London & Se Cold Spell Discussion

[dubmuffin]

Snowing here

lol - it always does snow here too albeit a bit sleety, dewpoint/temp slightly lower now, who knows we could be in for a surprise

[Downpour]

lol - it always does snow here too albeit a bit sleety, dewpoint/temp slightly lower now, who knows we could be in for a surprise

Um where has that lump of ppn come from? It does actually seem to be headed for london. Probably fall as sleet if it gets here lol

[Mikel Nimbus]

Thank you Mikel Nimbus for this. So overall 850 uppers of around -8C or less, plus 528 dam or less, plus dew point <0C, plus surface air temp of as close to 0C as possible (up to 2C?) is overall a higher probability for snow.

You've summed up in 3 lines what took me over 3 years to learn.

[nick sussex]

Dew points have lowered off the east coast of Kent and if a mini streamer is to set up theres the window for it now, next radar will either say yes or no!

[Neilsouth]

I have a dusting on my car and the road , apart from that pretty boring !

[dubmuffin]

RJM, on 10 January 2010 - 20:11 , said:

Thank you Mikel Nimbus for this. So overall 850 uppers of around -8C or less, plus 528 dam or less, plus dew point <0C, plus surface air temp of as close to 0C as possible (up to 2C?) is overall a higher probability for snow

Except when it isn't! Watch out for the warm sectors...

[xentrix]

Um where has that lump of ppn come from? It does actually seem to be headed for london. Probably fall as sleet if it gets here lol

Hmm after looking out my window by the lamplight it looks like sleet/rain but if that blob comes over this way ( currently hitting Margate as rain ) if our dewpoint is low we should get snow hopefully ...

[jafin]

Temp & D/P dropping here slightly - 1.1 & 0.4

[SMU]

You've summed up in 3 lines what took me over 3 years to learn.

Its not as easy as that-

http://www.wetterzentrale.de/pics/Rmgfs121.gif

This eve's thicknesses around 532 DAM- but there is sill snow falling-

radar is picking up all the time--- carries on the hills will get 2-5cm.....- almost as much as yesterdays SWW from the MET!!!!!!!!!

S

[staplehurst]

7C on Friday according to BBC 8pm update (12z model)!

[nick sussex]

You've summed up in 3 lines what took me over 3 years to learn.

Remember though with continental air masses 850's just under zero can still be sufficient, notice how snow is progged for the sw off 850's which are not that cold, the surface flow ahead of the low is off the continent.

[PLANET THANET]

Hmm after looking out my window by the lamplight it looks like sleet/rain but if that blob comes over this way ( currently hitting Margate as rain ) if our dewpoint is low we should get snow hopefully ...

that "blob" is actually falling as light snow in ramsgate, the temperature is 0.8c

[nanu]

err.. just like to point out that its raining here

[utdman_67]

What is happening tonight?? Its been sleet/snow here in Eltham for the last 2-3 hours and at times pretty moderate

I am confused as when I watched the weather forecast this afternoon they did not forecast any snow for this eve or tonight for this area

Are we to expect further snowfall during the night or is it to difficult to say

[staplehurst]

getting heavier as it moves across east Kent!

Estimate arrival here around 20:45ish

[xentrix]

that "blob" is actually falling as light snow in ramsgate, the temperature is 0.8c

Yes sorry meant to say rain/snow as depicted in the coloured labelling of this radar website http://www.raintoday.co.uk/

[Rinse The Raindrops]

Just starting to get wet snow here in Benfleet Essex

[cat0511]

light snow here in folkestone 20 mins or

[PLANET THANET]

snow is just starting to cover the grass from the earlier thaw, what a surprise

[Tom Montalbano]

Steve,

What's the betting the flow turns ESE and that ppn ends up in Essex!

12z GFS wind-streams for next few hours.

http://charts.netweather.tv/gfsimages/gfs.20100110/12/09/ukwind.png

http://charts.netweather.tv/gfsimages/gfs.20100110/12/12/ukwind.png

Regards,

Tom

[Vesuvius]

Something I've not really understood today is how it has snowed on and off whilst the snow on the ground has been melting (I'd say a good 40% of lying snow has gone).

I would have thought if its cold enough to snow it shouldn't melt but clearly not

[coldfingers]

Does the wind chill factor have any effect on whether precipitation falls as rain or snow despite actual temperature?

[Paul Sherman]

Still Raining in Leigh On Sea and has been for about 2 hours now

Positive Dewpoint not doing us any favours, enjoy the Snow further Inland later tonight, as Steve says you could end up with a surprise Cm or 2!

Still looking very good for the Re-Load, GFS Will come onside later this week of that I am sure, ECMWF Already putting down the marker. Jan 25th is my bet for the next shot as I stated this morning.

Paul S

[Mikel Nimbus]

Its not as easy as that-

Remember though with continental air masses 850's just under zero can still be sufficient, notice how snow is progged for the sw off 850's which are not that cold, the surface flow ahead of the low is off the continent.

Totally agree Nick and Steve. The point I was making is that when I started out I believed if it's below 0 it's got to snow, then someone introduced DP's, then RH, then air pressure, then 850's etc etc etc. So it was a long drawn out process to understand understand the many factors.

[xentrix]

Steve,

What's the betting the flow turns ESE and that ppn ends up in Essex!

12z GFS wind-streams for next few hours.

http://charts.netwea...2/09/ukwind.png

http://charts.netwea...2/12/ukwind.png

Regards,

Tom

Nice graphs if thats the case Tom we should see a good deal if anymore precip comes off the continent ...