Model Output Discussion - 18z - 6th December onward

[Jason M]

This is only a snowy breakdown from Inverness northwards. In southern England uppers are 2c in that frame.

No point in looking at the detail though as its GFs low res after 192. A ten year old with a scrap of paper and a pencil would have as much chance of getting a chart to verify!

As others have said in here, look closely up to 120 hours, note the content up to 168, maybe raise an eyebrow at the 192 chart, but anything post 200 hours just laugh at :-)

Very good charts again today. What's not to like !

Jason

[Geordiesnow]

Latest +96 fax chart and that will do nicely for me.

http://www.meteociel...ax96s.gif?06-12

Cold front clearing S with the chance of snow showers developing later on during Monday night in E areas.

Pretty much like the UKMO as per expected, just hope both the UKMO/ECM don't revert to the GFS 18Z run in the early frames, I mean, we could still get heights into Greenland even if we get an easterly flow earlier on in the run.

Its interesting too see the GFS still wants to drop the PV into Scandi, the experts think this is likely, details at this stage can only be for fun as these large deep cold PV's can be hard to predict correctly but one is hoping this trend will continue. One for our cold chances and secondly for Sea ice reasons in the Kara Sea especially!

[Dave Kightley]

The problem we have is once you have seen the weakening of heights at Northern latitudes - the yellows become the greens - then you are open to Atlantic attack, and that will usually end in what the 18z goes onto show at about T204, the archives shows lots of cold spells ending this way. Of course it may not happen like that, but I think the idea of this particular HP ending up over Greenland is now a fading possibility.

I disagree. Behind the shocking FI it is.. Look through FI you can see the "green" transfer over to Greenland.

[Rob K]

Exactly. Trying to pin down the 0c isotherm at 288 hours is just ridiculous. The general theme shown is for Atlantic lows to slide under a northern block. That means that a significant snow event becomes more likely, regardless of the specifics shown on each run.

[Bristawl Si]

Could be looking at a regen around the 20th bit too late for xmas snow. Can see scotland having snow over xmas. But i never pay much attention that far out!

Erm....xmas day is 25th.......as per every year.

There really are some bozos on here this eve.

Ciao!

[Dave Kightley]

Heights over Greenland later on FI

[Rob K]

120 hour fax chart http://www.meteociel.fr/ukmo/fax/fax120s.gif

All good.

[Mark Neal.]

Well, I hate to admit it guys, but the BEAST is dead.

Oh well, a couple more months of mild wet and windy weather, then we've got spring to look forward to.

I wouldn't speak to soon. We still end up with a cold airflow coming from that direction. Plus it's one run. Expect the 00z to bring a perhaps stronger easterly for the overnight runs. Another good day model watching, sometimes I wonder if people are reading the models with a blindfold.

Here's to tomorrow's output :-)

[Jason H]

120 hour fax chart http://www.meteociel...fax/fax120s.gif

All good.

Nice fax update there. Little troughs being picked up in the NE flow, but too far out to pin down the exact areas yet.

[Richie V]

Please, I aint trolling but I'm not convinced that any of this progged northern blocking is strong enough given the current situation. It pains me to say but I just think there's too much energy up north for any such strong 500hpa heights to take hold. This is demonstrated beautifully in the lower rez portion of the gfs 18. Gfs aint the best but it knows the game all too well regarding those pest from the west shortwaves. If I were to personally lay my neck on the line I'd strongly plump we're headed for quite a prolonged stretch of very cold NW - SE tilted zonality so that is hardly a bartlett scenario, could be way worse folks.

Just my thaughts after 13 hard winters chasing the perfect beasterly!

Ric.

Edit my last post... I ment higher rez portion of gfs.

[Allseasons-Si]

120 hour fax chart http://www.meteociel...fax/fax120s.gif

All good.

That chart is a beauty,i will sleep tonight,altough i wasn't worried anyway with the background signals,goodnight peeps.

[Alex95]

+120 FAX is beautiful for anyone in the North East (inc. E Scotland). A cold, unstable NE'ly with a trough in the North Sea. That is pretty much the ideal snow setup for NE England.

[Richie V]

120 hrs fax.... Pressure needs to be lower in the med or this will end in tears for coldies.

[Rob K]

120 hrs fax.... Pressure needs to be lower in the med or this will end in tears for coldies.

That chart is already cold. Dry your eyes.

[SouthPennine88]

120 hrs fax.... Pressure needs to be lower in the med or this will end in tears for coldies.

Maybe not tears, it wouldn't be a flip ...

Fax a good one for the North/East though.

[Thundery wintry showers]

The slack east to north-easterly flow shown on the current model outputs would most likely see snow showers restricted to the eastern half of the country, but I doubt that they would be confined to within 5-10 miles of the east coast- we'd be talking more like 40-50 miles at times IMHO. The GFS is pretty good at modelling coastal showers but often underestimates how far inland they penetrate when the airflow is off the North Sea- we've seen this quite a few times with recent northerly outbreaks.

My earlier assessment of, "unlikely to turn milder widely before the 19th December", is now looking rather more shaky as we are seeing increasing support for a breakdown from the SW around the 16th December- but I rather think that the Atlantic systems will make slower progress than the ECMWF ensemble mean currently indicates, and the 19th December may well be around the time that we see the (possibly temporary) return to milder conditions. I am still seeing evidence of retrogression of the high towards Greenland- "greens" may indicate a weakening of the northern blocking but the absence of "blues" in the area indicate that it is still there.

Edited December 6, 2012 by Thundery wintry showers

[Allseasons-Si]

I have saved that 120hrs fax chart for investigation to see if it verifies,obviousley there will be minor changes in trothes(sos for the spelling lol),but the overall looks good.

[Froze were the Days]

Just looked at the GFS pub run - very strange, brings the Atlantic in pretty quickly from around 184z but the synoptical pattern finishes almost the same at the end of the run. Really can't think that will happen (almost a stand off for numerous days).

[SnowObsessor90]

I wouldn't speak to soon. We still end up with a cold airflow coming from that direction. Plus it's one run. Expect the 00z to bring a perhaps stronger easterly for the overnight runs. Another good day model watching, sometimes I wonder if people are reading the models with a blindfold.

Here's to tomorrow's output :-)

I admit I jumped the gun far too prematurely earlier when the run the was still is it's very early stages. Still I hope we're not in a position where we're already looking towards the next bite of cherry after this Easterly has gone completely the way of the pear before got a chance to get of the ground over the next day or so, now that really would be a real kick in the gut.

[Mark Neal.]

I admit I jumped the gun far too prematurely earlier when the run the was still is it's very early stages. Still I hope we're not in a position where we're already looking towards the next bite of cherry after this Easterly has gone completely the way of the pear before got a chance to get of the ground over the next day or so, now that really would be a real kick in the gut.

Indeed that would be a kick in the teeth, although I don't think that would be the case; I think the only slight problem may well be the duration of the flow from the east and perhaps restricted showers to close proximity to the coast. Time will tell though.

[Dave Kightley]

A less eroded block over Greenland in FI and the track of low's further south.. FI would look very good indeed

[SouthPennine88]

I really cannot see too many flaws at all in tonight's fax, it looks very good especially for the North and East ... strong and bold ... fax is a gooden

[nick sussex]

Good start, dodgy for a while and then very interesting is how I'd sum up the GFS 18hrs run.

A small complication arises with a shortwave to the north of Scandi, this delays the sw momentum to drive the first shortwave into the continent.

Hence the flow slackens off, the most interesting aspect is that we see heights hold on longer to the north and then the Atlantic moves in at a more favourable attack angle.

Of course the lower resolution GFS couldn't bear to take the energy se with more trough disruption but instead reforms the football shaped troughing, yawn.....

Been there and thats so last year.....

So bin the lower resolution edge the pattern further west with more trough disruption, bingo cold stays entrenched, possible slider shortwave, some one gets lots of snow whilst those away from the favoured area gnash their teeth whilst not realizing that sometimes you have to take a hit for the team to lock in the cold pattern!

In terms of possible retrogression, modelling problems likely with when to go for this, so some volatility is likely to be the main theme for a few days.

Overall a good evenings output.

Edited December 6, 2012 by nick sussex

[Downburst]

you must be looking at the wrong charts, nothing ever set in stone this is why this is the called the model thred

Fax charts are great, next week and that's not long away, we will have some seriously low night time temps. It will be bitter. The straight easterly is not going to happen in the traditional 1987 sense but on the other hand a terribly cold slack air mass will move in for 4 days at least, perhaps longer. Now the despondency is 'cause a couple of the posters have been talking about snowmageddon etc. , like one experienced guy within minutes of the run said yet again he was expecting an epic run. So he is setting himself up as a hero, all he has to say is that and peole think he is a genius. Why can't the mods intervene as the guy is so wrong, as wrong as the doomsayers

[ITSY]

Just a quick mention that Philip Avery's 23:30 forecast followed the FAX output closely as it went to next Tuesday showing easterlies over the UK by Monday into Tuesday