Storm & Convective Discussion - 01/03/15 onwards

[Ben Sainsbury]

Does it?  UKMO has never modeled anything near what the GFS and ECM have. 

 

Regardless, the main point that needs driving home is we're discussing possible outlook 5-6 days away.  That's long range in convective forecast terms.  

GFS 12z emphasises a further eastward shift, with almost everyone missing out on Friday too! Hmm...

[East_England_Stormchaser91]

I know it's probably moonshine, but after what looks like it will be a failed attempt of a plume on Friday, early next week has ridiculous CAPE values of up to 3000 probably 3500j/kg and a LI of -12 over the East Midlands!

Best explosive chart I've ever seen put out yet. If only...

[Nimbus Nix]

I know it's probably moonshine, but after what looks like it will be a failed attempt of a plume on Friday, early next week has ridiculous CAPE values of up to 3000 probably 3500j/kg and a LI of -12 over the East Midlands!

Best explosive chart I've ever seen put out yet. If only...

 

And just like that, the explosive LI's and CAPEs are back out in FI...

 

Plan B: 

[Spikecollie]

Crikey...time even for me to hide under the bed!

 

And just like that, the explosive LI's and CAPEs are back out in FI...

 

Plan B: 

[Harry]

Indeed, a pretty staggering and significant change between the 6z and 12z - but then the emergence of instability early next week is a sudden change so not sure what to make of it all - other than to try and avoid chart gazing until Tuesday/Wednesday to see what's what.

As for -12 LI over the UK, that can be safely archived in the fantasy aisle that's not even common in the U.S.

Edited May 31, 2015 by Harry

[ChezWeather]

On June 9th 2014 I recorded this footage 

 

Heres to another 

 

https://www.youtube.com/watch?v=pOujf4eK04M

[East_England_Stormchaser91]

That would surely warrant a level 3 from estofex if that was to happen on the day!

[A.J]

That would surely warrant a level 3 from estofex if that was to happen on the day!

Estofex would not issue a level 3 warning (or any warning for that matter) just because of high sbcape & lifted index values.....if they did, pretty much the whole of mainland europe would be a level 3 warning every day for summer months of the year...lol......(there's a lot more to it than that!)

[Harry]

Estofex would not issue a level 3 warning (or any warning for that matter) just because of high sbcape & lifted index values.....if they did, pretty much the whole of mainland europe would be a level 3 warning every day for summer months of the year...lol......(there's a lot more to it than that!)

Indeed - but to be fair, the 06z for Friday (not the depressing 12z) could well be the closest I've seen to a possible level 3, but even then there are a a few factors which lead me away even then.

A level 3/'high risk' in the UK is extremely unlikely (certainly can't recall one ever in my lifetime). Conditions would have to be so so perfect which alas in a small temperate island nation are pretty hard to come by!!

[Supacell]

The WRF model is looking similar to the GFS 6z for Friday with big thunderstorms over the SE third of the UK. 

[Eye to the sky]

The WRF model is looking similar to the GFS 6z for Friday with big thunderstorms over the SE third of the UK.

I know it's a long way off Supacell,but if things were to stay as they are,what would our chances be here in the East Midlands of getting a good storm?!.

[East_England_Stormchaser91]

Estofex would not issue a level 3 warning (or any warning for that matter) just because of high sbcape & lifted index values.....if they did, pretty much the whole of mainland europe would be a level 3 warning every day for summer months of the year...lol......(there's a lot more to it than that!)

But a surface low, with the lower elevated peak district would act as a triggering mechanism from what I'm looking at on that chart. 

 

How could all of mainland Europe see that everyday? I,m pretty sure under a high pressure system with little converging winds, humidity, heat lows or plumes, you don't get the CAPE, especially of that extremity. Forgive me if I'm wrong?

Edited May 31, 2015 by East_England_Stormchaser91

[Raidan]

Going to leave it until Thursday night to see how things look for Friday and if it does look good then I may jump on a train to somewhere in the south east.i still think this is more likely than not to be a non event but who knows.

[DanN]

The WRF model is looking similar to the GFS 6z for Friday with big thunderstorms over the SE third of the UK. 

 

Out of interest, which WRF variant are you referring to? Most of the WRF's are run at the mesocale with their initial and boundary conditions coming from a global model, such as the GFS. If its a model initialised from the GFS then its not unusual for the WRF to have similar output - depending on model resolution, physics etc. 

[A.J]

But a surface low, with the lower elevated peak district would act as a triggering mechanism from what I'm looking at on that chart. 

 

How could all of mainland Europe see that everyday? I,m pretty sure under a high pressure system with little converging winds, humidity, heat lows or plumes, you don't get the CAPE, especially of that extremity. Forgive me if I'm wrong?

....on the mainland during summer months, sbcape builds up over several days, but the capping in place from high pressure prevents any real convection from occurring or surface lows from forming in general....storms break out in various parts of the mainland at times to to capping being eroded (in a predominately HP scenario).....have a look at the GFS run for mainland europe, (in particular cape & lift) you'll see that a big swathe of the interior generates high cape during daylight hours (energy at the ground level is transferred into the lowest levels of the atmosphere making the air want to rise, the capping layer above stops the air from rising further, so whilst the SBCAPE value is high, the capping mechanism stops convection from taking place at the capping layer)....during the nightime, SBCAPE values drop as the lower atmos becomes more stable as it loses diurnal energy....

 

are you referring to friday's charts?.....I can't see a surface low, the SLP & T850 charts infer a trough moving SW to NE with a parent low near Scotland...This trough could destabilize the airmass as it engages WAA (with very high theta-e values) over the SE portion of England giving elevated thunderstorms early friday morning in that part of the country

 

at least, that's how I see it....BF, Nick F or w09 can give you a better idea

Edited May 31, 2015 by ajpoolshark

[Harry]

The WRF model is looking similar to the GFS 6z for Friday with big thunderstorms over the SE third of the UK.

When was the last WRF model output Supacell?

Couldm be that it is based on similar data to GooFuS

Edited May 31, 2015 by Harry

[Supacell]

I know it's a long way off Supacell,but if things were to stay as they are,what would our chances be here in the East Midlands of getting a good storm?!.

 

It is too far off to make a call. Even if things stayed as they are, there are various different options on the table. For example, the 6z GFS would result in a high chance of a storm on Friday but the 12z sees everything on Friday miss our area to the south and east before getting clobbered next week. The WRF i spoke about would see us in with a shout.

 

Out of interest, which WRF variant are you referring to? Most of the WRF's are run at the mesocale with their initial and boundary conditions coming from a global model, such as the GFS. If its a model initialised from the GFS then its not unusual for the WRF to have similar output - depending on model resolution, physics etc. 

 

 

When was the last WRF model output Supacell?

Couldm be that it is based on similar data to GooFuS

 

 

It's this site that I use: http://www.meteocenter.eu/#model

 

I am not sure where these charts have come from. The site just states it uses the WRF model. No mention of when the run is from either, although it has updated since I last checked around 11am.

Edited May 31, 2015 by Supacell

[Harry]

The WRF looks remarkably like the 6z GFS - though if the time mark at the bottom of the chart is GMT or c.European (today at circa 5:30pm) then it'd be more recent that 12z GFS.

Edited May 31, 2015 by Harry

[DanN]

The WRF looks remarkably like the 6z GFS - though if the time mark at the bottom of the chart is GMT or c.European (today at circa 5:30pm) then it'd be more recent that 12z GFS.

 

My guess would be that's a model initialised from the GFS, the site is a bit sparse with regards model setup and configuration etc, though its free to access so can only assume its using GFS. Unless they have deep pockets to use the ECMWF data...who knows.

 

If its GFS data, then that's not available for a WRF to initialise until approx. 4 hours after the GFS run (e.g 16z for the 12z GFS). The current charts on their site could well be run from the 12z GFS, it just takes that long for their model to run after the GFS data becomes available.

Edited May 31, 2015 by DanN

[Eye to the sky]

The BBC,don't usually like using the word thunderstorms but on countryfile weather the word was used for next Friday.Watch it be down graded to thundery showers by next Wednesday though!!.

[Chris K]

The BBC,don't usually like using the word thunderstorms but on countryfile weather the word was used for next Friday.Watch it be down graded to thundery showers by next Wednesday though!!.

 

Or even worse..."thundery rain"

 

 

[A.J]

My guess would be that's a model initialised from the GFS, the site is a bit sparse with regards model setup and configuration etc, though its free to access so can only assume its using GFS. Unless they have deep pockets to use the ECMWF data...who knows.

 

If its GFS data, then that's not available for a WRF to initialise until approx. 4 hours after the GFS run (e.g 16z for the 12z GFS). The current charts on their site could well be run from the 12z GFS, it just takes that long for their model to run after the GFS data becomes available.

isn't the WRF model part of the NMM suite?......memory is hazy but it used to be on meteoceil (haven't checked in ages TBH)

Or even worse..."thundery rain"

 

 

Or drizzle    

[DanN]

isn't the WRF model part of the NMM suite?......memory is hazy but it used to be on meteoceil (haven't checked in ages TBH)

Or drizzle    

 

Not exactly, the WRF model has two core resolvers available, one of which is the NMM core, the other the ARW core. The NMM core is favoured by some as its generally a lot quicker to run when compared to the ARW core, useful if your forecasts are time sensitive etc. The ARW might be considered to be more accurate but it can be slower to run. The US HRRR model uses the WRF with the ARW core, I think Meteociel use the WRF with the NMM core, last time I used the Netweather high res suite, that was using the NMM core. They are all run independently of each other and can all be ran with different physics options/at different resolutions/nests-no nests (the ARW core actually has a lot more options in this regard) and might not all necessarily 'agree'. Getting a bit off topic now but I never know which particular model people are referring to when they mention the NMM/WRF etc...could be one of many!

 

Bit more info from the WRF site http://www.wrf-model.org/index.php

Edited May 31, 2015 by DanN

[Harry]

I am going to buy a video camera just in case there is action in the next week (or if not then over the summer). Looking at the Sony PJ620 - if anyone in the know could PM me whether they think it'd be a good purchase (particularly for night time storms) I'd be really grateful, or any other recommendations

Back on topic, like a poorly disciplined child I can't help getting a bit excited about a potential plume...year in year out I do it myself lol

[Dan the Man]

That would surely warrant a level 3 from estofex if that was to happen on the day!

 

Out of interest, what is the criteria/characteristics of a "Level 3"?