I’m not dreaming of a white Christmas…

Figure 1 – Courtesy of www.netweather.tv

The early signs from the latest T+348 of the GFS model aren’t looking too good for the chances of a white Christmas this year.

Figure 2 – Courtesy of William Hill

Yesterday’s snow

Figure 1 – Courtesy of NASA Worldview

What a great visible satellite image from NASA from earlier today showing the extent of the snowfall of the last few days across the country. I can now see that Exmoor did indeed get some snow as the occlusion pushed south later yesterday afternoon over north Devon.

Port of Calais closed as nor’easter continues

Figure 1

Severe northeasterly gales in the eastern English Channel have forced the closure of the Port Of Calais (fig 1). Low Yves/Ana tracking E’NE across the northeast of France is the culprit, although she is now beginning to steadily fill (fig 2). If you remember in the severe westerly gales of yesterday a P&O ferry ran aground on a sandbank in the port.

Figure 2

I can imagine it’s quite tricky getting into the Calais with a big high sided ferry when you’re being side-swiped by a gale force nor’easter (fig 3).

Figure 3 – Courtesy of Google

I bet there have been a few queasy passengers sweating it out trying to cross the English Channel in ferries during the last couple of days. This observation sequence (fig 4) is from the Channel lightship a little further west, where early yesterday it was blowing a gale from the southeast, before veering westerly and increasing severe gale with gusts to 74 knots. The winds did die down during the late afternoon and evening, only to veer northeast and pick up to gale force again with gusts to 55 knots today.

Figure 4

11 December – morning satellite and radar images

Figure 1

A very dramatic visible satellite image of the British Isles this morning, with yesterday’s snow clearly evident across Wales, along with the shadow of the frontal band from Yves, Ana or whatever they ended up calling the low over northern France (fig 1). The convective streamers are already in place down the Irish Sea, running from just south of the Isle of Man aligned N’NE-S’SW to the west of Cornwall, and are now showing up in the weather radar (fig 2). Moderate rain is edging into Sussex and Kent, if temperatures had been just a degree or so colder this would have fallen as snow even to low levels and caused travel chaos.

Figure 2

Right kind of snow – wrong kind of place

Figure 1 – Courtesy of Twitter and the Met Office (8 Dec 1303 UTC)

These image on the Met Office Twitter tell the story of the snowfall event on Sunday across England and Wales. Yes, the Met Office got it right, there was snow, and yes the estimated accumulations were quite accurate, but as you can see from these two images the heaviest of the snow was forecast to fall a little bit further north than it actually did. The NWP models ran low Xanthos perhaps 0.5° further north, maybe the later runs of the model nailed the track, but by then the alerts and nice graphics, had been tweeted and posted to Facebook, and it was too late now to make any final course corrections.

Figure 2 – Courtesy of Twitter and the Met Office (8 Dec 1422 UTC)

Even the amber alert they issued was for the wrong area. It was interesting to see that the BBC had even dispatched reporters further north to Llangollen and Nottingham to catch some shots based on this amber area (fig 3), when the reporters should have been in south Wales or High Wycombe to capture the worst of it!

Figure 3 – Courtesy of the Met Office

Here are the snowfall depths reported by the SYNOP stations at 18 UTC yesterday (fig 4). I’ll leave you to make your own minds up about how well they did and how far out they were. I suppose nothing really changes, every Winter we have to show off our total inability to cope with snow to Europe and the rest of the world. I just wonder how we would cope now if we saw a repeat of the snowy winter of 1946-47 or 1978-79?

Figure 4

Nor’easter UK style

Figure 1

It’s a pity that our nor’easter across the south this morning hasn’t brought more of the weather that our American cousins associate with their nor’easters. Across southern areas it just means a biting cold wind, leaden skies and outbreaks of rain or wet snow. Low Xanthos is now a shrunken shadow of its former self across northern Germany, overnight developments have meant that the new kid on the block is low Yves over Brittany, its centre is much deeper than Xanthos was yesterday, with a minimum central pressure that’s already less than 960 hPa (fig 1).

A hard frost further north across the borders were winds were lighter and skies remained clear (fig 2).

Figure 2

Rather surprisingly, the whole meridional theme of the last couple of days is simply washed away in the next 36 hours or so, as we switch back into zonal mode across the UK.

Today’s precipitation totals and risk of flooding in Devon

Figure 1

Apart from the bright banding from the Dean Hill radar, the two interesting  areas of precipitation accumulations for today are one northwest of London which produced a lot of snow today at High Wycombe, and the other area across central Devon and the Blackdown hills on the Devon-Somerset border (fig 1). The estimates from the weather radar for that area are in excess of 50 mm from 06 UTC this morning. I imagine that most of this will have been rain, but it has been snowing for most of the afternoon a little further northeast at Bristol Airport, so you never know. The only thing that I can attribute the band of higher totals to is the occlusion that aligned itself across central Devon for most of today. A severe flood alerts has been issued by the Environment Agency for the rivers Clyst and the Culm in south Devon (fig 2), that’s according to the FloodAlerts.com web application.

Figure 2 – Courtesy of floodalerts.com