Curse of the black pearl

Figure 1

The models captured the development of the low called Pearl very well as it deepened and tracked E’NE, and it’s all set to spoil the rest of the weekend with its rain and cloud especially across the southeast of the country. The low almost seems to be developing a black pearl like centre as it spirals round just southwest of the Scillies but that’s probably my over active imagination (fig 1).

Estimated rainfall totals since 18 UTC yesterday are starting to mount up across the southwest, with the first lime green pixels appearing over the Lizard and Bodmin moor (32-40 mm), I’m not sure whats wrong with the radar across the Celtic Sea though (fig 2).

Figure 2

Wall to wall sunshine in Scotland

If you’ve ever read a sunshine card from a Campbell–Stokes sunshine recorder then you’ll probably like this image generated by my SYNOP application. It takes the sunshine reported each hour throughout the day and generates a pseudo mega sunshine trace for all 50 odd SYNOP sunshine reporting stations in the UK (fig 1). I’ve even tried to match the colour of the chart to match that of the sunshine card from memory, but I may not have got the shade quite right.

Figure 1

What today’s mega sunshine card shows is that its been overcast and dull across many parts of the country except the north and west of Scotland and the southwest England, in fact in the Northern Isles the sunshine has been from dawn till dusk by the look of the pseudo trace. The low total from Camborne was a bit of a surprise, but that must have been the convective infill that produced the thunderstorm over west Dartmoor, which produced totals of over 32 mm if my weather radar estimates are to be believed (fig 2).

Figure 2

Today’s poor forecasts

It’s difficult to pin these two organisations down when it comes to verifying just how accurate their maximum temperature forecasts are. But the Met Office model is already one up after yesterday, so I thought I’d just see how they did today.

Figure 1 – Courtesy of the BBC and the Met Office

Here are the actual temperatures at 1600 BST today which I mark 76% to the Met Office. The forecast for London was really dreadful from both models, obviously they expected the stratus to clear but it didn’t. I can’t understand why MeteoGroup have labels for both Glasgow and Edinburgh, but only one temperature, and for which city it’s for. If anything MeteoGroup should have had the edge because the actual and forecast temperatures are both for 1600 BST, but that didn’t stop the Met Office taking a two nil lead.

It wasn’t only temperature that caught out both the Met Office and MeteoGroup today, there was also an area of heavy rainfall that extended across Humberside into Yorkshire during the afternoon that escaped both models. I watched the rolling news on the BBC news during the afternoon and I think even worse than the poor forecast was that the presenter never seemed to noticed that it was happening at all, let alone bothering mention it or show a real-time weather radar image. It reminded me of the taped forecast given by Michael Fish as the Boscastle flash floods was in progress in 2004. I can’t see why the Met Office have bothered to update their weather radar network when no one seems to look at it. Here’s the BBC forecast for the east Midland’s from yesterday evening (fig 2).

Figure 2 – Courtesy of the BBC

Overnight thunderstorms

Figure 1 – Courtesy of Blitzortung (10 Apr 1800 -11 Apr 0600)

There was some pretty heavy rain for a time overnight here in mid-Devon, but none of the overnight thunderstorms (fig 1) seemed to have survived the trip over the cold sea from Belgium and the Netherlands though. We certainly didn’t need any additional rainfall in our part of the world as the ground is already fully saturated.

Figure 2
Figure 3

Is it ever going to cheer up?

Figure 1

A thoroughly miserable wet and dull start to April in many parts of the UK, in stark contrast to the unusual warm and sunny spring being enjoyed in parts of Germany and eastern Europe. In the UK the contrast between Cornwall and Devon is large, with Camborne’s 37.8 hours of sunshine over twice that of Exeter’s 18.5 hours and poor old Liscombe with just 7.6 hours. The north and west of Scotland and the extreme west of England and Wales along with southeastern parts have also seen more sun, and the sunniest place in the UK so far this month is Tiree with 47.3 hours, but that figure is low in comparison to the 60 plus hours on the continent (fig 1).

Figure 1

A thoroughly wet start to April across most of the country apart from the drier northeast of Scotland and southeast of England (fig 2).  The 19.4 mm from Exeter airport looks dodgy as I’ve already recorded 45.7 mm so far this month only 10 km away to the north. I’m afraid that this spring is looking like it’s going to be a cold wet protracted affair in the UK.

Is Cape Town’s drought coming to an end?

Figure 1

I’ve just been looking back at the rainfall statistics for Cape Town which as you probably know is suffering its worst drought since at least 1933. They knock out a good SYNOP at Cape Town international airport, so it wasn’t that difficult to add up the 24 hour rainfall totals to find that in the last 12 months 266.2 mm of rain has fallen there (fig 1). That doesn’t sound too bad on the face of it, but in the last five months, that’s since the start of November, there has been only 51.7 mm of rain.

The climate here is pretty equable as you can see from the six hourly temperatures for the last year (fig 2).

Figure 3 – Water levels in the Western Cape’s six largest reservoirs – courtesy of Wikipedia

Apparently Day Zero, the day when water runs out completely, and which was expected to occur this April, has now been pushed back to 2019. Let’s hope (no pun intended) that the 6 mm of rain that fell in the last week is an omen of a wet winter to come for Cape Town’s sake.

Yesterdays unexpected snow

Figure 1

My estimates of the 24 hour precipitation totals up to 06 UTC this morning may appear to have been a little high for Liscombe (fig 1 & 2), but at this resolution, you only need to be a pixel or two out to make a big difference – well that’s my excuse anyway.

Figure 2

But apart from yesterday being such a cold and miserable day in east Devon and west Somerset, the wet snow that fell for much of the afternoon made it rather unusual too. Here are the plotted observations for Dunkeswell in Devon (fig 3), the snow started here at 13 UTC, perversely the warmest time of the day, and lasted until 17 UTC, before milder air from the northwest lifted temperatures and turned it to rain.

Figure 3

Full marks to the Met Office about yesterdays warning for heavy rain in this part of the world, especially Exmoor (fig 4).

Figure 4 – Courtesy of the Met Office

I think the widespread nature of the wet snow falling across lower lying parts east Devon and west Somerset yesterday afternoon caught them out though. The photo of the snow at Christ Cross above Silverton yesterday afternoon is rather appropriate taken as it was on Good Friday (fig 5)

Figure 5 – Courtesy of Warren ‘Weatherman’ Radmore

Intense rain NE Scotland

Figure 1

An area of heavy rain has developed in the last hour over northeast Scotland (fig 1). It doesn’t get much more intense that 16-32 mm per hour, well actually it does, the pixels turn white with intensities of 32 mm per hour and higher. According to the UKMO analysis it looks like it’s a very active bent back occlusion that’s behind it (fig 2).

I did notice that the rain never even got a mention in the BBC weather at 12.58 pm, although we did get Sarah Keith-Lucas showing us a couple of  nice pictures, one by Geoff of Histon in Cambrideshire, and the other by Alan in Topsham in Devon!

Figure 2

Are winters becoming milder and wetter?

Figure 1

Q: Are winters becoming milder and wetter?

A: The short answer is yes they are. The Central England temperature series [CET] reveals that winters [DJF] are now on average 1°C warmer that they were 140 years ago back in 1878 (fig 1), and the England Wales Precipitation [EWP] series indicate that they’re also 18.6% wetter (fig 2).

Figure 2

Rainfall 14-15 March 2018

Figure 1

It’s been a very wet 24 hour’s down here in Devon, although there seems to be a curious mismatch between the estimates of what the radar saw (fig 1), and the rainfall that found its way into the gauges of the AWS at all the various SYNOP stations across the country (fig 2). Capel Curig just 2mm? The river Culm has certainly burst its banks locally and flooded all the water meadows that surround it.

Figure 2

Locally in Bradninch I only measured just over 19 mm in the 24 hours, but Exeter had almost 30 mm, and Dunkeswell close to 40 mm, so either the rainfall was very sporadic, or I’ve still got a spider’s web in my AWS connected to my tipping bucket.

Figure 3 – Station road, Hele
Figure 4 – looking down the Culm
Figure 5 – Station road, Hele
Figure 6 – looking across the Culm Valley