Storm & Convective Discussion April 2016 Onwards

[Arnie Pie]

Thank you alexisj9......There was a lot of sheer about

2nd strike 10 or so mins later

 

[Ben Sainsbury]

For those who are intrigued about the storm forecasts tomorrow here is mine:

Forecast: 9am – 6pm

We have a low pressure system running through the channel, whilst an occluded front passing SE’wards across the country, originally the risk exists further SW you are, but as we reach mid-afternoon this is where the greatest potential exists, most likely across CS and SE England, up into East Anglia.

With the prospect of a cloudy day, temps of 12-13 at best, we are looking at 300-400 J/Kg of CAPE, along with fairly steep lapse rates. Low Level Wind Shear looks to be highest over SE England, along with Deep Layer Shear at around 20kts. This could see storms becoming organised at times. SRH looks to sit around 100-150m^2s^-2.Therefore there is the chance of the odd funnel cloud, most especially across SE areas. But main risks seem to be Lightning and Strong Wind Gusts; along with intense rainfall as a result of storms merging into longer spells of rain. (My Picture:)

ESTOFEX:

ConvectiveWeather: 

Tony Gilbert UKWeatherWorld:

Forecast: 9am – 6pm

Slight Risk of Thundery Showers with Risk of FC/ Weak TN Southern UK 08z-19z

Some potential for an interesting day ahead

Long wave upper trough continues to influence UK. Upper jet stream remains south of the UK. Slack low pressure traverses southern UK from SW to NE. Wrapped occlusion expected to develop rain and showers. Some of which could turn thundery.

Whilst GFS and WRF develops workable CAPE, some uncertainties regarding instability due to potential for heavy cloud cover. This issue will be the deciding factor for convection.

The most interesting feature looks to be conducive convergence with very low LCL. This combination has been mostly missing for the past few outlooks. Pre formed horizontal vorticity is better pulled into updrafts when cloud bases are low. It is therefore quite possible that southern regions could see a number of FC/ weak tornadoes.

This would be better addressed in the morning.

 

 

 

Edited April 14, 2016 by Ben Sainsbury

[Wilxy]

Tomorrow looks promising for some cloud photography, which is good enough for me even if there isn't any thunder, should still be some decent showers around, just hope there isn't to much cloud around, as the last few days have been lovely.

[Mesoscale]

Check out this Tornado in Iraq today, looks pretty violent. There were two at one point as well.
 

 

Edited April 14, 2016 by Mesoscale

[Mapantz]

Estimates have come in that it did $6 billion worth of improvements.

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Fri 15 Apr 2016 - 05:59 UTC Sat 16 Apr 2016

ISSUED 20:47 UTC Thu 14 Apr 2016

ISSUED BY: Dan

Surface low will drift NE across southern England on Friday - on its northern flank, provided cloud breaks allow sufficient insolation to develop, combined with slack flow and low-level convergence, then there exists the potential for convection to form along zone of enhanced surface convergence. Instability is rather limited (couple hundred Jkg-1 CAPE) but should be sufficient enough for some heavy showers to develop, with perhaps some sporadic lightning. Once again, slow storm motion brings the risk of local flash flooding issues (10-15mm in an hour), especially where shower-training occurs - particularly from south Midlands across Northern Home Counties to East Anglia. Backed surface winds may allow one or two funnels to form, with perhaps hail up to 1.0cm in diameter from any stronger cells.

Cold airmass returns from the north, with deep convection bringing scattered showers and the risk of isolated lightning to the Northern Isles and NE Scotland.

http://www.convectiveweather.co.uk/forecast.php?date=2016-04-15

 

Edited April 15, 2016 by Summer Sun

[Arnie Pie]

Couple of short clips from last nights storms,,,,,They were pretty rapid strikes so i`ve slowed them down a bit

 

[Ben Sainsbury]

In regards to Cloud Cover today, hopefully as the low pressure pushes NE'wards, we can hopefully see a clear slot before the next band of showers move in (in the channel), as indicated by the thinning of the cloud along the northern/eastern flank of the low pressure.

Edited April 15, 2016 by Ben Sainsbury

[NO LONGER POSTING]

Sunshine?! 

[Mapantz]

Moderate, dynamic rain here.

[Gordon Webb]

looks like a lot of the activity will be south of me today

consider myself lucky yesterday that i saw nothing of note

[Ben Sainsbury]

This is where I expect developments to be within the course of the day. Already signs of this NW of Canterbury! However most organised showers in SE.

Edited April 15, 2016 by Ben Sainsbury

[alexisj9]

1 minute ago, Ben Sainsbury said:

This is where I expect developments to be within the course of the day. Already signs of this NW of Canterbury!

Yep the sun came out and it didn't take long for something to build and cover it again, although it not heavy.

[Ben Sainsbury]

7 minutes ago, alexisj9 said:

Yep the sun came out and it didn't take long for something to build and cover it again, although it not heavy.

Nevertheless it is promising to see small developments at this point as temperatures having not reached maximum and we should hope to see more sunshine this afternoon, that's when things should kick off!

[Nick F]

Some nice breaks and warm sunshine developing here and the Cu con is popping up all over the shop in the moist airmass. Low risk of storms for S England today, but if you catch one could have hail and chance of funnels along southern counties as that low tracks east and creates convergence.

Storm & Convective Forecast

Issued 2016-04-15 08:38:12

Valid: 15/04/2016 0600z to 16/04/2016 0600z

CONVECTIVE FORECAST - FRIDAY 15TH APRIL 2016

Synopsis

Broad upper trough extends SW across UK and Ireland, with a cyclonic SWly veering Wly flow across Sern UK, veering Nly further north. An area of low pressure will drift east along southern England on Friday. A cold Nly flow sweeps south across the UK behind the low overnight.

... S ENGLAND and E ANGLIA ...

To the south of frontal rainfall spreading slowly north overnight, sunny spells developing across parts of southern England and a moist airmass will allow for some instability to develop in the above areas this morning and afternoon. A few 100 j/kg CAPE forecast and weak capping will allow heavy showers and perhaps a few thunderstorms to develop, though storms will likely be isolated. Vertical shear will be rather weak, so no severe weather is anticipated, though storms will be slow-moving leading to a risk of localised flooding and may also be accompanied by hail locally. Surface convergence along southern counties in vicinity of low pressure moving east may allow funnel clouds and even brief/weak tornadoes to  develop with stronger updrafts into storms.

[alexisj9]

1 hour ago, Ben Sainsbury said:

Nevertheless it is promising to see small developments at this point as temperatures having not reached maximum and we should hope to see more sunshine this afternoon, that's when things should kick off!

I meant that when the sun pops out, convection is already quite quick. Something builds straight away but so far is light.

[Greeny]

I see theres been a couple of strikes detected London way in the most potent cell

Edited April 15, 2016 by Greenday

[NO LONGER POSTING]

So so strange I work about 20 miles from home and that small distance has meant here it has been pretty dry all day odd bit of sun and rain.. 

 

Mum however, at home has said the rain has been mental with a little bit of hail in the heavier bursts and looking at the radar she is quite right

 

Amazing the small diffrences make! 

[loopydreamer]

There's been heavy bursts of rain... mostly pretty consistent for most of this morning. The sun has struggled to break through but it just has in the last few minutes. ... hoping to see some stormy weather this afternoon fingers crossed

[lassie23]

Another heavy shower moving through, some thunder but where is the lightning?

[Paul1968]

Apart from the leading edge,the rest of this band just looks like normal frontal rain to me ?

[Ben Sainsbury]

7 minutes ago, Paul1968 said:

Apart from the leading edge,the rest of this band just looks like normal frontal rain to me ?

True but this is all dependant on cloud cover and let's think what time storms started brewing yesterday. Possibly 2-9pm? So that's the time period which is most looking forward to today.

[Andy Bown]

36 minutes ago, Paul1968 said:

Apart from the leading edge,the rest of this band just looks like normal frontal rain to me ?

I was able to discern what looked like an embedded CB just over half an hour ago during a brighter spell and sure enough as that moved over the rain got heavy and convective in nature.

[NO LONGER POSTING]

Close but no cigar.. Yet 

[Greeny]

Im on the A505 heading to Luton for work at the moment. I can see the long frontal line in the diatance. Apart from that nothing major, lots of cloud around.