turn more to the southeast as the rain out west pushes slowly northeast later in the day with the blocking high to the east of the UK allowing this rain to make more progress. dry to start though for northern and Eastern areas.. 

Into Friday the band of rain becomes confined to Scotland and northeast England elsewhere turning mostly dry with sunny spells and milder than recently as winds blow from the south the winds then start to turn to the southeast again as the centre of low pressure slips southeast as it isn't able to push into the north sea and fills because of the blocking high out east still has enough of an influence to deflect this to the south like I mentioned..what this process does do is push an area of rain back northwest to southwest England later in the day..

Friday morning and Friday night..

Saturday morning more rain pushes up from the south giving a very wet day to England and Wales drier for Scotland and Northern Ireland for a time.. 

Saturday night the rain becomes confined to Eastern Scotland turning dry elsewhere.. The centre of low pressure fills to the south as shown below..

Sunday night into Monday morning on the image below a very active frontal band of rain pushes into much of the west of the UK the stubborn high pressure to the east of the UK has now eased away to allow this rain to push in with more momentum.. some of this rain shown to be very heavy particularly for the southwest of England even torrential locally and this then pushes fairly quickly northeast giving a very wet start to Monday windy too with this rain but then it turns much drier from the west with only a few showers still mild.. 

25th..

Wind gusts.. 

Staying unsettled into next week potentially very windy for southern England during the middle of next week with yet more rain but drier spells too staying mild.. 

Remember this is just a snapshot of what the Gfs is showing the very wet conditions are likely but detail especially for next week is subject to change and shouldn't be taken too literally but it gives you a general idea of what conditions to expect..

5 day maximum and minimum temperature expected over the next 5 days.. Mild by day and milder at night too after tonight's cold night which is responsible for why the 5 day minimum temperature is showing as low as near or around freezing and below for Scotland.  

Edited November 19, 2019 by jordan smith

[Kentspur]

Although I wasnt impressed with the likes of ECM I found some positive aspects on some of the "lesser models" Here the GEM the JMA and The Russian model have some "potential," meanwhile the GFS 0z ensembles have some cold options further along- the Op run has a little support it seems

Edited November 19, 2019 by Kentspur

[carinthian]

UK fax puts a real squeeze on the fronts towards weekend. Could be some significant rainfall for the SE on Saturday .Most models seem to suggest the next Newfoundland Lows will make  further in -roads into the buffer out East.. However, again its noted put back another 24 hours. Seems to be the trend. GFS and ECM have a different picture at 240t but maybe best not looking further than 96h as changes seem slow.

C

[bluearmy]

Ec cannot get the low heights east of the meridian south of 70N and ukmo looks unconvincing re the Atlantic ..... the block’s last hurrah or has its demise been overstated ????

[IDO]

9 minutes ago, bluearmy said:

Ec cannot get the low heights east of the meridian south of 70N and ukmo looks unconvincing re the Atlantic ..... the block’s last hurrah or has its demise been overstated ????

Yes, the ECM stalls the westerly flow around T192 with a height rise over the Eastern Canadian seaboard enabling the Euro block to hang on for longer:

EC D8>EC D10>

The GFS has a flatter upstream enabling the westerly flow to keep the pressure on and slowly easing the block away:

GFS D8>GFS D10>

The GEFS have a good cluster aligned to the ECM outcome, so we could be in for a further delay of this unhelpful pattern. The ECM mean at D10 suggests the main cluster supports the op:

Neither scenario really excites me so Que será, será.

[jules216]

Just now, IDO said:

Yes, the ECM stalls the westerly flow around T192 with a height rise over the Eastern Canadian seaboard enabling the Euro block to hang on for longer:

EC D8>EC D10>

The GFS has a flatter upstream enabling the westerly flow to keep the pressure on and slowly easing the block away:

GFS D8>GFS D10>

The GEFS have a good cluster aligned to the ECM outcome, so we could be in for a further delay of this unhelpful pattern. The ECM mean at D10 suggests the main cluster supports the op:

Neither scenario really excites me so Que será, será.

Somehow I now hope for GFS to verify then ECMWF which once again brings cut of low and stalls it around UK. This will only serve to prop the Euro high again. I would rather have the Azores high bring a temporary NW flow when aplified, as Euro high and cut of low will never ever deliver anything.

[knocker]

No significant changes with ext EPS this morning

Salient points

Vortex north Russia with trough extensions to north of the UK and north Canada with the latter still adjacent to the Greenland ridge,

Still a strong westerly upper flow exiting the eastern seaboard south of this across the Atlantic via an anomalously negative trough mid Atlantic to the UK

The block in the east now eroded

This indicates unsettled with temps a tad above average

 

Edited November 19, 2019 by knocker

[mb018538]

35 minutes ago, IDO said:

Yes, the ECM stalls the westerly flow around T192 with a height rise over the Eastern Canadian seaboard enabling the Euro block to hang on for longer:

EC D8>EC D10>

The GFS has a flatter upstream enabling the westerly flow to keep the pressure on and slowly easing the block away:

GFS D8>GFS D10>

The GEFS have a good cluster aligned to the ECM outcome, so we could be in for a further delay of this unhelpful pattern. The ECM mean at D10 suggests the main cluster supports the op:

Neither scenario really excites me so Que será, será.

Big Siberian High/Aleutian Low combination though....let the warming commence!

[Blessed Weather]

Looking at the ECM and GFS 3-day mean NH 500hPa heights anomaly from 26th to 28th November there's some significant differences between the 2 models. ECM much stronger with heights to our north, running from Greenland through to Siberia, with Atlantic trough and Jetstream further south. ECM also showing the opposite heights to GFS over the US.

To me the chart also suggests that ECM is being more consistent with it's synoptic pattern output over the 3 days, with the muted anomalies shown by GFS indicative of output that has varied run-to-run, with height variance cancelling each other out to some extent?

3-day mean anomaly:

Latest NH for 29th Nov and ECM again consistent with its 3-day mean:

ECM  GFS

[Methuselah]

Hardly the most snow-laden of GEFS 00Z ensembles, this morning?

Never mind, though -- just keep calm, everyone? 

[johnholmes]

The major change in the 500 mb anomaly charts I use is the return on all 3 to a marked trough/low close by the UK rather than the tentative suggestion of ridging that I showed on them I think on Saturday but also that NOAA did not, nor subsequently, go for this idea.below is what I posted on Saturday

Saturday 16 november

I wonder if the ec-gfs this morning is a ‘real’ signal for something of a change in pattern? Gfs is really the only one yet to show +ve heights and ridging rather than marked/deep troughing affecting the uk, ec, so far, has just changed to troughing to a much weaker looking flow with the +ve heights and ridging much as before. No sign of last evening noaa changing to this though, but it has very little sign of the contour ridging sw of the uk it had a week ago, so watch and wait for a couple of days!

So the latest outputs shown below do seem a better representation of what the upper pattern may  be in the next 6-14 days? All along NOAA has kept the idea of +ve heights in a band from N Norway across Greenland into NE America/Canada, along with the Atlantic flow into a marked trough/low as shown on the latest. This of course has changed in shape, depth and position over the past week.

So to me the outlook is for changeable rather than settled in the broad scale with details to come from the synoptic models closer to the time frame. 

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Jordan S]

42 minutes ago, Ed Stone said:

Hardly the most snow-laden of GEFS 00Z ensembles, this morning?

Never mind, though -- just keep calm, everyone? 

Anyway didn't post the Ecmwf as it hadn't updated when I posted earlier but it seems to keep pressure higher to the east for longest at the end of this week into next which indicates frontal systems next week may be slower moving for a time. 

25th..

27th..

29th..

Gem ensembles.. Big spread showing up but some very mild ensembles in there the signal that's most consistent is most definitely the rainfall. Very unsettled. 

Edited November 19, 2019 by jordan smith

[northwestsnow]

^^

Grim viewing, EC looks like locking us into a very zonal pattern this morning.

The million dollar question is for how long...

[Frosty.]

No sign of anything wintry on the Ecm 0z ensemble mean, indeed the trend is milder and staying unsettled..which has been the case for days now.