South West and Central Southern England Regional Weather Discussion 03/03/2018 Onwards

[khodds]

Nothing here. Falling or settled. Just hit 0c and DP -7.0. 

[Bristawl Si]

What is latest snow update for Bristol area tonight/tom guys?

Are we on the edge or is it really a Devon/Cornwall affair?

[noggin]

Just now, Bristle boy said:

What is latest snow update for Bristol area tonight/tom guys?

Are we on the edge or is it really a Devon/Cornwall affair?

From what I've see  it looks like a downgrade. The amber warning on the MetO warning map has shrunk markedly and faded to yellow. Don't know how much to trust that, but on their video thing, it shows the big snow only for the far SW and the Bristol area isn't anywhere near the yellow warning area. Looking proper pants now. ?? 

If someone can give me some hope, I would be grateful. ??

[MidnightSnow]

5 minutes ago, Bristle boy said:

What is latest snow update for Bristol area tonight/tom guys?

Are we on the edge or is it really a Devon/Cornwall affair?

HIRLAM and BBC graphics showed us well in the zone.

[Wilxy]

3 minutes ago, noggin said:

From what I've see  it looks like a downgrade. The amber warning on the MetO warning map has shrunk markedly and faded to yellow. Don't know how much to trust that, but on their video thing, it shows the big snow only for the far SW and the Bristol area isn't anywhere near the yellow warning area. Looking proper pants now. ?? 

If someone can give me some hope, I would be grateful. ??

I have faith in my Hirlam model haha!

[EllyTech]

4 minutes ago, noggin said:

From what I've see  it looks like a downgrade. The amber warning on the MetO warning map has shrunk markedly and faded to yellow. Don't know how much to trust that, but on their video thing, it shows the big snow only for the far SW and the Bristol area isn't anywhere near the yellow warning area. Looking proper pants now. ?? 

If someone can give me some hope, I would be grateful. ??

 

[noggin]

1 minute ago, MidnightSnow said:

HIRLAM and BBC graphics showed us well in the zone.

I must be looking in the wrong place then. ?? Happy to be proved wrong though. Mind you, I'm not much good at this sort of thing........I'll just sit quietly on the sidelines for a bit. ???

[Richard Fisher]

1 minute ago, Bristle boy said:

What is latest snow update for Bristol area tonight/tom guys?

Are we on the edge or is it really a Devon/Cornwall affair?

Up to 10cm. Not sure why Bristol is not yet in the Amber warning area. BBC show heavy snow all over Bristol for most of the night

[suxer]

Hi everyone

Have a look at the met office  video forecast on their website looks decent for our area.

[knocker]

Specifically for the south west

 

[AWD]

4 minutes ago, Richard Fisher said:

Up to 10cm. Not sure why Bristol is not yet in the Amber warning area. BBC show heavy snow all over Bristol for most of the night

I will eat my dirty pants if Bristol gets anything near 10cm of snow mate.  

[Nights King]

1 minute ago, Richard Fisher said:

Up to 10cm. Not sure why Bristol is not yet in the Amber warning area. BBC show heavy snow all over Bristol for most of the night

Yes i doubt they see a point in moving the zones 20 miles north, south, east or west from run to run. Whole region is under a yellow zone with amber not far from Bristol.

Might update later in night I suppose once event starts but i wouldn't get the Bbq out just yet if your just outside of amber zone. 

 

[Guest]

LET'S GO "GIF" MAD WITH THE 12z ARPEGE

I've set the times from 1500 GMT Sat Mar 17th for 60 hours to 0000 GMT Tue Mar 20th at hourly intervals at a nice slow pace:

                      Pressure                                                     2 m Temps                                          Dew Point Temps                                           850 Temps                                           Wind Chill Temps        

                                                         

       Wind Direction & Speed at 10 m         Jet Stream at 300 hPa (km per hour)                       Precipitation                           Snow Accumulation (see note below)       Pressure, Cloud & Precipitation

            

Note: The snow accumulation chart does not show what will be on the ground in any particular time frame. It shows the total amount of falling snow, which may or may not settle. Arpege assume that 1 mm of rainfall will represent 1 cm on snow (a 10 to 1 ratio). Most all the snowfall in this spell is the very dry and powdery type and the ratio will be much higher. For example, 1 mm of rain might be the equivalent of 40 to 50 mm of dry powder snow or 10 mm of wet snow.  This is why when powder snow thaws it causes far less flooding than wet snow.  

The Arpege 12z charts are quite similar to those from the 6z run. The minor LP develops north of Cherbourg and drifts westward down the Channel. Surface temps remain close to or below zero for most of the period. Dew points are well below zero until later on Monday. The 850s for the south-west are somewhat lower. with the sub -10s covering all of us during tonight and tomorrow. The wind speed and direction chart also shows the movement in the flow. You can see the disturbance running from the eastern Channel westwards before it links up with the minor surface LP. The jet stream shows the upper low that is pushing southwestwards across our region overnight and this is associated with an upper cold pool and partly responsible for tonight's snowfall. Arpege picks out the precipitation (all snow over us) that develops overnight. Unlike several of the other models, it also has further precipitation revolving around the main LP circulation that moves out of north-west France on Monday morning with a further band of snow moving across the far south from Kent to Cornwall. As I said earlier, we cannot pin down the micro detail properly for tonight's and Sunday's snowfall and it's far too early to consider developments for Monday. Arpege does show substantial snow accumulations for all of southern England as well as the south Midlands and south Wales. Most of the very heavy snow still looks likely from around IOW westwards and I still will not be surprised to see the amber warning area expanded and still a chance of a red warning for blizzard conditions in Devon and Cornwall (or even more widely - see below).  Now, I must post the live radar and satelitte charts as we need to follow these all night if you are a serious snow watcher   I'll add several more radar charts too:

  NW Rain/Snow Radar 1755              Live UK Rain/Snow Radar                          Live UK Rain/Snow Radar                                   Live Satelitte                                      Live Infra Red Satelitte

                      

Notice how the Thames streamer has now developed bang on schedule. In fact the snowfall there has rapidly expanded and intensified during the last hour or so and will reach much of our region this evening (perhaps by 2000 to 2100) as a band of continuous snow moderate to heavy snow. All this prior to the main event. It's possible that the snow bands to the north of our region, plus the snow in the south-east plus the snow from the cold front now in the Channel will all merge as the minor (or perhaps not so minor) LP feature develops during this evening. We might well end up with far heavier snowfall over a much wider area. Now surely that's worth sacrificing a little sleep for?   

Finally, I have been given permission to copy some satelitte charts from a restricted site but I cannot disclose the full source or the website, so please do not ask, otherwise I will lose this special privilege. What I can say is that this is NOT the same pay to view site that Knocker has access to. These are all for around 1715 today. I do not have full details of exactly what each chart shows but most of them are pretty obvious. I like the 3D effect. I should be able to update these later this evening when the developing snow area should start to show up very well.

          

 

Edited March 17, 2018 by Guest
Correct typos and check charts

[Mapantz]

0-2cm here!

[Bristawl Si]

Ok so we dont really know - nowcast situ via window and to lampost

[Mapantz]

Current conditions at home:

[chris55]

Met office radar looks to be pepping up the ppn as it's heading west towards the region, that first little wave could well hit some Bristol/glos area 

[jtay]

Current conditions at home:

[karlos1983]

I have assumed my position, and have perfect view of the street light from my sofa in the lounge. Bar tender (the boy) on hand to fetch drinks upon request. 

Currently snowing!

Happy as a pig in ?

Edited March 17, 2018 by karlos1983

[EllyTech]

2 minutes ago, chris55 said:

Met office radar looks to be pepping up the ppn as it's heading west towards the region, that first little wave could well hit some Bristol/glos area 

It looks very light snow, in comparison with the bright echos to the North and South of us.

[Leon1]

am i first to have successful lampost watching this evening? i can see snow (light but big flakes!)

[Wilxy]

wish my lampost didn't turn off in the middle of the night

[Leon1]

Just now, tomjwlx said:

wish my lampost didn't turn off in the middle of the night

i sometimes use a torch

[Jayfromcardiff]

4 minutes ago, karlos1983 said:

I have assumed my position, and have perfect view of the street light from my sofa in the lounge. Bar tender (the boy) on hand to fetch drinks upon request. 

Currently snowing!

Happy as a pig in ?

I'm watching Wales against France, keeping an eye on Aston villa losing! Curtain open incase snow starts and thinking about a Cardiff city win tomorrow lol.

[Frosty_wsm]

29 minutes ago, noggin said:

From what I've see  it looks like a downgrade. The amber warning on the MetO warning map has shrunk markedly and faded to yellow. Don't know how much to trust that, but on their video thing, it shows the big snow only for the far SW and the Bristol area isn't anywhere near the yellow warning area. Looking proper pants now. ?? 

If someone can give me some hope, I would be grateful. ??

Really, not sure what site your looking at but just checked the met office weather warnings and the amber zone has expanded and extended all the way down to the tip up Cornwall. 

Edited March 17, 2018 by Smartie