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Paul

Model Output Discussion - Stormy Period Inbound...

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Well, wow, GFSP will be a cheerful sight for cold lovers. Shades of 1978/9 about that. Its sister output doesn't share quite the same outcome and the differences so far as my amateur I can see are very slight. In the main op run the Biscay low from T168 is similar but the Azores high behind it, or rather west of it, belly-flops across the UK much more quickly. In the GFSP the high takes longer to form, and actually for a brief moment links to the Scandinavian high pulling in a bitter north-easterly flow. You can see this around T186.  

 

These are not outlandish timeframes but so much could go wrong with that kind of development.

 

Meantime we're in for some fun and games for the remainder of the week. Some snow potential in the showers even down to low levels today and tonight. And then the latest fax charts are pretty dramatic for tomorrow 00h00 on the leading edge of the low as the warm front pushes through. Hold onto your hats. http://www.weathercharts.org/ukmomslp.htm

 

By UK standards this is interesting stuff, so I hope there's a bit of something for everyone.

Edited by West is Best

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GEFS don't, as of yet, go the way of the GFSP;

post-12721-0-17759500-1421129399_thumb.jpost-12721-0-41269000-1421129413_thumb.j

Although plenty of scope for further marginal snow events across parts of the UK at times, so not all that bad.

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Blimey o'reilly. I've just seen UKMO 0z. That is a thing of beauty for cold lovers. The evolution is sooooooo precarious but that's the holy grail of a Svalbard high is it not (Steve Murr?).

 

As I say, incredibly precarious and therefore bet it doesn't come off. Fun to look at though! It's only T144 folks :)   :cold:

Edited by West is Best

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The interesting time frame on the P this morning (probably won't verify) is around T162 when a little low forms on the front near Ireland and travels ESE into Biscay and eventually over Barcelona. The precipitation doesn't affect the UK but en route it manages to drag some quite cold air in from the NE. It gets a little interesting after that with HP to the NE orientated SW/NE over the UK with well below average temps but very dry.

Charts courtesy weatherbell

post-12275-0-44321900-1421130367_thumb.p

post-12275-0-31251800-1421130376_thumb.p

Edited by knocker

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ECM has the wedge 

ECM1-144.GIF?13-12

decent output this morning with a real chance of creating some frontal snow events from beyond this coming weekend.

Low pressure pretty much slides SE through the UK, given the 850s, we must be pretty close to a decent snow event here

ECM1-192.GIF?13-12

Edited by Captain shortwave

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It is clear there is high uncertainty at the moment especially as to where the "10%" Atlantic low goes. UKMO and GEM continue to send it to the UK:

 

post-14819-0-46318100-1421130208_thumb.p  post-14819-0-84525500-1421130208_thumb.g

 

Even then there are differences with respect to the amplification to it's rear. This is no surprise as we have had these a few times this winter and the models always struggle. The GEFS have moved towards the GEM/UKMO solution with about 50% now going with that Atlantic low much further east (and mixing with the Scandi trough) than diving towards Portugal. However it is very fluid how that low interacts on both routes. It is clearly a period of model watching where anything after Friday is pure FI.

 

ECM for instance breaks up the Atlantic low in the Azores High so has little impact on the pattern: post-14819-0-78569800-1421130745_thumb.g

 

As for snow later today and tomorrow, there is very little according to the hi-res models. Again high ground favoured. Very narrow bands moving west to east:

 

post-14819-0-64702600-1421131052_thumb.p  post-14819-0-31155700-1421131052_thumb.p

 

Though frequent showers in the NW/W and maybe Central Scotland more organised.

 

Still strong winds Wed night to Thur Morning: post-14819-0-92933600-1421131051_thumb.p Wet: post-14819-0-42920000-1421131268_thumb.p

 

ECM at D7 keeps the wedge of heights to the north and an undercut: 

 

post-14819-0-86596200-1421131406_thumb.g  post-14819-0-38714600-1421131697_thumb.g post-14819-0-94501500-1421131786_thumb.g

 

Much better than last night's and more in line with the GEFS and ECM mean.

 

 

 

 

 

 

Edited by i'm dreaming of...

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ECM picking up on the developing trend...not too shabby at day 9!

 

post-2071-0-53877800-1421132400_thumb.gi

 

Chart of the winter for day 10...

 

post-2071-0-89576300-1421132614_thumb.gi

Edited by KTtom

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I agree with ido with the situation after the weekend. It could be anything at this stage. The ecm drops the low over the UK and then there is a general area of low pressure to the SE over Europe, the HP over the UK isn't developed and eventually another system enters the scene from the west. All fairy land stuff at the moment.

 

The GEFS anomaly at T240 supports the Ps surface take but it's very transitional indeed and is consistent with last nights ext, anomaly.  Watch this space.

Edited by knocker

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ECM remains consistent with its mean anomolys. The 'messy' period between the weekend scandi trough and ensuing euro trough perhaps becoming a little clearer although the gfs brothers are still overly interested with high SLP compared to the ens.

I would suggest the ECM 00z op provides a compromise between its previous interim modelling and the gfs amplification. To me, it's the best way forward if you want sustained cold.

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Well we have a totally different outcome on all models this morning out into fi. But the ECM looks best of the bunch at 240hrs. But as we know that's day 10. So a lot can change before then.

Edited by terrier

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Yep that ECM at T240 is pretty outstanding. Well, especially if you like easterlies. That puts us into the deepfreeze:

 

As others have said above though, there's so much uncertainty about the evolution, with several variables and possible outcomes (including return to zonality) so it's just fun to watch at the moment. If none of it comes off it will have helped January pass. And you never know, they just might.


Well we have a totally different outcome on all models this morning out into fi. But the ECM looks worsts of the bunch at 240hrs. But as we know that's day 10. So a lot can change before then.

 

You mean best for cold? As KTtom has said, that's the chart of the winter. Look at those upper temps!

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Yep that ECM at T240 is pretty outstanding. Well, especially if you like easterlies. That puts us into the deepfreeze:

 

As others have said above though, there's so much uncertainty about the evolution, with several variables and possible outcomes (including return to zonality) so it's just fun to watch at the moment. If none of it comes off it will have helped January pass. And you never know, they just might.

 

You mean best for cold? As KTtom has said, that's the chart of the winter. Look at those upper temps!

yes sorry not woken up yet lol

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ECM remains consistent with its mean anomolys. The 'messy' period between the weekend scandi trough and ensuing euro trough perhaps becoming a little clearer although the gfs brothers are still overly interested with high SLP compared to the ens.

I would suggest the ECM 00z op provides a compromise between its previous interim modelling and the gfs amplification. To me, it's the best way forward if you want sustained cold.

I sense your not overly confident of longer and better colder chances.

Surely this could be the effects of recent strat events!.

The ukmo looks good ecm been a good model recently and has shoot down other models especially when cold set ups pop up the ecm normally kicks the butts of other models.

I think the gfs both parallel and operational are way over excited the ukmo looks ok ecm not really that good so Id be inclined to follow the ukmo I to feel very uneasy about mid term developments although end of jan normally is the time when we see the high pressures become more of a feature.

But I'm on the fence can't really see much for us on the south coast in terms of snow but will feel cold in polar air.

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Those who wrote off winter must be feeling pretty embarrassed now

Some stunning charts, frontal snow, sliders, easterly, all in FI admittedly, but the trend is for colder weather

The cold heart of winter is coming

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Don't know if If this was posted on here last night. Don't recall seeing it....

Fergie on TWO:-

UKMO latest assessment (just issued) into trend period concludes: "...the period looks like being the most prolonged spell of below average temperatures since August 2014. No exceptionally cold weather is signalled, but the longevity of the below average temperature regime is notable after the very mild autumn/winter so far." You'll recall that GloSea5 called for Jan to end-up as probably a tad below average...

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Dear me, this will be a cold spell built on sand as it's all down to the movement and alignment of low pressure systems rather than a controlling block.

Precarious is putting it mildly but opportunities for snow will be plenty and if I was a BBC weather forecaster I would order a large batch of Paracetomol!

They are going to need it.

Andy

Don't know if If this was posted on here last night. Don't recall seeing it....

Fergie on TWO:-

UKMO latest assessment (just issued) into trend period concludes: "...the period looks like being the most prolonged spell of below average temperatures since August 2014. No exceptionally cold weather is signalled, but the longevity of the below average temperature regime is notable after the very mild autumn/winter so far." You'll recall that GloSea5 called for Jan to end-up as probably a tad below average...

For the CET for January to end up a tad below average the next two weeks will have to be very cold!

Andy

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Promising ecm ens mean incoming re anomolys and uppers (both heights and 850's)

Edited by bluearmy

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Just to add a word of caution that the meto aren't expecting any significant cold even though they're expecting below average temps, so until this changes the likelihood is that some of the more appealing permutations (like the GFSP) won't verify, though some cold is likely to. I only say this as they've been right on the money so far and it's important to bear in mind before running away with the possibilities.

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Well we can all say a big farewell to the GFS and welcome in the GFS parallel, as from tomorrow it replaces its older brother for good. Tis pleasing to cold fans that the parallel shows the best of any cold/snow chances.

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There does seem to be a bit of correlation between the GFS now and the ECM which is always nice to see and the UKMO isn't a trillion miles away from both either.

 

This chart reminds me very much of March 2013, when we had Low pressure slipping South East ,  centered just West of the UK which ended up in a South Easterly feed coming off a cold continent and many areas especially along the South Coast saw copious amounts of snow from that...

 

ECM1_168_GIF_13_12.gif

 

I recall the charts showing something very similar and then as the runs went on the Low pressure system kept getting shunted West, but the difference then was that the cold air was already in place across the whole of Europe , this time it's different. 

 

However, it just goes to show how the charts can change, I recall about 10 days ago the feeling that we were all looking down the barrel of a long Atlantic steam train, indeed almost everyone was writing off the first half of Jan for cold prospects and today it's going to snow in many places. 

 

Let's hope the trend to colder conditions continues, Feb is always in my experience the best time of year to experience snow so long as it's earlier in Feb.

 

Exciting times, but I'm not holding out much hope IMBY 

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