Model output discussion - 20th Feb onwards

[Snowynorth]

2 hours ago, emotional rollercoaster said:

Well the last cold snap recently had higher dew points than the coming set up and it snowed that was from nw flow so I'm somewhat perplexed by -7 not enough to cut it we seen snow on the south coast in April from as low dew points 

the warmer North Sea temps will help to aid in better convection and with cold air in place across parts of the U.K. I'd think that a ne flow or Arctic flow would be ideal for some convective snowfall.

although features running along the south depending how far south they slide then mixing out cold uppers could well be a feature.

but this mornings ecm and the gfs6z show the Scandinavian deep purples getting closer and closer to the uk which also could well set us up for better instability along with added bonus of frontal systems running threw the channel this also possible.

i got my towel out the ring I'm keeping hold of it until I see a complete breakdown of the cold signal.

In bold yes exactly what I said on my earlier post.

I just noticed your location, seems you're talking from an IMBY point of view, I'm talking about UK wide, big difference! 

As I said, upper air temperature alone does not determine snowfall... You need to look at parameters at the surface and between 850hpa not just at the 850hpa temp..

 

Edited February 22, 2016 by Snowynorth

[karlos1983]

10 minutes ago, Snowynorth said:

In bold yes exactly what I said on my earlier post.

I just noticed your location, seems you're talking from an IMBY point of view, I'm talking about UK wide, big difference! 

As I said, upper air temperature alone does not determine snowfall... You need to look at parameters at the surface and between 850hpa not just at the 850hpa temp..

 

I'm pretty certain, being on the South Coast, he is not talking in an IMBY point of view. Convective snow off North Sea is about as much use as chocolate tea pot for the South Coast, unless you live in Kent and occasionally East Sussex. 

Edited February 22, 2016 by karlos1983

[mushymanrob]

saying march will be cold (and the current outputs dont give much hope of warmth into early march) isnt the same as saying march will have a big freeze like 2013. to me, when the outlook is either 'below average' or 'cold' it means just that - cold for the time of year - below average.  so we get 6-7c maxs instead of 9-10c , but in any sun and out any breeze itll feel much better at 6c then a breezy overcast 10c.  (figures are just examples).

[MR EXTREMES]

42 minutes ago, karlos1983 said:

I'm pretty certain, being on the South Coast, he is not talking in an IMBY point of view. Convective snow off North Sea is about as much use as chocolate tea pot for the South Coast, unless you live in Kent and occasionally East Sussex. 

I'm talking in general northeast eastern England southeast and the south coast seen many many winters of snow cover from convection from north east even more so than straight easterly 

[karlos1983]

Almost a nice snow event for the Southwest at +96 on the GFS

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=96&mode=0

[winterof79]

Nice convective easterly

And yes its cold too

 

[karlos1983]

4 minutes ago, winterof79 said:

Nice convective easterly

And yes its cold too

 

I would imagine showers galore just about anywhere in that sort of setup.

UKMO agrees also

Edited February 22, 2016 by karlos1983

[winterof79]

5 minutes ago, karlos1983 said:

I would imagine showers galore just about anywhere in that sort of setup.

One would think so and driven well in land on a stiff breeze. Just all week to wait Lol. It could upgrade though and deepen a little more tightening those isobars

 

UKMO

Edited February 22, 2016 by winterof79

[Lampostwatcher]

Lots of snow showers coming in from the east on the latest gfs looks great for the eastern side of the uk from sat

[feb1991blizzard]

2 minutes ago, karlos1983 said:

I would imagine showers galore just about anywhere in that sort of setup.

A few light showers in the south and marginal.

[Jimmyh]

Just now, feb1991blizzard said:

A few light showers in the south and marginal.

where is the marginality in that I see know westerly regime on these outlooks to make it marginal with a -8   easterly incoming or am I missing something??

[Frost HoIIow]

1 minute ago, winterof79 said:

Nice convective easterly

And yes its cold too

 

And in an easterly flow we do not need Jan 1987 style uppers for snow as the dew point is much lower from the continent compared to other directions so even low ground can get in on act. Would be great to get those -15C to -19C uppers from 1987 but hey ho lol

[karlos1983]

3 minutes ago, feb1991blizzard said:

A few light showers in the south and marginal.

IMO I dont think it would be marginal, not with uppers of -7 and -8 with a continental element

[feb1991blizzard]

Just now, Essex snowman said:

Feb1991 U NEED TO READ THE CHARTS WITH your GLASSES ON :-) 

Everone was saying this with an Easterly in Feb 2013 which had 850mb temps of -12c and it still delivered relatively little, go through your archives and look at the great Easterlies, they all have one thing in common deeply low heights at 500mb with steep lapse rates.

[MR EXTREMES]

2 minutes ago, feb1991blizzard said:

A few light showers in the south and marginal.

Really would love you to enlighten us on why marginal 

 

unless of of coarse you are talking about a specific location.

gfs and ukmo as I suspected throwing out the surprises will the ecm agree I'd be inclined to think yes it will.

will these charts come to fruition well there's certainly a broad agreement although I still want to see these runs on tomorrow evenings output but certainly exciting stuff.

[Jimmyh]

Just now, feb1991blizzard said:

Everone was saying this with an Easterly in Feb 2013 which had 850mb temps of -12c and it still delivered relatively little, go through your archives and look at the great Easterlies, they all have one thing in common deeply low heights at 500mb with steep lapse rates.

we aren't saying this will be a great easterly we are saying for the south starved people is best chance of some convectivity and showersn off a warm north sea. better to b half full than half empty

[feb1991blizzard]

[karlos1983]

UKMO @ 144 would feel raw in the south

 

 

[Captain Shortwave]

The marginality with easterlies isn't necessarily the precipitation type but the need to have cold enough 850s and low enough 500mb heights to generate showers instead of a cloudy and dry set up. The GFS tend to show coastal drizzle/snow grains as opposed to the 06z where 850s were a touch colder and 500mb heights were lower which meant a more sun and showers type set up.

The models are starting to faff around with the clearance of those low heights over Iceland at the end of the week which is a little concerning as this hold up is tending to hinder the development of a showery east/north easterly as the low clears into Iberia, along with the flatter upstream pattern for the same reason.

GFS/UKMO at day 5

   

The quicker the low/cold pooling moves into Iberia the better, it also maximises the opportunity of the same system linking up with the trough to our north east which of course lower the 850s and 500mb heights.

I will say at this stage that there is every possibility of something being throw west/north west from the system later on in the weekend which could cause a surprise.

Edited February 22, 2016 by Captain Shortwave

[Gowon]

3 minutes ago, feb1991blizzard said:

A few light showers in the south and marginal.

I agree.. it looks great, but the uppers are crap.. I'm a bit underwhelmed tbh.

 

Just now, Jimmyh said:

we aren't saying this will be a great easterly we are saying for the south starved people is best chance of some convectivity and showersn off a warm north sea. better to b half full than half empty

yeah, but gonna need lower uppers to generate proper snow showers.

[feb1991blizzard]

5 minutes ago, emotional rollercoaster said:

Really would love you to enlighten us on why marginal 

 

unless of of coarse you are talking about a specific location.

gfs and ukmo as I suspected throwing out the surprises will the ecm agree I'd be inclined to think yes it will.

will these charts come to fruition well there's certainly a broad agreement although I still want to see these runs on tomorrow evenings output but certainly exciting stuff.

I guarantee you will get Jack with that, don't forget there was rain in some parts of the SE on feb 1st 2009 with uppers even lower.

 

IN fact the PPN type charts are showing marginality and that's on a model that massively exaggerates the snow risk!!

Edited February 22, 2016 by feb1991blizzard

[winterof79]

3 minutes ago, feb1991blizzard said:

Everone was saying this with an Easterly in Feb 2013 which had 850mb temps of -12c and it still delivered relatively little, go through your archives and look at the great Easterlies, they all have one thing in common deeply low heights at 500mb with steep lapse rates.

Delivered  knowt here

 

[Banbury]

3 minutes ago, Vivian said:

I agree.. it looks great, but the uppers are crap.. I'm a bit underwhelmed tbh.

 

yeah, but gonna need lower uppers to generate proper snow showers.

Crap uppers??

 

What an odd comment

[feb1991blizzard]

1 minute ago, winterof79 said:

Delivered  knowt here

 

That wasn't replicated in most areas though.

[mulzy]

A cool largely dry spell with night-time frosts is now to be expected according to the latest NWP.  There is a risk of some precipitation in the west on Friday which may turn wintry in places (UKMO day 4 chart is more suggestive of this).