Wales (Cymru) Regional Discussion 20/01/13 ----->

[J10]

Ian Fergusson â€@fergieweather

"@jgyap57: Hell of a complex occlusion incoming - may even come down to "nowcasting" Oh, unquestionably so, given convective components...

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My Comment

This is much trickier to forecast compared to last Friday, was a basic front pushing from South West

This is a very small developing low pressure system, compare the forecast position of the low at 06 Tuesday from the last 4 NAE runs.

http://expert-images...012206_2112.gif

http://expert-images...012206_2106.gif

http://expert-images...012206_2100.gif

http://expert-images...012206_2018.gif

If a severe weather warning was issued on 12Hz run, and the 06Hz run came to fruition, then the snowfall may be completely in the wrong place. Very difficult forecast tonight.

Just to make clear that comment above the line was from Fergie,and below the line was me making it,

It is a developing situation, and a wide variety of outcomes are possible, Definitely worth watching 18HZ NAE, which should start coming out at 9 to 9.30pm. The first charts out are the accumulate precipitation whihc are the correct ones, even though the other charts wouldn't be up at that stage.

As for temps they do seem to be dropping after the earlier rise.

[benb]

NetWeather radar showing freezing rain over SW tip of Cornwall- not sure if that's a good sign or not!

Currently 0.5c here, partial cloud cover and still.

Frost on the car!!!!! (Got to set the winter weather excitement bar a bit lower in this location!)

[snowy36]

Thats the great thing about living in the Great British isle's, will it or wont it snow i bet they ( scandainavian's) dont have as much enjoyment model watching or when it snow's.

[Gorky101]

so where is the band of precipitation that will hit south wales currently

[bradymk]

Latest Metoffice radar shows precipitation staying clear away from SE Wales and its going to W.Wales however looking how it has performed in the last couple of days, it has been quite poor and changes every hour to something different!

It does show something for Wednesday night but not buying into anything just yet!

http://www.metoffice...-4.00&lat=52.77

Yes performed well for Friday but not so accurate since. I hope we do something here in W.Wales as we're about the only place that is still bloomin green

[snowy36]

Well we can see it on the radar, does it have our name on it.........Croeso i Gymru

[bradymk]

Regarding tomorrows potential snowfall event, i will have a better look after the 18z NAE. An important NAE coming up, whether it goes with its 6z output or the different scenario on the 12z output. It has changed every run but it should be a lot better now considering the event is only 12-15 hours away. We still have disagreement between most of the models but i think the 18z set will resolve tomorrows situation model wise but this of course doesn't mean it is right, will be a nowcast situation, again........

[keithlucky]

so where is the band of precipitation that will hit south wales currently

Just reached Cornwall sleet now falling in Swansea nothing on radar. Edited January 21, 2013 by keithlucky

[legritter]

HI to you all in wales ,temp over here on mendip currently plus 0.6 c ,moon shining brightly with a slight thaw going on but very slow thaw .looking very interesting for some of you lot and us over this side of bristol channell ,i had a look at some of my collection of charts and tonights and tomorrows feature is a hard one to call ,some places could get a good fall and others miss out . this feature could stall later tomorrow .temp will be generally cold enough for snow going by current synoptics . me and my wife went to Tenby back in october very atmospheric place ,i saw some very nice snow scenes in local gallery and on pub walls i think of snow event back in early winter 2010 possible lake effect .if you think you get too much snow anytime just send it over to somerset ,cheers legritter .

[J10]

Just reached Cornwall sleet now falling in Swansea nothing on radar.

Its on the radar, snizzle here.

As for earlier request about the overnight precipitation, it is starting to edge in the radar to the South West.

[bradymk]

The precip band now in Cornwall will head our way, and looks like hitting me in Pembrokeshire around or just after midnight. Now its 0.1c here now and I fear this band may fall as freezing rain. The initial band was always forecast to be rain here first in the early hours before the potential for snow tomorrow a.m as the colder air digs back in on an easterly wind. But with temperatures dropping below freezing, colder than forecast, freezing rain may be a problem here tonight. We shall see.

Edited January 21, 2013 by bradythemole

[impster]

What's the chances of getting some snow up our neck of the woods (Machynlleth, Mid Wales)? S4C weather bulleting putting the snow firmly over South East Wales, with Pembs getting a bit later on. Any expert amateurs care to give their views (I have 3 kids desperate to make another snowman)...?!!?!

[welshwizard]

Regarding tomorrows potential snowfall event, i will have a better look after the 18z NAE. An important NAE coming up, whether it goes with its 6z output or the different scenario on the 12z output. It has changed every run but it should be a lot better now considering the event is only 12-15 hours away. We still have disagreement between most of the models but i think the 18z set will resolve tomorrows situation model wise but this of course doesn't mean it is right, will be a nowcast situation, again........

hi there I thought this snow event was coming in by 3 in the morn? not 12 to 15 hrs away. am I wrong? don't worry I nearly always am ha ha

[bradymk]

hi there I thought this snow event was coming in by 3 in the morn? not 12 to 15 hrs away. am I wrong? don't worry I nearly always am ha ha

umm was not an accurate time however the best chance for snowfall, especially coastal areas in the south looks tomorrow morning 9-12am as this is when the colder air digs back in but it depends on your location. We will have a better idea in 20 minutes, i will post thoughts on 18z NAE Edited January 21, 2013 by bradythemole

[welshwizard]

umm was not an accurate time however the best chance for snowfall, especially coastal areas in the south looks tomorrow morning 9-12am as this is when the colder air digs back in but it depends on your location. We will have a better idea in 20 minutes, i will post thoughts on 18z NAE

Thanks for that

[J10]

NAE Precipitation for next 36 hours from 18Hz

Generally 10-15mm over much of South Wales, drier than this in far west, but drier than previous run.

Edited January 21, 2013 by Jackone

[snowy36]

Wow i think it's been downgraded. From 24mm to 10mm, perhaps thats why they kept quiet on the tv

[welshwizard]

NAE Precipitation for next 36 hours from 18Hz

Generally 10-15mm over much of South Wales, drier than this in far west, but drier than previous run.

if that comes off that be a tidy snow event fair play another 4 inches kids be well pleased sorry I miss read it in cm ha ha Edited January 21, 2013 by welshwizard

[snowy36]

What's the chances of getting some snow up our neck of the woods (Machynlleth, Mid Wales)? S4C weather bulleting putting the snow firmly over South East Wales, with Pembs getting a bit later on. Any expert amateurs care to give their views (I have 3 kids desperate to make another snowman)...?!!?!

Us in south wales will be lucky to get anything at this rate.

Edited January 21, 2013 by snowy36

[Wales123098]

Us in soutrh wales will be lucky to get anything at this rate.

10-15mm is 10-15cm I believe.

[J10]

I'd be more than happy at the moment, with a nice topup, after today's thaw.

Remember not to treat tonight's NAE as gospel, it may be that this run is correct, it may be that the 12Hz run was correct but remember the 12Hz run did not have widespread support from other UKMO models;

[snowy36]

10-15mm is 10-15cm I believe.

Wales i got greedy after last week, the band looks smaller and it looks like less impact for the whole of wales.

[J10]

Ian Fergusson â€@fergieweather

W COUNTRY High uncertainty tomorrow. Hopefully most of our areas stay snow-free until later tomorrow eve, when it spreads NE fairly rapidly.

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Of course by his area, he means SW England/West Country area.

[mickeyflyn]

Ive just been outside and there is a good thaw going on so unless the temp drops dramatically i`m going for rain in the am !!

[keithlucky]

Ive just been outside and there is a good thaw going on so unless the temp drops dramatically i`m going for rain in the am !!

I can"t disagree with that wish the LP over Scotland would push north it"s causing out S Westerly feed.