How Marginal Can It Get?

[Backtrack]

Just wondering how marginal snow can be?

For example, can it be snowing at one end of your street, but not at the other?

Or can it be snowing on the top floor of your house, but raining on the ground floor?

[BlueHedgehog074]

Snow, I think can be very marginal, although this sometimes depends on the conditions, like the wind direction, precipitation intensity and how much cold air is being injected over the area.

Sometimes, it could be snowing over a hill and mountain, but raining overlower ground with conditions being generally warmer the lower you go. It is amazing to think that even a little bit of height can make the difference between rain and sleet, or rain and snow. In most cases, the precipitation tends to be heavier over hilly areas which, during cold periods, can help with the lowered air temperatures, and as such, the snow cover is often deeper. For some situations, the snow may miss the hilly areas and fall over low ground instead.

The area you live in can have an effect, too. And it's possible that in one area of a city or town it could be snowing and in another area it could be just sleet/rain, although the height and the lack of industrial buildings will have an effect on this. It is also possible for one part of a city to be under a ridge of colder with other parts just missing out. Generally speaking, the more rural your area, the more the the precipitation will be of snow. The surfaces and structures, in the towns and cities, can easily be heated up by the solar energy, making the temperatures rise more than in rural areas. Any heat stored in the buildings at night time gradually rises into the air and this also helps to make the temperatures generally warmer in cities, meaning a lowered snow risk.

Around coastal areas, the difference between rain and snow can be huge. It has been know that areas just one mile inland have had a covering of snow, whereas locations right next to the sea have been empty of snow cover. During Winter, the warm breezes help to keep temperatures around the coasts higher than areas further inland. The effect of the sea breezes decrease rapidly the further away from the sea you are and can explain why places just a little inland are more likely to see to see the snow. Having said that, places near the sea have a better chance at receiving coastal wintry showers, which do not always make it that far into the inland areas and tend to loose alot of energy the further overland they travel. Nevertheless, during times of very high convection, the wintry showers may make it far inland and this is helped along by the strong winds and the warm sun. Some areas will clearly stay dry, with wintry showers bringing small concentrations of snow to places.

In general, the futher North you go, the colder it gets and and the chances of wintry precipitation become higher, (particularly over the Scottish Mountains), although this is not always the case. With atlantic Lows approaching the Southern areas and with the wind direction coming from a cold Northerly/North-Easterly source, the rain bands can often end up stalling to the South with enough cold air brought in to drag snow down to low levels. In these periods, a Northern and Southern split with the weather can happen; one time it could be snowy in the North and dry to the South and vice versa.

I think when the snow is not quite as marginal is when some extremely deep cold air gets blown down from the North and floods the whole of the United Kingdom, thanks to a consistant wind direction. The large spread of the very cold air with low dam numbers and low Dewpoints mean anywhere could see snow with widespread snowfalls possible.

When it reaches the night-time the marginality of the snow becomes reduced, in my opinion, with the temperatures becoming better supported for more locations during this time. So, on the whole, I would say snow can be a hit and miss event.

[frostyjoe]

A lot it was 1c all night and is now and is still sleeting... I mean how marginal is that

[Andy Bown]

For example, can it be snowing at one end of your street, but not at the other?

If your street is on a slope then definitely, also depends if the set up is showery with a snow shower at one end of the road and dry at the other.

[Tim B]

I've seen one snow shower followed by a rain storm, followed by another snow shower and so on a lot at this time of year. Driving through a rain shower then into a snow shower at lower altitude is another one I've seen a few times during the spring.

[Interitus]

Or can it be snowing on the top floor of your house, but raining on the ground floor?

Depends how tall your house is

[Thundery wintry showers]

In the Tyne and Wear area, the difference between snow inland and sleet or even rain at the coast can be extremely marked. There have been occasions when Cleadon had a barrage of sleet, and then when I looked out the front window the next morning, there was a deep snow cover starting just a mile or two further inland.

On occasion when there's a relatively light wind off the North Sea the temperature differences between the coastal fringe and a couple of miles inland can be striking. Marsden is just two miles away from Cleadon, but early on the 8th January 2010, at one stage it was 1.5C at Marsden and -3.8C at Cleadon. Correspondingly, on quite a few occasions my parents have reported lying snow at Cleadon while Neil Bradshaw's webcam for Marsden has revealed nothing at all on the ground.

I haven't seen any situations with snow at one side of the street but not the other, or anything like that, but it will be feasible if you live on the side of a hill for example. For example in the Lancaster area, altitude rises abruptly as you head inland from Morecambe Bay and the dividing line between sleet and 2 inches of snow can be very sharp indeed.

[Backtrack]

Thanks for the helpful replies everyone.

[Rob]

At this time of the year its can be extremely extremely marginal, as i'm sure parts of Scotand will be finding out

[Terminal Moraine]

In situations where rain on low ground turns to snow with altitude there is always a transition zone where sleet is falling so, unless you have a very tall house, it's most unlikely that rain will be falling outside the lower windows and snow outside the upper ones.

The transition zone between no lying snow and lying snow can sometimes be very fine indeed. Occasionally I've seen a field at the back of my house with no lying snow at all at the lower end but the ground whitened with snow only 15-20 mts further in, with an increase in altitude of only 5 mts.

[Tim B]

Visual example I just snapped, if you squint you can just about make it out, snow at the tops of some fields but not at the bottom.

[shuggee]

There's snow up the slopes of Arthur's Seat (251m) in Edinburgh today - and nothing lying in 2/3rds of the city all around it. That's only the second time I have seen this to such a degree here in my 13 years.

An interesting lesson for me last night was how after over 36 hours of torrential rain (and boy it was persistently heavy), snow readily settled on all surfaces within an hour of the change from rain through sleet to snow - the dewpoint simply went down to 0ºC and the snow was heavy enough. Never let it be said that we need the soil to cool, or that the ground is too saturated etc etc - last night proved it means nothing in the right conditions.

[Backtrack]

Visual example I just snapped, if you squint you can just about make it out, snow at the tops of some fields but not at the bottom.

Thanks for that,

I saw that in Wales, but literally fields 5m further up had snow, 5m below didnt.

[Weather-history]

For example, can it be snowing at one end of your street, but not at the other?

It is possible and has happen even with no height difference along the length of the street but it is fleeting. The January 2004 thundersnow event is such an example where it suddenly turned from rain to snow that stuck straight away. So no doubt there was an instance of somewhere where one end of the street it was rain whilst the other end it was snow.

I remember the 1st March 1995 event here, we had heavy rain from a prolonged shower when suddenly it turned to icy rain then snow within a minute. The transistion was very rapid.

I suspect you are more likely to see some remarkable marginality for snow events in continental climes than in this country.

Edited March 31, 2010 by Mr_Data

[Summer of 95]

In the Tyne and Wear area, the difference between snow inland and sleet or even rain at the coast can be extremely marked. There have been occasions when Cleadon had a barrage of sleet, and then when I looked out the front window the next morning, there was a deep snow cover starting just a mile or two further inland.

On occasion when there's a relatively light wind off the North Sea the temperature differences between the coastal fringe and a couple of miles inland can be striking. Marsden is just two miles away from Cleadon, but early on the 8th January 2010, at one stage it was 1.5C at Marsden and -3.8C at Cleadon. Correspondingly, on quite a few occasions my parents have reported lying snow at Cleadon while Neil Bradshaw's webcam for Marsden has revealed nothing at all on the ground.

I haven't seen any situations with snow at one side of the street but not the other, or anything like that, but it will be feasible if you live on the side of a hill for example. For example in the Lancaster area, altitude rises abruptly as you head inland from Morecambe Bay and the dividing line between sleet and 2 inches of snow can be very sharp indeed.

When I lived in Newcastle I once saw sleet down on the quayside, wet non-sticky snow at Gallowgate, and snow settling well in Fenham. Amazing. This was in March 2001, I think around the 17-18th.

[Guest]

The heavy snow which fell here the other night was extremely marginal. We left the village where we live and literally 1/2 mile outside the village there was no snow at all. That then explained to me why we had several hours of what passes for a blizzard these days yet we only accumulated an inch or two of snow. We were right on the line at which the snow was gathering (at 100m). Coming back to the village on Wednesday afternoon there was a very visibile snow line across some fields in so much that a distance of 50m saw a transition from no snow to a covering. Quite amazing to see, shame I didn't have my camera as it would have illustrated your thread perfectly.

[Thundery wintry showers]

When I lived in Newcastle I once saw sleet down on the quayside, wet non-sticky snow at Gallowgate, and snow settling well in Fenham. Amazing. This was in March 2001, I think around the 17-18th.

The 17th/18th March 2001 was notable for its marginality around Cleadon as well. Frequent heavy snow and hail showers fell during the intervening night, and the next morning there was nothing lying at Cleadon yet just a mile further inland there was suddenly thick snow. The snow partially melted inland during late morning, then at lunchtime a heavy snow shower failed to produce accumulations at Cleadon but restored the snow cover just a mile or two further inland.

[ScottSnow]

Gateshead is situated on a hill and although not high, often in marginal situations there can be no snow at the bottom in the town centre and quite a covering at the Q.E or Wrekenton at the top. The snowfall on Friday 26th Feb this year was the last time this occurred, the Team Valley had no snowcover while at the Q.E there was around 3 inches.

I was actually travelling back from Scotland that night and all the way down the A68 anywhere with a little height it was snowing heavily but in places like Hexham on the valley floor it was just rain.

[conor123]

I think it was 18/19th? November 2007 that was one of the most marginal events we have had.

Rain turned to sleet and then wet snow early afternoon and i went for a walk, by the time i was near the Wrekin around in an area about 200 meters above sea level the wet snow had stuck everywhere and there was about a 1cm covering, however i then walked back home (the wind was biting) and by the time i was back home (160-170 meters above sea level around here) it was raining and no snow had settled yet at the top of the very steep bank going up to 220 meters, there was a covering of snow, the rain then turned to snow here in the evening though by the next morning it was gone below 300 meters.

[BornFromTheVoid]

Here is a good example of how marginal it can be. Difference around 100m in height can make!