WS Evolution

Willy wonka faux snow! -7 in York this morning with localised "Diamond dust" falling through the night, giving a dusting of what looks like snow...All thanks to the nearby chocolate factory adding extra water vapor down wind of the factory. "To form diamond dust the temperature must be below the freezing point of water, 0 °C (32 °F), or the ice cannot form or would melt. However, diamond dust is not often observed at temperatures near 0 °C (32 °F). At temperatures between 0 °C (32 °F) and about −39 °C (−38 °F) increasing the relative humidity can cause either fog or diamond dust. This is because very small droplets of water can remain liquid well below the freezing point, a state known as supercooled water. In areas with a lot of small particles in the air, from human pollution or natural sources like dust, the water droplets are likely to be able to freeze at a temperature around −10 °C (14 °F)" Ref: http://en.wikipedia....ki/Diamond_dust Diamond dust on a willow tree in York @ 10am

1 hour 1/2 of snow so far, just north of York.

Cold air trapped at surface in the Vale of York. Snow cover will help but don’t think depth will make much difference. Typical under high pressure. Not seen anything over 1C since the snow arrived. "The vale is in the rain shadow of the Pennines so has a lower rainfall total than areas to the west. It is also subject to more fog and frosts in winter than other areas because of the tendency of cold air to drain into the vale from surrounding higher ground."

No sign of a thaw just yet here (7 miles north of York centre). was -4 @ 11am, with a low of -7 this morning. Photo: Moorlands Wood @ 12pm Tuesday 07 Feb 2012.

http://www.thenorthernecho.co.uk/news/9245701.Roof_collapses_at_County_Durham_industrial_estate/

"B6265 North Yorkshire - B6265 in Hebden closed near the Hebden junction, because of a fallen tree"

Tree down over the River Foss in York: http://www.yorkpress.co.uk/news/9245410.Trees_down_as_high_winds_batter_region/

Thunder storm currently North East of York.

North of York we have had lightning & thunder and rain (heavy on and off) for about 3 hours. I think its about done now, with light rain and brightening skies. We also had a storm at 7am.. Been very active day here so far.

25th Nov 2010: Gillamoor, North Yorkshire.

Used Fireworks 2004 -> used two layers, blend mode set to "color" for top layer (2010). Used Photoshop CS4 for pixel count, using histogram window to show pixels, with magic wand (Tolerance 0, anti-alias OFF, Contiguous OFF and Sample All Layers OFF.) to select colours.

If I have worked this out correctly: [based on pixel count] Last year had 3% higher snow cover at this stage: gray = 5214 green = 5995 white = 17929 this year = 23143 last year = 23924 This year cover is 97% of last year.

Hope this works and helps people compare last year: 2009 V 2010. Bright Green = Snow last year not this year Gray = Snow this year not last year Dark Yellow = Ice this year not last year White = Snow both years. Yellow = Ice both years

Lapland cams showing snow returning from the north east with snow falling now in the far north east. Across the boarder into north Sweden they are expecting quite a bit of snow today.

Paul Hudson going for a cold winter.... http://www.bbc.co.uk/blogs/paulhudson/ And once again, a colder than average winter looks the most likely outcome based on the latest projections. Paul Hudson