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Convective / Storm Discussion Thread - 31st May 2017 onwards


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Posted
  • Location: Bratislava, Slovakia
  • Location: Bratislava, Slovakia

Here in Slovakia there's a great light show happening to my east. Frequent lightning high in the atmosphere but with very little thunder.

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

First main showers beginning to form over Jersey now, this is where we should expect further developments in the next few hours.

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Posted
  • Location: Hull
  • Weather Preferences: Cold Snowy Winters, Hot Thundery Summers
  • Location: Hull

I think it's often interesting to see how well past events are forecast. Remember the storms of June 2012 that produced some large hail and supercells? Here was the forecast for that day during the morning....
 


So some storms may not be picked up that well, but caution is understandable given the last bust. However I think conditions are more favourable this time round in terms of the SLP pattern, then last time...

Edited by Quicksilver1989
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Posted
  • Location: Walsall, West Midlands 135m/442ft ASL
  • Weather Preferences: Heatwaves, thunderstorms, cold/snowy spells.
  • Location: Walsall, West Midlands 135m/442ft ASL

Interesting :)!!!

WIN_20170705_20_54_57_Pro.jpg

WIN_20170705_20_55_34_Pro.jpg

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Posted
  • Location: Whaley Bridge - Peak District
  • Location: Whaley Bridge - Peak District
2 minutes ago, Mokidugway said:

Just to remind everyone this doesn't happen in the uk ...:nonono:

IMG_1282.JPG

 

Not to that extent, but I did a self-study of the Hoghton (Lancs) Tornado back in 2005 and many times saw plywood and small-medium sized sticks impaled through caravans, roofs, and a barn that had 1/4 of it's side missing. 

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
6 minutes ago, Ben Sainsbury said:

First main showers beginning to form over Jersey now, this is where we should expect further developments in the next few hours.

They do seem to be moving ENE Ben and prob miss the uk.

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Posted
  • Location: Cheslyn Hay, South Staffordshire. UK 159mtrs ASL
  • Location: Cheslyn Hay, South Staffordshire. UK 159mtrs ASL
6 minutes ago, Sparkiee storm said:

Interesting :)!!!

WIN_20170705_20_54_57_Pro.jpg

WIN_20170705_20_55_34_Pro.jpg

Looking good got this here

19702538_10154682036022011_4599780994665885260_n.jpg

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Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol
2 minutes ago, Allseasons-si said:

They do seem to be moving ENE Ben and prob miss the uk.

Very much true, although skeptical about whats going to happen as the showers should be moving with the trough which is expected to move NNE/NE for the time being. Indicated through the Sat24 too. 

Maybe we should look for developments further west?

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
1 minute ago, Ben Sainsbury said:

Very much true, although skeptical about whats going to happen as the showers should be moving with the trough which is expected to move NNE/NE for the time being. Indicated through the Sat24 too. 

Maybe we should look for developments further west?

Yes,that is what i will be looking for later if anything:)

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Posted
  • Location: Walsall, West Midlands 135m/442ft ASL
  • Weather Preferences: Heatwaves, thunderstorms, cold/snowy spells.
  • Location: Walsall, West Midlands 135m/442ft ASL
2 minutes ago, LeeKay said:

Looking good got this here

19702538_10154682036022011_4599780994665885260_n.jpg

Nice, great first signs for us in the Midlands :) 

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Posted
  • Location: Nairn
  • Location: Nairn

Day 1 Convective Outlook

VALID 06:00 UTC Wed 05 Jul 2017 - 05:59 UTC Thu 06 Jul 2017

ISSUED 20:15 UTC Wed 05 Jul 2017

ISSUED BY: Dan

UPDATE 20:15 UTC General trend amongst latest guidance suggests more of an easterly component to storm tracks through tonight, such that developments over the English Channel may steer to the ENE, and hence a slower arrival inland across southern coastal counties. Nonetheless, a MDT has been issued where better clustering of storms may occur towards the end of the night and thence beyond this forecast period. More scattered thunderstorms will be possible in the SLGT, and even isolated cells could develop as far west as Devon

 

UPDATE 16:12 UTC SLGT shifted eastwards, in line with thoughts from this morning. Potential for upgrade to MDT over English Channel and adjacent coasts, but awaiting full 12z runs for any potential increase confidence. ECMWF and high-res AROME (which uses ECMWF boundary conditions) both consistently offer a much later development (i.e. after this forecast period) and only affect S/SE England on Thursday, which lowers confidence somewhat.

 

UPDATE 07:44 UTC No modifications to the map for now, just to add some commentary based on 00z guidance. ECMWF continues to keep developments farther south and therefore elevated thunderstorms only reach far south coast at the very end of the forecast period (06 UTC). Most other output continue to hint at developments being farther north (and hence earlier / quicker motion to the NE), though broad trend would be to shift the SLGT farther east from its current position, roughly Dorset eastwards - this may be required on further updates.

 

... N WALES / N MIDLANDS / N ENGLAND / S SCOTLAND ...

Diurnal heating of a warm and relatively moist surface airmass will likely develop some marginal instability across these areas - though in reality, surface-based parcels likely capped by a warm nose around 850mb suggesting lightning rather unlikely given limited depth to any convection. Given also little signal from most NWP output (ignoring GFS with its dewpoints of 16-18C vs EURO4 with 11-13C), have refrained from issuing a LOW threat level for now - but will need monitoring. Some residual elevated instability may also produce the odd shower over the Midlands into East Anglia too.

 

... S ENGLAND / S MIDLANDS / HOME COUNTIES / S WALES ...

Upper trough west of Iberia will continue to disrupt southwards, backing the flow and allowing advection of high WBPT airmass from Biscay to occur into southern England on Wednesday night. Falling heights aloft will result in an increase in coverage of elevated thunderstorms, though the exact forecast evolution is marked with some uncertainty.

 

The vast majority of guidance suggests a few thunderstorms will develop over the English Channel and/or S/SW England 23 - 02z, expanding in coverage through the remainder of Wednesday night as the focus shifts northwards and eastwards over S Britain as the new warm front lifts north - hence in a broad sense, probabilities per given location increases as you head farther north and east across the SLGT area. However, the ECMWF has been fairly consistent in keeping the main upper forcing a little farther south, and hence any thunderstorms may only graze the extreme south coast towards the end of the night. At the same time, it also allows more activation of the frontal boundary towards Northern Ireland and western Scotland. Given the ECMWFs history of generally having a good handle (compared to many other models) on medium-level instability events, this casts a little doubt on how widespread thunderstorms may be over southern England - though the degree of instability and very steep mid-level lapse rates would suggests any thunderstorms that do occur would be prolific lightning producers, perhaps capable of producing some hail and gusty winds. A MDT may be issued should confidence improve.

 

http://www.convectiveweather.co.uk/forecast.php?date=2017-07-05

Edited by Stuart
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Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol
5 minutes ago, Allseasons-si said:

Yes,that is what i will be looking for later if anything:)

Interesting to note GFS have done well with current timing of showers over Jersey (but as always over-egg the amount of precipitation). Bear in mind the normally reliable Euro4, didn't predict any precipitation to form whatsoever till midnight. Maybe if making an educated guess this could mean that Euro4 predictions could be brought forward and brings a greater risk to some more Central Southern areas.

 

Current ConvectiveWeather update is spot on for me!

Edited by Ben Sainsbury
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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)

Let's hope the storm track follows the ferry route from Santander:D

Plymouth-Santander.jpg

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Posted
  • Location: Bexhill-on-sea, East Sussex (11.8M ASL)
  • Weather Preferences: Thunderstorms, snow, and wind storms
  • Location: Bexhill-on-sea, East Sussex (11.8M ASL)

IM IN CONVECTIVE WEATHER'S MDT ZONE:bomb::yahoo:!! 

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Posted
  • Location: Kensington
  • Location: Kensington
2 minutes ago, Allseasons-si said:

Let's hope the storm track follows the ferry route from Santander:D

Plymouth-Santander.jpg

Hopefully there is one half a mile from here 

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Posted
  • Location: warminster Wiltshire
  • Weather Preferences: thunderstorms and snow
  • Location: warminster Wiltshire

Which way  those thunderstorms  move from bis bay

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

Day 1 Convective Outlook

VALID 06:00 UTC Wed 05 Jul 2017 - 05:59 UTC Thu 06 Jul 2017

ISSUED 20:22 UTC Wed 05 Jul 2017

ISSUED BY: Dan

UPDATE 20:22 UTC General trend amongst latest guidance suggests more of an easterly component to storm tracks through tonight, such that developments over the English Channel may steer to the ENE, and hence a slower arrival inland across southern coastal counties. Nonetheless, a MDT has been issued where better clustering of storms may occur towards the end of the night and thence beyond this forecast period. More scattered thunderstorms will be possible in the SLGT, and even isolated cells could develop as far west as Devon. LOW threat level also introduced for N/NE England with an increase in elevated convection likely here towards the end of Thursday night

UPDATE 16:12 UTC SLGT shifted eastwards, in line with thoughts from this morning. Potential for upgrade to MDT over English Channel and adjacent coasts, but awaiting full 12z runs for any potential increase confidence. ECMWF and high-res AROME (which uses ECMWF boundary conditions) both consistently offer a much later development (i.e. after this forecast period) and only affect S/SE England on Thursday, which lowers confidence somewhat.

UPDATE 07:44 UTC No modifications to the map for now, just to add some commentary based on 00z guidance. ECMWF continues to keep developments farther south and therefore elevated thunderstorms only reach far south coast at the very end of the forecast period (06 UTC). Most other output continue to hint at developments being farther north (and hence earlier / quicker motion to the NE), though broad trend would be to shift the SLGT farther east from its current position, roughly Dorset eastwards - this may be required on further updates.

... N WALES / N MIDLANDS / N ENGLAND / S SCOTLAND ...

Diurnal heating of a warm and relatively moist surface airmass will likely develop some marginal instability across these areas - though in reality, surface-based parcels likely capped by a warm nose around 850mb suggesting lightning rather unlikely given limited depth to any convection. Given also little signal from most NWP output (ignoring GFS with its dewpoints of 16-18C vs EURO4 with 11-13C), have refrained from issuing a LOW threat level for now - but will need monitoring. Some residual elevated instability may also produce the odd shower over the Midlands into East Anglia too.

... S ENGLAND / S MIDLANDS / HOME COUNTIES / S WALES ...

Upper trough west of Iberia will continue to disrupt southwards, backing the flow and allowing advection of high WBPT airmass from Biscay to occur into southern England on Wednesday night. Falling heights aloft will result in an increase in coverage of elevated thunderstorms, though the exact forecast evolution is marked with some uncertainty.

The vast majority of guidance suggests a few thunderstorms will develop over the English Channel and/or S/SW England 23 - 02z, expanding in coverage through the remainder of Wednesday night as the focus shifts northwards and eastwards over S Britain as the new warm front lifts north - hence in a broad sense, probabilities per given location increases as you head farther north and east across the SLGT area. However, the ECMWF has been fairly consistent in keeping the main upper forcing a little farther south, and hence any thunderstorms may only graze the extreme south coast towards the end of the night. At the same time, it also allows more activation of the frontal boundary towards Northern Ireland and western Scotland. Given the ECMWFs history of generally having a good handle (compared to many other models) on medium-level instability events, this casts a little doubt on how widespread thunderstorms may be over southern England - though the degree of instability and very steep mid-level lapse rates would suggests any thunderstorms that do occur would be prolific lightning producers, perhaps capable of producing some hail and gusty winds. A MDT may be issued should confidence improve.

http://www.convectiveweather.co.uk/forecast.php?date=2017-07-05

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
2 minutes ago, tomdewey said:

Which way  those thunderstorms  move from bis bay

N/NNE at the moment.

Edited by Allseasons-si
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Posted
  • Location: Near Hull
  • Weather Preferences: Severe storms and heavy snow
  • Location: Near Hull
1 hour ago, Dami said:

said in jest.:cc_confused:

Apologies I always forgot I'm with fellow weather geeks on here. 

 

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Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

First signs of some AcCas drifting in - nothing record breaking but tentative signs nonetheless 

IMG_1153.JPG

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Posted
  • Location: Walsall, West Midlands 135m/442ft ASL
  • Weather Preferences: Heatwaves, thunderstorms, cold/snowy spells.
  • Location: Walsall, West Midlands 135m/442ft ASL

Like some others, I am too feeling a lot more hopeful this time around as (IMBY) anyway, I haven't seen skies like this this year yet and that is unusual for the Midlands.

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

Philip makes me laugh on the BBC Video forecasts mind, "a few showers moving into Southern Areas with the odd rumble of thunder". Oh I better hope it ain't just the odd rumble, ain't staying up for that rubbish! :nonono:

Edited by Ben Sainsbury
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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset

Interesting seeing the pictures of ACCAS, Cirrus Floccus etc absolutely none of that here.

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