SnowStorm(Jamie)

Tomorrow looks wintry for some parts of Wales as colder air spreads in from the North West. A snapshot of some of the GFS 12z data for tomorrow morning: Best chances will be in North & East Wales, higher ground of South Wales possible but I'm sceptical of the Dew Points shown especially at lower resolution. Will await EURO4 & NMM 12z data. A real mix either way with hail and thunder thrown in.

Indeed, thats my current thoughts also. Here are some of my amateur thoughts currently. Netwx model (12Z data) shows incoming precipitation on Wednesday afternoon with rising temps, NE Wales see the lower temperatures. EURO 4 (12Data) Showing Precipitation & Dew points: Again as precipitation moves in Dew points also rising, likely due to the switch in flow from NW to a More West then South West: I think its worth pointing out the GFS also does this but then colder air filters in from the NW again later Wednesday evening into Thursday which makes things tricky as there is potential for a rain to snow event but not everywhere of course. GFS 12z Wednesday night into Thursday: However its still a long way out and not in full range of high resolution models yet so changes highly likely, but it does make for interesting model watching as always! Cheers, Jamie

After a few light snow & hail showers last night it has been largely dry today. So this time around the NNW flow produced some snow, including coverings for those inland and on high ground. Over the last few days dew points were marginal most the time especially in the south and west, with the colder upper air getting mixed out at times to. Still remaining cold and dry as the high pressure system begins to take control.

Wintry showers of rain/hail/sleet here currently.

I see warnings out from the Met Office for snow/ice for Wales also mentioning a more general area of light snow. Cant seem to identify this on the EURO 4 other than the possible snow in the east of the UK. Perhaps the UKV model is hinting at showers clustering together more and moving slightly more in land, we will see I wouldn't be surprised if it stays largely dry away from the far South West.

Looking at the radar a streamer has set up just to the west of Swansea with some heavy showers embedded within that, wouldn't be surprised if we start seeing some lightning strikes over western coasts over the next few hours. The flow is set to gradually switch to a more NNW direction with upper air temperatures falling by the afternoon & into the evening, dew points remaining a marginal factor but the GFS does show these to drop along with the freezing level during the afternoon also. Im not sure how much precipitation will be around by this point as it may be the drop coincides with the precipitation clearing through. Radar shows quite a bit of precipitation to the South of London, precipitation type shows its mostly snow - Lucky them if it is!

Looks like winds will veer more NNW through Saturday AM, allowing for more organised precipitation over W/SW Wales (Streamer). However when looking at upper 850hpa temperatures they vary from -6 to -4C and dew points 0- 1C (Looking at EURO 4). Looks marginal for snow away from about 200m with costal areas seeing rain/sleet/hail, its not to rule out in much heavier bursts the snow will work its way down to low levels for a time but nothing of any substance I don't think. Heres the Met Office forecast for Wales: "This Evening and Tonight: Isolated wintry showers this evening, but then a more defined line of showers travelling south across country from around midnight. This clearing before dawn, then icy stretches developing. Some showers lingering. Becoming very windy, gales likely at coasts. Feeling cold. Minimum Temperature -2 °C. Saturday: Cold and mostly dry with sunny spells, but some showers lingering across southwest Wales. Wintry showers becoming more frequent from evening. Winds increasing, with gales along coasts. Maximum Temperature 6 °C. Updated: 1524 on Fri 30 Jan 2015"

Had quite a few snow showers here in Swansea today again right down to sea level, no sticking though of course. Tonight is very interesting with the development of that low pressure system referred to as a polar low by Ian F on twitter. You can read more about polar lows here: http://www.weatheronline.co.uk/reports/wxfacts/The-Polar-low---the-arctic-hurricane.htm As you can read they develop over warmer waters when colder polar/arctic air is advected over it. ​The exact track will come down to radar watching and there is already discrepancies showing up between the NetWx Model and the EURO 4 for example in terms of precipitation distribution. You can see the low pressure system on the 850hpa upper air charts here (Friday @ 3am): A track running through NW Wales south eastwards to effect E & SE wales with quite a more organised area of precipitation: Now lets look at the NetWx model for precipitation distribution overnight: I would say the NetWx takes it slightly further south and west in comparison to the EURO 4. (Looking at 12z data) Using the EURO 4 to look at dew points overnight they appear to be around 0C to 1C: Id say on this information NE & Mid Wales quite likely to see some snow further south and west it depends on how much precipitation is around (if any) and the dew point temperature. Its worth pointing out that during this period slightly warmer upper air temps move in to be around -5c to -4c. Just some thoughts thats all, will be interesting to see how it actually works out.

Perhaps the shorter sea track is playing a factor in less shower activity. Just had a light rain shower here

EURO 4 12z doesn't show much in the way of precipitation across Wales for tonight and early hours of the morning. NMM 3km gives more in the way of showers to much of Wales with snow generally falling away from the south west of the region. It will be interesting to see which one is correct.

I think another positive for any wintry weather is the flow from the North/North West to last for quite some as shown on the ECM Mean: Details will be fine tuned over the next 24 hours regarding Thursday morning. One thing is noticeable is that the strong NW wind driving these showers well inland NMM 3km shows quite frequent snow showers for Mid & North Wales.

Haven't seen the BBC regional forecast from Derek yet, so don't know if he mentioned the possible cold front moving through during the early hours of Thursday, Ian F mentioned this earlier. Bringing more organisation to showers I believe its shown best on the EURO 4 06z: The Met Office will likely update the warnings tomorrow to highlight the snow/ice risk across some parts of the region.

Lots of potential for next weeks cold spell, always makes for interesting model watching. There appears to be a few things to watch here: A) How much mixing out of the colder upper air will there be due to shortwaves interrupting the cold northerly flow. B) The longevity of the cold spell & possibility of reloads bringing colder air from the North/North West C) How much effect will any westerly flow have on dew points across the South & West? - The recent cold shot with a westerly component delivered snow to sea level here albeit temporarily. D) I believe there is certainly potential for Thundersnow again, especially across the North/North West of region where colder upper air runs over warmer waters. As ever nothing is set in stone, lets see what the models show over the coming days, once colder air becomes established we can then use the higher resolution models NMM and EURO 4 which will fine tune details on any wintry potential. Met Office Outlook for Wales: "Outlook for Tuesday to Thursday: Bright to start. Cloud spreading south, but mostly dry on Tuesday. Unsettled Wednesday and Thursday, with outbreaks of rain and blustery showers turning increasingly wintry, and with strong winds. Cold. Updated at: 0226 on Sun 25 Jan 2015"

The Euro 4 is quite interesting for N/C/E Wales it brings the front in overnight when dew points are lower these higher towards the south and west where rain seems more likely and quite heavy to. Comparing the 06z to 12Z the feature seems to be digging further south on the 12z with slower progression eastwards. 06z: 12z: 12z Dew points with Rain/Snow distribution: Dew Points: Rain/Snow: There will be some changing to the snow areas, as models fine tune the positioning of this occluded front but a few CM's possible especially in N and E Wales. Jamie

Yup, turned to snow right down to sea level in Swansea for a time earlier, didn't last to long but still better than nothing.

Updated Met Office graphic posted about an hour ago on twitter: https://twitter.com/Sue_Charles/status/548242439044345856 EURO4 18Z seems to extend the snow risk slightly further south but much of the south remains in a mild sector while precipitation is present.

I'm also slightly confused by that to, GFS 18Z keeps the track of the low similar to previous runs. I agree with you with regards to the top of Valleys likely being the southern extent going by recent GFS/NMM/EURO4 data. BBC stressing uncertainty on twitter with regards to this: https://twitter.com/bbcweather

General track of the low on EURO4 12z remains similar to previous runs but a slight shift northwards Id say. ECM snowfall distribution chart screenshot was posted in the model thread which agreed with the idea of snow mostly to North Wales and Midlands. Rain mostly for low ground in South Wales, possibility of it turning to sleet/snow for inland areas as the low heads south east before precipitation clears away.

GFS goes for the more northerly track, allowing the frontal system to effect NW England and N Ireland, where as the EURO4 06z has the focus of precipitation over Wales, Midlands moving east. So awaiting 12z data from EURO4.

Looking at the Euro4 18z, 0z & 06z the track has been pretty consistent giving snow to East and North Wales. In the past we have seen these type of features get pushed further south as we get closer to the event but that's not to say it will this time. Looking at the broad scale MetO warnings it appears to take into consideration both northern and southern tracks. Makes interesting model watching indeed.

Hi Guys, Interesting to see the idea of a more southerly tracking low, opening up wintry potential to some parts of Wales. EURO4 is now starting to show us how this might shape up, I wouldn't at all be surprised to see further changes in the track of this system in the next 48 hours. Ive been keeping an eye on how the models develop this low, I took screenshots of the UKMO 12Z on the 21st and 22nd for the same time (27th) see below: Todays UKMO 12Z: There are differences of course, the main one being the low isn't as deep as initially thought, but the idea of a flow from the North West behind the low seems pretty consistent to me. 12Z Euro 4 data shows some heavy precipitation moving in, a mild sector is present but also there is colder air flooding in on the NW flank of the low. A tricky one, Its going to be interesting to see how this one pans out but my thinking is a spell of snow is possible for Mid/East Wales, then wintry showers from the North West flow as the low heads south east. Merry Christmas everyone! Jamie

Happy new year to everyone! More heavy rain to come this evening according to the NAE: http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2014/01/01/basis06/ukuk/prec/14010118_0106.gif @12hrs http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2014/01/01/basis06/ukuk/prec/14010121_0106.gif @ 15hrs Looking at Met Office observation data a gust of 61mph @ Mumbles recorded at 11am. Gusts into the high 50's across western coastal fringes this morning. The main focus on this system though is the rainfall and here are the flood warnings in force across Wales: http://www.environment-agency.gov.uk/homeandleisure/floods/34678.aspx?type=Region&term=Wales&from=fl

Yet again another low pressure system is set to move in from the Atlantic with more heavy rain and strong winds. NAE 18Z shows the heavy rain for new years day with the heaviest precipitation over the South: http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2013/12/30/basis18/ukuk/prec/14010112_3018.gif Although taking into account that rivers are already high its not going to help the flooding situation. The low pressure system itself is quite deep and forecast to head in a North East direction. Again the winds are forecast to be strong gusting around 60mph possibly 70mph on western coastal fringes. Looking through the GFS, ECM & UKMO 12z data there seems to be little change to the Atlantic dominated theme. Again lets look to the ECM Ensemble mean chart at 144hrs: We see a trough to our West extending its influence over the UK and Western Europe. GEFS Ensemble mean for the same time (144hrs): Both showing the same theme, so i think we are to expect more of the same wind/rain and a general flow from the west or south west.

Had plenty of hail showers here over the last few days. Over the next week it looks like we will see much of the same weather with a long wave trough over or just to the west of the UK with storms running up towards the NW of the UK as shown by the ECM Ensemble mean chart @144 hours: http://images.meteociel.fr/im/5745/EDH1-144_jkt8.GIF Also negative anomalies/lower heights shown on the ECM over the Atlantic & UK: http://images.meteociel.fr/im/4429/ECH101-144_uvg9.GIF Looking at the GFS data it also shows a strong jet stream during this period so the likely outcome is more low pressure systems coming our way even though it does tend to edge slightly further south with time on the 12z GFS data. Not the best news for those areas affected by the floods and as ever finer details on strong low pressure systems will show up as they come into the more reliable timeframe.

Merry Christmas everyone, hope everyone is having a great day! Some snow here on the higher ground of Llandovery with rain and hail to lower levels this morning. Attached are some pictures I took this morning up the hills. Uploaded from my phone so sorry if theres poor formating.