pyrotech

Thunder snow reports in the South West forum

Its actually very high cloud with ice crystals, at the height we are talking you can get ice crystals there at almost any time of year. Its not a sign of snow unless you get a halo from low level cloud caused by ice crystals. High level cloud often runs ahead of weather fronts often 100s of miles infront, especially warm fronts.

Yes GFS 12z today was very similar to NMM and had worst snow later than NAE starting tomorrow night. seems this is a total watch it happen event. I think some places will be lucky and others not so, Could even be a case of mass disapointment tomorrow morning changing to mega excitement tomorrow evening. It really is that bad to forecast, models are in total dasarray

I think tomorrows snow may be downgraded for us for morning, but extending into wednesday like NMM shows, apparently from what i can gather the GM shows something more like NMM than NAE

Looking at the NMM thats much more in line with what Ian tweeted to us about the GM , compared to the NAE

I think its in reference to what the models are trending towards and the discussion about unwanted rainfall in the Southwest and although IMBY for them could well become the story as the weeks evolve. The story is about that part of our country still being at flood risk and that a normal settled period has not evolved and Snow that most of us have enjoyed has been rain in some of those pre xmas flood areas. Its another concern as we watch the models over the next two weeks

Look again at the isobars, them kinks indicate weather fronts off that huge low with persistant heavy rain embedded. The Southwest UK has still not recovered and water table still very high, so maybe the winds will spare us the worst, but for those in the Southwest that is certainly a storm system that can be the start of another miserable period. what many down there want, is a blocking right over the UK with settled conditions and its the one thing the models are not trending or hinting towards.

Glad to hear baby home safe and congradulations to you both

GFS plays it diferently with snow right thru till Thursday. So models struggling with how this will evolve in under 18 hours. I think it will be now casting but the met office will look at outputs from all models and try to find areas consistantly being forecast to be at risk, put them on Amber and areas that models are on their own for, on yellow Alert. It really is one of those situations. I think somewhere will have a pasting and late on someone will get a red warning a second in under a week.

That image is pretty much exactly what the NAE shows for that time, with sleet on far south coastal areas then becoming snow during the morning. Will be interesting to see the Meto update between 11am and 12 today. This place will be mad again if it verifies

They will wait for the latest model runs, in fairness they have been very accurate over the last few days, this all depends on the Mogreps if it shows same as NAE then warnings will be issued, it would hazzard a guess that something similar to NAE is being shown and its now about getting the exact location that it will stall. I suspect Yellow Warnings accross Most of Powys, Amber Bridgend to Monmouth and red around Brecon and heads of valleys if similar to NAE. We will know before 1pm

The NAE has performed extremely well recently, What matters now is what the Mogreps is showing. I suspect if anything like the NAE we will see a second rare Red Warning for Wales for tomorrow. Its worrying that NMM has nothing, but like i said NAE was pretty much on the mark over the last few days. The NAE could easily give 25cm over the same areas that it had red warning for last week if it verified. We will know what MOGREPS shows by mid day, as if its anything like NAE amber and red warnings will be issued.

What makes this close to 2010 event, is not so much the snow depth, but the events over the last week have been almost countrywide snow events. Also so often we get a 1 day snowfall followed by a rapid thaw, but again like 2010 we get low temperatures keeping the thaw at bay, allowing everyone that wants to to get out and enjoy the snow. Lets not get too picky, most on here would of given anything for half the amount and just one days lying snow prior to xmas when we had the rain, rain and more rain. It looks like winter and feels like winter and my four year old has seen proper snow for first time that he can remember ( he was two in 2010 and remembers nothing)

Freezing rain is extremely dangerous, can obviously cause black ice in large stretches of road, often washing any salt away, but it also freezes on inpact on any object. So trees, powerlines etc etc get cased in ice which causes them to break due to weight. Known as ice storms in the USA. So if its rain you have and 2m temps are below zero you have freezing rain. Its caused just as Panayiotis said. Sometimes a layer of less cold air becomes trapped in a pocket as two air masses meet.

Regarding thunder snow, the showers behind the main band should have greatest chance, but not looked at charts. it would certainly be nice

With this senario current temperature and dew point for Cardiff is enough for snow, and both dew point and temperature falling steadily.

I am bouncing off the ceiling, we have had upgrade after upgrade over the last 3 days Sledges selling out fast thou. Enjoy the Snow

Im nights tonight in Cwmbran, finishing at 9am, wonder if i will get home, and if i will get back into work Friday night for 6pm

Im not expecting any red warnings at this time The warnings go on likelyhood and severity of disruption. So Amber fits best as disruption very likely and severe, liklihood increasing however still time for some changes. For instance the worst snow could move in any direction over the next 18 hours so still possible of adjustments. As we seen overnight as snow goes now right to West coast. I would expect the worst areas to be somewhere where the Amber is shown now, but in the iminent new warnings expect the Amber to adjust further South and West, A small change and perhaps extend would be better word than move. Red warnings often reserved for during event, but perhaps they will be proactive on this event but prudent more likely.

Yep Although we have warm atlantic air pushing in, it will ride over the more dense Cold air, The winds will be from a South Easterly direction. What is likely to happen is ... wet bulb freezing level between 200m to 100m Dew points below zero due to air from continent being dragged in and layer mixing. ( a very important factor for snow) We also get evaporative cooling, this is most evident when the percipitation is falling in dryer air, the cold air is dryer than warm air. If anything the dew points look like falling further on Saturday, Currently your temperature is ok or snow, but your dew point is not

light / moderate snow in Cardiff, stucking too even on roads.

Met office going for upto 20cm for Bristol / Glous so thats 8 inch for them, i would say 4 -8 is possible at North Cardiff if that is true. apparently they were live on a radio in the Southwest a little time ago talking to Exeter. "will it snow in Cardiff .......... JAY lol .......... YES YES YES

Yes still light snow in Cardiff. however its stuck on cold sufaces so no real accumalations worth talking about, but nice to see anyway. Plus any lying snow will help keep temperatures down.

A little update for our friends to our South The percipitation tonight seems to be easing Southwards, i was not expecting to see anything in Cardiff. However we have pure snow in Cardiff Albeit light snow. I would say if it makes it accross the Bristol Channel those the other side might get a little bit more due to the warm temperature of the water. So hopefully you get something this evening. Started in Cardiff about 30 mins ago and yes its snow, not sleet and not melting

Just starting snowing in Cardiff