Come to Daddy

That is though stunning Happy Christmas from the ECM !

No lump of FI coal there.  I hope that the trend can be held over the next few days. 

Personally for me the key is to get maximum WAA into the Arctic over the next 5-6 days.

It has been in the pub!

Only kidding, lol! Seriously though, if the model runs maintain this through the weekend and into early next week, I think there's a distinct possibility that the MetO might have to dramatically alter their 6-15 and 16-30 day updates from what they issued today and over many recent days.

Thats the key it would seem.

A thing of beauty on Wetterzentrale looks abit Jan 87ish.

http://www.wetterzentrale.de/pics/Recm2402.html

Yes, a stunner.  Bound to go tits up, but hey its Christmas, lets enjoy the moment (that is 10 days away LoL)

ECM is very snowy. I have drawn the fronts on the 192hr onwards. 

At 192 we have the first potential area of snow, this one is not coming into particularly cold air so it is pretty uncertain. However evaporation cooling may turn the precipitation on this very slow moving front to snow. If it does this is potentially a 10cm event, since the front is still there 24 hours later (see 216 image).

At 216 we have a rapidly occluding low moving gradually north east. This is a classic warm occlusion and will dump ALOT of snow, and yes it will be completely snow for everywhere north of the triple point, and potentially snow for those east of the warm front. This occluded front is also slow-moving and its remnants can be seen on the 240hr image. This one could drop 15-20cm locally. Parts of the North midlands, Wales, NW england, SW scotland and N ireland would be in the firing line for this. 

At 240 we have yet another feature moving up from the south, this an occluded front wrapping around a secluded warm centre. Again this could drop several cm in a very narrow band for parts of the midlands. In the 240hr image we would also have lake effect snow to contend with for SE England. 

Also noteworthy the polar front (boundry between polar and sub tropical airmasses) becomes increasingly well defined. Note how it moves very far south. At 192hours its the same latitude as newfoundland and the UK, by 216hours it stretches on a long SW to NE trajectory ending in SW England and by 240 hours it stretches right across the atlantic to the mediteranian.

Actually the 216hr chart is far snowier, 240 has snow on it but mostly reserved for a select few in the midlands and the SE. The 216 hour chart has widespread heavy snowfall. Also tbh the lake effect probably wouldn't be that good at 240 because there is quite strong directional sheer.

Interesting that GFS is a zonalfest with almost all the very cold outliers gone. Indeed the ensembles are classicly zonal although more westerly than the deep tm based stuff we have presently.

If I read this thread in isolation I would think that we were about to enter a very cold easterly driven spell. The above should be noted as caution 

I can hear Steve Murr dusting off his laptop

the key is the WAA at 96 & 120

x

I now believe!

good to see you about Steve, looking forwards to some of your in depth analysis should this unfold. 

Told ya!

Does anyone remember the pattern of the GFS seeing something, then dumping it only for the ECM and UKMO to get interested.

From what I recall, it never tends to end well for cold.

Isn't it typical that when a GFS operational run backs off we get ECM producing an effective block, albeit near the end of the run.

I think I'd like to see where this sits against the ensemble run.

Of course it may just be a blip in the prevailing pattern and whilst the 6-15 day outlook might change it wouldn't suprise me if the 16-30 day one reverted to the theme of a mild mobile pattern; we don't see far enough ahead to know.

horrible experience in here followed.

Wasn't it GEM that first came up with the idea of an Easterly???

Below are a few comments from several days back

The models remain very poor, I doubt if deep down anyone really expects a change from this mild regime for the rest of the winter. 

From Shropshire ....Dec 17th

You could be on to something Mr Moomin, although it wouldn't surprise me to see the change just after Christmas. Too early to say but there does seem to be more evidence of a pattern change than has been the case in the last few days. It will be interesting to see what the charts show for the post Christmas period in a couple of days.

From Doc  18th Dec .............Very sensible

If we want what the ECM shows to happen then it just shows how bad the position is.

What happened to the warming event that people were talking about for esrly January, doesn't seem to be on according to the other side, I've noticed Steve Murr and the Jam Tamara woman don't seem to be on there anymore.

 From the vanishing Shropshire Dec 18th

Its a good chart but we've been here before with Ecm day 10 charts. We're still 2 or 3 weeks away from any serious cold at least all the ensembles at the moment are shocking.

 From Ally Pally Dec  18th .......whoops

Steve Ive been watching the WAA for that S-N orientation.  It simply hasn't even been modelled right let alone happened.  Its always as you say been SW-NE which simply locks us into THE MILDNESS.

To get S-N oriented WAA at this you need a wall of high pressure all the way up into the Arctic to our east.  Without this very rare occurrence the WAA from the deep TM air masses is simply wasted.

It is definitely a case of making the most of what you've got and until something changes dramatically upstream, the only way out to cold is the S-N WAA scenario with a hoped for compensatory plunge south of frigid air.

Its all such a long way off. 1% hope.

From Weather Idle  Dec 18th .........1% eh ?

any cold in FI is just that, fantasy, just noise.

white noise.

From Stone Cold ........no surprise Dec 19th

Yes, a Paul Simon song springs to mind but we shall see. The problem is the whole process could take several weeks.

From Brian Gaze  Dec 19th.......just shows you can't go on past experiences

I feel the models, especially the ECM, are suggesting a post Christmad pattern change

From Doc again......Dec19th

And Ally Pally's reply to the above

The ensembles just don't suggest this at the moment though neither ecm or GFS. Looks mild beyond new year to me .

We will have to wait until February at the earliest

From Maunder Dec 19th

With these forecasted blocks to the East, 9 times out of ten in my experience it gets pushed away and flattened by the jet back into a Euro high, giving us another sustained spell of Atlantic westerlies. To me it looks like this is what's going to happen this time, especially as the jet looks strong .

From Fothergill  Dec 19th

Never say never, but I think the more "seasoned " campaigners can see where this one is likely to be headed

 From Weather Idle  Dec 19th ..................of course WI means though who thought cold was around the corner ......lol....................not

As for early Jan it looks quite unsettled based on the GEFS. Despite what some people say on the forums, I seriously doubt whether MOGREPS and the European ensembles show a significantly different picture to GEFS except on very rare occasions

From Brian Gaze 20th Dec

I'm not saying a raging Easterly is likely but even some of 'The big boys' were thinking cold is weeks and weeks away , yet 7 days or so later we have an Easterly showing up on several models.  It  doesn't really matter what experience you have you can never outbox the weather .

Interesting times.............................hopefully

I seem to recall that someone, Retron probably, confirming that in an easterly you don't need such low 850s or thickness because the surface layer is colder.

It's somewhat academic at ten days out but the 500-1,00hPa values around the northern Home Counties are high 520s and with 850s at -5C to -6C I wouldn't discount sleet and snow away from coastal areas and the lowest ground.

Indeed.  The fact that this WAA is within the reliable time frame means that at least some of the necessary jigsaw pieces will be in place by 120 hours.  A lot needs to fall into place after that, but the exceptional, off the scale, sustained warmth moving from tropic to pole  of this ridiculous month may just end up having a big effect on our weather in 10 days time.  We shall see. 

Nailed on as I fly off.

I think the main thing to point out is that the METO don't even see the possibility of a battle in their medium term outlook, perhaps the models are overreacting to the MJO uncertainty, whereas of course we know that the ENSO and immense PV can overwhelm this factor.

The ECM 32 dayer remains very progressive through to the end of January.

Merry Xmas everyone 

Personally I go with a front based system, something like this for 850hpa temp benchmarks for snow.

Warm sector: -8C

Cold front: -7C

Kata warm front: -7C

Lake effect: -6C

Cold occlusion: -5C

Ana warm front: -2C

Warm occlusion: -2C

is a rough guide but it is pretty situational. Personally I only glance at the 850hpas and rely mostly on the SLP.

A short sea crossing combined with 850s of say -5c in cold surface air is enough to produce snow.  late December 2005 saw snow accumulate at 0c on the surface with uppers of -2 to 0c, in a south-easterly.