Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Convective/Storm Discussion Thread - 1st August onwards


Supacell

Recommended Posts

Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol

Yet to see any forecasts for any of the storm forecasters at ESTOFEX and ConvectiveWeaher and understandably so. Very limited convection as high pressure strongly in charge we may have to wait until Saturday at the earliest!

Edited by Ben Sainsbury
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Day 2 Convective Outlook

VALID 06:00 UTC Fri 20 Apr 2018 - 05:59 UTC Sat 21 Apr 2018

ISSUED 21:42 UTC Thu 19 Apr 2018

ISSUED BY: Dan

Increased boundary layer moisture, with surface dewpoints of 14-16C likely, combined with breeze convergence / urban heat island may allow an isolated heavy shower or two to develop late Friday afternoon and into the evening - with particular focus on London, Essex and Kent. However, forecast profiles are very dry, and so any convection that attempts to develop will struggle to gain much height - hence a very low risk of lightning.

 
On Friday night, the approaching subtle upper trough from Biscay will begin to destabilise a high ThetaW airmass advecting from France across the English Channel into S / SW England. There is some uncertainty at this range as to the degree of overlap between upper forcing and plume coming out of France, and this will affect how quickly elevated thunderstorms can develop.
For now, have issued a SLGT for the Channel Islands and adjacent English Channel for early hours of Saturday given lightning will likely be fairly frequent with any thunderstorms that do develop, but this may need extending northwards into Devon east to the IoW, depending on how quickly destabilisation occurs in this forecast period (up to 06z Saturday).
 
  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Lincoln, Lincolnshire
  • Location: Lincoln, Lincolnshire
18 minutes ago, Summer Sun said:

Things could go bang during tomorrow as some thunderstorms move up the country

nmm-1-35-0.thumb.png.b392899559475b51a51d85ad8dc2acda.pngnmm-1-39-0.thumb.png.87243757cd3c248a2df95dd13913ddab.png

Hoping Middlesbrough gets some good lightning displays on Saturday

Link to comment
Share on other sites

Posted
  • Location: Chesterfield, Derbyshire, 110m
  • Location: Chesterfield, Derbyshire, 110m

Good potential for some storms tomorrow afternoon! Its nice to be back in this thread after what seemed like an eternal winter!

 

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Belper, Derbyshire
  • Weather Preferences: Thunderstorms
  • Location: Belper, Derbyshire

After a remarkably warm/hot few days it looks like the first proper thundery spell of the season is upon some of us for tomorrow. As low pressure moves in from the west it combines with a plume of warm, humid air from the south to bring the risk of thunderstorms.

It is still too early to get a true grasp on exactly where the storms will be as models are not in total agreement but Saturday will start dry and sunny. Temperatures are likely to rise into the high teens or low 20's across most of England and Wales with dew points also increasing and so it will start to feel more humid.

Most models are showing the general idea of the first showers and thunderstorms developing across the SW at some point tomorrow morning before pushing them NNE through Wales, the Midlands and up into the North of England through the afternoon and evening. CAPE values in the region of 500-1000j/kg (dependent on which model you look at) would indicate that storms have the potential to produce frequent lightning and 1-2cm hail.

Some are then picking up on a second round of storms moving into the south coast through the evening and across the south-east quadrant of the UK overnight. ECM seem very keen on this idea. There is doubt as to how much of the UK these will affect, with areas to the south-east most at risk I would say. These are likely to be elevated in nature but with some exceptional CAPE values for this time of year they would again bring the risk of frequent lightning and hail of 2-3cm.

GFS storm risk for 6pm and then midnight

5ad9d84f35bb6_CAPEGFS18z.thumb.png.16750fe5fd8f50144b548a8a3adc90d9.png5ad9d84cdded5_CAPEGFS00z.thumb.png.8c2855d37bee223965a37f72d5d0f802.png  

 

5ad9d858885da_GFS18z.thumb.png.7c012983fe0a12b9d585b4bc61c6300a.png

NMM CAPE values for 6pm and midnight (this is MUCAPE and so combines both surface based and elevated CAPE)

5ad9d85413f9c_CAPENMM18z.thumb.png.cf34e74f683a82238338cc0114b6a7e5.png5ad9d8519ae9b_CAPENMM00z.thumb.png.b84a93e683dbfaa1135bb7a5d174cc4f.png

On the downside, deep layer shear is not great tomorrow, but with high levels of CAPE it is still possible there could be some more organised storms that develop and push NE through the course of tomorrow afternoon, evening and night. Regardless, any storms that do occur will produce torrential rainfall with a risk of localised flooding and possibly also gusty winds.

So it seems there is some consensus on there being two main rounds of thunderstorms. Round one will start of in the SW and move NNE to affect parts of Wales and the Midlands and then N England through the afternoon and evening. Round two will move into the south coast during the evening and move NE to affect SE parts. The question is where these storms will track, as some places will inevitably miss out where others get a very decent storm. It is also feasible that storms develop more widely as some of the models have storm activity exploding into life tomorrow evening and night as low pressure and associated cool air from the west moves over the top of the warm plume that will be in place across England and Wales by this point. All in all a very exciting 36-48 hours (or more as a further risk of storms looks likely across East Anglia and the far SE on Sunday afternoon/evening).

NMM extent of convective precipitation by midnight and NMM precipitation rates at 4pm, 9pm and then midnight.

5ad9d8562a559_convprecip.thumb.png.711df633209c55b6a15780caac6526ed.png  

5ad9d9dc52624_NMMprecipitation4pm.thumb.png.77cd44cd15ee5e7f20a60f7059b119c0.png  5ad9d85ad1601_NMMprecipitation.thumb.png.b9f7ad95bb79cbf6aa94b7e4a17542f4.png  5ad9d9ded1e49_NMMprecipitationmidnight.thumb.png.165fc3277026864fda56c47397843a45.png

All subject to changes of course, it is very difficult to pinpoint the exact location of storms even at 3-6 hours ahead but a general idea can at least be attained. I am going to be interested to hear the thoughts of the experts/storm forecasting sites this evening :) 

  • Like 6
Link to comment
Share on other sites

Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming

I’ve been expecting evening storms in our area on Saturday for the last few days. As regards the earlier risk in the West - I might consider having a little chase during the day and then returning home for the chance of a night light show there...

Definately an exciting period of weather over the next few days, fingers crossed and eyes peeled!

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Whaley Bridge - Peak District
  • Location: Whaley Bridge - Peak District

Keeping a eye on the convective potential here in the Peaks for tomorrow afternoon as i'll be fell-race supporting on Bleaklow Plateau at the time of storm initiation. Great for the views across the Cheshire plain and SW, not too great being stuck up on the tops being the tallest thing (with a camera and phone) for miles around.

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Witney, Oxon
  • Weather Preferences: Storms!
  • Location: Witney, Oxon

And so begins the annual inevitable disappointment when nothing happens in my area! Still, I think the anticipation is almost as exciting.....

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Abbeymead ,Glos Member Since: July 16, 2003
  • Weather Preferences: Hot and thundery or Cold and snowy.
  • Location: Abbeymead ,Glos Member Since: July 16, 2003
14 minutes ago, Vestan said:

And so begins the annual inevitable disappointment when nothing happens in my area! Still, I think the anticipation is almost as exciting.....

I used to get so excited about the storms. Id go chasing them half way across the country mostly to find disappointment.

Unless estofex have a level2 for my area etc, I dont get my hopes up

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Leeds
  • Weather Preferences: snow, heat, thunderstorms
  • Location: Leeds

Those NMM charts look potentially very good for Leeds. The Met Office have the thunderstorm icon for Saturday evening, and the BBC are showing thunder on Saturday evening too.

Edited by cheese
Link to comment
Share on other sites

Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset

It looks as though further North will stand the better chances of storms. Strong capping early tomorrow morning, but that get's eroded away by the late afternoon/early evening. Showers will push up from France, but CIN may well put pay to any storms down here, unless there's any other forcing mechanisms that will help?!

Link to comment
Share on other sites

Posted
  • Location: oxford, uk
  • Location: oxford, uk
7 minutes ago, Mapantz said:

It looks as though further North will stand the better chances of storms. Strong capping early tomorrow morning, but that get's eroded away by the late afternoon/early evening. Showers will push up from France, but CIN may well put pay to any storms down here, unless there's any other forcing mechanisms that will help?!

The metoffice has a shortwave across central England Saturday night - could be enough to kick off some elevated storms.

68523839.gif

Edited by convector
to include image
Link to comment
Share on other sites

Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

I guess it will be a case of radar watching tomorrow when I'm not gardening. Then it'll be watching Chezweather getting all the storms then some light drizzle going over here and me then towers building as the stuff heads of towards towards Donny and Leeds giving them a good storm. I'll probably hear the Sheffield shield powering up after lunch time.

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: NW Bexley, Kent
  • Weather Preferences: Storms, rain, tornados, funnel clouds and the northern lights
  • Location: NW Bexley, Kent

I'll be watching the radar and skies tomorrow evening then and keeping my fingers crossed for some decent elevated storms, all the while bracing myself for the inevitable disapointment when any storms that do occur track parallel to me before drifting over to Essex and firing up. :wallbash:

I really wish for a decent nightime elevated storm, and on a night when I don't have to get up early the next day as well. That would be so perfect. We will see...

Edited by Windblade
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Near Hull
  • Weather Preferences: Severe storms and heavy snow
  • Location: Near Hull

Caught sight of some mid level convection with a pileus cap about half an hour ago towards the east. Seems to have collapsed now though. 

Link to comment
Share on other sites

Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol

Quite astonishing and something I rarely see on hi-res models. The Netweather NMM model 12z, caught my eye as a small area of Wales witness significantly lower temperatures than the near surrounding area of which this area moves north over time. Check this chart out for tomorrow at 3pm.

5ada2fb199186_TempSat3pm.thumb.jpg.987ea991c47f96ea4816d82a9febb41c.jpg

This really could only mean one thing... SOMETHING must be causing this; some extremely heavy precipitation. After looking at the following CAPE chart, it was obvious a large area of violent thunderstorms must have formed.

5ada300c9a4e1_CAPESat3pm.thumb.jpg.1feda2bbd436698d9781f07abbcb24d1.jpg5ada301090910_PrecipSat3pm.thumb.jpg.8347fd6df7f39055fd8fba5e92c659c5.jpg

If this is to happen, then I would expect some extremely violent and well structured multi-cell/squall like feature to form and move northeastwards tomorrow. Interesting times!

 

 

Edited by Ben Sainsbury
  • Like 5
Link to comment
Share on other sites

Posted
  • Location: NW Bexley, Kent
  • Weather Preferences: Storms, rain, tornados, funnel clouds and the northern lights
  • Location: NW Bexley, Kent
6 minutes ago, Ben Sainsbury said:

Quite astonishing and something I rarely see on hi-res models. The Netweather NMM model 12z, caught my eye as a small area of Wales witness significantly lower temperatures than the near surrounding area of which this area moves north over time. Check this chart out for tomorrow at 3pm.

5ada2fb199186_TempSat3pm.thumb.jpg.987ea991c47f96ea4816d82a9febb41c.jpg

This really could only mean one thing... SOMETHING must be causing this; some extremely heavy precipitation. After looking at the following CAPE chart, it was obvious a large area of violent thunderstorms must have formed.

5ada300c9a4e1_CAPESat3pm.thumb.jpg.1feda2bbd436698d9781f07abbcb24d1.jpg5ada301090910_PrecipSat3pm.thumb.jpg.8347fd6df7f39055fd8fba5e92c659c5.jpg

If this is to happen, then I would expect some extremely violent and decently structured multi-cell/squall like feature to form and move northeastwards tomorrow. Interesting times!

 

 

Possible supercell?

Link to comment
Share on other sites

Posted
  • Location: Wrexham,NE Wales - 89m
  • Weather Preferences: Hot and Sunny Summers/Cold Wintry Winters
  • Location: Wrexham,NE Wales - 89m
8 minutes ago, Ben Sainsbury said:

Quite astonishing and something I rarely see on hi-res models. The Netweather NMM model 12z, caught my eye as a small area of Wales witness significantly lower temperatures than the near surrounding area of which this area moves north over time. Check this chart out for tomorrow at 3pm.

5ada2fb199186_TempSat3pm.thumb.jpg.987ea991c47f96ea4816d82a9febb41c.jpg

This really could only mean one thing... SOMETHING must be causing this; some extremely heavy precipitation. After looking at the following CAPE chart, it was obvious a large area of violent thunderstorms must have formed.

5ada300c9a4e1_CAPESat3pm.thumb.jpg.1feda2bbd436698d9781f07abbcb24d1.jpg5ada301090910_PrecipSat3pm.thumb.jpg.8347fd6df7f39055fd8fba5e92c659c5.jpg

If this is to happen, then I would expect some extremely violent and decently structured multi-cell/squall like feature to form and move northeastwards tomorrow. Interesting times!

 

 

Bring it on i live around there :D Thanks for the informative posts as well Ben.

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol
2 minutes ago, Windblade said:

Possible supercell?

Unfortunately the other parameters aren't quite there for supercell development. But nevertheless with such large CAPE values (for this time of the year anyway) there will be some prolific lightning.

Link to comment
Share on other sites

Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

Probably a data glitch. Sadly these runs are more often wrong than right and only a very rough guide

Link to comment
Share on other sites

Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset
35 minutes ago, The PIT said:

Probably a data glitch. 

Yeah, looks like it. Nothing like that showing on the MR version. The CAPE just vanishes on the SR.

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
  • UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-29 07:13:16 Valid: 29/03/2024 0600 - 30/03/2024 0600 THUNDERSTORM WATCH - FRI 29 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather

    Difficult travel conditions as the Easter break begins

    Low Nelson is throwing wind and rain at the UK before it impacts mainland Spain at Easter. Wild condtions in the English Channel, and more rain and lightning here on Thursday. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-28 09:16:06 Valid: 28/03/2024 0800 - 29/03/2024 0600 SEVERE THUNDERSTORM WATCH - THURS 28 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather
×
×
  • Create New...