The weather of the last week has provided a welcome fillip to April’s sunshine totals. Sunniest places during the last week in the UK were in the far southeast, with the last four days being sunny from dawn till dusk.
Here are a few graphics to show the extent of this early thundery spell across the country, the severity and extent of which caught both the ECMWF and the UKMO NWP models out yesterday. As far as I can see most of the lightning was from unstable medium level cloud rather than the more traditional cumulonimbus (fig 1). The rainfall from the thunderstorms looks to have been concentrated in a swathe SSW-NNE through Hampshire, where my estimates from weather radar suggest that as much as 32-40 mm fell in the wettest areas (fig 2).
I won’t go on about just how poor or late the warnings were for yesterdays thunderstorms from the Met Office, or just how divorced the NWP graphics used by either themselves or the BBC was from reality, the following screen shots will have to suffice (fig 4).
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.
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).
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.
Nothing, except being on top of Great Dun Fell, topped the 96 mph gust that we saw at Connaught yesterday evening, and storm Eleanor is now in the mid North Sea with a minimum central pressure of around 967 hPa at 06 UTC (fig 1).
The original yellow warning of gusts to “60-70 mph along exposed coasts” with “the more exposed locations seeing gusts close to 80 mph” just about covered it, and they were completely correct in saying “inland gusts exceeding 60 mph are possible“, but an open-ended threshold like that is not precise and works even for the gust of 96 mph at Connaught airport! The Met Office underplayed it for Dylan which worked, and I think they decided to take a similar approach with Eleanor, but the gust to 87 mph at Mace Head at 17 UTC rattled them, and they decided to play it safe and go for amber which is good.
A very windy night across a large part of northwest Europe with gusts to gale force in many places. A gust of 67 mph at Exeter at 01 UTC must have been the highest for quite a while, accompanied by a couple of rumbles of thunder (fig 2). All in all Dylan and Eleanor have made it an eventful start to the New Year, I wonder if there are more storms waiting to come in the pipeline, or should that be the jet stream?
27 July 2017 – Severe thunderstorms in Turkey
There were many injuries as hailstones as large as golf balls fell from severe thunderstorms that swept across Turkey on Thursday (27 July). This Guardian article has most of the details, and also includes a video of the hailstorm. Several airliners landing at Istanbul Atatürk airport reported major hail damage during the passage of a severe cold front (fig 1). I was late on this one, but have been watching the reports and videos on the Severe Weather Europe website, what a great site this is, and what a clever idea. All that I can add is a plotted chart for that part of the world for 18 UTC (fig 2), and a plotted grid of observations for Istanbul airport on the day in question (fig 3).
Is it me, or have the number of hailstorms increased in 2017?
Is it me, or have number of hailstorms and the size of hail stones that fall out of them grown this year, particularly across continental Europe? It’s obviously linked to the explosion in numbers of mobile phones with inbuilt cameras that has happened in recent years, and their ability to take high-resolution video that has made the difference. We now have high quality evidence from anywhere in the world when a severe hailstorm occurs. At one time a fuzzy photo of a hailstone the size of a grapefruit in the Guinness book of Records is all you got, now we are literally inundated with footage of videos of them falling from the sky, and the damage that they cause.
The English Channel seems to be full of thunderstorms this evening and they are all marching steadily northward. The rainfall intensity is similar to the storms this afternoon of the Lizard, and I wonder if we could have a repeat occurrence of what happened at Coverack somewhere else along the south coast tonight?
The current yellow warning from the Met Office runs out at 2355 BST. Tomorrows warning for much further north doesn’t start till 0005 BST, so technically there is no warning out for around midnight – bizarre. I would have thought now would be a good time for the Chief forecaster to extend the one for the south coast, as I type this, it’s 2320 BST and they still haven’t done it – very odd. In light of the Coverack event earlier today, I thought it might be even worth them ‘upping’ the warning to amber might be in order, I say that as I listen to the Blitzortung website crackling away on my computer, and flashes every 10 seconds out of my Velux windows to the south.
There are two large CB cells to the southwest now, one just south of Plymouth, and the other close to St Malo. The cirrus that’s plumed of the top of the more northern one has just about covered most of Cornwall and Devon bu 12 UTC (fig 1). The shield of cloud thickened up here in mid Devon from CS to AS in the last hour, but the lightning activity is still well out to sea (fig 2). I estimate from the visible satellite image, that the closer one of the two cells, is moving 030° at around 30 knots, although the rain seems to be tracking almost due north.
The rain looks quite intense as you would expect (fig 3), but because the cell is moving quite quickly it shouldn’t cause too many problems, having said that there are some white pixels now showing up in the image (>32 mm/hour intensity) so famous last words. Whilst I’m busy putting my foot in it, I suppose that once this one has cleared away later this afternoon, that might be it for our part of the world, although the radar is now showing some more scattered showers to the southwest of the Lizard.
Story delayed due to power cut – what’s wrong with the infrastructure of this country when a lightning strike 70 miles away takes out the whole county?
Never an easy one to get right as regards warnings for heavy rain from thunderstorms is concerned, but I think the Met Office forecasters just about got it right today with the thundery showers that affected the country (fig 2). I notice that they did shrink the warnings area during the day to exclude Kent and Sussex, although I did notice another large CB that’s developed over NE France on the visible satellite image late this afternoon.
What particularly fascinated me about today’s weather was the arc of AC castellanus that developed and extended from Exmouth E’NEward towards East Anglia through the morning, and gradually thickened to produce quite an active band of thunderstorms during the afternoon.
The very thick cirrus spissatus that rolled in from the west this afternoon across Devon, did take the edge of the extremely bright and burning sunshine, on what was the hottest day of the year here (maximum 31.6°C, yes I know, is far too high, but the AWS is getting on a bit like me). I was surprised that the LCBR at Exeter airport didn’t detect it, but I noticed that the AWS at Dunkeswell did report half cover at 23,000 feet last hour.