Model Output Discussion - Tuesday 20:25 -->

[warrenb]

Well i think you guys summed that run up perfectly.The 12z would simply be the best freeze up since 1995 .

Some places north and east could be absolutely hammered with the white stuff.

Thats 1 out of 3 firmly in the bag.

We now await biting our nails for ukmo to confirm,i repeat,possibly the best spell of winter weather since 1995.

Im in shock guys.

I almost dont want to look at 12z ukmo due to be absolutely petrified it will say no.

The Parallel is just mad, cold all the way with another shot at the end.

[LomondSnowstorm]

Another stunning day of model output, with only the UKMO giving the slightest hint of doubt about a decent easterly. The odd thing has been how few downgrades we've had so far, though I realise this could all change. This cold spell has generated huge amounts of interest in the forum as well: around 500 users looking at the Model Output Discussion, the most I can remember(considering I joined during the day when the most users were on the forum, 1st Feb this year.) Anyway, let's hope the UKMO reverts back to the colder setup in an hour or so, if so I feel we are almost home and dry, with just the details to think about.

LS

edit: sorry, didn't notice the UKMO 12Z was out!

Edited December 9, 2009 by LomondSnowstorm

[chionomaniac]

Can't moan at this UKMO 144

Edited December 9, 2009 by chionomaniac

[SMU]

Afternoon All-

Im sure by know people are beginning to pick themselves iff the floor, not once for the operational, but twice for the parallel- this brings the deep cold air slower, but actually could bring in a larger risk of frontal snow as the air ahead of it would have been fully mixed down to the surface for longer & it would be entrenched cold ( not often we see that these days.....

I suppose everyone will have their chart of the day, & yes the T180-252 region is certainly one of the most extreme air masses we will have observed before- but I have a MORE exreme chart from the parallel that will i guess NEVER have been seen before-

VV this-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-300.png?12

When we talk about a surpressed jet we usually see it running to the south of the UK- IIRC Dec 81 had the trough allignment from the NE coast of the US in a line across to the NW part of France-

Now look again at that-

The jet & the polar front are alligned to PORTUGAL- If you want extreme for the UK then the 528 line would be WAYYY south & if you wanted extreme temps then if the winds slackened up every day- shawbrooks record would most certainly be in jeopardy...

however we are not home & dry- another 24 hours of models---- I want the 12z tomorrow to be identical to today & I will be on the ramp up then....

UKMO ON BOARD!!!!

S

[Iceberg]

Meto is fully out on meteociel and leans more towards GFS but only 70%, so some backtrack, but not a complete one. Still alot better than 00Z.

[ChartViewer]

Hi,

To me the most pleasing aspect of of these charts is the great big fat stonking YELLOW HIGH

over Greenie. What a sight. For those that are new, to get that has been a sort of Holy Grail to everyone here who has been subjected to Topplers, Purple and Blue Heights over Greenland which arenot the real deal.

The UKMO and ECM tonight are huge but cannot see how they will backtrack the building blocks

with such a stonking -AO etc in place. Details details details but what a sight the Models are right now.

Regards CV

[NorthantsSnow]

Numerous widespread ice days...

http://www.wzkarten.de/pics/Rtavn21617.png

Sub zero minima as far south as N Spain...

http://www.wzkarten.de/pics/Rtavn25217.png

[johnholmes]

for those wanting a slightly less frenetic look at how this predicted set up is unfolding, why and what is the likely outcome see below

http://forum.netweather.tv/topic/57953-the-predicted-pattern-change/page__st__17__gopid__1631198&

[kold weather]

UKMO is a very good run with a nice cold easterly at 120hrs, then a shortwave heading down the north sea, looks very similar to the GFS evolution in general, the real cold air would be coming in behind that shortwave and funs and games would ensure.

Anyway the 12z GFS P is utterly amazing as well, both of the models would suggest a cold outbreak the type we haven't seen since probably 96-97 if not the 80s. No doubt we are getting some seriously interesting runs, of course the risk for it to all mess up increases when we transition from the HP dominance to the more cyclonic flow but with the jet so far south odds are in our favour for once.

[Bottesford]

Mods please allow a RAMP.

We'll let that one go but please keep this thread for model talk! I know its all very exciting (heck even I'm excited about cold!) but lets keep this thread for actually discussing the models!

Thanks and please ramp away in the ramping thread

Edit - ok a fellow team member beat me to it and removed it but I'll leave this message in anyway

[Geordiesnow]

Nice UKMO and certainly better than this mornings. I would of like it to go 168 hours so we know what the UKMO would do with shortwave, does it head Southwards and give us an NE'ly or does it stall? I would like to hope it heads South.

Our luck would however tell us that the ecm is waiting to give us a scare, i really do not hope it shows signs of trending towards this morning's UKMO.

Colder temps are nailed, it's the snow potential which is far from nailed on.

[NorthantsSnow]

2/2 so far. If the ECM is in an equally bullish mood when that comes out later perhaps we'll manage a full house for once.

Ensemble mean looks very good by the way:

http://91.121.94.83/modeles/gens/run/gens-21-1-180.png?12

[Michael Fishermans Friend]

Watch the ECM collapse in an hour or so! - Be nice to see al models in fairly good agreement. I'll give it another 48hrs before I'm jumping on board, looks mouth watering though!

[kold weather]

Expect the shortwave to give the models all sorts of headaches, we have so many different possible solutions that they aren't going to get any real grip of the eventual outcome for a while yet IMO.

For example the control run brings it SW across the UK then absorbs it into the Atlantic low. This is by far IMO the biggest risk to a cold spell there is, however equally it coulkd give some severe cold the likes not seen in many years if it pulled off.

Ultimatly I think the models are being a little progressive on the removal of the upper high, these things tend to be very stubborn and can stay about, but equally the Atlantic will try to kick in but will have a real fight on its hands thanks to the jet being on such a southerly course, in that period the risk of a mammoth snow event is much higher then normal.

[andy_leics22]

What I find the most incredible about these charts is that it's mid December when they are projected to happen. In the past I have known charts like these to show up in Feb when the sun is a bit stronger and the days are longer. If this came off then it would be colder and more severe than the February event we had this year? I don't know, time will tell and that February event will take some beating but it's certainly possible if the models continue with this.

Edited December 9, 2009 by andy_leics22

[cooling climate]

It just goes to show when you get true heights to the north it makes all the difference rather than

the Azores high trying to send a weak ridge to Greenland.

That is why when myself and others saw the GFS modeling a negative Arctic oscillation some 10 days

or so ago heading for our neck of the woods we knew this could be the real deal.

The model runs are incredible for cold and snow its just about detail now so I do not think there is

anything to worry about regards the ECM run due to start coming out in about 40 minutes.

[TEITS]

Only had a brief look at the models but dare I say we are slowly starting to see a clear trend with these models.

In summary it looks as though come Sun/Mon we are going to see an E,ly set in with possible wintry showers. However this is only the starter before the main course because from +144 +192 we see the main course tracking S down the North Sea and behind this is some bitter cold and where some serious snowfall could occur.

Who cares about the dessert!

[Snowaddict]

The latest GEM T+120 also has 850's of -8 over SE England, with a widespread cold pool across the British Isles, along with a Shortwave beginning to drop down from Scandi (just north of Norway at T+120).

That's the 12Z: GFS, GFS (P), GME/DWD, GEM, UKMO.

That's fantastic, even stunning agreement, even at T+96 with the colder continental air well and truly arriving..

[kold weather]

Yep very good agreement on the intial easterly shot now, and we are getting at the range now where the odds of it happening are very high.

Beyond that, most models do look very good, if we you want to see my worst fear however take a look at P1 of the GFS ensembles...thats why we can't look too far into the future, however the 12z GFS suite does tend to be the most progressive of models.

[Paul Sherman]

I think we can all see now what proper Model Watching is all about, this site has been here for 7 years next February 27th and in all that time we have NEVER Seen a Possible Set-Up like what these charts are showing, it just goes to show what garbage and straw clutching we went through at times when the SW Dominated Winters gave us a 2-3 day cold snap and snow melting before Lunchtime once during January and a few times in February. I really hope this comes off because most of the members on here simply do not remember what real winter Cold spells are like, I am talking 78/79 - 1981 - 1982 - 1984 - 1986 - 1987 and 1991

These charts are reminiscent to the Archived charts from wetterzentrale that we gaze over and dream about our 14 days of snow on the ground and 10 foot drifts.

Just savour these and hope it does not all go pear shaped.

Paul S

[TEITS]

But eye if this were to happen wouldn't it put your christmas plans in danger of being cancelled? Besides i will not allow you to keep my snow i have an industrial vacum cleaner pointed straight at your neck of the woods mwahaaaaa.

Indeed it will mean baked beans on toast with my cat as company. Still I wouldn't mind as what the models are suggesting is what i've been looking out for since I joined this forum.

Back to the models and if this current output continues then its going to very different to what we usually experience. Normally when we follow the models its a case of watching the cold spell approach +0 and then enjoying it. However this could be a cold spell that we need to closely monitor whilst we're actually experiencing the cold spell, if that makes sense.

The GEM continues with some excellent output and again we see the E,ly followed by a SW tracking S which would introduce even colder air!

[Thundery wintry showers]

What I find the most incredible about these charts is that it's mid December when they are projected to happen. In the past I have known charts like these to show up in Feb when the sun is a bit stronger and the days are longer. If this came off then it would be colder and more severe than the February event we had this year? I don't know, time will tell and that February event will take some beating but it's certainly possible if the models continue with this.

This type of synoptic setup, with the omega block, used to crop up from time to time in January or even late December prior to around 1988, with a very notable instance of it in early January 1985. However, to my knowledge, it has always been very rare in mid-December. While I'm not as big a subscriber to Ian Brown's "modern winter" theory as he is, I genuinely thought that the recent synoptic changes to the NH associated with the so-called "modern winter" had made the development of omega blocks exceedingly unlikely any earlier in the season than February (let alone mid-December). Thus I am extremely surprised that this omega block is looking set to come to fruition. With what happened last year and now this, perhaps the synoptic trends of the past 20 years are showing signs of relenting?

UKMO btw looks very similar to GFS to me. The UKMO model outputs tend to lack detail relative to those of the ECMWF and GFS, so the "look" is a bit different but I feel the overall pattern is exactly the same.

I must say I am, personally, struggling to keep my personal "rampometer" at ground level, as the sort of setup progged by the models traditionally gives the Norwich and Tyne & Wear area their biggest snowfalls. However while a cold spell of some kind looks almost certain (see the update to John Holmes's blog for the reasons why), it is still by no means certain that we'll get a snowy north-easterly.

Edited December 9, 2009 by Thundery wintry showers

[kold weather]

The models look exceptionally for Scotland by the way, good agreement on the ensembles for the upper high to decay vetween 168-264hrs however thats a long way off, I think its fair to say we could get a very exceptional cold spell, but we have got a while yet and just about anything can happen.

Paul, these charts look a lot like the cold spells from the 60s, the ones that often are dominated by a southerly jet and LP's driving southwards in Scandinaviawith the southerly jet pilling into the S.Europe.

Just need the 12z ECM to pull off however, no doubt it will mess us about tonight, gotta be one of the moels that looks poor, there always is!

[memories of 63]

Just had a quick look and (whisper it) the operational and control GEFS are warm outliers in far FI

[Frosty.]

Probably the most wintry looking ukmo 12z T+144 chart I have seen in the last 4 years, the trough to the northeast is poised to throw open the ice-gates and unleash bitterly cold air and snow showers, especially but not exclusively to northern and eastern uk. It looks like frosts next week will become hard and penetrating and the wind-chill factor which I don't think anyone has mentioned yet, will be large...let's hope the ecm is still in party mood so we can have a full support. If the models look the same in 24 hours from now, it will probably be game set and match.