Model Output Discussion - 30th November onwards

[Cecil Hogmanay Melchett]

Well there is at least better agreement on the end of the week as you would expect as it moves to 4/5 day timeframe, a short northerly blast with snow showers for Scotland and the NE.

 

Beyond that it isn't a typical toppler but talk of a Scandi High, or at least a Scandi High that can influence the UK is very fanciful with so much energy in the Northern arm. 

Yes,i think a standard toppler will be prevented as the low will dive into Europe.

Whilst not ideal we may well end up with some kind of UK high as ECM shows which will bring cold frosty weather for the UK.After that who knows...

Edited December 1, 2013 by happy days

[Ian Brown]

Interesting developments post Northerly but im not sure the models have the correct setup with the Northerly yet.

The stronger the flow(tighter isobars the better).

From an IMBY point of view its gone a bit pairshaped over the last 24 hours with more of N/NNWy which maywell leave the spine of the UK mainly dry.

All depends on troughts etc in the flow i guess...

 

There isn't time for anything to get going shower wise on the Western side of the UK apart from NW Scotland and maybe N Ireland for a few hours.

[phil nw.]

It does like reasonably good agreement this morning from the main 3 for a notable but short northerly before the block rebuilds towards W.Europe/UK area.

Looking at the UKMO outputs for the next 5 days, including the fax's, we can see the changes coming in behind 2 cold fronts as the High is split and regresses back into the Atlantic.

 

First at T72hrs and then T120hrs.

 

 

 

That's a remarkable depth of cold just to our north being modeled with -14C uppers for Shetland!

A short but very cold Arctic outbreak coming right through by the end of the week before it get's cut off by a rebuild of pressure.Snow showers and bitter winds for many,especially further north and exposed coastal areas.

Continuing surface cold would keep daytime max's low with widespread night frosts in the following days as the high rebuilds.

 

[BLAST FROM THE PAST]

 

Most important chart of the day this.with that LP staying west of the southern tip of Greenland...UKMO is definitely onside with ECM....so if it maintains then well done to ECM and those that saw through the mirk.

Second, nice to see Dave aka TEITS posting again, always look out for his posts as another who 'feels' and 'reads' beyond the models.

Thirdly, polar low is possible feeding down of the west coast of Norway...but we won't know until its developing.

Fourthly, how the hell I can post charts again....I have no idea...but who cares I can!!!!

Fifthly, I agree with Nick Sussex, interesting beyond.  I think we have a slow burning pattern building here and we will get to a point where it will suddenly come upon us.

 

That is going to be a really cold blast on the weekend, and ....well lovely!!

 

BFTP

[bluearmy]

Well there is at least better agreement on the end of the week as you would expect as it moves to 4/5 day timeframe, a short northerly blast with snow showers for Scotland and the NE.

 

Beyond that it isn't a typical toppler but talk of a Scandi High, or at least a Scandi High that can influence the UK is very fanciful with so much energy in the Northern arm. 

 

day 10 will see a ridge over n scandi.  

 

naefs 00z shows a developing sceuro block of some size. forget zonality - it isnt going to happen for a while yet.  the runs which show it are notable by their inconsistent occurence.  no appetite on the 850  naefs spreads to advect deep cold our way. height spreads show the block getting further north rather than sinking.  that means a wide spread of surface solutions for us - most of which are cool/cold although a pleasant southerly flow cannot be ruled out. 

[SMU]

45 northeasterly 90 easterly and so on. Was it a rough night?lol

Yes square eyesSo the mean is actually getting less zonal at the endInteresting that wind chart would be better to analize trends that the 500 mean...Cheers

[BLAST FROM THE PAST]

 

Ian B 

I take it the chart you posted re very poor set up going forward has updated and didn't show this????

 

BFTP

[Purga]

Better all round this morning form the NWP with GFS as follows:

 

 

ECM

Even finishes with the hint of an easterly

UKMO better as well

 

The Eye in the Flointment however, is the ENS which paint a strongly mild picture after the cold snap

 

 

 

Although the 2M Mean does show that the surface may not be too mild i.e. , 10C at ground level in the south.

The North could be much milder if the synoptics are to be believed.

Edited December 1, 2013 by Purga

[Summer Sun]

Once again this morning the ECM gives 3 days of -5 or lower (-10 for Scotland) 850's before they start to relax

 

 

The GFS ensemble also shows a few cold days before a rise in the 850's albeit quicker than ECM

 

[Cecil Hogmanay Melchett]

There isn't time for anything to get going shower wise on the Western side of the UK apart from NW Scotland and maybe N Ireland for a few hours.

ECM precip chart shows moderate snow across MUCH of NW Britain Thursady evening.

Edited December 1, 2013 by happy days

[That ECM]

Well there is at least better agreement on the end of the week as you would expect as it moves to 4/5 day timeframe, a short northerly blast with snow showers for Scotland and the NE. Beyond that it isn't a typical toppler but talk of a Scandi High, or at least a Scandi High that can influence the UK is very fanciful with so much energy in the Northern arm.

Nearly unnoticed but biggest revelation of the morning. Not a toppler/ typical toppler!! Only joking IB.

[Polar Maritime]

It will still be cold Gav, not as cold but still cold. Look at the surface temps for the 9th...

 

[Snowman.]

Better all round this morning form the NWP with GFS as follows:

 

 

 

 

ECM

 

Even finishes with the hint of an easterly

 

 

UKMO better as well

 

 

The Eye in the Flointment however, is the ENS which paint a strongly mild picture after the cold snap

 

 

 

 

 

Although the 2M Mean does show that the surface may not be too mild i.e. , 10C at ground level in the south.

The North could be much milder if the synoptics are to be believed.

I would just ignore the Ensembles until we get the GFS on board with another model.

[nick sussex]

The GFS 06hrs run at T42hrs is already slower upstream, perhaps another small step towards the Euros, hopefully a better northerly than on the 00hrs run.

Edited December 1, 2013 by nick sussex

[cooling climate]

Great to see the ECM called this one correctly restoring my faith

in the model somewhat. Quite a potent northerly with one or two ice

days for many especially in Scotland.

Some lucky locations will also see some snowfall with snow showers

for others should give a covering.It would be nice to see the pattern

back a couple of hundred miles west as we go through the week but I

would rather take what it is showing now than have the pattern even

further east.

The ECM t240 chart looks very promising for heights to build in the

Atlantic north pulling in the cold uppers from the east perhap.

[Weathizard]

I don't see much to be that excited about in the charts, is it just me? I mean it's looking good for a day or so cold snap before high pressure builds again from the west and temperatures return to normal or just below.

I think we are pretty much stuck in a mid-latitude blocking situation until something significant changes, I certainly don't see any prolonged cold in the next two to three weeks.

[Cecil Hogmanay Melchett]

The GFS 06hrs run at T42hrs is already slower upstream, perhaps another small step towards the Euros, hopefully a better northerly than on the 00hrs run.

Yup,my goodness GFS is getting dragged kicking and screaming with this one.

Talk about dragging you feet!!

[lorenzo]

Bone chilling blast of cold, sharpest of the Northerly hits so far, great to be seeing proper wintry looking output on 01st December.

 

 

Satellite will definitely be worth a watch for non NWP features going by the 500hPa temp profile. Stunning. 

 

Out to mid month and commented on by Nick wrt NAEFS anomaly, the ECM control run in FI also parks this Scandi/Euro Block.

 

Which would lead to another spell of good model watching, with NWP notoriously wobbly in modelling strong cold blocks, with the addition of frontolysis and fronts getting chewed up. How much colder can this weeks blast get...

 

 

 

[johnholmes]

Well there is at least better agreement on the end of the week as you would expect as it moves to 4/5 day timeframe, a short northerly blast with snow showers for Scotland and the NE.

 

Beyond that it isn't a typical toppler but talk of a Scandi High, or at least a Scandi High that can influence the UK is very fanciful with so much energy in the Northern arm. 

looking at how the anomaly charts are showing Ian the output from NOAA would tend to suggest no marked sign of any ridge or even +ve anomalies into Scandinavia after the cold shot, and that looks about 3 days, +/- 2 say. However the other two ECMWF-GFS have shown this as a probabiltu over the last couple of days and do go for it in quite a marked way this morning, see link below. To me there is not enough continuity between these 3 outputs to be sure of what is goingto happen 10-14 days down the line after the cold snap but it is something to watch. Or at least it is for me on the anomaly side of things.

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

the anomaly charts were also quite good in terms of making a reasonably early solid call by Wed 27 November for this cold spell. These are the notes I made Wednesday morning. There had been some indications even before that but not with enough continuity for me to take them as read.

IF these things continue as they seem to be proceeding over the last 2-3 days for the next 2-3 and with a meridional flow looking more coherent over the states with a subsequent effect down wind over the atlantic towards the uk then a colder spell would develop. To me it would be a fairly short lived spell 2-4 days perhaps, unlikely to be a week or so. Why? The +ve areas show little if any sign of migrating into the Greenland/Iceland areas but stay over the atlantic south of 60n. This rarely leads to anything more than a shortish cold spell.

Timing currently IF all the pieces fall into place would be about 10 days from now?

Edited December 1, 2013 by johnholmes

[Summer Sun]

Looking at ECM there is a 2 day window for snow before high pressure moves in

 

 

By Sunday pressure rises so still cold but more settled

 

 

GFS has snow for Scotland and some western parts the rest of it stays in the north sea though some coastal districts could catch some wintry stuff at times

 

Edited December 1, 2013 by Summer Sun

[Cecil Hogmanay Melchett]

Thursday is going to be an interesting day as the 528 DAM line sweeps south easterwards.Plenty of precip about i wouyld imagine rain turning to snow as the day goes on with places with decent elevation 200m could see some accumulations.

[cooling climate]

Watching the GFS 06z run come out it is like watching a different model

compared to its runs yesterday as we can now clearly see the back track

by the GFS with the Atlantic high now ridging north as the low off the

coast of the US traves north rather than east/northeast.

The 06z is actually a bit more amplified with the low slightly further

north and held back east more. That is a very potent blast of Arctic air

with the pattern slightly further west.

T126 and -12c uppers all the way down to the se corner of

the country.

Edited December 1, 2013 by cooling climate

[SMU]

GFS 96 06 z is finally there...

All the way around to the ECM - its only taken 5 days.....

Watch a very quick shift in the next 18 hours of the gfs ensembles and watch much quicker the scandi heights suddenly appear....

From this fiasco of the gfs if you look at ensemble watch the worst run has been the12z gfs which has been flat and wayyyyy to far east- which underpins the assessment of it having a strong eastward bias.

I do and explain the rationale and what it all means- I guess people just ignore it.

S

Edited December 1, 2013 by Steve Murr

[tight isobar]

Gfs 6 z and finaly It's on board!!, be intresting to see how latter frames play out...scandi block...!!

[Polar Maritime]

-12 uppers getting into the Midlands and the S/E. A real shock to the system...