Winter Model Discussion 18Z 19/1/13 onwards.

[nick sussex]

The UKMO have made some modifications to their raw output at T96hrs.

The ridge to the ne is placed a little further sw and some adjustments also made upstream. Certainly better than the raw output in terms of cold.

[chris55]

Another snow event for many come Friday, slightly more marginal, but the risk is there

Cold digs back in again Sat, although the Atlantic is lurking.

[Jason M]

Greeny high fi?

Out to 276 and still no. It's very odd really that we can't seem to get a full on HLB given that some of the charts we are seeing are just screaming for it.

Jason

[Panayiotis]

Ha that low in the Atlantic at 360hrs just went round in a circle (pardon the pun).

Edited January 19, 2013 by Panayiotis

[TEITS]

Have to laugh at the model output at the moment.

http://www.wetterzentrale.de/pics/Rtavn1441.png

At +144 that is a massive difference compared to recent GFS runs.

Even the Met O don't trust their own model with quiet a shift SW of the ridge of HP.

Really can't be bothered looking beyond +72 and shall just concentrate on the snow potential for the next few days, starting with tomorrow!

[David 'Minty' Hill]

You know people talk about FL a lot, I tell you what tho the snow event that happened on friday for here was in FL way before because I actually posted a pic of it on my facebook account saying if this came off we are looking at soem heavy snowfall and it did bang on cue. FL does sometimes come true and at 360 nice new high forming over scandi

[Froze were the Days]

I haven't had a look at the 18z GFS but going by the posts it's just another typical run after the block has eventually been broken down suggesting very little in the longer term outlook. No shock there.

[Continental Climate]

thats a deep low by gfs http://www.wetterzentrale.de/pics/Rtavn1561.png!! How low is it 930

[Ice Day]

thats a deep low by gfs http://www.wetterzen...s/Rtavn1561.png!! How low is it 930

Good grief, I hope the UK is anchored down or we'll get sucked into it!!!!!

[Jason M]

One thing is for sure and that is the fact that by next weekend we will have some very cold uppers not far away to our east and northeast. Some very small changes in the medium term charts could make this weekend look benign. Of course it has been in essex and Kent thus far but that's another story :-)

[J10]

Reliable timeframe i.e. out to next Thursday roughly, all models continue to show a cold outlook, with further outbreaks of snow affecting areas which have already been heavily affected by snow in recent days, namely SE Eng, E Anglia, Lincs, East Yorkshire, NE England, Borders and NE Scotland tomorrow and Monday and probably SW parts and west midlands/west country on Tuesday.

However, all the models are showing a breakdown of the cold by the end of next week, with rain and strong winds off the atlantic crashing into the country quickly, a rapid thaw would ensue - and no doubt further flooding misery, so by this time next week we could all be looking at a very grey wet scene...

I was anticipating we might see some height rises into Greenland later this month, given the state of the stratosphere.. still believe we will see them in February, but we might have to endure another spell of atlantic weather - but nothing as long lasting or as mild as the last one...

but nothing as long lasting or as mild as the last one... or as wet hopefully

[Jason H]

I haven't had a look at the 18z GFS but going by the posts it's just another typical run after the block has eventually been broken down suggesting very little in the longer term outlook. No shock there.

I suggest you take a look Alan.

[Rocheydub]

You know people talk about FL a lot, I tell you what tho the snow event that happened on friday for here was in FL way before because I actually posted a pic of it on my facebook account saying if this came off we are looking at soem heavy snowfall and it did bang on cue. FL does sometimes come true and at 360 nice new high forming over scandi

What is FL?

Long time here and a lot longer weather watching, no idea what an FL is...

[David 'Minty' Hill]

What is FL?

Long time here and a lot longer weather watching, no idea what an FL is...

Fantasy Land = more than 144 Hours on the charts so its basically a computer trying to guess whats going to happen and usually gets it wrong. Maths can not always be applied to everything

[Panayiotis]

You know people talk about FL a lot, I tell you what tho the snow event that happened on friday for here was in FL way before because I actually posted a pic of it on my facebook account saying if this came off we are looking at soem heavy snowfall and it did bang on cue. FL does sometimes come true and at 360 nice new high forming over scandi

Yes it also happened in 2010 but the models were consistently showing Fi as being cold, therefore the signal was strong, however the 18z looks similar to something which was shown yesterday on 2 of the runs, but if you dont want to put yourself in the deep end dont look at Fi.

What is FL?

Long time here and a lot longer weather watching, no idea what an FL is...

I think he either misread FI as FL or he meant fantasy land?

[Rocheydub]

Fantasy Land = more than 144 Hours on the charts so its basically a computer trying to guess whats going to happen and usually gets it wrong. Maths can not always be applied to everything

Oooops. You mean FI, as in "fantasy Island"

Slightly rosey cheeked I'd imagine...

[Cheshire Freeze]

I haven't had a look at the 18z GFS but going by the posts it's just another typical run after the block has eventually been broken down suggesting very little in the longer term outlook. No shock there.

No, the 18z is cold throughout IMO

[goosey007]

Fantasy Land = more than 144 Hours on the charts so its basically a computer trying to guess whats going to happen and usually gets it wrong. Maths can not always be applied to everything

the term is better known as FI...... fantasy island but your close enough

[Cloud 10]

what in your opnion is causing this ? and what could it mean? ........

The jet-stream is being repelled by a stubborn upper high sat NE of the UK brought about

by the SSW (sudden stratospheric warming).

Some of the model output has suggested a breakdown of this high,therefore allowing atlantic

weather systems and less cold weather to affect the UK,however,the 18z keeps the cold

spell going a bit longer as the high is more resistant.

[David 'Minty' Hill]

Oooops. You mean FI, as in "fantasy Island"

Slightly rosey cheeked I'd imagine...

OOOOOOPSY but both mean same thing tho I suppose

[Panayiotis]

Fantasy Land = more than 144 Hours on the charts so its basically a computer trying to guess whats going to happen and usually gets it wrong. Maths can not always be applied to everything

Math is what makes the models, however there an infinite of solutions from what the chaotic weather will be like in 2 weeks, and one out of the Fi charts will be right but its finding which one is the question. Its like trying to know what you will be doing at this exact time in 2 weeks time, there are infinite of solutions! Edited January 19, 2013 by Panayiotis

[weatherguy]

Fantasy Land = more than 144 Hours on the charts so its basically a computer trying to guess whats going to happen and usually gets it wrong. Maths can not always be applied to everything

FI is actually much closer than that right now and has been for a couple of weeks, at somewhere around +96 or +72. I said earlier that the models are having trouble resolving short-term solutions caused my the negative zonal winds coming up against a strong jetstream coming off the eastern seaboard. The predicted low pressure systems have been very large and very progressive (which would be logical from the strong jet, fuelled by the canadian PV), but by the time they near T+0 they have seemingly hit an invisible brick wall and slid SE, undercutting the block. This is the work of the SSW and those negative zonal winds.

Of course I'm not saying this will continue, but what the models have shown today is similar to what happened a week or so ago when the block looks to be crushed, but gradual backtracks both extending the cold spell and sending those systems south east with the associated trough disruption.

I'm hopeful we will see this again, with the GFS 18z and the ECM 12z being encouraging when compared with previous runs.

[Davey80]

The whole GFS run looks snowy apart from a a couple of 2 day mild spells. Next Friday looks a repeat performance of yesterday too

Edited January 19, 2013 by Davey80

[goosey007]

The jet-stream is being repelled by a stubborn upper high sat NE of the UK brought about

by the SSW (sudden stratospheric warming).

Some of the model output has suggested a breakdown of this high,therefore allowing atlantic

weather systems and less cold weather to affect the UK,however,the 18z keeps the cold

spell going a bit longer as the high is more resistant.

thanks I have a general understanding of it and would was have guessed the scandi high was doing this. It was recent comments about the high being blasted to moscow at this point of the run that had me a little confused Edited January 19, 2013 by goosey007

[liam300]

Hi guys is there any websites for predicted dew points from the models? Assume it

will be on meteociel but can't read french