Thunderstorms

Mothman

BB reported 5 loud claps during past 10 minutes, Wexford/Wicklow border. Moving out to sea now

Make that 6 ,5 of which were long and loud.
3 over head with almost instantaneous lightening.
Number 4 or 5 were just off the coast and the 6th one was out to sea and fainter.
Heavy sometimes medium sized hailstones throughout.
The whole thing lasted about 25 minutes or so.
It got very dark at the height of it and as it approached but the sun is out now.

Snowbie

DOCARCH wrote: »

Looks now like a more orgainsed line of heavy showers has formed from Waterford up to Sligo/Leitrim?

When i said organised i meant a proper convergence type squall line, its just seperate convective showers on radar.

CAPE is around 350j/kg over Dublin and a tad higher down in the SE and West at 400j/kg. LI is negative throughout the country. A weak storm cant be ruled out almost anywhere.

MM i say with the west wind aided by valley warming you can expect to see some heavy showers down there or possible storm. You be more favoured than here.

The storm here snowbie for a small cell was quite active.
It headed out into Arklow Bay.
Most of the active lightning that I observed was on the southern end of the wall of the shower and boy did it get dark on it's approach and during it.

Snowbie

Deleted User wrote: »

The storm here snowbie for a small cell was quite active.
It headed out into Arklow Bay.
Most of the active lightning that I observed was on the southern end of the wall of the shower and boy did it get dark on it's approach and during it.

Usually the best ones to observe BB.
A couple of rumbles here now also hail thrown in with a vicious looking sky overhead.

Mothman

Snowbie wrote: »

MM i say with the west wind aided by valley warming you can expect to see some heavy showers down there or possible storm. You be more favoured than here.

With the slightly north track, I may get north end of approaching shower that is to my SW

Theres a dark one approaching here now.It's cloud base is above 2000ft.It looks exactly like the last one here except theres no thunder (yet).
The thunder with the last one didn't start untill the hail did and I heard no thunder on it's approach either.
It's as if it had just started to get electrified.

I type too soon.
More booms just now.
This is turning out to be an interesting day!

Forked lightning.Constant noise.
Straight down into the field behind the house!
The dogs are going mad!

Now that DEFINITELY was an IMPRESSIVE storm.
A lot of forked lightning and constant long rolls of thunder with the lightning directly overhead.At one stage there was a line across the southern sky with a lot of twirl shaped forks coming out of it.
The storm has moved out to sea now just off the north co wexford coast.

I actually rang mothman during it and as he 'll confirm during our short conversation in between me yelping,he would have heard 3 long loud bangs!

Snowbie

Excellent BB,
I think i sussed out that ranging problem over the mountains with your location with that storm. I should be able to correct that now.

Mothman

Deleted User wrote: »

I actually rang mothman during it and as he 'll confirm during our short conversation in between me yelping,he would have heard 3 long loud bangs!

All south of me. Came out of the dark cloud I mentioned earlier and was willing to come a little north. Not a rumble here, except in my ear while on the phone to BB. 3 loud rumbles.

I sincerely hope all the cows are OK.

Dark cloud to my north west, looks like it'll pass north of me.

Villain

Some nice flashes of lighting in Tullow I hear, power was gone for an hour

Snowbie

Snowbie wrote: »

Excellent BB,
I think i sussed out that ranging problem over the mountains with your location with that storm. I should be able to correct that now.

Yeah I was looking at your detector page,it's got an awfull lot of strikes probably about 20 miles south or so of where they should be.The strikes looked pretty much an accurate reflection of what was going on over head here.Though thats just a guess from me, so forgive me as I was more interested in looking at the lightning and worrying about animals at the time as that was a severe one.
The storm was pretty fast moving though so as I wasn't clock watching.
I see I called mothman at around 450 near the end of the storm.

Mobhi1

Some rumbles here in Blackrock, Co. Dublin now.

darkman2

A couple of rumbles here - nothing too much. Some activity approaching from the west may reach Dublin this evening. Some impressive looking storms around the country atm especially across the South.

Snowbie

Here is your storm BB

Mothman

Snowbie wrote: »

Here is your storm BB

Both storms!

ninebeanrows

Vicious hailstorms encircling the city now.

The clouds look so intense and angry.

Some tasty looking storms to move through in the next few hours.

Paddy.1

Witnessed a funnel cloud develop over the small hills to the north of me 15 minutes ago, It seem to be approximatley over the Clonfad area just inside the Roscommon border. Tried to take a snap the the sky and lighting is very bad. Still heavy showers with no thunder to report in this spot. :rolleyes:

ninebeanrows

Severe looking clouds to my WNW at the minute,

Looks like its got some circulation as moving SE when it should be moving NNE

darkman2

Very dark here alright - no sign of any thunder or lightning as of yet.

ninebeanrows

Sky to my northwest is really something!

darkman2

rain/sleet here - temperature drop is quite something in the showers. No thunder or lightning.

ninebeanrows

Moderate hail here,

The week of hail tis been!

Snowbie

Yeah pitch black to the NW. Got the southern side of that with bits of hail.

Looking to the SW and there is a shower building over Kildare that is developing.
No Sfeics at all yet.

Mothman

Mothman wrote: »

Both storms!

Yeah the one an hour previous was steaming like the holyhead slow ferry,it hadnt got that far out the Irish sea according to snowbies screen grab.

All quiet here since except fo the loads of decaying anvils about and a big shower dissappearing to the SE that never got here.

All in all an eventfull afternoon!

Paddy.1

Deleted User wrote: »

Yeah the one an hour previous was steaming like the holyhead slow ferry,it hadnt got that far out the Irish sea according to snowbies screen grab.

All quiet here since except fo the loads of decaying anvils about and a big shower dissappearing to the SE that never got here.

All in all an eventfull afternoon!

So you hogged all the storms to yourself all day. How selfish of you. 2 in one day. Now that is just pure greed BB. I am now almost 3 months without a direct hit. We are talking famime here....

Supercell

Yep BB send those storms a bit northwards please!!

Snowbie

And quiet, zip, not a spark at all. But why?
Here is some useful or useless information if anyone is interested or not.

April showers Vs Summer storms whats the difference?

April showers or storms occur as residual winter cold from the north usually pools down from polar or polar maritime regions(ever hear the saying,air moves from a cold place to a warm place ie:sea breeze on a summers day, well this is similar but on a larger scale from PA or PM air down to more maritime regions)

So we have a cold airmass moving in from the W,NW or N and being April there is heat in the sun. So the sun gets to work on the land creating surface heating which rises, cools rapidly as there is cold air aloft creating instability(lapse rates) and forms cumuli clouds.
As the air cools quickly due to a lower to the surface freezing level, the air is supercooled as it travels up through the clouds(up drafts) creating hail more quicker than in summer due to the lower 0c level.

Now the creation of lightning is due to ice.To simply put it, friction and static charge builds up and discharges creating lightning, thunder is the air expanding as lightning is over 30,000c and travels at 186,000miles a second.

So why does the thunder and lightning stop when the sun goes down?
The power of the sun on surface warming ceases and the cumuli clouds lose their updraft(convection) and basically distintergrate from the bottom up and your left with high level cirrus(ex anvil) or alto cirrus depending on the cumuli cloud.

So why do showers keep going over the sea?
The sea doesnt regulate the temperature of the air above it as much as the land. So warm air can be present over sea and the instability regenerates again.

This is a decaying shower that produced lightning in Carlow now over Wicklow at 1955(just left of top of pic or west of wicklow head)



Now this is the same shower at 2140 over the Irish sea(top right)



So why do summer storms continue into the night after the sun goes down?

Nocturnal cooling of the Anvil on top of the Cb cloud is in a layer of deep cold air of -40c and below(remember the ice for lightning creation), while at the surface the left over warmth of a summers day is still providing a warm updraft of air fueling the storm.The difference between surface to the Anvil can be 60 to 70c in summer during the day.
But the freezing level is much much higher so hail can melt before hitting the ground and or evaporate just like rain in a warm dry level under the storm known as virga.

Very rare in Ireland, a multicellular system(MCS) can form from downdrafts from the parent cloud to form seperate cells that join in force, these would later have the characteristics of a supacell.

Summer storms in Ireland are mostly of the homegrown type, very rare we get imports here but sometimes an active cold front is moving in from the west and advects warm air ahead of it and creates a squall line with continuous lightning for several hours on end. [thread=296970]Eg1985[/thread]

Danno

Excellent analysis there Snowbie! One for the Weather Education Thread that will be created [suggestion] :D