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

[chillyblast]

Is there any certainty or high probability as to when the percepitation will start in the morning? Only I was planning on venturing out for four hours from 6am is it likely I'd get soaked? Bedfordshire region. Thanks 

[Panayiotis]

A little look at the models regarding tomorrows situation:

GFS, develops showers later on in the day:

EURO4 develops them from midday on a more easterly route:

:

HIRLAM similar to EURO4, with the earlier start but like the GFS starts them from South East Wales, ie mix of GFS and EURO4:

NMM develops them much later, and storms follow a route close to the HIRLAM and GFS:

Models seem to have a general agreement that there will be showers tomorrow which will intensify as they move NE, location wise these storms are likely to develop from SE Wales and move north-eastwards towards Birmingham. The only model which disagrees on this is the EURO4. Timing is the biggest difference between the models, and is a tough one to call...

My prediction is that storms will start to develop around 1pm over Newport/Bristol area and move NE towards Birmingham, a triangle between Birmingham-Northampton-Leicester seems the area to be in tomorrow... 

Edited August 26, 2016 by Panayiotis

[Speedway Slider]

Best advice I would say is radar watch,      you just cannot tell with this sort of weather set-up..

[chillyblast]

Thanks all appreciated, looking forward to a good storm when I get back!

[dave48]

To add to Panayiotis' analysis, ECMWF with the euro4, a touch east.

Tomorrow holds a lot of potential, potential for some strong or even severe storms.

[Flash bang flash bang etc]

14 hours ago, Windblade said:

OK, so yesterday was flipping unbearable. 36c and clear skies. Hottest part of the country, no rain, no storms, nothing. Just sweltering, boiling, melting, sticky, sweaty, uncomfortable, smelly, disgusting relentless heat. Trying to sleep last night (it was still 30c indoors way past midnight) was pretty difficult to say the least. Looks like any storm potential for this weekend for my area has disappeared after looking so promising a couple of days ago. Yeah, I'm fed up. Sorry if I'm being overly negative, just venting my frustration at what has been the worst summer for storms, while simultaneously having the highest temeratures I can ever remember.

I am happy for others that got to see something though. Please send some of your luck my way!

Better watch out mate you'll get an earful from other members of the forum for being 'a bit disappointed'

Anyway moving on... I dunno how I can say this without being told I'm getting my hopes up but the Synoptics are all there - I'd just like it if we get just one little look in tonight or tomorrow cos I've waited all summer.

but I need to remember that really really wanting a thunderstorm apparently makes me 'sad'. Such a shame.

Fingers crossed but I'll be swearing into my pillow tomorrow morning if Kent or Warwick get all the fun tomo...

[Buckster]

18z seems to have pushed things a bit further East

these things always move East

will be in North Sea by 06z run tomorrow !

[shaky]

18z seems to have moved the stronger cape values further north for tomorrow afternoon and more into the midlands!!looking very interesting tomorrow now!looks like theres gona be 2 storm batches!one moving north along the border of wales and another east anglia and up through lincolnshire and into the north sea!

[wimblettben]

I take it the risk is moving away from our zone then based on latest outputs?

I really want us to get something here tomorrow as I don't want us to completely end up missing everything from this two week forecast thundery period.

[Flash bang flash bang etc]

15 hours ago, Wivenswold said:

So it's Netweather's fault? Or is it your fault because you live in a country that doesn't always deliver on the storm front?

Everytime there's a threat of storms I see the same people getting overly excited and then getting narky when it doesn't transpire exactly how they'd decided it was going to. Sad really. 

Sorry I need to reply to this despite wanting to ignore it.

just to say I was actually thanking netweather for their help DESPITE it being a shocking year for my part of the world for storms. And it really is a shocking year and where else am I going to say that? On the BBC local news pages? On Twitter?

no - most likely on a weather forum particularly focused on storms.

Can you possibly accept occasionally strongly angled opinions from people who might have a vaguely acceptable reason for voicing them? It's been a bad summer but made worse as others have mentioned for ppl in the SE who have days of unbearable heat and humidity to see storms track toward their area, die off, then reinvigorate somewhere else on a regular basis - as if it was some sort of system set in place to cause as much annoyance as possible. Then last night storms pass by way over to the east - despite favourable Synoptics ... Again.

i know it's just weather and I'm over it now - hoping vaguely for something tonight because surrey, Hants, and Wiltshire really deserve the one shot before summer is out - but I wasn't BLAMING netweather for the lack of storms in my area. I'm not stupid - they clearly don't control the weather.

I actually WAS saying 'thanks' - because it's a great resource for all things weather related not just storms.

ALSO by saying 'I give up' I actually am considering giving up chasing storms because it's too much effort based on quite flimsy forecasts. No ones fault I've just realised we can't forecast storms very accurately because we live in a country where we have a very unpredictable climate. I understand that (re: me not being completely stupid).

I'll follow this up with a more practical post - but I needed to write this. Hope ppl understand.

NB: regardless of my ranting I wish you well with tonight / tomorrow's potential. Essex doesn't get many storms these days...

Edited August 26, 2016 by Flash bang flash bang etc

[Flash bang flash bang etc]

I was wondering about the timings for tonight's / tomorrow's fronts. I thought it was going to be post midnight / pre sunrise but now I'm detecting this may not be the case. Any clarification on this?

i'd love a night light show - but failing that a good storm will do in any format as long as it's relatively close!

[Ben Sainsbury]

ConvectiveWeather:

Day 2 Convective Outlook

VALID 06:00 UTC Sat 27 Aug 2016 - 05:59 UTC Sun 28 Aug 2016

ISSUED 22:13 UTC Fri 26 Aug 2016

ISSUED BY: Dan

This particular plume destabilisation event carries an unusual amount of uncertainty, even at this short range. Below is the most likely forecast evolution based on guidance at the time of issuance - it is certainly possible some aspect will change with time, and we may not be able to update as this is a voluntary service.

Elevated convection is expected to be ongoing with isolated to widely-scattered thunderstorms (albeit with not much precipitation reaching the surface initially) across parts of the south Midlands, East Anglia and southern England at the beginning of this forecast period, through isentropic upglide as the warm front lifts slowly northwards across England and Wales. This process is expected to continue during Saturday, with thunderstorm coverage (or at least showery precipitation) expanding through the day, mostly across the southeastern half of England - although even here some areas are likely to remain void of precipitation/thunderstorms (taking a theme amongst most NWP output would suggest parts of E Kent up into Suffolk and E Essex are least likely to see thunderstorm activity - but models should never be relied upon to that level of precision, hence are still included in the SLGT). PWAT values in the high 30s or low 40s mm brings the risk of localised flash flooding issues. MDT has been issued where the best overlap between numerous models suggest thunderstorms may develop - although this zone could be shifted to the NW.

Along and south of the SW-NE orientated warm front, environmental conditions will be favourable for severe convection should any storms become rooted in the boundary layer. If this were to occur, then large hail to 3.0cm in diameter and possibly a tornado would be possible, especially close to the frontal boundary where low-level convergence will be maximized. This places the risk of severe convection greatest in a corridor from SE Wales / W Country / Cen S England NE-wards across the S + E Midlands to East Anglia. Extensive cloud may inhibit this potential to a certain extent.

Through the evening hours, the approaching Atlantic upper trough will serve to increase convection coverage across N Wales initially, this also extending across northern England. Given the two zones with greatest potential (the MDT and this second zone through the evening hours), this then may leave a corridor of relative low activity from C + E Wales through the N + W Midlands - not to be taken literally, but emphasizing that some parts of the SLGT are likely to remain lightning-free.

 

[Mapantz]

Have a look at the German model (updated just a moment ago)

http://www.warehamwx.co.uk/cumulus/ewn/map.php

Change to DWD ICON, and select 'precipitation+clouds' - Have a run through that lol

[Ben Sainsbury]

4 minutes ago, Mapantz said:

Have a look at the German model (updated just a moment ago)

http://www.warehamwx.co.uk/cumulus/ewn/map.php

Change to DWD ICON, and select 'precipitation+clouds' - Have a run through that lol

Doesn't seem to let me view the model for some reason? Screen is just white?

[Flash bang flash bang etc]

Yeah doesn't wanna load.

bums.

[Flash bang flash bang etc]

Got it working. The wind map is cool!

[Mapantz]

3 minutes ago, Ben Sainsbury said:

Doesn't seem to let me view the model for some reason? Screen is just white?

 

1 minute ago, Flash bang flash bang etc said:

Yeah doesn't wanna load.

bums.

Strange - working ok on pc/phone and tablet..
Even using it via a proxy on another browser works. :s

[Flash bang flash bang etc]

2 minutes ago, Mapantz said:

 

Strange - working ok on pc/phone and tablet..
Even using it via a proxy on another browser works. :s

On me iPhone I had to close safari and reload it - then it worked

[Ben Sainsbury]

3 minutes ago, Mapantz said:

 

Strange - working ok on pc/phone and tablet..
Even using it via a proxy on another browser works. :s

Didn't work on Firefox did on Chrome, I was gonna say what looked so special, then I realised as time went on! Dont wanna spoil!

[Mapantz]

1 minute ago, Ben Sainsbury said:

Didn't work on Firefox did on Chrome, I was gonna say what looked so special, then I realised as time went on! Dont wanna spoil!

That's weird as it works on my FF. lol

Anyway, I didn't want to flood the page with lots of screen dumps, but the first part looks in accordance to convectiveweather's warning, then it just goes on the steroids tomorrow night.   

[samadamsuk]

Hey all,

Some great looking dynamics  tomorrow .. out of the recent 'potential' situations, I'll take this one.  Cloud cover will be the key I suspect.. Samos

 

[Nick F]

Storm & Convective Forecast

Issued 2016-08-26 23:02:33

Valid: 27/08/16 06z to 28/08/16 06z

CONVECTIVE/STORM FORECAST - SAT 27TH-AUG-2016

Synopsis

Upper trough to the west of the British Isles will slowly advance eastwards during Saturday. Ahead of the trough, a plume of warm and moist air, characterised by WBPT/Theta-w values reaching 16-18C, advects north in across S England early Saturday. A warm front will move in across S England by 12z Saturday marking the boundary of warm and humid air moving in from the south at the surface.

… E WALES, S ENGLAND, MIDLANDS, E ANGLIA, N ENGLAND …

An elevated mixed layer (EML) characterised by steep mid-level lapse rates will move north in tandem with plume of warm/moist air below. Isentropic lift of the plume ahead of the warm front may create sufficient instability in the mid-levels above a stable cooler and drier boundary layer to support development of scattered heavy showers and perhaps isolated elevated thunderstorms early on in the day across English Channel and southern counties of England. These early showers and isolated storms tending to drift NE across The Midlands and Eastern parts of England during the day north of the warm front above a stable cool/dry boundary layer. Any elevated storms could produce frequent cloud-to-ground lightning locally and also a risk of flash-flooding. So have issued a marginal risk for severe weather.

Drier and sunnier conditions returning to S/SE England late AM into PM, where surface will likely remain capped, but with surface heating of humid airmass yielding towards 1000 j/kg CAPE. There is a small risk that surface convergence and surface heating will be sufficient to overcome the cap to produce some isolated thunderstorms here later afternoon/early evening. Any sfc-based storm that does develop may  organise, given 30-40 knts of DL shear, to produce large hail and torrential rain leading to flash-flooding. Parameters, such as LL shear and LCLs look favourable for storm rotation that may lead to a tornado too. But risk is too low to warrant more than the MGNL risk for the elevated storm risk as above.

Likewise, increasing large scale ascent by upper trough approaching from the west, lift from shortwave trough moving in across the SW early evening and increasingly cyclonic and strengthening mid-level flow may trigger some surface-based storms along the edge of unstable plume across E Wales, Midlands, Lincs and parts of N England during the evening. These storms could produce large hail and a risk of flash-flooding, but given uncertainties over extent, will stick with the MGNL risk for now.

Issued by: Nick Finnis

http://www.netweather.tv/index.cgi?action=convective;sess=

Edited August 26, 2016 by Nick F

[Boro Snow]

On that black line again grrrrrrrrrrrrrr

Edited August 26, 2016 by Boro Snow

[Chris.R]

 Well I was rather surprised before to see that there is a lot of CAPE and  instability (1000 J/kg/-4) showing for my area tomorrow night. I thought I was too far west but going by that I'd say it looks more promising for me. I should add that was the GFS  though. 

Edited August 26, 2016 by Chris.R

[shaky]

Any updates on euro4?