Ian Docwra

Another major BBC self-contradiction this morning - the TV forecast told of a battle between mild and cold air masses this weekend, with the cold winning, whereas their web pages show double-figure temperatures for the SE next week!

Depends where you are - how thick the cloud is, etc. Heavier snow showers will both cut out the solar warming and bring colder air down with the snow, lowering the temperature. The same cycle can continue until late afternoon when the sun's warmth is gone. Then the opposite effect takes over - clear skies lead to rapid cooling as the earth radiates heat away, but clouds limit the cooling through their insulating effect.

An easterly flow gives a shorter sea track than the north-easterly we've been having. Trace back from, say, the Thames estuary along each track and see the distances involved before hitting land again.

It'll probably run along the channel to N. France.

Regarding temperatures, something that may be worth bearing in mind is that the sun at the moment is getting high enough to provide a little warmth even through moderate cloud. This means that its radiative effect can warm many surfaces and objects enough to raise them a little above freezing even when it's snowing lightly. This includes cars and conservatories, paths with some bare areas showing (dark absorbs heat much more than snow) and metal garden furniture, for example. These can all be sitting at a degree or so above freezing even if the air temperature is not. The stronger wind reduces the effect as it drags the heat away and evaporation cools the surface. Today's wind is much lighter than yesterday's and the warming effect is more apparent. If we were in mid-December, solar warming would be much less significant.

No streamers around the SE, but one in the Channel and another, smaller, one over north Hampshire/Dorset.

It's nowhere near heavy enough for Amber! There would need to be major streamers delivering huge amounts to warrant that (as with EA over the last two days). The amount heading across barely even warrants a Yellow warning.

A number of reasons are possible - for a start: 1. Drains or pipes running underneath (we have this with our front path) 2. The ground still has some deeper warmth from the mild weather before the snow and this leaches upwards 3. Salt residue 4. Generally, slabs and concrete transmit heat better than grass, and heat leaks from houses' foundations to surrounding areas and warms them enough to prevent anything but brief freezing in strong winds, when the heat leaking out is overwhelmed by the constant influx of colder air. Lighter winds can't take that heat away fast enough.

At the moment it looks as if the colder influence will dominate for the foreseeable future - how cold exactly is unclear, but we are getting to mid-February soon and the sun is getting stronger. However, clear nights can still produce some very low minima over snow cover (-15C last night in Scotland, and the same tonight).

The wind has been coming off the North Sea for the entire cold spell. An E, rather than NE, wind has a shorter sea track so should make it colder still, but there are other factors at play - the wind is a little lighter today and there is a little more solar warming through the thinner clouds, pushing the temperature up a tad. Remember we are now nearly a month and a half on from the shortest day so the sun is gaining a little more power. We are now at -0.6c here (from -1.2C an hour ago) in NE Surrey with a few flakes falling, but the sky is much brighter than yesterday - i.e. more insolation reaching the surface.

It seems that the whole area of snow over Essex/N Kent, although generally weakening slowly, is steadily translating SW, such that while individual pulses come and go, they are replaced by new ones a little further SW.

By the way, I'm sure this has been answered countless times, but what IS the strong radar signal just off Thanet's east coast which shows intense activity but sits there unmoving for hours at a time?

The BBC even now is showing heavy snow showers for Kenley, Surrey for hours to come. It simply isn't the case as the heavier snow is weakening very rapidly as it comes off the estuary. Inland progress diminishes the snow to a few flakes in about ten miles.

That may have a bearing on it.

I did note from the Met Office pressure charts that the high over southern Scandinavia is set to intensify quite quickly by late in the week (to 1043mb), which may provide renewed blocking.

Yes, after a day-time maximum of -1.3c, we are now at -1.1C after it fell to -1.6C earlier in the evening. The breeze is strong enough that this isn't due to clear/cloudy variations, but the very feeble warmer sector.

To see the strange power of streamers have a look at the radar for The Wash streamer and look at the sudden heavier blob near...Hereford!

Not to be taken literally - they are just indicative of showers/streamers in general.

The further NE you are the better, so a little better than Godalming, but it won't be spectacular.

The large area of snow over SW Essex looks to be weakening rapidly now - to be expected, but hopes picked up a little there for some photos tonight!

Sadly for us, unless it's a particularly vigorous one, not much. I'm a little further E than you, but unless a strong and concerted streamer sets up it will lose potency after a few tens of miles in most cases meaning relatively little down here.

Did you mean ENE there?

Perhaps, but bear in mind that an easterly component will have a shorter sea track and therefore less moisture can be collected and then released as snow.

The radar echoes from the EA/Essex area of snowfall seems to have several gaps where it goes from heavy snow to nothing without any gradation at all, almost as if in a dead zone. What's causing this, as I can't see it actually being the case that there are small fixed areas embedded in heavy snow where it's bone dry without any tail-off into those areas? In the screenshot they are the white patches in the leading area of green, which, on the animation, stay where they are as the green echoes pass by (like rocks in a stream).

Apart from the downright fun of having some heavy snow, as a keen photographer, I'm hoping to get some night shots of falling snow with various light sources, so I'm watching the progress of the area of snow over Essex with interest for a possible arrival here in NE Surrey after dark.