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Jane Louise

Convective / Storm Discussion - 22nd December 2013 - 2014 onwards

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Noth Leics-30 minutes of intense thunder and lighting, started very quickly from seeing dark clouds approaching with the odd rumble, all of a sudden it was overhead (or very close) with constant flashes and loud thunder with a very heavy hailstorm, hail stopped and turned to rain for a few minutes now the sky is clearing, the storm stopped as fast as it started.

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I luurve the lightning maps! Puts our European friends to shame although, come the summer months, I am sure they will have the last laugh.....again! Posted Image

 

Temperature here now down to 5.2°C, a drop of 4.7°C in half an hour: this is pretty impressive at any time of the year.

 

Looking at the radar there does appear to be a rash of showers out West, however, in this location, they typically do not make it over the Pennines and then the Wolds. That is why the NW is a poor direction for snow in these parts, even if showers are rattling in to the NW of England. We shall see what happens next week: last January there was a few days with thundersnow, but today was the first thunder here since August 2013.

 

Here's hoping for next week, but really we need an easterly feed to produce thundersnow here. Fingers crossed.....

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Posted Image

 

Around 900 strikes now and counting, not bad for January!

Britain the most thundery place in Europe

 

Posted Image

For a change....

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should  be interesting when it hit the east/southeast should  be here  in about hour

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You effing watch, France/Benelux will have 19,000 strikes per hour in the Summer Months, narrowly missing the UK!

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Trough is now passing through here, no T&L alas but 20 minutes of torrential rain and some of the strongest gusts of wind I've experienced since moving down here, certainly on par with the St Jude's day storm (we're on top of an windward facing escarpement)...Considering the shear noise of the wind and the amount of branches now on the ground, it wouldn't surprise me if the wind gusted well in excess of 60mph.

 

Also great to see plenty of thunderstorms around further north in the Midlands this afternoon, it goes to show just how lucky we are in this nation that we can get such a variety of weather all year around! Posted Image

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25 minutes of torrential rain, pea sized hail and house shaking pink positive CG lightning, the thunder was incredibly loud at one point, even made me take cover and close the window, moving away now though, be prepared further SE of here around Luton area for surface flooding of roads and garden areas. Posted ImageForgot to mention the strong straight line wind gusts, probably hitting 55-60 mph while the hail was falling horizontally.

Edited by SnowJoke

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You effing watch, France/Benelux will have 19,000 strikes per hour in the Summer Months, narrowly missing the UK!

Twas ever so Robbie Posted Image

In response to Tiny Bill, the squall line now stretches from The Wash to Wells, so looks like Hunstanton and Salisbury next places to get hit. Let's see what reports come in.

Interesting weather for the time of year though. Incidentally the temp here has now settled at 4.8°C - five degrees below the temp in advance of the front. The sun is going down now so we may even get a frost.....

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Brilliant vid, Supa. Heart skipped at beat at 2:14. Cheers. Posted Image

 

Had some close strikes here, but not that close lol.

 

Believe me, so did mine :D

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Ok, here is a quick upload of the first couple of minutes as the squall line went through. Turn volume up to max for full effect Posted Image

 

 

Most of the lightning was observed as the storm moved away, but only one capture on camera as most of the brighter strikes were overhead IC's:

 

 

Was very similar to that here, took me by suprise. It would have been a nice little storm in the summer let alone January! 

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Squall line now coming into the London area. Looks like the heaviest precipitation has crossed the M25 and is now around Watford. Should be fun on the radio stations covering the football shortly. I bet if Alan Green was on Radio 5, he would be complaining Posted Image  No change there then.......

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...looks like Hunstanton and Salisbury next places to get hit. Let's see what reports come in.

 

We got hit at 4pm and we're just to the North of Andover (about 17miles north east of Salisbury). It was pretty violent, but lasted less than 10 mins.

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Had a lovely organge glow as this lot approached, now gone very dark. Distance lightning flash (IC Lightning) and very windy now.  No Thunder as of yet.

 

Edit, omg that was massive lightning and thunder. Very intense storm right now!!

Edited by Robbie Garrett

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Just heard a rumble here, no lightning but off to look out the windows with camera at the ready.

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Had a lovely organge glow as this lot approached, now gone very dark. Distance lightning flash (IC Lightning) and very windy now.  No Thunder as of yet.

 

Edit, omg that was massive lightning and thunder. Very intense storm right now!!

Some strikes now showing up in the SW London.....

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I wonder how many people got caught out in this. According to our forecast there was a 20% chance of rain with sunny intervals.

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Well that was some squall line. It reached here ( nw London ) around 4.30 and for for 5 minutes the rain was insane. The winds lasted a lot longer and at times the gusts were quite scary. As the rain belt cleared through there was some spectacular pink lightning on the back edge, 6 or 7 strikes in all but the thunder was barely audible.

 

Thats probably the closest I have seen to a derecho...........incredible.

Edited by Bluebreezer54

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The extremely violent squall not long ago went through my area Stanwell (next to Heathrow AP) planes were grounded during this didn't notice any taking off. This was so violent and torrential one of the most severe have experienced, the winds estimated 50-70mph gusts and appeared to have had damaging potential, were very noisy on roof, and trees were violently moving

 

Also lightning several flashes, and on the back edge,  sounded like thunder heard as distance rumbles.

 

Lots of surface flooding right now. 

 

 

This potentially damaging squall line heading through the Southeast now, arriving into Sussex and Kent.

Edited by ElectricSnowStorm

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 A vicious line  - from Friday's Netweather forecast...

Certainly was!!

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Some strikes now showing up in the SW London.....

Yes, 5 or 6 strikes with thunder in total here in Putney - four of them very close - accompanying sheets of torrential horizontal rain for a few minutes. Wish I'd had my camera to hand...by the time I had it sorted it was all over.

Edited by osmposm

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Well that was fast and furious! Some good rumbles of thunder (now disappearing away south east I suppose), massive squally winds for a few moments, there may have been a CG among the lightning but certainly saw some good bright flashes. Rain looked like fog, it was so intense. Wouldn't have liked to be outside in those moments.

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Some strikes now showing up in the SW London.....

 

Yeah that was pretty spectacular, quite amazing to think I've had 4 thunderstorms in 25 days, that's 1/4 of what I've had in 2013.   Ever since Christmas we've had quite a few decent Thunderstorms in London, mostly in the dark hours.

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Incredible... Such different extreme events at such short distance in Western Europe, this is truly amazing! I've rarely see such a wide variety of extremities in such a short distance from each other!

 

I'll give a short summary of the extreme events in the UK, and especially the Netherlands, below:

 

The KNMI (the Dutch equivalent to UKMET) has issued 3 consecutive warnings for parts of the Netherlands, creating a kind of "ring of fire". The map can be seen below:

 

Posted Image

 

The yellow color indicates warning conditions are likely to be met at a short timeframe (2 days).

 

What can be seen is a risk on snow in the north of Holland today and tomorrow, accumulation is forecast to be around 5 cm max. Moreover, there is a warning of strong winds in the western parts of the Netherlands (gusts up to 100 km/h are forecast). And finally, there is a risk of lightning in the southern parts of the Netherlands. This is an unique variety of events at such small scale!

 

Synoptic situation

 

The reason for all this hazardous weather is a low pressure area (currently a well-defined trough, i.e. the isobars are not closed yet), forecast to move from Scotland and the North Sea toward the central part of the Netherlands. The trough can be seen below:

Posted Image

Hirlam T06 (12Z)

 

Note the sharp dip in pressure over the central North sea extending northward.

 

Eight hours later, the low pressure area is forecast to be located over the border of the Netherlands and Germany.

 

Posted Image

Hirlam T14 (12Z)

 

Squall line

 

Associated with the trough is a squall line (the second in January), currently extending from London to the central North Sea. The squall line caused heavy precipitation, as well as lightning (very extreme for January), to Wales and central England. This line is now forecast to move along with the low toward the Benelux, while (seemingly) deactivating. Estofex has issued no warning about the system in advance, and the KNMI also didn't have this intense area in their forecast. Therefore, it appears to have become a surprise for many!

 

A real-time image of the squall line can be seen on the link below:

http://europa.buienradar.nl/images.aspx?jaar=2014&maand=01&dag=25&uur=18&minuut=15&c=&type=

 

 

 

Wind

 

The sharp trough is also having a rather strong wind field around it, as can be seen below:

Posted Image

Hirlam T07 (12Z)

 

The map above shows the average wind speed forecast (BFT). What can be seen is an 8 BFT emerging in the Cahnnel and near the southwestern part of the Netherlands. Also note the 10BFT just to the souheast of Norway. As stated in previous posts, numerous gusts have been recorded over England as well, though they aren't exactly linked to the trough.

 

Snow

 

As a result of the trough, there is also forecast to be some snowfall over the northeastern parts of the Netherlands and Scotland. The snowfall over Scotland is mostly over elevated regions and is a result of very cold upper temperatures. The snowfall over northeastern Holland has a different origin. It is caused by low level easterlies forecast to develop on the northern flank of the trough, as can be seen above. The northeastern part of the Netherlands lies directly in the battleground line between arctic air caused by a high pressure area to the northeast (over Scandinavia), and mild Atlantic air from the southwest. The trough is essentially activating the battleground frontal zones.

 

Temperature gradient

 

Finally, there is a very sharp temperature gradient located over the Netherlands. What can be seen is a difference of 8*C over just 100 km, as seen below:

Posted Image

 

The temperature gradient is forecast to persist over the next couple of days, with an increasing likehood of cold conditions over the complete country in a few days.

 

Of note is that a very small shift in the movement of the low pressure area can cause a major difference in the areas impacted by snowfall, the temperatures, the forecasted wind, and finally the southern extent and intensity of the squall line. It is, to keep it short, a very interesting situation, to say the least Posted Image

 

There is so much to tell about the current situation, that I think I would be able to write a full page about this event. But for now, I'll keep watching the situation with excitement, and just be surprised Posted Image

 

Sources:

http://www.knmi.nl/waarschuwingen_en_verwachtingen/regio.php?pr=ZH

http://www.weeronline.nl/vakman-index/130/0

http://europa.buienradar.nl/images.aspx?jaar=2014&maand=01&dag=25&uur=17&minuut=30&c=&type=

http://www.estofex.org/

http://www.weerplaza.nl/gdata/10min/GMT_TTTT_latest.png

Edited by Vorticity0123

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