Model Output Discussion

[Thundery wintry showers]

I've read the forecast blog by John and I think his assessment is spot on. The formation of the omega block has near-unanimous model agreement and is within the reliable timeframe so it is a pretty safe bet that this block is going to come off.

Then the rest lies in the detail. An omega block is a sure sign that the weather over Britain, and indeed a huge swathe of Europe, will have below-average temperatures and some frost. But whether Britain gets any widespread snow events out of it depends on whether a blocking high manages to stick around the vicinity of the British Isles throughout the entire period, preventing blasts of particularly cold air from occurring and restricting the amount of precipitation.

That is the most likely way that the British snow potential could fail to be realised. Another is a succession of half-hearted northerly and easterly outbreaks, each failing to bring particularly cold air across and bringing just a wintry mix at low levels, but that would require a more elaborate set of synoptic events, and most likely, again, rely on high pressure being there or thereabouts for a large majority of the time.

However history teaches that more often than not, when an omega block forms the British Isles experiences at least one or two widespread snow events.

[chionomaniac]

528's into the south east on mondays UKMO. the ecm 12z has upgraded on the 00z on the past two days. lets hope for the hat trick.

I reckon that the ECM is marginally better already at T+72

[Snowaddict]

Hi Snow addict! what does that mean? coldest since then?

Not necessarily the coldest clark3r but in terms of hemispheric patterns, UKMO is stunning in my opinion, with cold air getting into the SE from T+120 and across the UK by T+144.

[snowray]

Maybe they are trying to "hide the decline"? <_<

Late meto runs do tend to be good ones don't they?

Indeed, and yes they are looking good with the high ending up further North and a much nicer shape by T144, now its all down to the ECM.

[TEITS]

Excellent UKMO this evening.

Note the energy is going under the block. If there was a +168 chart the HP would move further NW and an even colder E,ly would set in.

Looks even better on wetterzentrale!

http://www.wetterzentrale.de/pics/Rukm1441.gif

[cooling climate]

ECM at t96 and better heights to the north. This should be a much better run than the 0z.

[NorthantsSnow]

Out to +96 on the ECM and the high is already centred much further east than the UKMO.

[kold weather]

12z ECM coming out, the upper ridge no where near as advanced on the UKMO was at 96hrs, so hard to tell whether its better then the 0z run at this stage.

[D KARLSON]

Excellent UKMO this evening.

Note the energy is going under the block. If there was a +168 chart the HP would move further NW and an even colder E,ly would set in.

Looks even better on wetterzentrale!

http://www.wetterzentrale.de/pics/Rukm1441.gif

Indeed the high is nicely sandwiched in and it looks like the energy going underneath the block could make the low to the south a much more vigorous feature in future charts ,so we certainly cant predict the precise nature of the synoptics to come but perhaps more of an easterly at this juncture

[cooling climate]

ECM at t144 excellent.

[SMU]

OMG ECM IS ........................

AT 144....

Steve

[on the coast]

ECM at t144 excellent.

Absolute belter <_<

[Snowaddict]

This is nerve shredding, I've never seen it so close to the wire!

However ECMWF MUCH better this evening, retrogression clearly beginning at T+120, cold air filtering in at T+144 as the trough drops down through Scandi!

[Lewis]

OMG ECM IS ........................

AT 144....

Steve

Is that ECM chart good?

[Thundery wintry showers]

ECM T+144 bears a striking resemblance to the evolution of the GFS 06Z run that some (including myself) rubbished. What is clear is that the models are not falling into line with this morning's ECM.

[Cecil Hogmanay Melchett]

ecm <_<

[TEITS]

Only just had a glance at the ECM +144 (watching blizzard in the US!). However in my eyes the ECM so far is very similiar to what the GFS parallel has been suggesting and the GEM. A simply stunning chart. <_<

[kold weather]

Well the 12z ECM is certainly an upgrade on the 0z thats for sure!

Models coming into the middle, interestingly the 12z GFS is on its own tonight with regards to the shortwave's evolution...cold air coming down after 144hrs as well.

[Cal]

Peach <_<

[D KARLSON]

OMG ECM IS ........................

AT 144....

Steve

looks a bit tasty to say the least !!!!!!

[Cecil Hogmanay Melchett]

OMG ECM IS ........................

AT 144....

Steve

<_<

RAMP IT UP STEVE BOY HERE WE GO!!!!!!!!!

[Geordiesnow]

Nice ecm at 144 hours, looks more in line with the GFS 06Z run too me which is good of course

Not too sure what to make of the UKMO run, it might result in an easterly but this morning's UKMO probably had more potential with the slider low.

Anyways, whatever model you look at, the risk of an easterly is there. <_<

[bluearmy]

the ecm 12z is soooo different in the w atlantic with the trough energy headed se instead of ne. where there was a high this morning, there now sits the trough. can we really trust what we are seeing beyond T120 ????

[snowmadchrisuk]

I told you all ECM would be good tonight . 18z is now going to be more Important than usual being it is the Pub Run . Excellent .

[kold weather]

Well we now have agreement between the 12z models about the general overall evolution of the pattern. The main disagreement is still with regards to the shortwave with the 12z evolving it differently, however it does semm that it was something of an outlier in its own ensembles.