Snow Reports 19th Feb

[lesta_snow]

very random snow hahe =]

never seen such a harsh frost as this morning it lasted

all day on the trees and the frost was so thick

i thought they where snow flakes

[johnholmes]

you do not get showers out of fog, there is no cloud other than very low Stratus with a top of about 1200ft!

[disco-barry]

That's exactly what i was thinking! lol

[Derbyshire_snow]

well it definately Snowedin Sheffield because when i went to visit my Nan in Abbeydale there was a Car there with about 1 inch of snow on it i couldn't believe my eyes,I thought no it couldn't possibly be but then i got a phone call from my partner telling me that it was snowing at Crystal Peaks in Sheffield.

[WS Evolution]

Paul Hudson explained it as frizzing drizzle... there was more last night in parts of North York.. Pictures will be added to the photography forum

Edited February 20, 2008 by WS Evolution

[flagpole]

Does rime not accumulate like snow? Is that not the point John Holmes was making? It can't snow out of fog?

We had at least a centimetre covering yesterday morning but there is no way on earth it was snow.

[Evening thunder]

Well looking at the pictures people have posted and what they have said i would call it snow. just as people would if the fog was higher up (cloud)

its the same process i would guess just in fog?

I am very suprised that the fog could create this much stuff though and i have not heard of this before.

[flagpole]

Well looking at the pictures people have posted and what they have said i would call it snow. just as people would if the fog was higher up (cloud)

its the same process i would guess just in fog?

I am very suprised that the fog could create this much stuff though and i have not heard of this before.

Well what we had was definitely an accumulation of ice crystals from the fog. Even I'm not so desperate for snow to call it that

[johnholmes]

I'll try one more time to explain the process which occurred yesterday.

2 processes in fact

1. Rime deposited on surfaces NOT falling.

2. snow grains FALLING out of the fog. There was no snow as is normally understood. Snow falls out of thick clouds, be that convective or layered cloud on fronts, or a mix of both.Yesterday there was no cloud other than low Stratus/fog. See the sat picc I posted and the explanation along with my comments regarding the upper air information - ascents, t-phis/skew-t diagrams which show the temperature and dewpoint structure from the surface all the way into the higher atmosphere, way above 40,000ft.

None of them showed anything above about 1000-1500ft, the top of the fog/Stratus.

In very cold conditions as we had yesterday with thick fog both 1 and 2 can and do occur. In some instances yesterday the snow grains combined into larger aggregations of crystals to form what looked like snow flakes to some, a picture taken by a forum member clearly showed this. Just what caused this is not easy to discover, there had to be an additional source of moisture, a chimney, be it for a factory, power station, even a brewery, whatever, in a very localised area that caused up to 2cm of 'snow' to fall in places. Not to be confused with the rime/snow grains which subsequently fell off trees.

If I get time I will try and collate the sat piccs/photos etc and put them into the NW Guides so that everyone can refer to them at any time.

I hope this helps explain what happened yesterday.

Edited February 20, 2008 by johnholmes

[WS Evolution]

I'll try one more time to explain the process which occurred yesterday.

2 processes in fact

1. Rime deposited on surfaces NOT falling.

2. snow grains FALLING out of the fog. There was no snow as is normally understood. Snow falls out of thick clouds, be that convective or layered cloud on fronts, or a mix of both.Yesterday there was no cloud other than low Stratus/fog. See the sat picc I posted and the explanation along with my comments regarding the upper air information - ascents, t-phis/skew-t diagrams which show the temperature and dewpoint structure from the surface all the way into the higher atmosphere, way above 40,000ft.

None of them showed anything above about 1000-1500ft, the top of the fog/Stratus.

In very cold conditions as we had yesterday with thick fog both 1 and 2 can and do occur. In some instances yesterday the snow grains combined into larger aggregations of crystals to form what looked like snow flakes to some, a picture taken by a forum member clearly showed this. Just what caused this is not easy to discover, there had to be an additional source of moisture, a chimney, be it for a factory, power station, even a brewery, whatever, in a very localised area that caused up to 2cm of 'snow' to fall in places. Not to be confused with the rime/snow grains which subsequently fell off trees.

If I get time I will try and collate the sat piccs/photos etc and put them into the NW Guides so that everyone can refer to them at any time.

I hope this helps explain what happened yesterday.

The source would have been sewage works, large chimney and the river Ouse. in Clifton Moor, York. all up wind of the localized event and all close by. There was a very slight breeze!.

There was more last night in the same location see my latest pics in the forum! http://www.netweather.tv/forum/index.php?showtopic=45847

The first and third pic where taken in the snow grain falling areas.

Edited February 20, 2008 by WS Evolution

[Coast]

I hope this helps explain what happened yesterday.

Works for me John and is based on some pretty tried and tested meteorology from the looks of your explanation.

I think we should take the time to consider that whatever its called and however its formed, if you get a white winter effect with accumulations of a freezing cold substance on the landscape etc, then you are doing well these days and the pictures that came out of the event looked great - I would have been happy to have had it here!

[andy_leics22]

Whatever it was it has been something unexpected and it's even had the most experienced forecasters stumped as to find out what exactly happened! So it was a pretty interesting phenomina

[WS Evolution]

The map shows the area of north York that had the snow grains falling and settling like snow. I have marked possible sites of added moisture and pollution in yellow. Snow grain falling area in white, thicker areas had more.

Edited February 20, 2008 by WS Evolution

[Evening thunder]

I'll try one more time to explain the process which occurred yesterday.

2 processes in fact

1. Rime deposited on surfaces NOT falling.

2. snow grains FALLING out of the fog. There was no snow as is normally understood. Snow falls out of thick clouds, be that convective or layered cloud on fronts, or a mix of both.Yesterday there was no cloud other than low Stratus/fog. See the sat picc I posted and the explanation along with my comments regarding the upper air information - ascents, t-phis/skew-t diagrams which show the temperature and dewpoint structure from the surface all the way into the higher atmosphere, way above 40,000ft.

None of them showed anything above about 1000-1500ft, the top of the fog/Stratus.

In very cold conditions as we had yesterday with thick fog both 1 and 2 can and do occur. In some instances yesterday the snow grains combined into larger aggregations of crystals to form what looked like snow flakes to some, a picture taken by a forum member clearly showed this. Just what caused this is not easy to discover, there had to be an additional source of moisture, a chimney, be it for a factory, power station, even a brewery, whatever, in a very localised area that caused up to 2cm of 'snow' to fall in places. Not to be confused with the rime/snow grains which subsequently fell off trees.

If I get time I will try and collate the sat piccs/photos etc and put them into the NW Guides so that everyone can refer to them at any time.

I hope this helps explain what happened yesterday.

yes thanks for that john. that must have been what happend. i was just suprised at the amounts that the fog was able to create for some areas even with added moisture. very interesting and detailed post there as always :lol:

[johnholmes]

The map shows the area of north York that had the snow grains falling and settling like snow. I have marked possible sites of added moisture and pollution in yellow. Snow grain falling area in white, thicker areas had more.

tks for posting that WS I may use that if its okay with you when I get round to doing a guide on it?

[Storm Animal]

Had a nice pleasant surprise snowfall this morning around about 9am, went on for quite some time and left a widespread covering, stuck immediately, as temp was down to -6oC overnight.....The snow seemed to be falling from the thick foggy skies.....probably only 0.5cm, but looked like a winter wonderland, even down in the town centre of Oldham & lasted til early afternoon :lol:

[WS Evolution]

tks for posting that WS I may use that if its okay with you when I get round to doing a guide on it?

Sure go for it.

[Costa Del Fal]

Here on the 19th there was a light covering of snow. Not complete covering but on the grass you could tell there had been some snow.

[Guest Shetland Coastie]

Currently mixed wintry showers here in Shetland with hail, sleet and snow. The snow sometimes lovely big fluffy flakes but nothing lying, very wet.

[Guest Shetland Coastie]

Again another mixed bag of wintry showers today with hail, sleet and occasional wet snow.