Model Output Discussion - 23rd Jan - 12z onwards

[DIS1970]

Beware, that azoreshigh is moving in on day 10 again.

Edited January 25, 2015 by DIS1970

[Troubleatmill]

lol, I didn't think Edmonton, London was on the south coast, correct me if I am wrong!

Prety sure Mods know IP adresses.....

[stewfox]

 

deleted

Edited January 25, 2015 by stewfox

[doctor32]

Beware, that azores high is moving in on day 10 again.

 

One run that is 10 days away... will look totally different in a few runs time anyway.

[bluearmy]

Can someone help explain a little for a complete novice.

Recently there were charts for extrem cold and showing 3 polar lows. While this didn't materialise there was cold over the country and heavy snow in the North. Here where I live we were occasionally under -5 850 but still had cold rain even at elevation.

These next runs on late Wednesday Thrusday onward show the same temps for where I live in Somerset, yet many are now saying snow. What's the difference between the recent cold spell to this one as temps all look the same as then for my part of the world.

Also I note much coming down from the North I would of thought would of been much colder at this time of the year.

Many thanks for any explanations to the difference this time round.

Just to say that there were no polar lows. I can't remember the last time we saw a true polar low. and the cold period just ended only really promised cold uppers in the unreliable op timeframe (some op runs did bring in a nor'easter under the sinking low but they weren't consistent. ) tbh, the DP's look sustainably low after the day 5/6 front and that's currently unclear as to how it will traverse north to south.

This is a different evolution to last week. however, the detail is just as elusive.

[J10]

Some pretty impressive models today.

 

ECM giving a very cold and clean northerly, very good for wishbone effect and am sure other events.

 

GFS a bit messier with "shortwaves" but still with general snow opportunities some definite and some "marginal".

 

Given the winter so far you would take GFS, and the fact that this is not as good as ECM show us how good ECM is.

Edited January 25, 2015 by J10

[Biggin]

The Netweather forecasts don't support any optimism for the South.

No chance of a quote?? What do they say??

[Captain Shortwave]

A white blanket starts to be unrolled over the country...........

Whilst hideously unreliable. I think that chart does show well the potential for snow to fall anywhere Wednesday night into Thursday given the initial surge of cold air and the deeply unstable airmass. Of course areas close to exposed coasts will definitely be favoured for significant accumulations. A dusting could occur almost anywhere though.

[snow freak]

A white blanket starts to be unrolled over the country...........

except us in the east midlands and east Anglia that is.  just so typical of this winter.  when we get the potential for snow it doesn't make it to us and then when it turns milder we end up with the rain.  abysmal

[TEITS]

Despite the disagreement within the models the general theme is apparant to me.

 

Snow showers Wednesday night/Thurs as I mentioned earlier (odd Wales isn't included in the Met O warnings).Less cold thereafter before turning colder again into the weekend. However any snow showers into the weekend are likely to be restricted to coastal counties.

 

So like I said this morning the best snow potential is Wed night/Thurs. Beyond and I personally cannot see anything to get excited about at this stage.

[bluearmy]

Please people - get the cold in and see what happens. Don't make assumptions on precip this far out.

also, I wonder if there is a misconception on what a cold showery airstream delivers. As I recall, you saw the dk grey cloud in the distance. The vista disappeared as the snow came in and you could then see the flakes coming. Then it arrived and it was like a blizzard for a few mins. Not much settled and the ground became wet as the snow melted. Then the skies cleared and the ground dried. That's a snow shower. a trough is different as it delivers a more sustained period of snowfall which can indeed lead to cover. Of course, at night, you can't see it coming but on the flip side, the showers generally leave a dusting that survives till morning.

There endeth the lesson!

Edited January 25, 2015 by bluearmy

[IDO]

ECM 10 day totals clearly show the favoured areas with east and south coasts trace amounts and the SE small amounts. High snow amounts on hills and mountains with a NW and W bias:

 

  MarkVogan
ECMWF Europe SNOW COVER by day 10. Worst on winter coming up... http://t.co/hXZPryze5U
25/01/2015 11:05

 

Obviously with snow these are very rough but it does help with hot spots and therefore where the most likely heavy falls will be.

[J10]

Despite the disagreement within the models the general theme is apparant to me.

 

Snow showers Wednesday night/Thurs as I mentioned earlier (odd Wales isn't included in the Met O warnings).Less cold thereafter before turning colder again into the weekend. However any snow showers into the weekend are likely to be restricted to coastal counties.

 

So like I said this morning the best snow potential is Wed night/Thurs. Beyond and I personally cannot see anything to get excited about at this stage.

 

Probably a bit early further south. Still plenty of time, and it is better to give warning to the most obvious locations, rather than dish out a warning today and then remove it tomorrow.

[weather_it_will]

It actually seems to me that this could be the most severe spell for a few years considering it is coinciding with the coldest part of winter.

Are you serious? I detect an IMBY.

 

These northerly type of events rarely produce anything worthwhile away from coastal areas and high ground.

 

GFS chart for Thursday below shows this is a marginal event for North Wales and the North East.

 

[Polar Maritime]

Wise words there Blue, It's the general theme thats important atm. Way to early for surface detail.

Edited January 25, 2015 by Polar Maritime

[stratty]

Please people - get the cold in and see what happens. Don't make assumptions on precip this far out.

also, I wonder if there is a misconception on what a cold showery airstream delivers. As I recall, you saw the dk grey cloud in the distance. The vista disappeared as the snow came in and you could then see the flakes coming. Then it arrived and it was like a blizzard for a few mins. Not much settled and the ground became wet as the snow melted. Then the skies cleared and the ground dried. That's a snow shower. a trough is different as it delivers a more sustained period of snowfall which can indeed lead to cover. Of course, at night, you can't see it coming but on the flip side, the showers generally leave a dusting that survives till morning.

There endeth the lesson!

 

.........question

 

When we do get a 'wishbone' effect, how come France/mainland Europe seems to keep hold of it's showers/precipitation longer....or are they more 'home-grown'? I understand the English Channel can pep them up somewhat, but to such a huge degree that they can then travel over land so much longer than the UK?

[Banbury]

Are you serious? I detect an IMBY.

 

These northerly type of events rarely produce anything worthwhile away from coastal areas and high ground.

 

GFS chart for Thursday below shows this is a marginal event for North Wales and the North East.

 

To show an even argument you should also post ECM and GFS to even things out

[The Weather Dragon]

Ok - cold yes that's on its way - exceptional cold NO

A potent PM airmass brings snow for the favoured areas late Weds/Thursday

Then we rely on some Mid Atlantic ridging for the weekend and first few days of Feb - not expecting much from this - but some will do ok

Far from a Nationwide Event

Not being purposely negative - just realistic

[Continental Climate]

Ok - cold yes that's on its way - exceptional cold NO

A potent PM airmass brings snow for the favoured areas late Weds/Thursday

Then we rely on some Mid Atlantic ridging for the weekend and first few days of Feb - not expecting much from this - but some will do ok

Far from a Nationwide Event

Not being purposely negative - just realistic

A very relaistic post, have we learned nothing from the recent disappointment we suffered last week? This will favour hills and some western parts of the UK but the heavily populated south and east of the UK will get nothing from this 'spell', Im just trying to temper expectations and stop toys getting thrown out of prams when nowt arrives for the majority. To have a nationwide snow event we need sustained Northern blocking and that isn't on show im afraid. 

[Jason M]

GEFS better IMHO.

By day 9 a real mix but ptrb 18 is currently going all cobra :-)

http://www.meteociel.fr/modeles/gefs_cartes.php?code=18&ech=276&mode=0&carte=0

Edited January 25, 2015 by Jason M

[lorenzo]

Well, if you are quibbling over charts like these and looking for the 850 temps being 'marginal' or 'mixed out' , 'mixed up' good luck tearing your hair out with that !

 

This is not far away from black hole territory on ECM Anom plot and a noteworthy trough in any month of winter, okay it isn't a beasterly and it doesn't stand up to the trop vortex diving into N. Conus. But, that said it's pretty damn good. Charts speak for themselves so won't go into detail, coupled with clear early warnings issued from mid week. A model thread with the theme of hunting for cold continues.

 

 

 

 

[bluearmy]

.........question

 

When we do get a 'wishbone' effect, how come France/mainland Europe seems to keep hold of it's showers/precipitation longer....or are they more 'home-grown'? I understand the English Channel can pep them up somewhat, but to such a huge degree that they can then travel over land so much longer than the UK?

I don't believe that a n/nw airflow delivers showers well inland into Europe stratty ??

Take into account that there it also helps to have hills and mountains to break up the showers.

[sorepaw1]

I will stick my new reputation on the line and say virtually everywhere by next Sunday will have experienced snow to lower levels

and don't forget the wind strength which there should be some impressive drifting off snow.to exposed hills and open low lying fields,this isn't a ramp it's based on previous experience with this current chart set up and what the models are showing.i don't really like to forecast snow even this close but to me it seems inevitable imo,and that's all it is..it's worth watching Nina ridge weather presenter on the bbc iplayer website

[bluearmy]

Ok - cold yes that's on its way - exceptional cold NO

A potent PM airmass brings snow for the favoured areas late Weds/Thursday

Then we rely on some Mid Atlantic ridging for the weekend and first few days of Feb - not expecting much from this - but some will do ok

Far from a Nationwide Event

Not being purposely negative - just realistic

A very relaistic post, have we learned nothing from the recent disappointment we suffered last week? This will favour hills and some western parts of the UK but the heavily populated south and east of the UK will get nothing from this 'spell', Im just trying to temper expectations and stop toys getting thrown out of prams when nowt arrives for the majority. To have a nationwide snow event we need sustained Northern blocking and that isn't on show im afraid.

Maybe. Maybe not. It's Sunday. The cold doesn't arrive in the south till early Thursday.

This is NOT the same as last week. This a trough led event, not a block. No continental feed. As such, the London temps are impressive for a week.

http://www.meteo24.fr/fr/home/meteo-france-et-europe/passion-meteo/ensemble-de-previsions.html?eps=london

Note the tight temps coupled with a steady mean increase in precip.

Anyway, people believe what they want to and if it saves them coming on here going nuts when the snow doesn't settle or, god help us, falls twenty miles up the road, then that's fine by me.

Edited January 25, 2015 by bluearmy

[khodds]

I will stick my new reputation on the line and say virtually everywhere by next Sunday will have experienced snow to lower levels

and don't forget the wind strength which there should be some impressive drifting off snow.to exposed hills and open low lying fields,this isn't a ramp it's based on previous experience with this current chart set up and what the models are showing.i don't really like to forecast snow even this close but to me it seems inevitable imo,and that's all it is..it's worth watching Nina ridge weather presenter on the bbc iplayer website

Hi Sorepaw,

Nice to see you posting on here - I remember you from the MM days, your input is most appreciated