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South West and Central Southern England Regional Weather Discussion 22/02/2018 Onwards


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Moderate  intensity snow. lol

I've just cleared some of the ice off of the shed roof due to the excessive weight. I can't believe i'm doing these things.. haha

Edited by Mapantz
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Sod the snow, Tom Baker is trying to steal your car. 

I want to see this in the morning.  

Good afternoon all ,with the passing of my beautifull wife last Autumn things have been rather busy at home but now starting to quieten down ,so today i,v been for a great walk up local woods .with th

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This whole event has been a wtf .. we're the equivalent of Florida down here near the coast, this kind of thing shouldn't be happening lol

Snow is pitching on surfaces no problem!

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SOME PICS + FREEZING RAIN BACK TO SNOW WATCH FOR ALL OUR COASTAL MEMBERS

Good morning everyone, Exmouth reporting :D   -1c,  about 18 cm (7") of level snow, 30 cm to 90 cm drifts (1 to 3 feet) up to 1.5 cm (2/3rd") of ice on all surfaces, then ice pellets (more on all this below)

I will write a short update post with the latest charts etc for lunchtime but first of all a different type of post:

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I'm at the top of a hill (only 65 m) and no traffic can get up or down. I cannot get to the local post office (over 2 miles away) and nor can the postmaster - so it's closed anyway! I had some business post and walked down to my local box early this morning in time for the 9 am collection - not that Royal Mail are likely to empty it for some time!  It's about 1/4 mile slightly down hill. I wrapped up well and tried out my new ice grips which fitted perfectly to my shoes - they're brilliant. The few people who had cleared their paths were left with ice rinks. If anyone clears their snow, you'll need to salt or grit it immediately to prevent ice build-up if you're under the freezing rain area. This will apply until any precipitation stops and the "ground" temp rises above zero even if the air temp rises, this might take a few days). The ice has formed a thick 1.5 cm crust on top of the powder snow and you can lift off the ice sheets to get at the real snow - although it 's not ideal for snowballs or snowmen. Here's a construction idea - use a snow/ice combo. Try building a wall - slabs of ice as the bricks and then powder snow as the mortar :D. Although I feel like a 65 year old child right now - I'll leave that idea for some of you to try out. The serious side to all this is the extreme danger this ice presents.

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I hope that some of my neighbours didn't mind me snooping around their driveways, bins and cars :D Some wonderful icicles which have stopped dripping with the temp comfortably back below zero again. 

 

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Cars, windward windows, door etc all have a thick coating of ice on them. Here's a 60 cm (2 feet) drift and a neighbour assures me that there are a few much bigger ones around our area. It felt so cold this morning compared to the dry cold of the last few days, so I returned home quickly.

THE GREAT FREEZING RAIN DEBATE AND AN APPEAL FOR A FREEZING RAIN WATCH AND A POSSIBLE CHANGE BACK TO SNOW PREDICTOR:

I noted the "debate" over what is freezing rain on here last night when many of us "coastal" folk saw about 10 hours of dry powder snow turn to rain (around 10 pm here) with the temp still sub -2c. I posted on it and provided a Wikipedia definition. Well I have read up on it even more now and I declare it a draw! One group were arguing that freezing rain is always super-cooled raindrops that freeze on impact on any solid sub zero surface (right, apart from the "always"). The other group were arguing that ice pellets were freezing rain - denied by the first group (but this is also correct). Normally, high up the precipitation starts off as snow. Then it falls through the above zero layer (from around and/or below the 850s height for quite a way down to the surface layer) and melts into rain. This cold rain then falls through the sub zero surface layer and is super-cooled. Then this is where both scenarios are possible. 1. If the surface layer is quite shallow, the rain drops carry on until they hit the surface and then freeze on impact. Most of us who had freezing rain saw this type for many hours and it's this that builds up the dangerous ice coating or "glazed frost". 2. If the surface layer is much deeper, then the cold raindrops have enough time to re-freeze into into ice. For smaller drops this will be small, roughly circular globules (which can be called "graupel" but that term mainly applies to "soft hail" formed with a slightly different process but I'm not going to get into a second debate now :) ). For larger raindrops, their weight and gravity draw them out into a more oval or elongated "raindrop" shape. When these re-freeze they form eiither long rectangular shapes or the long narrow pin shapes. It would have been these ice pellets or pins that you would have heard impacting on your windows. 

Some of us (perhaps most of us) would have had a bit of both types. Here, for example, I had many hours of powder snow for slightly longer than other coastal spots east or west of here as Exmouth is in a big indent in the coastline (just look on a map if you're unfamiliar) and this meant that we stayed marginally north of the coastal freezing rain zone for slightly longer. It also meant that we missed out on that snow streamer on Wednesday by less than 5 miles at times (grrrrh!). Then the snow stopped and shortly afterwards I noted the first type of freezing rain which lasted for many hours and produced the 1.5 cm ice sheet. The temp at the surface had risen to just below 0 c. By this morning it had fallen back again slightly. The surface layer must have deepened too as I noted the ice pellets and the pins too. This type is not dangerous in itself but it settled on the ice from the earlier type and if it had lasted longer it might have covered up that ice (as would a return to any snow falling). Judging by reports from a few of you last night  like @karlos1983 you seem to have experienced the full menu, alternating between unfrozen raindrops (with ice formation), ice pellets and ice pins. No wonder this sparked a robust debate :D. To add to the confusion, Wikipedia quote US examples and definitions. The US define "sleet" as any form of wintry precipitation that is not snow. Everyone else (or at least the UK and Europe) define it strictly as partially melted snow falling and this can appear to look like rain and snow but it all actually starts off as snow that has fallen from slightly different altitudes with some flakes having a longer melt period than others), 

Leaving aside the dangers and worries that this ice causes, this is a really fascinating and quite a rare combination of weather phenomena. It was the highly complex set up that caused such marginal conditions. The extremely low 850s (sub -14s down here until midnight on Wednesday) being displaced slightly northwards and replaced by values between -2 c and +2 c for a few hours and now they have fallen back to sub -2s again. This changed the high level precipitation from snow to rain and back to snow again. Then we had the record low max temps 9for march) during the day on Thursday (the very late recovery meant that we were beaten into second place by a low lying station in mid Wales but did we beat the English record? (all subject to final verification and with some isolated weather station readings only being read weekly). The surface temps near the coast also rose to near zero and I imagine a few spots went just above briefly, Then these temps fell back slightly to mostly between -0.5 c and -2 c (around -1 c here). For a while the flow had veered slightly to the south-east and Emma pumped in less cold air from the south with a succession of fronts moving northwards. With the different type of freezing rain and many inland areas staying all snow (or snow for much longer), this tells us that the depth as well as the temp of the surface layer fluctuated. The changes only need to be very small  (just either side of zero) to make all the difference. This morning the flow has backed to more of an east-south-easterly to almost due east with the winds (which are deflected slightly towards LPs) coming much more across land sourced from north France or Belgium and traversing the far south of England. So there should be rather less moderation of the surface layers than the earlier longer sea crossing.

What an extraordinary set of micro and macro conditions! In due course, I'll develop this post and aim it at a specialist NW thread or even set up a new one for a debate. There is so much that we can learn from this event and it's easy to see how the rain/snow radars struggled to show it properly with all the marginal layers with slightly different temps and precipitation types. It almost needs a new colour with shades of blue, green, purple (freezing rain), pink, red and white!  This type of regional thread with all the local reports is a great way of piecing the jig saw together. We can use this again this afternoon and this evening when another band of heavier precipitation is set to move across our region. Conditions are still marginal, especially right by the coast. The surface layer has still not been properly penetrated by storm Emma with temps close to or still slightly below zero. Winds should have a slightly greater land fetch. The 850s have dropped to sub zero again (not that low) and the dew point temps were well below zero (earlier this morning). I will check all this when I do my full update report during the next hour or so). All your local readings and precipitation reports (it's dry here right now but still near -1c ) this afternoon will allow us to assess all the layers above us and trump the radar to some extent. So, join me on another "possible" snow/freezing rain event later this afternoon and into this evening.  I am not predicting another blizzard but a little more snow is on the cards. At the moment it's more in the south-east.

If you have read all this and later on you think others who provide regular updates and readings on here might have missed my "appeal" for this "snow/fr.rain watch", perhaps you can send them a reminder post, PM or sticky note.

I'll be back soon.  :)   David.      

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15 minutes ago, karlos1983 said:

Snowing! Nice way to end this. It’s not much but it’s lifted my mood ?

just spent an hour clearing the garden and making snowman. Kids happy, I’m happy everybody is happy!

i have beer now also :D

Personally I'm chuffed to bits over what we've had. Snow and ice days. Well happy. 

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Just now, Nights King said:

all going north of here and with a gradual northern push I dont see somerset or dorset seeing anything from this :nonono:

I'm not sure sure Nights king some thing brewing over the Brest peninusla at the moment. Looking alot heavier than stuff over the south at the moment.

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