Convective Storm/Discussion thread - 16/07/16 onwards

[legritter]

evening all ,thought earlier  that i would completely miss out  but just had some very large spots of rain no lightning ,hoping that some cells could fire up even in somerset later ,best of luck for those hoping .pretty sure though that some parts of uk tonight will have a good display especially further north and west ,heres hoping ,cheers ,

[Ben Sainsbury]

For any of you that didn't see, ConvectiveWeather edited their forecast for tonight!

UPDATE 21:42 UTC MDT over Wales/NW England nudged further S, and marginally shrunk in eastern extent. MDT also added over NW Scotland for an increase in coverage likely through the early hours. MDT also shrunk in NE extent over NW Ireland. Overall, similar expectations remain as to those highlighted in the original forecast below, with perhaps some subtle shifts to the SE, and perhaps a slightly slower onset of more widespread thunderstorm activity later tonight.

Shortwave trough is likely to engage with instability axis as it crosses NW Ireland / Northern Ireland on Tuesday afternoon/evening, with an environment with Tds in the high teens Celsius, yielding 1,000-2,000 Jkg-1 MLCAPE. Scattered thunderstorms are expected to erupt late afternoon through the evening hours, drifting to the N/NE. Given high CAPE, 30-40kts DLS and backed surface winds, any discrete storms may become supercells, at least for a time, with an associated risk of hail to 3.5cm in diameter, strong, gusty winds and perhaps a tornado - SVR issued to cover all three threats. Some parts of C and W Scotland may require an upgrade to MDT for activity expected this evening/tonight - trends will be monitored.

 

Elsewhere, falling heights in advance of the upper trough will lead to destabilisation during late Tuesday evening and through early hours of Wednesday, with scattered thunderstorm development occurring during the evening hours, these moving NE-wards through the night while expanding in coverage - MDT issued where risk of thunderstorms is considered higher, but as is often the case in such situations, this area may need to be modified in placement/size as convective trends become more clear nearer the event.

Given nocturnal cooling will have occurred to a certain extent before any significant convection develops, most cells will be elevated but still pose a risk of local flash flooding from heavy downpours and elements of backbuilding, and also a hail threat - SVR then issued to cover the greatest risk of flooding / large hail. Significant CAPE and steep lapse rates suggests lightning could be quite prolific in places.

[Sparkiee storm]

Wonder if those small light showers in Somerset, will explode and then push into the West Midlands

[Frosty hollows]

17 minutes ago, Roger J Smith said:

Patience is required if you're in Britain, the best conditions won't develop until well after midnight. I think there will be a serious light show in western portions of Britain after 0200h most likely towards 0500h. The most active zone for you is still southwest of the Channel approaches. In western Ulster it's on now, there's a massive cell over the ocean just south of Carrick (co. Donegal) and widespread moderate thunderstorm activity in Connacht. 

I am going to drop my "screw zone" to patchy fail zones within the general area outlined before but everyone is going to be close enough that lightning should be seen if not right in the vicinity. So anyway, enjoy the light show, you may be asleep when it starts. 

Thanks so much for your informative posts!Learning so much.

[Ben Sainsbury]

Can anyone even believe a Lifted Index of -12 over Liverpool area this evening! According to GFS 18z!

A definite SE shift of precipitation on the GFS 18z charts. More of South Wales and SW England covered by precipitation and Midlands getting smashed.

[BornFromTheVoid]

The reports coming from NW Ireland sound impressive. Should be some videos up soon hopefully

[East_England_Stormchaser91]

4 minutes ago, Ben Sainsbury said:

Can anyone even believe a Lifted Index of -12 over Liverpool area this evening! According to GFS 18z!

A definite SE shift of precipitation on the GFS 18z charts. More of South Wales and SW England covered by precipitation and Midlands getting smashed.

Wondering if that lot over the Celtic sea may be the precursor of what is to come? 

[Frosty hollows]

That weird unstable mass of cloud I saw earlier has hit the chilterns and exploded into ...light showers. 

[PersianPaladin]

Jay Wynne's latest BBC weather forecast mentioned absolutely nothing about any thunder storms across England tommorow. In direct contradiction with the local forecast a few hours earlier. WTF?

Edited July 19, 2016 by PersianPaladin

[MP-R]

Brief but moderate shower of very large raindrops here. Was quite refreshing stood outside without my shirt on haha.

[Sparkiee storm]

Just now, MP-R said:

Brief but moderate shower of very large raindrops here. Was quite refreshing stood outside without my shirt on haha.

That would be convective then wouldn't it?

[Speedway Slider]

Ok, here is the situation at approx 23:15 Tuesday 19th July 2016 over the UK....

West of Ireland, North West England, South West Scotland having action at the moment....

Also, keep an eye on the cell moving north east out of Biscay...

Is it strong enough to make landfall over Cornwall? And then press on into the Midlands....!! Perhaps..!

[andymusic]

Just now, Speedway Slider said:

Ok, here is the situation at approx 23:15 Tuesday 19th July 2016 over the UK....

West of Ireland, North West England, South West Scotland having action at the moment....

Also, keep an eye on the cell moving north east out of Biscay...

Is it strong enough to make landfall over Cornwall? And then press on into the Midlands....!! Perhaps..!

turning into a juicy MCS????????

[Ben Sainsbury]

1 minute ago, andymusic said:

turning into a juicy MCS????????

I'm sure that's what every bunch of storms turns into right?;)... Oh I wish!

[Geordiesnow]

7 minutes ago, PersianPaladin said:

Jay Wynne's latest BBC weather forecast mentioned absolutely nothing about any thunder storms across England tommorow. In direct contradiction with the local forecast a few hours earlier. WTF?

Not a big fan of the forecaster to begin with but the graphics have shown a shift to a less thundery Wednesday however I would not be surprised if things were totally different again by tomorrow morning's forecast. 

Of course, if things do go not according to plan, it would be nice too have some sort of explanation to it but I somehow doubt that would be the case. 

At the moment, all the action is on the extreme tip of North Western Ireland and more scattered across SW Scotland, so kind of going to forecast so far that being said. Looks like all the CAPE is out in the Atlantic with those bright echos, hopefully radar echoes like those can be repeated around these shores! Its all a bit of a waiting game at the moment. 

[PersianPaladin]

1 minute ago, Geordiesnow said:

Not a big fan of the forecaster to begin with but the graphics have shown a shift to a less thundery Wednesday however I would not be surprised if things were totally different again by tomorrow morning's forecast. 

Of course, if things do go not according to plan, it would be nice too have some sort of explanation to it but I somehow doubt that would be the case. 

At the moment, all the action is on the extreme tip of North Western Ireland and more scattered across SW Scotland, so kind of going to forecast so far that being said. Looks like all the CAPE is out in the Atlantic with those bright echos, hopefully radar echoes like those can be repeated around these shores! Its all a bit of a waiting game at the moment. 

Contradicts the latest GFS anyway. Are they going by the latest FAX charts or now-casting?

[Mapantz]

Just rip them up, and throw them away!

 

[MP-R]

11 minutes ago, Sparkiee storm said:

That would be convective then wouldn't it?

Yes indeed. There does seem to be some very low key rain activity in this area recently. Will have to watch this space.

[Chris.R]

Doing an all-nighter here in Holyhead, in my tent.  I have actually got an audio stream I sep up  which I'm listening to, so i've got the best of both worlds if anything happens their as well.  I could be in the great position of experiencing 2 thunderstorms in 1 night. 

 A few spots of rain here recently. 

 The stream is  set up at home I should  mention. 

Edited July 19, 2016 by Chris.R

[dave reid]

7 minutes ago, Geordiesnow said:

Looks like all the CAPE is out in the Atlantic with those bright echos

The CAPE is over most of the UK, just need a lifting mech.

 

[Convective]

I can confirm that none of the lightning detectors are picking up even a fraction of sferics. Them two cells that have recently gone up to the north of the island were putting out around 20-30 strikes a minute, all intra-cloud. Don't be fooled by the number of cloud-ground strikes being detected, there's a lot more there! Some absolutely fantastic crawler lightning, too!

Edited July 19, 2016 by Convective

[Cheshire Freeze]

5 minutes ago, Mapantz said:

Just rip them up, and throw them away!

 

Radar looks pretty close to the GFS tbh

[Supacell]

Just now, CreweCold said:

Radar looks pretty close to the GFS tbh

Which bodes well for both of us tomorrow

 

[Mapantz]

3 minutes ago, CreweCold said:

Radar looks pretty close to the GFS tbh

It looks better, but it still shows that in these volatile situations, they are mostly a waste of bandwidth.

It's the colours I get most enjoyment from.   

Edited July 19, 2016 by Mapantz

[Ross Andrew Hemphill]

everything is to the west of me, come on!!