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Model output discussion 25th Jan - The final third of winter beckons..


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Knee-jerk, a joke!?...if that is what you believe then simply don't follow. I was simply highlighting what the EC ENS are showing and to be honest certain people need to read before commentating, perh

Yes, I recognise these sage pieces of sentiment so well. The signals are always wrong, and the professionals (and others) who try to present and explain them, when an operational appears to take away

This is an unusual set up for the UK, hence the model variations. The bigger picture according to seriously knowledgeable people like @Tamara tends to suggest that the hemispheric factors that actuall

Posted Images

So the models all show a cold east/northeast/southeast flow from wednesday till early next week, then who knows where we go after... also snow chances increasing over weekend with some accumulations possible.

Capture.thumb.JPG.d35b638b6142e89e16b79b8e671d9caf.JPG

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1 minute ago, blizzard81 said:

The ecm op looks to be quite a big upgrade in the short term. Very happy with that.

Yes I agree, FI is FI and we will have to wait and see but ECM has been upgrading and prolonging the cold spell by a day every day so if it doesn't improve again tomorrow from 144 I might consider it a little more seriously.

JMA does give it support though so it will be interesting to see how well the Op is represented from day 8 within its ensembles.

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15 minutes ago, doctor32 said:

So the models all show a cold east/northeast/southeast flow from wednesday till early next week, then who knows where we go after... also snow chances increasing over weekend with some accumulations possible.

Capture.thumb.JPG.d35b638b6142e89e16b79b8e671d9caf.JPG

I'll take that everyday of the week :)

Happy with the models today, could potentially be the start of the best cold spell in years. Still think there could be a few upgrades with regards snowfall, often happens in these setups

Edited by North East Blizzard
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Excuse the basic nature of the questioning, but is the basic set up for the weekend coming locked in now? 

We have the low that moves from Biscay all the way down past Madeira between Friday and Sunday, with the Azores high out halfway to Bermuda. I can't help but think theres more to develop in this respect.

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10 minutes ago, Singularity said:

Fun fact from another strange looking ECM run in the longer-term: before that malarkey, the long-draw SE upper flow draws in such high uppers because of a foehn effect off the Alps at the border of Italy. Run +144 to +192 and you can really see how the warmer uppers spring up just NW of the mountain range.

With the surface flow more to the east it's hard to discern whether such a warming effect would be in place for the surface air. Just imagine if we were bathed in air warmed by descent down the slopes of the Alps... that's be an incredible case of irony given how SE flows usually are at this time of year. In any case, at least a brief less cold interlude is looking likely by mid-next week unless a low can develop on the NE flank of the plume exiting Africa in about a week's time.

ecmt850.168.png

With the clash of warm and cold air in that area, it seems plausible that such a low could develop. After all, it's how a lot of our summer plumes get broken down prematurely :rolleyes::D

 

So those later stages of the run... well, at +168 as shown above, you have the polar vortex clearing off to Siberia and a huge cut-off trough in the mid-Atlantic (too huge? Seems a bit much!) which on the face of it is ideal for having a blocking high move from our SE to our NW. Trouble is ECM leaves a shortwave low behind which causes the jet stream, heading NW having curved away from the block over S. Scandinavia, to then curve back north when we'd like it to just continue on NW. 

Technically it's feasible but it would be against the odds - in light of which its extraordinary that the 12z GFS was along similar lines (but with a shallow low nudging in from the Atlantic early next week which is why it turns mild at the surface so soon. Naughty GFS). At least GFS shows us that cold could quickly return past day 10. ECM would need a day or two longer for things to rearrange sufficiently; it sure does get itself in a right state days 9-10.

I think even the ECM would get there eventually. I think the easterly and then Greenland heights are two separate evolutions- it's just it had looked initially like we may go seamlessly from one to the other. As often is the case where the UK is concerned, it very rarely pans out like that. 

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UW144-21.GIF?06-18 gfs-0-144.png?12 gem-0-144.png?12

Playing a bit of spot the differences here at +144, for the heck of it. Seems GEM just decides to give the deep trough a neutral rather than positive tilt between +120 and the above which allows the block to build more to our NW prior to the transferal of the vortex to Siberia. Meanwhile the low S of the UK is a little further east, which helps keep the high orientated better over the following days.

UKMO is closest to GEM in terms of positioning of broad scale features, but still different enough that it would likely not play out so wondrously going forward.

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17 minutes ago, Singularity said:

Fun fact from another strange looking ECM run in the longer-term: before that malarkey, the long-draw SE upper flow draws in such high uppers because of a foehn effect off the Alps at the border of Italy. Run +144 to +192 and you can really see how the warmer uppers spring up just NW of the mountain range.

With the surface flow more to the east it's hard to discern whether such a warming effect would be in place for the surface air. Just imagine if we were bathed in air warmed by descent down the slopes of the Alps... that's be an incredible case of irony given how SE flows usually are at this time of year. In any case, at least a brief less cold interlude is looking likely by mid-next week unless a low can develop on the NE flank of the plume exiting Africa in about a week's time.

ecmt850.168.png

With the clash of warm and cold air in that area, it seems plausible that such a low could develop. After all, it's how a lot of our summer plumes get broken down prematurely :rolleyes::D

 

So those later stages of the run... well, at +168 as shown above, you have the polar vortex clearing off to Siberia and a huge cut-off trough in the mid-Atlantic (too huge? Seems a bit much!) which on the face of it is ideal for having a blocking high move from our SE to our NW. Trouble is ECM leaves a shortwave low behind which causes the jet stream, heading NW having curved away from the block over S. Scandinavia, to then curve back north when we'd like it to just continue on NW. 

Technically it's feasible but it would be against the odds - in light of which its extraordinary that the 12z GFS was along similar lines (but with a shallow low nudging in from the Atlantic early next week which is why it turns mild at the surface so soon. Naughty GFS). At least GFS shows us that cold could quickly return past day 10. ECM would need a day or two longer for things to rearrange sufficiently; it sure does get itself in a right state days 9-10.

Give it another couple of runs, a different scenario will probably develop. This idea will go straight out the window probably, depending on the behaviour of that low pressure to the SW and the direction it decides to take over the next couple of days. 

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Just now, East_England_Stormchaser91 said:

Give it another couple of runs, a different scenario will probably develop. This idea will go straight out the window probably, depending on the behaviour of that low pressure to the SW and the direction it decides to take over the next couple of days. 

Absolutely, and I see Steve M has posted some similar ideas with respect to the distribution of low pressure over S. Europe. At the moment it all looks a bit intuitive to me; I can't recall a case in times past when things have panned out as currently being shown from where we look to be this weekend.

When it comes down to it, I just really enjoy picking apart model runs. I'm probably sub-sane by some people's standards :laugh:

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56 minutes ago, Frosty. said:

I don't think it's time to hit the panic button..we have a cold spell in the bag and nobody knows how next week onwards will look with any confidence so just enjoy the very cold Easterly.

Wasn't it mid Jan recently we had 'HP TO THE EAST OF THE UK' and the models were showing the Atlantic to come flooding in around Sunday Jan 22nd, did it happen.... Nope!!!  

That week the 26th we had temps at 0c and below during the daytime and the models 7days prior had us for rain, wind and double fig temps :nonono:

What stopped this.....HP/blocking:cold:

Edited by Dancerwithwings
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8 minutes ago, Nouska said:

Psssstt......

The daily ECM 00Z may not have been great but the monthly run from same time frame comes up with goodies. :D

 

Is that January?

Edit: I see you've changed them - tasty!!

Edited by Man With Beard
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11 minutes ago, Steve Murr said:

Evening All -

So another day at the office & finally we are now seeing some indications that the very dry boring Easterly might not be a very dry boring Easterly...

Modelling today has seen better agreement in the flow becoming ENE across the week courtesy of a developing area of lower heights somewhere close to the E or SE -

This will enhance the instability for the E & SE but also support the push west of the cold uppers- creating more in the way of snow flurries-

Its pretty easy to suggest the areas prone to seeing snow - however if I was pressed to pinpoint the region most at risk from 'disruption' It would be Lincs up to tyne & wear - however the models especially the euros that the risk moves further towards the SE fri / sat & early sun...

The rest of the country is dependent on how much the Easterly onshore flow can project those showers across & again Friday > Saturday looks best with low maxima & solid frosts-

Detail is a bit sketchy but an area of snow could cross southern areas Sunday - which also may herald milder air from the SE-

Post 144 the models have 'edged' towards the ever progressive ECM - with the wedge of high pressure from the atlantic following a rainbow shaped journey from the azores via Iceland then on down to scandi - encouraging low heights over spain to lift up Northwards-

however this by no means a done deal as its theory is based on model assumptions in areas where they have been totally wrong in the last few days

* The path could be interupted by a shortwave in 'any' location-

* The SE flow at 144 > 168 could still sharpen up to Easterly - why? The modelling of the Iberian low has been to deep & on the flip side of that the modelling of any italian heights has been to shallow- so the seesaw could swing towards a flatter flow..

like this

http://www.meteociel.fr/modeles/gefs_cartes.php?code=1&ech=6&carte=1&mode=0

* The high pressure may stretch/shear east & west rather than just 1 blob-...

which leads onto the final point.. The greenland high...

In the timeline about 216-240 we see 'potential' for a sharp rise in pressure over Greenland, remember after research the Greenland high really only develops from 2  regions

* azores high ridging North 

* Scandi high angled NW 

or both- ( Nov 2010 was both ) 

Ive picked a chart from todays 12z - 

IMG_2377.thumb.PNG.7e430aa39f5b4e8ec5e0b499ac7d1b9c.PNG

Note the allignment of the flow is from SE to NW - you have all that energy essentially reversed against the jet & what happens is the jet gets smashed upwards over Greenland - hence greenland high...

So, in summary tonight- cold from Weds, poss snow in the NE along the stalled front before it fizzles... flurries Thurs in the SE/E& NE- with everything pushing further inland Fri / Sat- .... poss band of snow over the SE > then south / midlands / SW on sun...

Some accumulations possible...

S

Cheers Steve, some great insight there.

For us in the SE do you think there's any chance of some sort of streamer setting up going by the current output a la Feb 2009? Some good accumulations here in NW Kent from a streamer off the Thames

thanks

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well i must admit after reading the views of people here this morning and getting a little excited, i am now feeling slightly deflated, lol, just trying to get a take on what areas of the uk are going to experience the upcomming chilly/cold spell, from an imby its no snow, no frost and nothing really cold

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12 minutes ago, cjwardy said:

Cheers Steve, some great insight there.

For us in the SE do you think there's any chance of some sort of streamer setting up going by the current output a la Feb 2009? Some good accumulations here in NW Kent from a streamer off the Thames

thanks

Just quickly- at this stage thats unlikely ( was 30cm widely ) sub 10cm is the expectation ATM - at least though the flow is slower so PPN will last longer just probably lighter- however lets see how things develop-

NB heights & how much lower they were

IMG_2378.thumb.PNG.234f5c77ce61a6d10608d9afea19dbbe.PNG

best

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4 minutes ago, sparky1972 said:

well i must admit after reading the views of people here this morning and getting a little excited, i am now feeling slightly deflated, lol, just trying to get a take on what areas of the uk are going to experience the upcomming chilly/cold spell, from an imby its no snow, no frost and nothing really cold

Sorry  your in a prime position as it currently stands  a stiff easterly showers off the North Sea. Happy days 

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Op on the mild side of the EPS again for de bilt, especially at day 10. Also some cold options showing up, 15 day EPS may show this better....

IMG_4212.PNG

Edited by Ali1977
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