Model output discussion - mid-winter

[nick sussex]

Just now, aggy said:

How’s the precipitation looking as I can’t see anything significant to cause major issues with snow ?

The models are hopeless with precip if it’s in relation to showers. They generally do okay though with frontal snow.

[Sky Full]

OMG!!!  Arctic blast on the way!  Polar Vortex targets UK!  UK colder than the North Pole!  Britain to be buried in deepest snow for a generation!  Shops say sales of snow shovels up by 500%!  Councils say not enough grit available to keep major roads open!  Airports facing three day closure!  Snowmegeddon ahead!!!

   

   

   

Sorry.....slipped into Daily Express mode there for a moment.  I'm alright now.   I've taken my pills. 

But - could all this happen in ten days time?  It's not impossible.....

[Carl46Wrexham]

9 minutes ago, Sky Full said:

OMG!!!  Arctic blast on the way!  Polar Vortex targets UK!  UK colder than the North Pole!  Britain to be buried in deepest snow for a generation!  Shops say sales of snow shovels up by 500%!  Councils say not enough grit available to keep major roads open!  Airports facing three day closure!  Snowmegeddon ahead!!!

   

   

   

Sorry.....slipped into Daily Express mode there for a moment.  I'm alright now.   I've taken my pills. 

But - could all this happen in ten days time?  It's not impossible.....

You are Nathan Rao and I claim my £5

[Daniel*]

28 minutes ago, MattStoke said:

There's talking about the wintry prospects with a level head and then there's going OTT with claims of it being the most potent in years. It is the latter I disagree with. Shame people don't understand the difference.

Better stick to the regional forum instead from now on. Clearly trying to be realistic, with a slightly different opinion and having the nerve to respond to those addressing me is upsetting some people.

Apologies to the mods. Will show myself out.

In December we had a fairly potent PM blast however there was more of an arctic northerly influence hence why there was colder uppers widespread -8c to -10c at a time, this has a more westerly component to it. The uppers and thicknesses are still really good in fact this looks to be the most wintriest cold zonal flow in a long time to me. There looks to be a lot of widespread showers, chance of thunder snow is there particularly for NW coastal areas or near to.

Edited January 12, 2018 by Daniel*

[Summer Sun]

ECM and UKMO at t168

[mulzy]

5 minutes ago, Summer Sun said:

ECM and UKMO at t168

The UKMO looks very progressive - let's hope the ECM is closer to the mark.

[stewfox]

1 hour ago, MattStoke said:

Merely responding to those quoting me but  won't bother anymore. I guess people will always dislike anyone with an alternative view to the talking up of cold weather, no matter how respectful they try and put their points across.

Are you basing that on the 850s ? Or historic NW'ly that have delivered much more ?

I think people can say what they want but there are some folks who just post for a reaction. So would be interested in why you feel ?

""Just can't see how it's going to be the most potent NW'ly in many years, that's all."

 

[carinthian]

2 hours ago, carinthian said:

Morning all, GFS ends with winter dream charts which looks a reasonable outcome to me. However, in the medium term there seems a variance to the flow profile at 144t between the UK/ECM run and the GFS. The chart below shows a more westerly flow at that stage . ThIs 500mb pressure /temp profile chart from UKMO at 144t highlights a tightening pressure and upper air temperature gradient to the southwest and what looks like a wave formation to develop. So not that straight forward to cold into Southern Britain as the south /SW  could yet be in line for some very stormy weather by the end of next week. Longer term looks cold for all with snow in favoured locations as Polar Continent air mixes in with the unstable Pm flow. Looks very interesting weather next week that should keep many cold fans interested in developments. Will get back this afternoon with a report from our Portal weather Service providers, specifics regarding UK next week.

C

Looks like the extended UKMO charts have rushed the developing wave through across Southern Britain between 144t-156 h to leave all in a cold unstable Pm air flow by 168t and with a Polar Continental increasing in the mix towards the end of next week. Looking good.

C

[Ruzzi]

1 hour ago, MattStoke said:

It wasn’t a slider that gave all the snow. There were showers feeding in from the North West, as there will be next week. Both December’s spell and next week will have seen flow from the NW, whether that flow is initially sourced from the Atlantic or Arctic, and next week's doesn't look anywhere near as potent.  NNW or WNW - They are both from a NW'ly direction. It is nonsense that next week will see the most potent NW'ly in years.

If you back it up with a few charts then people will stop arguing to the contrary and Vice Versa, the charts won't lie and will prove the point one way or the other. I have to say, I think this upcoming spell is definitely up there in terms of potency for a NW for some time, based on the 850's coupled with how long they last, and the fact that it's not just a 24 hour toppled with decent 850's. 

[andymusic]

6 minutes ago, Ruzzi said:

If you back it up with a few charts then people will stop arguing to the contrary and Vice Versa, the charts won't lie and will prove the point one way or the other. I have to say, I think this upcoming spell is definitely up there in terms of potency for a NW for some time, based on the 850's coupled with how long they last, and the fact that it's not just a 24 hour toppled with decent 850's. 

yes - it's the right part of winter, the longer the cold holds, then the ground temps go down too, which will make it a lot easier for accumulations of snow to get a grip, got a heavy major frost here right now and the ground looks solid and freezing, so all preperations for the snow to come

eyes down 6z trickling out - 00z was a belter, let's see if it can do as well or better

Edited January 12, 2018 by andymusic

[offerman]

Slight downgrade on gfs charts for next week in comparison to yesterday. Low pressure much further north as opposed to over us on yesterday’s runs. I’d only one run though and things could still change again for the better. Cold still looks likely with chance of some snow for some. 

 

Bloody azores high needs to stretch vertically not flat , and also it needs to move further westward too. 

[andymusic]

snow amounts won't be known in detail till closer to the time, we haven't even got into detailed model territory yet, so no-one knows exactly how much will be on it's way, but the general theme is looking excellent

looks potent to me - and that's just for starters

[Nick F]

The 00z EPS 5 day H500 mean between days 10-15 indicates weak ridging around the Iceland area with a deep trough over central/eastern Europe, which suggests that the flow could stay locked between NW, N and NE. Corresponding 5 day T850 mean at least a few degrees below average.

Edited January 12, 2018 by Nick F

[shaky]

Shortwave alert at 96 hours!!here we go again!!!

[SMU]

GFS sees an increase in instability around 120

trough over scotland & an open wave in the Atlantic....

[andymusic]

Tuesday

[DIS1970]

Huge blob of green heading this way.

[andymusic]

Wednesday

Edited January 12, 2018 by andymusic

[SMU]

If we look now ( as opposed to last night ) the low pressure is becoming more elongated ... 

still think it might split-

[andymusic]

Thursday - potential for more of us to join the party

[Man With Beard]

GFS T132 - Runner low alert - snow on northern edge

  

and then back-edge T138

Edited January 12, 2018 by Man With Beard

[Thunderywintrysnow]

Runner runner chicken dinner.

[snowice]

Gfs just loves the shortwave

[Frosty.]

The Gfs 6z screams wintry potential next week, turning much colder from early next week as we import an air mass with origins in Greenland / Northern Canada..plenty of increasingly squally wintry showers, turning more to snow..I have to say next week is looking more white than wet to me with even a spell of heavy persistent snow on the 6z later next week..  

[MR EXTREMES]

4 minutes ago, Man With Beard said:

GFS T132 - Runner low alert - snow on northern edge

  

and then back-edge T138

It's been a feature so far this autumn and winter migration of the vortex and differences in temperature gradient really can throw up surprises.

Much like winter 2009 2010 and more so in the 80s