Thunderstorms

Snowbie

Post here of all things thunderstorm related,whether it be radar,maps,charts,forecasts or just simple discussions.
Over the months you will find some variables or terms describing suitability of storms which are:
CAPE - This is the amount of potential energy in the atmosphere. High CAPE will indicate a high chance of thunderstorms.
LI - Lifted Index (LI) displays the 'trigger' potential at the surface to initiate unstable conditions. A low or negative LI will indicate conditions for thunderstorms are favourable.
Cb-Cumulonimbus or thundercloud.
Anvil-Where the top of the Cb reaches the stratosphere and spreads out like a flat top.
Cell or Supercell-An individual storm or a violent storm.
Squall line-Multi cellular organised storms forming in a line usually ahead or parallel to cold fronts.
Embedded Storms-Storms that are contained in overcast conditions
Convection-Warm air rising,cools,condenses forming cumuli clouds.
Orographic lift-Low level winds are forced to rise against rising terrain ie:mountains.Prevailing wind on a hot summers day,this lift can produce rapid convection.
Convergence zone-usually refers to a region in the atmosphere where two prevailing winds meet and interact, usually resulting in turbulent weather.
Lapse rate steepeing-is another fancy term for instability.
Sferics-Sound of low-frequency radio signals that derive from lightning strikes.Common terms would be strikes or strokes.
Some useful links
http://www.irlweather.com
http://www.gyweather.com/
http://www.isleofwightweather.co.uk/live_storm_data_sound.htm
http://www.wetterzentrale.de/pics/Rsfloc.html
Estofex
http://www.blitzortung.org/index.php?mode=0&map=5&lang=e
http://www.nowcast.co.uk/lightning/
http://meteocentre.com/lightning/map_sfuk.php?time=0&lang=en&map=Europe
http://www.estofex.org/guide/
If anyone has any more feel free to post them.

Snowbie

A fresh new thread. Looks ripe for storms out there with mid level altocumulus a plenty.

That storm last night off the coast continued right upto Malin head this morning.

That storm last night snowbie-Was that from the storms that built up over sw wales yesterday evening ,then drifted north over west wales and then out into the irish sea?
Thats an amazing track to say it was still going this morning-t'was mentioned on the BBC forecast this morning.

Meanwhile,I saw some fully developed cb's as early as 7am this morning inland over wexford.
Even then the breeze was off the sea.It's highly probable that some convergence activity might occur inland in that alley known for it from Mt Linster NE to West wicklow.

Snowbie

Yeah BB have mentioned and explained it in the other thread. Watched those building up over Wales yesterday pushing NW. Hit the cool Irish sea and died.
With left over moisture in the atmosphere from the showers, a cool sea and a warm plume pushing up from the south, instability arose again over the sea, very localised in nature but a very successful cell tbh.

Snowbie

The highest Cape is over Paddys area at 400j/kg with a LI -1.

Some showers might break out ahead of the front but its hard to pinpoint where storms(if any) will occur. Temps are high enough over land but conditions are far from perfect for TS development for now on a widespread scale.

Too windy here off the sea anyhow.
Very sunny though so who knows what might happen as that sea wind meets the land heat.

Deep Easterly

Snowbie wrote: »

The highest Cape is over Paddys area at 400j/kg with a LI -1.

Some showers might break out ahead of the front but its hard to pinpoint where storms(if any) will occur. Temps are high enough over land but conditions are far from perfect for TS development for now on a widespread scale.

Exactly. Very hard to pinpoint alright Snowbie, I am not to hopeful for here to be honest as it pretty windy again even though I am 29 miles inland!!:(,+ haze is all but gone again which suggests Atlantic influence is undercutting again. Would have a better chance if the winds slackened a bit to allow development to be sufficent at a local scale.

I wouldn't rule out showers/thunder in the east/southeast/south later though, the Celtic and Irish sea can throw up some beauts out of the blue. Last night proved that!!!

Snowbie

Heavy showers have developed over Tipp and the south midlands moving in a NE direction in the last while.

Danno

This is my NexStorm image from tonight... (Also got my CVM Map)

http://durrow.athost.net/images/08052008%202326z%20-%20Lightning%20Screenshot.JPG

I think there is alot of noise picked up.

Snowbie

Looks like your picking up noise tbh.
Must be noise pollution close by. Electric fence, dimmer switch, a gen.
Plays havok with the detector now and again. I dont know too much about the lite version as i have the full but can you change your noise setting to high from default. Gets rid of artifical noise for the time being.

Also, try ranging the squelch to 2. This helps sometimes but dont range it more than 4 as it wont detect the weaker signals from lightning.

just passing through.
Could someone do an analysis of the thunder risk over the next 36 hours-I see met Éireann are almost in over kill mentioning it.

I don't have the time,but I do want to know.
This message took 10 seconds to write-it might be 10hrs before I read the reply[ies] (well 3 or 4 anyway).

Snowbie

With heat there is a possibilty of an isolated shower but the chance of storms on this island is minimal over the next couple of days.
Rain approaching from the south might have a rumble or two in it but imo there is zip% of anything occuring overall.

Supercell

Yep, now if you were in central Engerland on the otherhand.....

Nope the field I want to plough is in central south wickla!
And I don't want rain.
I know theres some coming tonight and according to met Éireann it's to be thundery at times or heavy .
The GFS looks wet but if it's anything like last night we'll have nothing.
Crosses fingers.

Radar shows a narrow line of heavy rain knocking on my door.
It's dry here but I can see the wall of that rain now.
It looks impressive,it's a wall that runs for miles east west to the south of here.

Snowbie

SE Wales is having some fireworks display over there atm. With nocturnal cooling of the cloud tops the storm is intensifying and moving NW. Although slow moving, it is a similar set up to the Wednesday night/Thursday morning storm off the east coast..

There is a constant feed of moist humid air being driven northwards up through and over a cool Irish sea so instability could develop once again. This time the dewpoints are 1c lower this time but could threaten our SE coast later. Will watch this one closely.

darkman2

Snowbie wrote: »

SE Wales is having some fireworks display over there atm. With nocturnal cooling of the cloud tops the storm is intensifying and moving NW. Although slow moving, it is a similar set up to the Wednesday night/Thursday morning storm off the east coast..

There is a constant feed of moist humid air being driven northwards up through and over a cool Irish sea so instability could develop once again. This time the dewpoints are 1c lower this time but could threaten our SE coast later. Will watch this one closely.

Ive been watching those storms on radar - chance of an import later? Will be the early hours of the morning before we find out.

Snowbie

Has moved off now to the north of Cardiff and with some orographic lift over the mountain range more intensification possible. Attach shows a single cell storm but a very big one at that.

darkman2

Snowbie wrote: »

Has moved off now to the north of Cardiff and with some orographic lift over the mountain range more intensification possible. Attach shows a single cell storm but a very big one at that.

If it makes it into the Irish sea then we should comfortably be able to see the flashes from here. I dont expect it to make Ireland intact but you never know.

Snowbie

With this cloud cover it would have to be well into the sea to observe the lightning. It will die but it could intensify later. Time will tell.

Deep Easterly

Snowbie wrote: »

Has moved off now to the north of Cardiff and with some orographic lift over the mountain range more intensification possible. Attach shows a single cell storm but a very big one at that.

I insist on some video footage if they make it across tonight Snowbie. I need to see some night time lightning before I spontaniously combust with the lack of it here!!! Should be good to get some clouds lighting up even half way across the Irish sea!!

Danno

Hi Snowbie. I am trying to match up my recorded strikes with your online one using the ranging tool. I seem to be getting similar data to you!

Snowbie

Dan, there is now 2 cells over Wales. The enormous one that is over South Wales and the one that has really developed over North Wales. With the line of sight i have the southern one is in direct line of sight with your detector while the north Wales one is direct to me. Remember the mountains both here and over there can sometime block lightning ground signals, what are you seeing atm? The north one seems much more intense from here for obvious reasons.

Danno

I have the two cells identified - North Wales is W408-2 - South Wales is R457-3

Your northern storm is more "clustered" than mine

Your southern storm appears more into the Irish sea off Pembrookshire.

Snowbie

Yep the mountains unfortunately reflect the signal.You should have a clearer line of sight to the southern one while i have a clearer sight to the northern one.The Wicklow mountains will probably interfere with the northern storm from your point.
It takes awhile for the segmented ranging to re-range the strike while the line of sight storms are bang on.

Danno

http://durrow.athost.net/images/10052008-0022z.GIF is my 12.22am shot.

Snowbie

The southern cell is just moving into Cardigan bay while the North one is slightly SW of Mersyside atm. Use the plot scale to adjust your ranging to bring both sets of cells a tad closer and the detector will do the rest and adjust itself.

Danno

LOL!!! Just done that there now! Awaiting the 0030 radar from Metoffice.com to make final ranging adjustment!

We both should see better of the southern one as it clears the South Wales hills and enters the Irish sea. Although it'll probably die off 20 miles out over the bay. But it gives me a window from now to 1am to align the ranging.

Danno

Got the 0030 radar now and it looks fairly right. Error margin of approx 10 miles. But not bad for one hours messing about, eh?

Snowbie

South Wales storm has weakened while the northern cell keeps going strong. Will the Irish sea favour this, for now looks very unlikely across Cardigan bay and as expected. Always a chance of intensifying out over the sea with a more favourable environment.

Snowbie

Danno wrote: »

Got the 0030 radar now and it looks fairly right. Error margin of approx 10 miles. But not bad for one hours messing about, eh?

Thats sound Danno. The closer the storm the better the ranging and accuracy. What height did you install the antenna at?

Danno

Antenna is in the attic facing 5 deg off south (SSE). Standard two storey house. When a storm breaks out over Northern Kildare we shall have some fun matching map data. I'd have a clear line of sight to there as would you.

Would the slieve bloom mountains (500m) about 20 miles NW of here cause bad readings for say a storm over Athlone?