poseidon
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Posts posted by poseidon
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Given the lack of UK storms again atm, take a look at this 8 min vid I shot on Sunday morning before sunrise in Italy. The intensity ramps up through the video as the storm passes over my location (on top of a hill). It occurred on the boundary between Estofex level 1 and level 2 alert areas. I abandoned filming in the end as rain was pouring in. The wind was so high (the foreground trees were being battered from 6:00 onwards) that there was quite a force on the window. Listen to it on headphones with the volume up for best effect and make sure your laptop screen is at the right angle as it's quite dark. Quality's not great as it's shot through a mosquito mesh, I was getting hosed with rain and YouTube seems to have lost the HD resolution. Gives an idea of what it was like though. Once I stopped filming there were a number of extremely loud shotgun thunder claps right overhead that vibrated the building. It lasted 2 hours. I was pretty lucky as we had 4 thunderstorms while I was there, this being the best of the bunch.
Here's what Estofex had to say...
Storm Forecast
Valid: Sun 25 Aug 2013 06:00 to Mon 26 Aug 2013 06:00 UTC
Issued: Sun 25 Aug 2013 05:27
Forecaster: VAN DER VELDEA level 2 was issued for Italy and northwestern Balkan mainly for severe convective wind gusts and large hail.
A level 1 was issued for Italy and northwestern Balkan mainly for severe convective wind gusts, large hail and tornadoes.
SYNOPSIS
A multicore low pressure system is situated over France, Germany and northern Italy. Cool airmass has entered France and the northwestern Mediterranean. Warm unstable airmass is sticking around Italy and the western Balkan, as well as in a small pocket over eastern Spain. An occluded front with weak conditional instability stretches from the Alps to the Netherlands. From Czechia to Moldova it has the form of a warm front. A merry-go-round of shortwave upper troughs affect Netherlands, western France, northern Italy and Hungary.
An occlusion of another low with a zone of unstable air is present over western Russia. Northern Africa is also active and very high-based.
Model buoyancy profiles look weak in the mixed phase region over France, Germany, Romania and Russia, with reduced potential for significant electrification and hail production.
DISCUSSION
...Italy, Slovenia, Croatia and surrounding area...
A large area with 500-1500 J/kg MLCAPE and 15-20 m/s deep layer shear is expected to continue producing severe storms. The Adriatic CAPE is a bit more capped. The highest potential is over northeastern parts of Italy and the northwestern Balkan, because these areas are crossed by upper shortwave troughs which can destabilize mid levels and enhance upper winds and shear. GFS model hodographs appear the roundest over eastern Italy, while over Slovenia and Croatia they look more helical in the lowest levels. Supercells and mesoscale convective systems are the expected mode. Large hail is likely. Of particular interest is delta-theta-e, enhanced over 16-20K over a large area, apparently created with help from cooler, drier mid level air behind the mid level cold front overrunning the warm moist low level air. This parameter suggests enhanced downdraft intensity with severe gusts, and combined with mesoscale forcing widespread damaging winds may occur. Tornadoes are not that likely given a not very low cloud base height and somewhat weak 0-1 km shear, but local orographic enhancing factors combined with veering profiles in a large region probably will allow an isolated event.
After the big storms, (18Z and later) waterspout tornado potential increases over the northern Adriatic as low level lapse rates steepen during the night as cooler air comes in.-
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It looked a lot more impressive last night, covering a good chunk of land mass - should have done a screen capture instead of copy/paste as it's still updating - hence shows not much happening now in the morning. And yes, looks like a nice conveyor of storms going through down there.
Better on the equator!
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Another average day on the continent....
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After all the excitement recently, looks like a bit of a boring week ahead storm wise.
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I've been pro-nuclear for decades, S...Do you recall all those daft protests, about storing waste, back in the '80s? What could be safer than putting the stuff miles underground, in a geologically stable area? Or even in deep ocean trenches, from where it won't re-emerge for 200 million years?
And, of course, it does decay!
Nobody wants waste stored anywhere near them. There's still no long term storage and therefore all the waste has to be stored at the plants and at Sellafield. This waste is stored in pools with minimal containment. If there was a loss of coolant as nearly happened at Sizewell A, where a major accident was only prevented by pure luck, a couple of years ago, then the fuel rods would catch fire and vaporise caesium, strontium etc into the atmosphere - you cannot put such a fire out with water. The US is already experiencing problems with deep storage where highly radioactive waste has begun leaking from containers, after only a few decades. Some transuranic elements in the waste can take over 30 million years to decay. Storage is a major issue that gets continually swept under the carpet.
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This is true, but had we invested in nuclear twenty years ago then that would have given us more time in order to invest in viable alternatives. It's a depressing scenario Pete, we can all see problems ahead yet successive governments fail too see any sense of urgency or even have a contingency plan in place. Ostriches, sand and buried!
Unfortunately the nuclear option is a pretty scary one at the moment. The UK gov has gone for the EPR reactor design. This design is currently being built in Finland and France. The Finnish one is 6 years behind schedule and the French one 3 years. Both have experienced massive cost overruns, but more worryingly numerous construction faults have been found by inspectors - weld issues, incorrect concrete mixes, pressure vessel issues, all manner of stuff. In addition, it's bigger and uses MOX fuel which contains more Plutonium so things could get rather messy in a major accident scenario. It's also still a PWR and so suffers from the some of the same issues as current PWRs, including the use of Zirconium cased fuel rods that can generate Hydrogen in a power excursion, leading to an explosion. In a country with such a small land size we cannot afford one accident and we cannot afford France to have any accidents either. IMHO, the risk is too great.
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Bit of a disappointment really. Looked like the estofex/torro forecast was justified for a while, but didn't last long around here.
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Had rumble of thunder and some lightning here. Skies looked nasty on way home from work with heavy rain, moved North now and it's blue sky again.
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Looks like a storm heading towards London from the S coast?
Looks like it's bang on target for me, question is will it survive the trip cross country.
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Virtual constant thunder at one stage but didn't see any lightning.
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- have to get going for work now so am probably going to miss it.
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I think the day's finished early here - it's gone back to night again.
overhead clap of thunder and it's starting to rain.
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Only one rumble here so far. Seems like lightning activity over central London has ceased which is a annoying as it looked like it was destined for me.
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Just had quite a dark mass of Ac-Cas come over - blocked the sun out for a while, to my north, west to east. To the west it's looking pretty dark cause of cloud build up
Starting to break up a little again now. Think the cloud here was the top of the line of cloud that came East from Brighton.
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Just had quite a dark mass of Ac-Cas come over - blocked the sun out for a while, to my north, west to east. To the west it's looking pretty dark cause of cloud build up
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Few light showers forming from Brighton up to St Albans?
Looks like the Met Office have forecast this already for Brighton.
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Some pictures I took out and about yesterday in Herts and Essex....
https://forum.netweather.tv/gallery/image/18763-taken-from-the-car/
Think this is a flanking line (with anvil in the background). Cell moved up from London, with torrential rain and a bit of thunder and lightning...https://forum.netweather.tv/gallery/image/18757-rear-flanking-line-with-the-anvil-behind/
This looks to me like a shelf cloud. CG lightning was produced to the rear of this...Any extra insight regarding the features visible in the pictures of the London cell would be much appreciated. More pictures from yesterday in my gallery.
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Just come back from chasing the local cells. Bit of lightning/thunder and got a pasting with torrential rain. But the best bit was the cloudscape - the most stunning I've seen for quite a while especially with the sun setting. Can't remember seeing so many anvil clouds in the sky at once.
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I'm very near to those anvils in S-East and they don't seem to be doing a lot ...
Umm, activity seems have decreased a bit on blitzortung.
Had a rally vivid double rainbow here.
Ah ha, just as I write this, had a big flash and decent rumble of thunder!
Might take a drive down your way a bit to intercept it.
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Excellent storms heading towards this area.... Nice to these parts getting some good storms.
A nice pack of storms heading this way working their way across north London.
MagicBat
fingers crossed
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Can hear rumbles of thunder now
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Just had a nice little display here in Nw London, only lasted about 20 minutes but still not bad.
I think the front of the anvil is approaching me now. White cloud all splayed out of the top and getting very dark.
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In the end the met office forecast for my area was fairy accurate apart from getting the timing out by 2 hours. They said thundery rain and we had that [just]. Once we had the miniscule thunder though it seems that they decided it was necessary to change the forecast to thunder, even though by that time the rain had near enough stopped.
Looks like there's already a cell trying to cross the channel towards the SW nr the channel islands.
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Something suitable for us southerners this evening...
- have to get going for work now so am probably going to miss it.
Convective / Storm Discussion - 23rd August onwards 2013
in Storms & Severe Weather
Posted
Some new research on tornado tracks....
http://phys.org/news/2013-08-tornadoes-tend-higher-elevations-greater.html