Model output discussion 25th Jan - The final third of winter beckons..

[blizzard81]

I will always remember the classic Feb 91 easterly. It all got going on weds Feb 06th. On that particular day I went to Hawes in the Yorkshire Dales to do my A Level geography fieldwork trip. On the way there was more frequent snow showers that got more intense the higher up we travelled. The snow kept building up. There was then a lull with bright sunshine but it was absolutely perishing. I have not experienced wind chill like that to  this very day. As we travelled back home I remember being so excited as I had seen the morning bbc forecast that showed continuous heavy snowfall from Weds night right through to and including  Friday the 8th Feb with temps sub zero throughout. Absolutely magical :). Sorry mods,  I just had to share this. 

[Ali1977]

I like the 20% much colder idea with snow showers 

Edited February 4, 2017 by Ali1977

[Scandinavian High.]

15 minutes ago, Ali1977 said:

I like the 20% much colder idea with snow showers 

I like sound of that Steve murr said earlier give models time and we get upgrade meto update too interesting times ahead.

Edited February 4, 2017 by abbie123

[Guest]

TIME FOR A GOOD "OLD-FASHIONED" LOOK AT THE FAX CHARTS AND THE DEVELOPMENT OF OUR BEAUTIFUL SCANDINAVIAN HIGH PRESSURE      

Those members from my generation were brought up with hand drawn charts. I used to spend many hours as a child studying these and this continued for many years afterwards. I used to cut the charts out from the weather reports in the Daily Telegraph and saved them for about 30 years! I saw many easterlies develop in the 1960s to 1980s - rather rarer these days but one looks highly likely now. I still prefer to look at these charts in conjunction with the modern model output. I like to see the fronts and troughs and which direction they are moving in. This still gives me a far better clue of the shorter term detail. The current crop of Met Office fax charts show the steady development of the Scandinavian HP which, as I demonstrated in my post earlier today (on page 81) is just starting to show the initial signs of its birth right now.

          CURRENT 0600 FEB 4TH                                  T+24 FEB 5TH                                          T+36 FEB 6TH                                         T+48 FEB 6TH                                         T+60 FEB 7TH

                   

                 T+72 FEB 7TH                                             T+84 FEB 8TH                                         T+96 FEB 8TH                                        T+120 FEB 9TH                                UKMO 0Z T+144 FEB 10TH

               

COMMENTS:

Firstly, note that the fax charts are today's 6z output which go out to Feb 9th. I include the UKMO 0z T+144 for comparison but you can already see that the HP is further north on the T+120 final fax chart and it looks highly likely that it will hold in a similar position. This on its own is extremely encouraging news and probably also explains the generally colder Met Office 6 to 15 day written outlook released around midday. 

The T+24 chart shows the HP building down from the Arctic into north-east Scandinavia with the cold front introducing some much colder air that is currently over north-west Russia (see my latest temperature charts on page 81). On the T+36 and T+48 charts you can see the HP building strongly south-south-westwards through northern and central Scandinavia and already starting to push back westwards the stalling Atlantic occluded fronts. Then at T+60 through to T+120 the Atlantic has its final fling and tries hard to push the fronts back north-eastwards but this is a big "south-westerly fail" - how often does anyone say that on the MOD? There is a temporary battle ground right over us with the latest forecast suggesting that any rain will turn to sleet or snow (probably not at all significant) as it all marches south-westwards and fizzles out. Meanwhile our now "true" Scandinavian HP holds its central pressure around 1046 to 1049 mb and re-orientates itself to establish the easterly. This is all aided by 4 small areas of LP - one over north France (moving south-eastwards) , two in the Mediterranean and one over the Black Sea. All of them propping up the HP. Voila!   

Now, will this verify? It is the latest update and can be compared to the GFS and GEFS 6z outputs - which present a rather different solution. If we can get the HP centred around Finland with a nice ridge towards Scotland, this has huge potential to drag much colder air across us further down the line (T+144 to T+180) from the end of next week.  I am, for one, feeling very bullish right now. Now let's see how the 12z models handle this.

 

Edited February 4, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.

[Summer Sun]

 

[A Frayed Knot]

3 minutes ago, abbie123 said:

That odd because meto are going  for very cold and chance of the white stuff .

Yes it is very odd as IF is also noting heavy snow showers into next week ' someone is telling porkies i think ...lol

[Seasonality]

4 minutes ago, abbie123 said:

That odd because meto are going  for very cold and chance of the white stuff .

Matt Hugo's post is factually correct. It isn't a full on blast of an easterly for the UK and not in the same vein as 1991 or 1987. Doesn't mean it won't be chilly or not snow.

Edited February 4, 2017 by Seasonality

[Weathizard]

6 minutes ago, abbie123 said:

That odd because meto are for very cold and chance of the white stuff .

Any easterly will feel very cold, the meto echo basically what Matt has said: a predominantly dry but very cold easterly flow with snow flurries primarily in the northeast. Personally I think despite talk of upgrades it's not realistic to expect any changes as big as we'd need for widespread snow and sustained deep cold that some want, we need several factors to go in our favour.

 

[SMU]

Just updated - very late

NAVGEM 84 06z - almost identical to JMA with the cold pool alligned towards England & a sharper cut off low

[Scandinavian High.]

1 minute ago, A Frayed Knot said:

Yes it is very odd as IF is also noting heavy snow showers into next week ' someone is telling porkies i think ...lol

That's what meto update says is very cold with some snow showers or have Iooked at old update and  Ian f tweets .     very confuseing.

[Frosty.]

I will settle for a prolonged cold spell with plenty of frosts, some ice days and snow showers / flurries which is what the models are showing..much better than mild zonal dross.

[Polar Maritime]

Please use the meto outlook thread for any further discussion on it, Thanks.

[nick sussex]

I'm not sure anyone expected a 1987 1991 repeat so its stating the obvious. In other news the sky is blue! No output bar one GEM run showed anything close to that anyway. Can we just ban twitter it gets on my txts!

[mcweather]

Indeed the charts are not suggesting an 1991or1987 repeat at the moment to be honest I have never expect them to firm up to something like that  but as Matt has also said in his tweet '

'details yet to be determined'  and I can no reason for there not to be the odd kink or disturbance in the flow that could give some worth while regional or local falls. as ever this will not become clear until probably t24 for any given instance.

In the mean time let us rejoice that an end to the past weeks wind rain is in sight.

Edited February 4, 2017 by mcweather

[SMU]

Indeed ^^^^

So off we go then - The 12z is under starters orders....

In respect to everything available at the moment inc the 06z runs & known bias from models we cannot 'expect' The GFS poor solution to be correct- however based on history & the aforementioned bias / weaknesses of this model I would forecast the 12z + 18z & 00z to move to the more Easterly flow as per the JMA 06z-

GFS is also poor with euro heights between around 114-144 in these scenarios often being around 8 dam to high- so all if this Should change & manifest in the next 24-36 hours....

S

Edited February 4, 2017 by Steve Murr

[Frosty.]

7 minutes ago, nick sussex said:

I'm not sure anyone expected a 1987 1991 repeat so its stating the obvious. In other news the sky is blue! No output bar one GEM run showed anything close to that anyway. Can we just ban twitter it gets on my txts!

I agree Nick, however, it looks increasingly like a prolonged cold spell is on the way, very cold at times with snow for some of us. By far the best spell of the winter thus far nationwide..happiest I've been about wintry prospects for a long time! :- )

Edited February 4, 2017 by Frosty.

[CK1981]

3 minutes ago, Frosty. said:

I agree Nick, however, it looks increasingly like a prolonged cold spell is on the way, very cold at times with snow for some of us. By far the best spell of the winter thus far nationwide..happiest I've been about wintry prospects for a long time! :- )

Have to agree, Frosty!

[snowfish1]

Steve, are you saying that you think GFS is out of kilter with the pattern other models are showing? And what do u base this on? (Learning! Thank you 

[JamesL]

Alignment of flow on southern flank of HP already moved by around 3-5 degrees more  favourably than the 6z 

[SMU]

12 minutes ago, snowfish1 said:

Steve, are you saying that you think GFS is out of kilter with the pattern other models are showing? And what do u base this on? (Learning! Thank you 

Yes - 

GFS model bias

- to far east every time

- Heights to high in Europe

- No energy seperation on trough disruption 

- 06z & 18z worthless...

 

GFS @ 42 already changing

-Better flow across europe

-4 dam lower heights in the core cold

- atlantic low now has a small kink in the SW quadrant which will develop into our cut off low - The fact it wasnt there on the 06z shows its starting to seperate & resolve energy streams more accurate...

[JamesL]

Here's the 850 charts for same time and cold pool further west by 50-100 miles too 

[Mucka]

This will be the best cold spell of the winter and hopefully some will see snow but it still looks like being cold and dry for many, especially in the West.

For it be that bit more exciting we really needed some decent trough disruption and undercut from 48h. Unfortunately there is little disruption and most of the energy goes North which pushes the high SE and tilts it in a counterproductive manner cutting off the cold feed into the continent and lessening the available cold pool for the UK.

It also means the high less well aligned to resist the Atlantic and force undercut in the next phase which ultimately results in the high declining SE rather than having any chance of retrogressing. It is about worse case scenario once we have ripe conditions for such a powerful block to our NE yet it will still be very cold and at least feel like Winter. If we had any kind of winter though I think folk would of been rather disappointed with how things have progressed.

On the plus side there is still time for improvements and unexpected snow possibilities cropping up which isn't a bad position to be in.

Also, as mentioned yesterday, there is a clear indication that blocking may well become dominant again fairly quickly, there may not even be a breakdown. Conditions remain ripe for blocking to our E/NE after mid month and there is the possibility that we get a sharper pattern across the Atlantic in conjunction with this to give us more sustained HLB with more chance of retrogression.

So other than my NIMBYism and disappointment that we look like getting a less exciting cold spell than potential would allow we are in a very good position and given the lack of Winter weather we have seen it will be nice to feel the crisp dry continental air with hopefully a surprise snow event or two.

[SMU]

Note @T48 the first SW vectored isoline appearing over central europe- totally missing before

[Hammer]

The cold pool 850's look slightly deeper and closer to east coast at same time frames from even the 6z. Assuming a good thing?

[Guest]

57 minutes ago, Tanden Sparkster said:

M.H. Has spoken....

he has been speaking all winter and mostly he has been way off the mark...