Snow Potential - Late March

[martinastro]

Synoptic Discussion - 30/31st March - Winter Returns

Deep low crosses the UK bringing Rain, Snow and Strong Winds

A sharpening upper trough is crossing NE across the UK deepening the surface depression under marked vorticity advection and upper level diffluence.  The Jet stream has moved south again with the main jet core now pushing through the Bay of Biscay into Europe.  Cold air is being dragged into the depression from the north. 

Over the next 24 hrs the effect of the upper trough deepens the low as it moves east across the UK.  The low currently over SW Wales and moving ENE (though actual movement will be a little north then south then east - but overall movement is NE) The low deepens to around 977-978mbs as it moves over the southern parts of N England overnight and through tomorrow.  The main problems are relating to the cold air which will become increasingly dominant around the northern and western parts of the low as it moves East.

WBFL's are currently reasonably high over most parts with sub 200m only over the highlands of Scotland, and sub 500m over Western N Ireland and the rest of Scotland (north of the central belt) Over the next 12hrs stronger cold advection, a deepening low and nocturnal cooling all act to produce cold advection below 850mbs across Scotland and Ireland and later parts of Wales and N W England.  Rain is currently falling over large parts of N Ireland and Scotland and largely is rain below 250m or so... However its already Mod Snow above 250m across Scotland and the highlands are seeing sig falls.  The mountains of N Ireland are already seeing snow and this snow level will drop as the day goes on with WBFLs below 200m across almost all of N Ireland and most of Scotland (except far SE) by 21Z tonight.  This means rain turning to snow even at low levels and accompanied by a very Strong NE Wind - as the low deepens gusts to 45-55mph are possible giving blizzard conditions and the weight of the snow causing potential problems to power distribution (very heavy wet snow)  Conditions could become VERY NASTY indeed across Scotland and N ireland this evening and overnight.  CAUTION Should be noted and travel will likely be disrupted.  By this evening snow in the Central belt and population centres of N Ireland likely to see 5-10cm of snow and lots more on high levels. 20-30cm easily possible, with both the NAE and GFS having spot 50cm+ totals over the Highlands and Sperrin mountains by 06Z tomorrow. Given BLizzards then spot blown accumulations could easily exceed 60-70cm snow.  The strong winds lasting into the night and tomorrow morning with further snow lasting through the night and tomorrow across Scotland - though WBFLs rising a little through N Ireland tomorrow.

Further South occlusion is coming east - reports of Snow on Dartmoor as its ushering in much colder air (okehampton just 1.7C at 10Z)  the cold air dragging WBFLs down to below 200m across Wales and N W England with risk of developing wrap around (which will form overnight) lingering across Wales and N W England later tonight and early tomorrow with snow descending to 100m or so over Wales and NW England and to 200-300m over Southern England and the SOuth Midlands. (10cm Lake district and NW Wales easily possible)

Strong winds developing to the South of the wraparound - with 40-50kn gusts likely over Southern England esp headlands where isolated 60mph+ gusts are possible overnight and at first tomorrow.

Heavy bursts of rain also possible at times in the south as the mild air is ushered out of the way. ....

PJB 11.35

[martinastro]

Conor and I spent the afternoon up Glenshane Pass - it was crazy with large snow drifts on the country roads and great blizzards causing white-outs, roads are a combination of snow and slippery slush making for dangerous driving conditions. Around 16.00 there where major traffic cues on the pass for miles. Very nasty and impressive weather!, We got some video and pics under very difficult conditions.

[martinastro]

Glenshane Pass reported as closed - lights blinking here.

[paulster78]

Same here lights blinking for last hour. Took a drive out to Gortin Glen around 7, roads in bad shape especially the higher you get. Road blocked by a gritter lorry that couldnt get up the hill, so I did a U turn came back down. The forest up there looked magical where the horizontal snow has blanketed the trees. Tried to get a few images but light was poor and couldnt find anywhere to pull in. Might try again in the morning.   
 Snow light here now but wind very strong.

[markt]

Sounds like you guys are having a wild time atm.  Stay safe!  Look forward to hearing your reports and seeing any pictures you have

[martinastro]

Conor and I went up to Glenshane Pass for our last run, this time between dusk and night fall, the road was closed by Police but we found another way up. On top the scene was astounding with +50mph dense blizzards with walls of snow blowing across the road higher than two cars stacked on top, it was a complete white-out with the car shaking like mad, it was impossible to see road markings or even lanes and cars and trucks where abandoned on top. We had to help push stranded cars back on centre. The blowing snow created huge drifts on the roadside over 1 m high which where sculptured into amazing shapes by the powerful winds, it looked like absolute insanity and unlike any snow storm we had witnessed before, it was more like a US major snow storm, we could describe the conditions as extreme. We got video and images, however at night it was dodgy going with slow shutter speeds and high ISOs which blurred due to the shaking of the car. A night I will never forget. Power is going on and off all over the place and the street lights are out with house lights flicking like mad. This is one nasty storm!

[martinastro]

20,000 homes without power in NI due to the snow storm...

http://news.bbc.co.uk/1/hi/northern_ireland/8594268.stm

[paulster78]

Some powerful gusts here now and still snowing-is it ever gonna stop, been snowing here now since 7am non-stop.  Not much on the ground though to show for it, maybe 2cm in the lawn slushy elsewhere.  If this storm had come in January when the ground temps were much colder it would have been an epic event.        Best blizzard ive seen to date.

[Padraig OBrien]

Seems to have be rough in northern areas  had blizzards down here but barely 2cm on grass this morning.

Read a Sky News article about the power cuts it mentioned The Glenshane Pass thats around you area is'nt it Martin, I mean obviously it is a higher elevated district is it?

I really do hope Martin that you do one of your great reports on this event, they are always great reads!

Lets hope for some thundery activity during the rest of the week.

[paulster78]

Some thundery showers showing up already Padraig, heavy snow shower as I write this. Went back up to Gortin Glen this morning, got a few images will post them later.

[martinastro]

Hi Padraig, Glenshane is near where I live, it's 1000ft above sea level and always gets it bad, last night was the worst most people have ever seen, major rescue operation last night by Police, Mountain Rescue, and Coast Guard choppers, people trapped in cars all night, the snow drifts are huge, Police said some of the cars where completely buried in snow to the extent that they almost missed the cars, this was on the main road. The winds were nasty and so were the blizzards, it's all over the news today. This has been a major event. It snowed heavly on low ground last night and the street lights were out for most of the night with our power going on and off, it has been years since that has happened. Remarkable storm!

[martinastro]

Here's BBC footage from Glenshane this morning...

http://news.bbc.co.uk/1/hi/northern_ireland/8597132.stm

Been hail and snow showers on and off here all day - almost 48 hrs of snow.

[martinastro]

We where back up Glenshane again, snow over our waist and even deeper, you can walk over fences due to the mad drfits. Still snowing up there with blizzards at times.

[markt]

Wow, thats some serious snow!  All i've had is rain with the occassional and briefest of wintry flurries...