Model Output Discussion - 05/01/2016 18z onwards

[chris55]

differences between the big three at 120  not huge but significant for our patch.

 

[BLAST FROM THE PAST]

Well models settling towards cold extending on.  For me correct.  

 

 

Great UKMO and ECM not too dissimilar and the crucial point for me. ECM continues to move the HP east but remains cold.  I'm thinking any higher pressure will be transitory and that we'll end up being a under very deep trough situation bringing air from arctic origin [where it places itself eg over us or just to our east of note ].  I think HP will remain in Greenland locale thus PV remaining disrupted/displaced,  but I'm seeing enough now that the models have got over their 'destroy the cold' wobbles and we move towards a very wintry period for the UK.  It remains that my thoughts for first half of Feb being in coldest part of winter remain, so onwards and upwards and enjoy the ride.

 

BFTP

 

 

BFTP

[Polar Maritime]

So the N/W flow wins out into week 2 and continuing cool, Just look how far South the Jet is over the Med pulling the cold air with it. Where will it go..

Edited January 10, 2016 by Polar Maritime

[Northern Sky]

Yes I agree IDO. The GFS has certainly been consistent while the euros have moved back and forth with their output to a greater extent. I've been watching the models for a few years now and I've seen the GFS out on its own a few times - sometimes it has a shown a dogged determination to stick to an incorrect solution right up to within T72hrs and at other times has led the way with the right outcome against all the other models.

The vast majority of the time we get a compromise, which is probably what will happen again.

[nick sussex]

Well reading some of the NCEP state discussions it seems that the UKMO has not gone completely mad this morning.

Although they don't refer to it specifically the actual expected pattern does lend support for the troughing to the west to sharpen up in response to more amplitude upstream.

They expect the pattern to flatten out temporarily before re-amplifying by next weekend with an eastern USA trough. The differences are really the degree of amplification and different handling of shortwaves running east between the respective outputs.

[Liam J]

Some very cold nights and some ice days on the GFS from Thursday to Sunday before the cold starts to get moderated into the start of next week as we lose the colder 850's with a flow from S/SW, frosts becoming less widespread. The far W/SW & NW close to double figures by Tuesday.  So 4/5 day cold/very cold spell before turning slowly milder, hope the ECM is nearer the mark keeping us cold out to day 10. 

 

[IDO]

10 minutes ago, Polar Maritime said:

So the N/W wins out into week 2, Just look how far South the Jet is over the Med pulling the cold air with it. Where will it go..

I would say of more concern for a sustainable up stream meridional pattern is the trend for the Pacific jet to go into turbo mode from around D6 right through till D16 on the GFS 0z. That dampens any hope (if it is correct) for any blocking to be in situ, more likely any MLB or HLB gets pushed east due to the flattening of the pattern from the upstream jet profile.

D15 jet is super charged now: 

Edited January 10, 2016 by IDO

[Connor Bailey Degnan]

Based on this mornings runs I think we can safely say a cold 'snap' is on the way atleast with the highest chance of any snow Thursday onwards. However, some parts could be disappointed. For snow to fall and settle, realistically you need a 0c dewpoint and upper air temperatures around -5. Based on the GFS 06z we eventually get everywhere into a -5 or below upper and dew points at freezing or below. Thursday is very interesting because we start the day in the east above -5 uppers and as high and 4c dewpoint. This would deliver rain virtually all day during Thursday the further east you go with the highest risk of snow further north and west until eventually during the evening on the 14th we see snow just about anywhere. Things could and probably will change.

[Chris1986]

Hi I'm new here,

I remember 2010 the long cold spell and lots of snow, which I believe was down to a sudden stratospheric warming which to my untrained eye it would appear will be happening over the next week or so. The snow in 2010 was caused by a filament of vorticity sitting over France generating shower trains into the SE. Wait and see I suppose I however believe this cold snap will be more prolonged than first thought. Models especially don't handle the effects of laying snow well with regards to boundary layer temps.

[Rocheydub]

Just now, Chris1986 said:

Hi I'm new here,

I remember 2010 the long cold spell and lots of snow, which I believe was down to a sudden stratospheric warming which to my untrained eye it would appear will be happening over the next week or so. The snow in 2010 was caused by a filament of vorticity sitting over France generating shower trains into the SE. Wait and see I suppose I however believe this cold snap will be more prolonged than first thought. Models especially don't handle the effects of laying snow well with regards to boundary layer temps.

This upcoming cold spell is not related to a SSW. It's tropospherically led.

[northwestsnow]

Just has a good look at gfs6z and the dew points unfortunately remain above zero for most of England and wales until late thur.

Not sure what the other models are showing at the same time but im not convinced gfs is showing snow during late wed into thur for most.

GFS6z does show a period of snow for the midlands thur night  as the colder uppers mix out the mild sector

Edited January 10, 2016 by northwestsnow

[Liam J]

12 minutes ago, IDO said:

I would say of more concern for a sustainable up stream meridional pattern is the trend for the Pacific jet to go into turbo mode from around D6 right through till D16 on the GFS 0z. That dampens any hope (if it is correct) for any blocking to be in situ, more likely any MLB or HLB gets pushed east due to the flattening of the pattern from the upstream jet profile.

D15 jet is super charged now: 

Yes, it's also two weeks away and very unlikely to be modelled correctly at this range, and on the other side of the hemisphere! 

[Ali1977]

Is this strong enough to class as a SSW? 

[Chris1986]

Quite a change in 48h.

[Chris1986]

11 minutes ago, Rocheydub said:

This upcoming cold spell is not related to a SSW. It's tropospherically led.

The stratosphere has a direct impact on the troposphere although we don't fully understand all of the details. Stratospheric warming should cool the troposphere... somehow... I'm not clever enough to know :$

[johnholmes]

I have made a pdf about the anomaly charts and this cold spell upcoming. This will avoid cluttering up this thread with current outputs.

sunday 10 jan 16 pdf.pdf

[Polar Maritime]

Let's please continue in here with what the models are showing please, There is the Stratt thread open for further discussion. Thanks.

[IDO]

5 minutes ago, *Sub*Zero* said:

Yes, it's also two weeks away and very unlikely to be modelled correctly at this range, and on the other side of the hemisphere! 

I disagree. The current EPO ridge is flattened by the Pacific jet at D3 and the relentless turbo charged Pacific jet gets super charged as we move to D13:

D3 turbo charged:  D16 super charged: 

That flattens the pattern further downstream (our locale) and is why the US trough is more inclined to send spoiler shortwaves into the Atlantic and for it also to generally ease the pattern east. That is possibly why the 06z is zonal from D8 to D16 with the PV regrouping (assuming that this is correct).

[Cheese Rice]

I think if you've got a bit of elevation, not much only about 100m then you should do well next week. 

The front pushing through on Thursday could deliver 2-5cm widely.

Current GFS is showing a very significant snowfall for higher elevations a good 10-20cm as the front lingers for 24 hours. But it's too far away to resolve these types of details so for now I'm sticking to 2-5cm.

The GFS/ECM allows the cold to dig in quite well in the south, didn't really think it would with the models trending away from cold establishing itself away from the north

 

 

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Edited January 10, 2016 by Cheese Rice

[PolarWarsaw]

I see a chilly week coming up, some frost, a bit of snow for higher elevations in the north. It looks currently very much like it will be incredibly marginal in built up areas without elevation from Northern England southwards. Next week see's a split between high pressure and frosty nights or a return to a westerly regime. 

Let's hope we see GP's torpedo showing up soon. 

Edited January 10, 2016 by Polar Maritime
To move discussion on..

[Man With Beard]

ECM London ensembles - the first time for days that the main cluster has turned away from major cold in the D10-D15 period. Of course, this is a mile away meteorologically

[phil nw.]

Hi WTO

Welcome,nice first post.

It would be good if you would enter your location in your avatar.

[TEITS]

The outlook is becoming clearer to me. After the potential snowfall at the end of the week, which I hasten to add im not expecting much for my location. I expect next weekend we shall see a settled period with max temps struggling to climb much above freezing and min temps well below in some locations. Thereafter into the following week becomes difficult. I still would not rule out a developing E,ly, but this is an outsider at the moment as high pressure will be unable to build far enough N due to low pressure systems tracking to the NE. More likely is the high pressure slowly sinking being followed by W,lys.

The spanner to the above is the UKMO output because the outlook described could be wrong if the UKMO is right. Still at least after the possible snowfall we should see a drier period which will be a relief to those affected by recent flooding.

[johnholmes]

1 hour ago, Northern Sky said:

Yes I agree IDO. The GFS has certainly been consistent while the euros have moved back and forth with their output to a greater extent. I've been watching the models for a few years now and I've seen the GFS out on its own a few times - sometimes it has a shown a dogged determination to stick to an incorrect solution right up to within T72hrs and at other times has led the way with the right outcome against all the other models.

The vast majority of the time we get a compromise, which is probably what will happen again.

I cannot see how you consider that GFS has been consistent. Take a look at how it has changed with its two main runs 00 and 12 on this site. You pick a date, I chose Sat 16th, and see how it changes?

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&CONT=euro&MODELL=gfs&MODELLTYP=1&VAR=prec&WMO=&ZOOM=0&RES=0&PERIOD=&PANEL=0&ARCHIV=0&BASE=201601100000%26HH%3D144

[carinthian]

32 minutes ago, johnholmes said:

I have made a pdf about the anomaly charts and this cold spell upcoming. This will avoid cluttering up this thread with current outputs.

sunday 10 jan 16 pdf.pdf

Well done John, now I know what you do with your Sunday mornings ! Looks like your thinking the same way of UKMO this morning. One of the Euros/UKMO or GFS will have to eat humble pie sooner or later. Its been great watching the models this weekend. Have to take rest now away from the computer and take my wife for a ski and lunch in the sun. Wish you were with us !

C