Thunderstorms and Convective Potential (Dublin Floods 9/8/08)

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://durrow.athost.net/lightning/
http://www.gyweather.com/
http://www.isleofwightweather.co.uk/live_storm_data_sound.htm
http://www.wetterzentrale.de/pics/Rsfloc.html
http://www.estofex.org
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/
http://www.strikestareu.com/
If anyone has any more feel free to post them.

Snowbie

Renewed risk today for some fireworks with most areas at risk of a storm.

squonk

That's what I want to hear. It's certainly humid and warm enough anyway!

force eleven

This mornings murk and rain have cleared from here, and its a breezy bright morning/midday. Certainly still warm and humid in that sun,with plenty of cumulus, though they don't look like developing into anything as yet, they are blowing along nicley on the breeze. We'll have to see what today brings,certainly the ingredients are there.

maquiladora

Snowbie wrote: »

Renewed risk today for some fireworks with most areas at risk of a storm.

What areas are looking to be most at risk today snowbie?

maquiladora

squonk

Serious rain pushing into Kerry just now. If this moves up the country, could it have the potential to kill off any potential? The approaching cloud would kill the sun's effect anyway?

maquiladora

squonk wrote: »

Serious rain pushing into Kerry just now. If this moves up the country, could it have the potential to kill off any potential? The approaching cloud would kill the sun's effect anyway?

Looks like that rain is moving west/southwest. It doesn't look like its going to move up the country.

Snowbie

That rain is circulating around the LP just off the SE coast.

Risk areas anywhere in the CAPE and LI values in the attach. But only if there is prolonged sunshine to generate surface warming. Total airmass setup. Hit and miss.
Anywhere away from the very east and south coast at first and SW will have a chance if sun pokes through. Radar and Satellite viewing will give you an indication.

Hal1

I can see some nice Culumus bubbling up outside from my front door. Still fairly cloudy overall but sun appearing now and again.

squonk

I was just outside to get lunch. To me it seems too fresh today for any major potential... but I could be wrong (and probably am)

shamwari

Just looked at StormVue, its reporting some sferics in a trail from Dublin Bay head SSE. Just off Wicklow looks particularly active, however there is nothing on any of the online rainfall radars to substantiate this. Can anyone confirm if we have a storm just off the coast?

Snowbie

shamwari wrote: »

Just looked at StormVue, its reporting some sferics in a trail from Dublin Bay head SSE. Just off Wicklow looks particularly active, however there is nothing on any of the online rainfall radars to substantiate this. Can anyone confirm if we have a storm just off the coast?

No storm. In laymans terms, this happens when a particular storm (in this case now over SW UK) signature sky hops untill the detector tracks the storm accurately.(depends on the strength of the storm, the more stronger the quicker the accuracy) This happens with all single point lightning detectors.

shamwari

Snowbie wrote: »

No storm. In laymans terms, this happens when a particular storm (in this case now over SW UK) signature sky hops untill the detector tracks the storm accurately.(depends on the strength of the storm, the more stronger the quicker the accuracy) This happens with all single point lightning detectors.

Interesting...a lightning anaprop!

Snowbie

shamwari wrote: »

Interesting...a lightning anaprop!

Similar but not quite. Anaprop is a false doppler return whereas you can have a false lightning strike from local interference. But on this occasion the signal is detected but ranged incorrectly.

Snowbie

Thunderstorms over Wales again now but depending on the track of the LP to the SE and how fast it moves up through England will not spiral them into the Irish sea or they just might if the LP becomes stationary. Interesting next few hours.

rc28

We had a torrential downpour about an hour ago with a few rumbles of thunder.

Snowbie

Anvils clearly visible from the Wales storms from here.

force eleven

Plenty of cumulonimbus visible inland here, but mostly swift moving showery type clouds, its been a mainly dry bright and breezy afternoon here.
I'd be very interested to get some rainfall figures from Kerry/Cork, as Met Eireann radar has shown that front pivoting around Kerry, no let up in rain since last night.

TheGreenGiant

got a good storm there about 2 hours ago up here in trim co.meath.fork lightning actually hit a neighbors television mast! the whole house shock from the thunder.sky here looks very promising indeed for the rest of the day.radar shows it.hope to get a good video.pity i missed that strike earlier on in the day

Snowbie

Snowbie wrote: »

Anvils clearly visible from the Wales storms from here.

Yeah I can see a good line of them and cb's out over the sea.
Checked am radio there and it's going mad with crackles.

squonk

Hope the house wasn't damaged and nobody was injured. It was only when the electricity went after a near overhead strike last night and I was sitting there wondering what was going to happen with the next strike that I realised that fun and all as the fireworks are, there's a dangerous side to them too.

TheGreenGiant

indeed.the house looks ok. i'd say who ever was in it got a fright.the flash was very bright but the clap of thunder was insane! hope more storms brew up later.wales are getting a hard pelting with them!

shamwari

Latest from StormVue, it looks like the storm off the Welsh Coast has blown east over Anglesey.

TheGreenGiant

dammit was hoping for it to head across the Irish sea since the low pressure is swinging right around

TheGreenGiant

gud thing is there's a storm back in Trim:)

andrewie

Thunder and Lightning around Kells for the last half hour.

IRISH RAIL

Lot of action on storm vue around south donegal but would love to be in england even on a plane to birmingham

TheGreenGiant

lots of anvils and distant rumbles of thunder forming around the trim area.

highdef

The anvil above Meath as seen from my balcony in Santry can be seen in the photo section

rc28

I could hear a lot of thunder from a large anvil in Dunshaughlin direction about 20 mins ago.