Storm & Convective Discussion - 20th August 2015 onwards

[Mokidugway]

And energy output of 1 TWh for a few milliseconds a lightning bolt lasting for 6 weeks could supply the worlds electrical needs for a year ,allegedly :0...

Oops, that was the vodka speaking...Can the temperature of lightning really be 5x that of the Solar surface (5700K)?  That's 285,000K?

oh dear ,Ed ..

[Methuselah]

285,000K? I think your calcs are a bit off there!

 

Lightning is about 30,000K

Okay, Nick..Maybe 2.85x10⁴...Still somewhat warm?

[Mokidugway]

Okay, Nick..Maybe 2.85x10⁴...Still somewhat warm?

do you exponents in your vodka ???.

[Supacell]

Considering going on a chase myself tomorrow. I think Nottinghamshire up into Derbyshire or South Yorkshire looks a decent shout, what do you think bud?

From current GFS/NMM/Euro 4 I would say yes. However Met Office have it more your way. I will be waiting for the morning to make a final decision. At the end of the day it will come down to radar watching, cloud spotting etc but it is helpful to be near where they are going to fire.

That tends to be the difficulty even if the models all agree. Maybe follow areas where wind convergence occurs as this may indicate a developing trough?

[Cheshire Freeze]

From current GFS/NMM/Euro 4 I would say yes. However Met Office have it more your way. I will be waiting for the morning to make a final decision. At the end of the day it will come down to radar watching, cloud spotting etc but it is helpful to be near where they are going to fire.

That tends to be the difficulty even if the models all agree. Maybe follow areas where wind convergence occurs as this may indicate a developing trough?

 

EURO 4 tomorrow 9pm...

 

 

GFS 9pm...

 

 

Not sure why the GFS is progging a rainshadow around Manchester there as this isn't likely to be frontal rain.

Edited August 21, 2015 by CreweCold

[Costa Del Fal]

EURO 4 tomorrow 9pm...

 

Definitely looks great for the West Midlands up towards you and then roughly Derby or Sheffield northwards.

[Boro Snow]

Whats peoples thoughts on Darlington tomorrow for storm or 2 we have done well this year it has to be said 

[A Frayed Knot]

Estofex warning is out

[Mokidugway]

Estofex warning is out

finally ..oh , level 1 too .. Edited August 21, 2015 by Mokidugway

[Boro Snow]

just on the east edge of that level 1 i will take that

[Mokidugway]

just on the east edge of that level 1 i will take that

boom or at least we hope so ..

[Costa Del Fal]

Very good Estofex warning! Organized and quite possibly severe early night storms likely.  http://www.estofex.org/

[Harry]

Hmmm...looking like I might miss out on tomorrow's drama, on eastern edge of estofex warning while convective weather UK forecast has no risk zone whatsoever. Will just try and enjoy the heat (and dissertation write book)

[William Grimsley]

Latest BBC forecast showing mainly heavy/thundery showers over me through late tomorrow evening and then general rain after that, I think the further north and west you are the more likely thunder is a possibility. Estofex Level 1 out for East Devon, Dorset and Somerset.

[pookie1989]

really dreading this working early sunday, really hate storms. Im in shropshire, hoping they are further west! 

[Boro Snow]

boom or at least we hope so ..

we will see what happens

[Costa Del Fal]

For a change I thought I would do a little forecast as to my interpretation of events this weekend, primarily about the areas most at risk I feel.

 

1) Saturday 22nd August 1400-2200:

 

Please see attachment 1. This map shows the areas I feel will be at risk of primarily surface based storms, a consequence of surface heating in the afternoon as temperatures rise to the mid to high 20s, possibly 30-31c around N London. With intense heating there is the potential for any storms to become quite intense especially as CAPE may reach up to ~1000j/kg so plenty of energy available. The best chance of these forming towards the East Midlands but particularly around Nottingham/Derby and Northwards. At least here they may become somewhat a little more widespread. Most models do not seem keen on producing precipitation around the SE. The risk is certainly there but they will be especially Isolated here. Rather a particular area of focus for initiation may originate around a convergence line which is forecast to lie from around the Birmingham area towards the Peak District/Pennines in the late afternoon. Regardless of location, storms may be intense and give flash flooding in a short space of time. DLS should increase further North slightly too, favouring more development and more organised cells. Isolated supercells are not out of the question though multicells are of greater likelihood. Large hail and the odd tornado cannot be ruled out. Peak initiation probably 4pm onwards and most likely weakening after sunset. Note: The arrows in the map indicate the likely direction of any cells.

 

2) Saturday 22nd August 2000-0600 Sunday 23rd August:

 

Please see attachment 2. This time frame and the areas shown should be the main focus for more organised thunderstorm activity as further destabilisation occurs closer to the approaching cold front. Storms are also expected to fire in Northern France and whilst likely to be surface based at first, will most likely become elevated in nature with time. Some may originate towards the Channel Islands/Devon and Somerset too. With greater DLS here in the west of the UK, storms should organize quite well bringing the potential for quite widespread and prolific lightning activity. If storms become elevated, the severe risks of large hail and tornadoes will decrease though the risk should not become entirely negligible. Instead, torrential rain and frequent IC and CG Lightning is the primary threat. The most organised storms will probably peak in an area from Gloucester northwards through the Midlands and perhaps into parts of NW England. Powys may also see some significant thundery weather for a time. In the early evening, upper steering winds will be around direct southerly. Later on after approximately 2200hrs they will become increasingly backed towards the SSE/SE hence storms may increasingly affect NE Wales and NW England for a time. The arrows on the maps indicate this with the dotted lined arrow showing the general upper air flow direction late evening onwards. Storms will probably begin to fade in the early hours of Sunday though some isolated cells may continue near the cold front, particularly around Devon and S/SE Wales. 

 

Into Sunday daytime there is a low risk the cold front approaching from the SW may invigorate some further storms, particularly in the Midlands though this risk is too low at this time to detail. 

 

Daytime Risk Map:

 

Evening/Overnight Risk Map: 

 

 

 

[Stormyking]

Hmm right Smack bang in the middle of that Level 1, we will see, I do have a feeling some nasty cells may pop during evening hours too

[lfcdude]

Oh dear how ridiculous 

 

Edited August 21, 2015 by lfcdude

[Speedway Slider]

For a change I thought I would do a little forecast as to my interpretation of events this weekend, primarily about the areas most at risk I feel.

1) Saturday 22nd August 1400-2200:

Please see attachment 1. This map shows the areas I feel will be at risk of primarily surface based storms, a consequence of surface heating in the afternoon as temperatures rise to the mid to high 20s, possibly 30-31c around N London. With intense heating there is the potential for any storms to become quite intense especially as CAPE may reach up to ~1000j/kg so plenty of energy available. The best chance of these forming towards the East Midlands but particularly around Nottingham/Derby and Northwards. At least here they may become somewhat a little more widespread. Most models do not seem keen on producing precipitation around the SE. The risk is certainly there but they will be especially Isolated here. Rather a particular area of focus for initiation may originate around a convergence line which is forecast to lie from around the Birmingham area towards the Peak District/Pennines in the late afternoon. Regardless of location, storms may be intense and give flash flooding in a short space of time. DLS should increase further North slightly too, favouring more development and more organised cells. Isolated supercells are not out of the question though multicells are of greater likelihood. Large hail and the odd tornado cannot be ruled out. Peak initiation probably 4pm onwards and most likely weakening after sunset. Note: The arrows in the map indicate the likely direction of any cells.

2) Saturday 22nd August 2000-0600 Sunday 23rd August:

Please see attachment 2. This time frame and the areas shown should be the main focus for more organised thunderstorm activity as further destabilisation occurs closer to the approaching cold front. Storms are also expected to fire in Northern France and whilst likely to be surface based at first, will most likely become elevated in nature with time. Some may originate towards the Channel Islands/Devon and Somerset too. With greater DLS here in the west of the UK, storms should organize quite well bringing the potential for quite widespread and prolific lightning activity. If storms become elevated, the severe risks of large hail and tornadoes will decrease though the risk should not become entirely negligible. Instead, torrential rain and frequent IC and CG Lightning is the primary threat. The most organised storms will probably peak in an area from Gloucester northwards through the Midlands and perhaps into parts of NW England. Powys may also see some significant thundery weather for a time. In the early evening, upper steering winds will be around direct southerly. Later on after approximately 2200hrs they will become increasingly backed towards the SSE/SE hence storms may increasingly affect NE Wales and NW England for a time. The arrows on the maps indicate this with the dotted lined arrow showing the general upper air flow direction late evening onwards. Storms will probably begin to fade in the early hours of Sunday though some isolated cells may continue near the cold front, particularly around Devon and S/SE Wales.

Into Sunday daytime there is a low risk the cold front approaching from the SW may invigorate some further storms, particularly in the Midlands though this risk is too low at this time to detail.

Daytime Risk Map:

Saturday 22nd Aug Daytime Risk.png

Evening/Overnight Risk Map:

Saturday 22nd Aug Evening Risk.png

Nice work chap, that's roughly the way I see tomorrows flashy-bang concerts going.....

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It missed the trees, rain off my

little diagram!

Edited August 21, 2015 by Speedway Slider

[Condor Vitesse]

The Level one is mainly for excessive rain, Large hail, severe wind gusts and tornadoes. 

[Harry]

Oh dear how ridiculous

I bet there will be a notable tornado now they've published that...

[Boro Snow]

The Level one is mainly for excessive rain, Large hail, severe wind gusts and tornadoes. 

ok do you not think there maybe a bit of convection in all that ie thunder and lightning 

Edited August 21, 2015 by Boro Snow

[Condor Vitesse]

Over Leeds!!!! You gotta be joking. Normally hits here then gets going further North so your chances look pretty good. .

Edited August 21, 2015 by Condor Vitesse

[alexisj9]

Oh dear how ridiculous 

TBH the possibility is there for some area's, I think tornado watch is more appropriate though.