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

[rory o gorman]

06z is far more in line with the ECM mean , Heights building back east and a much more pronounced gradient north of developing surface low.  

[MKN]

4 minutes ago, Harsh Climate said:

Checked this mornings run and we still have the BIG THREE emphatically on board (GFS,ECM/UKMO) with momentum building on a potentially great cold spell! Must admit I was kind of hiding behind my computer seat whilst checking the charts this morning as a downgrade would have been gut wrenching. If anything IMO we have an upgrade, rather than a predominantly dry northerly flow we are now looking at a , more unstable NE flow .

 

My favourite charts of the morning:

ECM 240

This looks very victorian winteresque with the level of cold just gradually creeping up on us with the potential of reloads injecting some serious deep cold over the uk!

 

 

Now I'm sorry but this on the gfs 00z is just sick:

 

one metre of snow in a strengthening easterly gale anyone?? 

With those 850's it would be rain for most

[nick sussex]

Amen to the GFS 06hrs run for not causing any drama with the Azores low!

This is what we want to see, get the block in the right place.

[Harsh Climate]

1 minute ago, coldcomfort said:

06 suggests getting this pattern east is going to be like pulling teeth with rusty pliers, but on the plus side it keeps the Az low at bay and eventually introduces a NE'erly. Interesting times ahead and one that will throw up many more emotional highs and lows before the fat lady eventually bursts into song.

 

I don't know why some folk are so obsessed with having everything further east. Too far east it all falls down, a sharp northerly followed by a collapsing blocking high with milder air rolling in from the northwest, no thanks! We want the greenland high as far west as possible but not so much that we have a west based negative NAO. 

[Polar Maritime]

Turning to nice N/E flow into the run. With frigid cold uppers over the UK allowing temps to drop to -10/12c.

 

Edited January 7, 2016 by Polar Maritime

[Eskimo]

For some posters, It's almost as if they didn't witness the warmest November and December in umpteen years. The prospect of ANY cold should be exciting, regardless or not it's 'dry'. 

GFS 06z far better this morning than the 0z.

Edited January 7, 2016 by PerfectStorm

[Ben Sainsbury]

2 minutes ago, SnowTornado said:

With those 850's it would be rain for most

I suppose for a time, on the northerly flank there would be snow, be as it makes way inland, it would readily turn to rain, esp lower ground.

[karlos1983]

1 minute ago, nick sussex said:

Amen to the GFS 06hrs run for not causing any drama with the Azores low!

This is what we want to see, get the block in the right place.

Yup, does exactly what we want it to do, it hasn't chucked anything out. So bearing in mind the Extended ECM and now the 06z, it seems that it is more unlikely than likely. Still, the cold has been watered down in the shorter term quite significantly and when it arrives. 

[tight isobar]

[nick sussex]

Just now, Harsh Climate said:

 

I don't know why some folk are so obsessed with having everything further east. Too far east it all falls down, a sharp northerly followed by a collapsing blocking high with milder air rolling in from the northwest, no thanks! We want the greenland high as far west as possible but not so much that we have a west based negative NAO.

No you can have a more central or eastern based negative NAO, this doesn't mean that the high will collapse.

Keep wishing for this western pattern set up and I can guarantee you it will end in tears. Get a strong block in the right place and good things will happen!

[Harsh Climate]

5 minutes ago, SnowTornado said:

With those 850's it would be rain for most

 

Nonsense on face value that would be very heavy snow for north midlands/northern england 100% guaranteed. The evaporative cooling alone in such precipitation would be imense!

[BLAST FROM THE PAST]

Well 06z trumps 00z with what is simply a stunning run with GHP and Atlantic ridge in total and utter charge, how many more stunning runs before reality is confirmed?  Whatever reality will be

Snow event with shallow channel low.  The following chart is 'FREEZING' with I suspect bucket loadss of snow

I mean...come on

 

BFTP

Edited January 7, 2016 by BLAST FROM THE PAST

[karlos1983]

Nice black hole

 

[tight isobar]

Well....that wait of turn may well be worth it!..

Dramatics unfold and we end up in a far better place than perceived. 

The evolution unfolds and veer's and east/north easterly inflow. ...

[Polar Maritime]

Much stronger ridging over Greenland prolonging the cold. Excellent runs this morning, Don't get hung up on snow detail..

 

Edited January 7, 2016 by Polar Maritime

[Nick L]

3 minutes ago, Harsh Climate said:

 

Nonsense on face value that would be very heavy snow for north midlands/northern england 100% guaranteed. The evaporative cooling alone in such precipitation would be imense!

That chart would be too windy for evaporative cooling. You need conditions as calm as possible to minimise mixing.

[Harsh Climate]

8 minutes ago, Harsh Climate said:

 

Nonsense on face value that would be very heavy snow for north midlands/northern england 100% guaranteed. The evaporative cooling alone in such precipitation would be imense!

 

And to back up my point on new years eve 2002 we got 1 foot of snow between around 9pm-3am with uppers of between -3 and -1 !!

 

Obiously it quickly melted the next morning as + uppers moved in.

Edited January 7, 2016 by Harsh Climate

[PolarWarsaw]

The low plays ball on this run...but as far as I can see, each run that gets closer to the time frame, waters the cold uppers out and delays them coming in.. the ECM last night and a couple of other runs in the last 48 hours had -7 uppers down over the centre of the spine of the country by Tuesday...then last night it's Wednesday...now it's Thursday and even then - they are modified. 

Not to be negative, the runs are very good - but these small features shouldn't go un-noticed. Its another very good run. But as far as I can see the main trend for today so far seems to be;

- Delay of the proper cold getting in.

- Snow chances reduced for the south/centre of England

- Colder uppers being modfieid to make things more marginal..

ONE HUGE Tick for the 6z..

- The low plays ball (thank god). 

 

 

9 minutes ago, PerfectStorm said:

For some posters, It's almost as if they didn't witness the warmest November and December in umpteen years. The prospect of ANY cold should be exciting, regardless or not it's 'dry'. 

GFS 06z far better this morning than the 0z.

 

Wrong. 

 

If someone said to me... I'll give you a 3 day cold spell, with temps hovering just on the marginal bracket, but you will get 2 systems that produce 5cm and then 8cm of accumulating snow...or I get 10 days of ice days, that are sunny and frosty but don't bring snow to anyone bar coast fringes and Scotland then I would take the first one with my eyes closed, enjoy it and then search for another spell. 

The greater majority of people want SNOW, not cold and frost. 

[london and south east kent]

The low coming up from south west has trended south then pulls Easterly wind in for the south there could be a some snow for  southen England..

 

 

[Polar Maritime]

Way out in the run, But it's nice to see the Highlands touching -14c   Fabulous 6z extending the cold again throughout the run. 

 

Edited January 7, 2016 by Polar Maritime

[carinthian]

37 minutes ago, nick sussex said:

You make a good point. The ECM low is too deep and the angle isn't great, this will mix out too much of the cold. You need to see a more oval low running further south and exiting over northern France not the North Sea.

 

 

Hi Nick, just been speaking to our snow portal service, they think that low just off the south of England to engage the colder air to the north may well go further south now, possibly into Northern France with  snow risk increasing across Southern England. All in all this would be the best option to prolong or even increase the cold. Western Alpine regions should have some good snowsfall early next week and transferring to the Eastern Alps later. We have forecast here of 50cm fresh snow by Friday am. Looking good, with the jet now going below 50N and there it best stays. Best see where tonights charts plot develop that snow potential for Southern England .

 C

[Nick L]

Just now, Harsh Climate said:

 

And to back up my point on new years eve 2002 we got 1 foot of snow between around 9pm-3am with uppers of between -3 and -1 !!

 

Obiously it quickly melted the next morning as + uppers moved in.

Yes, but with considerably lighter winds. Evaporative cooling cannot happen to a sufficient enough level when winds are strong. If you want to read further I put a guide together on this subject...

 

 

[Ben Sainsbury]

1 minute ago, abbie123456 said:

The low coming up from south west has trended south then pulls Easterly wind in for the south there could be a some snow for  southen England..

 

 

I saw this myself, certainly looked intriguing, yet so marginal! 850's hovering on the -5'c mark, battleground!

[nick sussex]

The GFS 06hrs if offered should be grabbed with open arms. The upstream pattern at T240hrs is a cold lock in as another high will move in as the pattern amplifies over in the eastern USA.

[johnholmes]

To answer one or two negative ideas about the upcoming cold spell.

Yes it is coming, yes it will be cold and yes some will see snow. The synoptic models almost always change from run to run as they converge on the actual weather. It happens throughout the year but is highlighted during the winter as folk search for their ideal cold and snow set up.

My use of the anomaly models does draw criticism at times but not to worry. As a retired professional I feel that using these, never on their own but looking at everything we have available on the free web, does allow for a more balanced view at times.

They, the 3 I use, have consistently, cross model and with each of their own outputs shown what the upper air pattern will be from about this weekend and, initially, for 3-5 days beyond that. Over the past 48 hours they have extended this slow moving pattern to suggest ‘cold’ may well last out to at least 21/22 January.  I never attempt to predict beyond 2 weeks or so. Detail of this will not really come from the anomaly charts although careful use over a long period does allow fairly decent forecasts to be put together. Currently NOAA 6-10 and 8-14 shows a fairly stationary wavelength, the ridge out west around 35-40 west with the trough fairly well east of the UK. This does look like not allowing any Atlantic breakthrough, as a few suggest will happen, well into January. Once this type of block sets up then with quite deep cold air only moving slowly any attempt to push through it is often slower than any model or human prediction suggests. Not always the case of course and the clever bit will be getting that breakdown correct.

In the meantime the series of Fax charts from UK Met shows that the arrival of ‘cold’ is a rather complex feature, (link below as are those for the anomaly charts). Their latter ideas T+120 onwards may well undergo some changes as is always the case with any weather pattern.

How much snow, how cold are questions to gleen from the models and Fax charts or indeed DIY using some of the tools available if we use ideas from the learning area on Net Weather.

I have lost count of the number of times I have urged caution in trying to predict snow falling. It is immensely complex with the first one getting PPN over your back garden to start. There are then approximately 6 maybe 8 other variables to factor in. Fun trying it so have a go. I cannot remember the Guide I posted in the learning area but I am sure someone will post it.

To repeat, don’t worry in the near time frames, say out to 120 hours of the models, upgrading/downgrading, they do it all the time throughout the year. The Atlantic will not roar in for 10-14 days at least, so enjoy the weather if you like cold and keep your fingers crossed you get some snow. Showers/frontal, whatever.

Cheers

Fax charts

http://www.weathercharts.org/ukmomslp.htm#t96

Anomaly charts

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

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

some of you may like to try this?

 

 

Edited January 7, 2016 by johnholmes
adding a link