Thames Snow Streamer Event 1/2nd Feb 2009

[Noctilucid]

Super report Paul, you've really done some hard work on this. B)

Indeed, towards sundown I could see updrafts and they were only really getting going overhead or just to the West, we ended up right under a red precip area.

Edited February 14, 2009 by jshaw

[snowray]

Just come across this thread, silly me, been baffled about this since it happened realy, why did the west of London get more snow than the east, just didn't make sence in this sort of set up. Thanks for giving it some thought and reasurching it Paul, truly great stuff.

Usually if anything is coming this way from the North sea its from a more Northerly direction, NEly, Nly, NWly, when the extreme East always does best and inland areas might only end up with the odd shower here and there, but on this ocasion the ENEly set up the Thames Streamer just perfectly it would seem.

Wasn't aware of the inversion though or that awful polystyrene stuff , no wonder so many people were so miserable. B)

[LomondSnowstorm]

oddly enough it almost worked out similarly here

for the first part of the night the snow started falling here but only as grainy stuff that wouldn't lie

we are not directly on the coast so eventually we did end up with a good few inches of snow by morning but for a long time it looked like a total non-event

further along the coast there was very little snow, although that is normally the case here

i suppose the forth/tay estuaries are both similar to the thames in the sense that they are on the east coast and are all fairly wide

[londonsnow]

fascinating post Paul. it does make you realise that the thames streamer is a complex affair, which can wrong for some. cheers LS

[mackerel sky]

Really intriguing stuff. On the Sunday we only had light snow showers and a drifted covering. Probably what annoys me a tad is that after the Thames Streamer came to an end, we had 12 days of 100% snow cover, culminating in over a foot of snow in the east of the county that didn't go anywhere fast, without the level of media coverage offered to the 2 days of snow cover in London. Partly because "Look East" or "Look Norwich" as it should be called didn't bother with the snow in Northants, neither did "East Midlands Today" or "Look Nottingham as it should be called, with maybes Derby and Leicester as an afterthought".

[Cheese Rice]

Very informative thanks

Can this happen anywhere else in the UK? Specifiaclly Hull because the river is quite wide leading out to sea ?

[Thundery wintry showers]

A similar process occurred in the Tyne & Wear area during the evening of the 1st. Lines of showers passed over the Sunderland area, while Cleadon just to the north stayed in the clear. However, this changed overnight as shower activity extended northwards through the region and snow showers affected all parts of the area and were scattered about pretty much at random. I have seen "lines" of showers similarly affect that area of the country in previous easterly spells- overnight 28/29 December 2005 for example when Cleadon reached 3cm, but further south, where lines of showers hit, depths approached 10cm.

But oddly, temperatures near the Tyneside coast were not significantly lower than they were during the easterly blast of 3 January 2008, despite the SSTs being considerably lower and the 850hPa temperatures being almost 5C lower. The lowest temperature during the easterly outbreak was 0.3C (compared with 0.7C on 3 January 2008), and it invariably jumped to 2 to 2.5C in the clear intervals in between the showers, even when the sun wasn't shining. As a result there was a freeze-thaw process and a slushy mess, except briefly around lunchtime when prolonged snow showers gave a couple of inches and that recording of 0.3C.

[JamesL]

Facinating stuff.

We had around 5cms from the convective stuff and another 5cms from the warm front so cant complain and that was pretty much at sea level. When I see the photos of SE/SW London however it shows that this really was a rare event

The best snow for mid and east Kent came from the 'suprise' snowfall two thursdays ago which left parts of the Kent N Downs under 10cms.

Do you also think that the pollution of London and the Thames Estuary region played a part in this event. More pollutants should in theory mean more for the ice crystals to hang on to?

James

[J07]

Do you also think that the pollution of London and the Thames Estuary region played a part in this event. More pollutants should in theory mean more for the ice crystals to hang on to?

James

Increased man made pollutants generally decrease the precipitation downstream (a noted effect in Colorado and China amongst others). Given how polluted SE England is I'd say there could well have been an effect from that.

If it were "pristine", purely maritime air there would be an abundance of salt particles (which are large compared with man made pollutants), and the precipitation would have been increased downstream. This is how we get rain down under from clouds that "should not" be precipitating compared with the theory that was written in the polluted northern hemisphere.