Wales Cymru Cold Spell Discussion

[Barb]

Just had some sleety showers here... signs the cold is coming back.

Met Offfice forecast this morning has snow for my town on Tuesday and Wednesday.

http://metoffice.gov.uk/weather/uk/wl/merthyr_tydfil_forecast_weather.html

The GFS is horrible for us in Wales, even N. Wales. But the ECM and the GEM are great. UKMO are OK especially for Mid Wales.

Edited December 27, 2009 by Barb

[Snowyowl9]

This really is a set-up that has never showed up before on the internet era,we have to go back to basics and the 80`s as this will bring severe weather in the form of drifting once the cold air digs in afterwards my favourite type of weather followed by thunderstorms,I`m very excited about this week.

Nobody for sure will know what will happen.

http://91.121.93.17/pics/brack0a.gif

http://91.121.93.17/pics/brack1a.gif

http://91.121.93.17/pics/brack2a.gif

Edited December 27, 2009 by Snowyowl9

[Barb]

This really is a set-up that has never showed up before on the internet era,we have to go back to basics and the 80`s as this will bring severe weather in the form of drifting once the cold air digs in afterwards my favourite type of weather after thunderstorms,I`m very excited about this week.

Nobody for sure will know what will happen.

http://91.121.93.17/pics/brack0a.gif

http://91.121.93.17/pics/brack1a.gif

http://91.121.93.17/pics/brack2a.gif

I'm not really an expert but those Faxs look pretty great to me. Especially for valleys/Mid Wales.

Even Cardiff/Swansea might get a dumping from that.

[CRACKPOT]

Hi Guys,

Well the summary from this morning is everything is going further north! Bah humbug!

A lot of the 'updated' websites are showing cold next week, but snow is only reserved for north midlands and scotland with an easterly slant. We will get the occasional snow showers at the end of the week and the charts on the whole are showing the low pressure arriving 200 miles further north hence when Tuesday / Wednesday comes - we are in cold rain!

Hopefully this will change by the end of today/tomorrow morning, but if not - we will not get the snow we were told was coming by the beeb - they will update their warnings later today and expect southern and mid wales to disappear from there.

Hope not!

JK

[J10]

This really is a very interesting situation that seldom comes this close to fruition. I think we can safely do a bit of IMBYism in here, and from this perspective the GFS is the worst model. It has the milder sector too far north from our perspective, as mentioned elsewhere it does tend to over develop the Low Pressure and is the the outlier at the moment, and possibly the least likely outcome.

UKMO looks more favourable for Wales, with heavy snow very likely for Mid and North Wales, with some snow as well for the south. The ECM would have a snow event for southern areas. The FAX is a bit of a mix of the ECM and the UKMO, and does give the chance of heavy snow for many areas, especially for Central and Northern parts of Wales.

Even though the thicknesses are an issue, all models have winds from the east, and surface temps are set to be cold.

Even looking at the mildest the GFS 06Hz run.

With evaporational cooling, temps would fall off, turning the rain to snow, however we would certainly prefer lower 850HPA temps as per the ECM and UKMO.

- ECM Perfect Temp Profiling, snow restricted to South

- Slightly Milder in South, Widespread Snow Mid/North Wales, perhaps later in South

[Barb]

Met Office just released new warnings for ALL of Wales:

http://metoffice.gov.uk/weather/uk/uk_forecast_warnings.html?day=2

Tuesday - There is a moderate risk of severe weather affecting parts of England and Wales during Tuesday.

Outbreaks of rain spreading slowly northwards will turn to sleet and snow with heavy falls and potential for disruption to travel possible. Accumulations of 5-10cm are possible at lower levels with a risk of 10-20cm at higher levels accompanied by strengthening easterly winds giving drifting in places. There remains uncertainty over the areas at risk which will be kept under review.

Wednesday - There is a moderate risk of severe weather continuing to affect parts of England and Wales on Wednesday.

Overnight snow, heavy at times, will become lighter and clear slowly southwards from some parts during the course of the day. Further accumulations of 5-10cm are possible in places. There remains uncertainty over the areas at risk which will be kept under review.

Reflecting the latest FAX charts I guess.

[CRACKPOT]

Met Office just released new warnings for ALL of Wales:

http://metoffice.gov.uk/weather/uk/uk_forecast_warnings.html?day=2

Reflecting the latest FAX charts I guess.

I think you will find these are the warnings I was referring to in my previous post - they have been there for the last 48 hours and have not been updated. There will probably be an updated after lunchtime today - but probably, as I said, removing us in the south and mid from the warnings. There will probably be snow, but not the heavy snow anticipated!

JK

Edited December 27, 2009 by CRACKPOT

[Marcus_surfer]

Hope this comes off, if it's just cold enough we might all get a dumping. Conditions could be just perfect if its cold enough.

Edited December 27, 2009 by Marcus_surfer

[Barb]

I think you will find these are the warnings I was referring to above - they have been there for the last 48 hours and have not been updated. There will probably be an updated after lunchtime today - but probably, as I said, removing us in the south and mid from the warnings. There will probably be snow, but not the heavy snow anticipated!

JK

No, they were updated 30 mins or so ago, they are new:

Issued at: 1109 Sun 27 Dec

[Cymro]

I think you will find these are the warnings I was referring to in my previous post - they have been there for the last 48 hours and have not been updated. There will probably be an updated after lunchtime today - but probably, as I said, removing us in the south and mid from the warnings. There will probably be snow, but not the heavy snow anticipated!

JK

They are not they are updated warnings take a read there is mention of snow depths now which wasnt before and if you see when it was issued youll find it's updated!!

[Barb]

Snow depth they estimate is 15-30cm, or ~6 inches on lower ground and ~12 inches (a foot) for higher areas. However there is still quite a bit of uncertainty so don't start planning hiring a JCB to dig yourself out of the house just yet.

[Cymro]

Snow depth they estimate is 15-30cm, or ~6 inches on lower ground and ~12 inches (a foot) for higher areas. However there is still quite a bit of uncertainty so don't start planning hiring a JCB to dig yourself out of the house just yet.

Where do you see that or are you adding totals from both warning?

[J10]

I think you will find these are the warnings I was referring to in my previous post - they have been there for the last 48 hours and have not been updated. There will probably be an updated after lunchtime today - but probably, as I said, removing us in the south and mid from the warnings. There will probably be snow, but not the heavy snow anticipated!

JK

These Severe Weather Watches were updated 1109 and 1111 this morning. Given this mornings output, there is no reason to remove South Wales from the warnings, there remains the very real risk of heavy snow for all parts, doesn't mean we will get it, but the risk is there.

Still prefer the old percentage risk charts though.

[Marcus_surfer]

Snow depth they estimate is 15-30cm, or ~6 inches on lower ground and ~12 inches (a foot) for higher areas. However there is still quite a bit of uncertainty so don't start planning hiring a JCB to dig yourself out of the house just yet.

Bring it on, id be happy with 6inches

These Severe Weather Watches were updated 1109 and 1111 this morning. Given this mornings output, there is no reason to remove South Wales from the warnings, there remains the very real risk of heavy snow for all parts, doesn't mean we will get it, but the risk is there.

Still prefer the old percentage risk charts though.

Well sometimes they get these warnings very wrong, but sometimes very right, so lets wait and see what happens.

[Barb]

Where do you see that or are you adding totals from both warning?

Well they say 10-20cm on Tuesday (4-8 inches) and a further 5-10cm (2-4 inches) on Wednesday, so 6-12 inches is the range.

[Cymro]

Well they say 10-20cm on Tuesday (4-8 inches) and a further 5-10cm (2-4 inches) on Wednesday, so 6-12 inches is the range.

Not necesarilly you could have snow melt, drifting which could benefit you or make things worse blow all the snow away :lol:, Dont be content yet.

[Barb]

Not necesarilly you could have snow melt, drifting which could benefit you or make things worse blow all the snow away :lol:, Dont be content yet.

Well I'm hoping for the best but expecting the worst.

[CRACKPOT]

I stand corrected - what I meant to say is they have not changed the warnings - they have just added the potential snow depths. These are still only advisories, and like Jackone said, they do not mean this will happen - they are only advisories!

Percentages are still the same as the last 48 hours, just the snow depth poetential!

JK

[Barb]

I stand corrected - what I meant to say is they have not changed the warnings - they have just added the potential snow depths. These are still only advisories, and like Jackone said, they do not mean this will happen - they are only advisories!

Percentages are still the same as the last 48 hours, just the snow depth poetential!

JK

But if they didn't think it was going to happen for us they would have removed the warnings or changed the area affected, which they haven't, so they still obviously expect significant snow for all of Wales.

[Cymro]

Although uncertain a great weather forecast for the week ahead for all of Wales I would say with snow with us from tuesday untill friday nearly:O if this verifyes again something fairy special a foot. Like the pun a foot there

[J10]

#$#$##4#$#

Missed the forecast, is it on Iplayer, or something like that.

This post was from Ian Fergusson in the MOD thread.

Agreed.

The latest UKMO MOGREPS probability output for spatial extent (and intensity) of snowfall makes interesting reading alongside the latest GM modelling and simulated ascents for SW Midlands and environs. Understandably 'rough-around-the-edges' but broad agreement for the Tues/Wed event in terms of perhaps 5-10cm snowfall into parts of the SW Midlands, much of central/east Wales and into other parts of the midlands and NW England (northern boundary remains uncertain). The current MO advisory adequately reflects the areas signalled in the GM run (expect this to be further tweaked in due course), albeit MOGREPS highlights a fair swathe of not insignificant snow probs across more northern-central stretches of the Westcountry (N Somerset, Bristol, S Glos and northwards, out through N Wilts and up into the Midlands), reflecting the somewhat troublesome pin-pointing of snow risk at a sub-regional scale at the present timeframe. Thus the elasticity remains a forecasting headache, not least given the very prominent temperature gradient being suggested in the UKMO output, which will promise hefty rainfall totals into much of far SW / southern England and a really knife-edge discrimination of where this turns (quickly?) to snow on the leading edge. Interesting stuff. The latest 6-10 day analysis looks equally spicy and will doubtless prove more than a tad newsworthy for various regions.

Best

Ian

[keithlucky]

I did notice sleet or rain more likely in the south on tuesday ,with the front trying to push up again wednesday this is when we most likely to see snow in south wales, where as north wales will see mostly snow all the time.

[Cymro]

I'm not sure it was straight after the news? I doubt it tbh but you can keep your eye out.

[keithlucky]

Jack one what tempretures like tues wednesday?france doesent look particulary cold at the momement.

Edited December 27, 2009 by keithlucky

[worldairgroup]

Jack one what tempretures like tues wednesday?france doesent look particulary cold at the momement.

morning all, hope you all had a good christmas! not been around after our let down with the snow just before christmas, but thought i would check in, given the latest interesting situation. i dont know how reliable you guys rate meteogroups charts, but it certainly is showing interesting reading from mon/tues 0000z right until thursday into friday. would be good to hear from the more experienced guys here what their thoughts are on the charts. only attaching one link and let you read through the forecast onwards from 0000z.

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/gfs_popup/archiv/NSea/pcp/2009122706/nothumb/on/42/ch/1a66d81445.html