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/
StrikestarEU
If anyone has any more feel free to post them.

Snowbie

Have been looking at this through the weekend for Monday and an interestng day to come again tomorrow Monday. It seems a wind convergence over the midlands could spark off some intense storms moving gradually ENE this time early on.
Wind flow will be coming in from the east and also from the west meeting over the midlands. Together with surface heating, the lift should be powerful to explode cells over a short time.
18z is not so generous with the lift but the convergence is shown clearly.

DOCARCH

Not much stirring (so far) today.

Clear blue sky with the exception of what appears to be a Cb in formation to the south-west of me - moving very slowly - but not in my direction.

Can be seen nicely developing - http://www.sat24.com/frame.php?html=view&country=gb

Snowbie

Yep very slow this morning. I can see the Cb over the mountains forming with also showers now breaking out through the midlands. Unless the predominant SW wind happens, everything will be pushed north instead of east.

nacho libre

the very northwest seems to be getting some action again today

Snowbie

Snowbie wrote: »

Have been looking at this through the weekend for Monday and an interestng day to come again tomorrow Monday. It seems a wind convergence over the midlands could spark off some intense storms moving gradually ENE this time early on.
Wind flow will be coming in from the east and also from the west meeting over the midlands. Together with surface heating, the lift should be powerful to explode cells over a short time.
18z is not so generous with the lift but the convergence is shown clearly.

As expected the wind convergence has happened just west of the midlands but much later than anticipated. What seems to be a developing squall line atm pushing ENE and then probably NNE later.

At this time Dublin could escape but as the front is moving in from the atlantic ,well ahead of this the squall seems to be developing nicely. How far south the line shall bulid determines if it reaches the east coast. Nowcasting from here on in.

kkontour

Good storm just passed over. About 10 seperate claps of thunder right overhead. Very heavy rain. lasted about 15minutes
Sligo

Danno

Where are you kkontour?

Weather BOFH

DOCARCH wrote: »

Clear blue sky with the exception of what appears to be a Cb in formation to the south-west of me - moving very slowly - but not in my direction.

Can be seen nicely developing - http://www.sat24.com/frame.php?html=view&country=gb

Been taking time lapse videos of everything since I got it set up!

I left it pointed out the window at this Cb building this morning and you can see the results here:

http://flickr.com/photos/nemonoid/2545772961/

nilhg

nemonoid wrote: »

Been taking time lapse videos of everything since I got it set up!

I left it pointed out the window at this Cb building this morning and you can see the results here:

http://flickr.com/photos/nemonoid/2545772961/

And after all that no rain.......

Cool video, well done.

Snowbie

Excellent vid again. Time lapse are brilliant. You can see and learn so much from them.

I was on Portmarnock beach this morning and early afternoon and had a good view of that same Cb (that wasn't) trying to build up. Convection was poor today even through the mountains with valley warming. A layer of upper warm air was the culprit. This cloud went on towards more favourable conditions over Meath and Cavan with a couple of strikes 6 hrs after it built over the mountains of Wicklow. Very slooow building Cb tbh.

DOCARCH

Great vid nemonoid - keep them coming!

Danno

Excellent video - that crow about 1/3 way in scared the sh1t out of me

DOCARCH

Thunder being reported at Knock and thunderstorms over Wales at present. Both seem to be being picked up fairly accuratley on the Snowbie detector.

Deep Easterly

Latest Hirlam run (18z) showing a lot of showers for Ireland tomorrow, hopfully some will bring a clap or 2..

Snowbie

Already some nice cumulus congestus floating about. Risk of a storm in the North midlands, risk moving towards the east later. Some beefy showers can be expected in these regions. View attach below.

Thunderstorm here for the last half hour.
At least 10 long loud claps at this stage.
The first bang I heard was in the Tesco car park in Arklow where it was lashing hail.

Several more en route out here where it is bone dry but you can see the lightning and hear the thunder.

I was talking on the mobile to MM who was listening to my thunder whilst describing another storm over greystones to the north.

Another big bang as I type.

skuzzb

One strike in North Dublin there, just out of the shower in time :eek:

Supercell

Can hear the odd rumble in the distance with one loud one, seem to be pretty localised looking at the radar.

Snowbie

The mother of all downpours here outside the job. Hail lightning and the lot.
It seems to be just side swiping where the station at home is.

There seems to be a mini trough hugging the coast.
The south east wind is dragging the storm back in from the sea.
Plenty rumbles from it,it doesnt want to go away.

Dogs are going mad.

Snowbie

That was a sweet downpour that has lasted over half an hour. Thunder still rumbling here too as i type.

Floods outside the back of the building here where i am today and only 4.3mm registered on AWS 1.5miles away. Hail must have clogged up the bucket or was bouncing out of it.
42.2mm/hr on the AWS but can tell you it would have been close to 100mm/hr or more where i am.

Trogdor

A few claps here earlier appearantly. Must've been from the cell over greystones BB mentioned

It might have been lighter at your home snowbie (though I wouldn't call 40mm/hr + "light") as down here there was a sharp fall off in the rain/hail once you moved inland.
None at all here,though plenty of banging from the storm over the town.
Driving out from Arklow,the road went dry 1 mile inland from the coast,we are 2 miles inland.

new storm approaching from the north now.
This is a more direct hit.
Saw two forks from this one as opposed to the cloud to cloud stuff in the last one.
Getting very loud and frequent now.

I'm also having power supply dips

Snowbie

Deleted User wrote: »

It might have been lighter at your home snowbie (though I wouldn't call 40mm/hr + "light") .

Too true.
Much more severe where i was and the longevity of it too. Torrents of water across the road, running off the pavements and just wet here as i got home and no sign of floods. Very localised.

I'm tracking that new storm down your way now.

About a strike a minute here.
Very very loud and over head.

I keep losing power and broadband during this.

This latest storm is very slow moving and building.
The rain is all around ity in narrow bands but only short bursts here.

Nearly half an hour of activity on this one now and countless strikes.

My sister has just told me the roads are rivers in Arklow town,just 1 mile east of here.
Very little rain here,just barely wet the ground.
The thunder is still banging though.

Supercell

Sounds great BB!, I'm very jealous , nothing here.

Deep Easterly

Some nice showers in Tuam today also, took this shot as I was driving outta town an hour ago to come to a much drier home:



Looking east as another shower built up. Only 1.0mm recorded here out the country. Hit 'n' miss types again..:rolleyes:

Gone quet now.
The shower is exiting out over Arklow Bay.

I rang MM again for some live reporting on that storm..I was standing out in the open looking up when a fork came down from an arc in the cloud in the field over head..making me stand on the big dogs tail further making him yelp with the jump I made.He wasn't leaving my side and had a funny look at me as If I was going to stop the thunder lol

Maybe not the safest thing to be doing

Mothman

Deleted User wrote: »

Gone quet now.
The shower is exiting out over Arklow Bay.

I rang MM again for some live reporting on that storm..I was standing out in the open looking up when a fork came down from an arc in the cloud in the field over head..making me stand on the big dogs tail further making him yelp with the jump I made.He wasn't leaving my side and had a funny look at me as If I was going to stop the thunder lol

Maybe not the safest thing to be doing

I got to hear more thunder today than in the last year...........almost all via BB's phone

DOCARCH

Managed a thundershower here (2 relatively loud claps of thunder) with 4.2mm of rain between 5.15 and 5.45pm. 6.0mm in total from showers to date today.

Weather BOFH

Absolutly nothing at all here, about 10 drops of rain in total!

As usual I took a time lapse which you can see here:

http://flickr.com/photos/nemonoid/2556208343/

Hal1

Ah yes, thats made my day now Feck all rain here today.

The tax man

Another nice time lapse vid nemonoid. Can I ask what the time interval between each shot is?

Weather BOFH

The tax man wrote: »

Can I ask what the time interval between each shot is?

Shots were taken every 5 seconds over around 3 hours 30 minutes and encoded to video at 50fps. I have to reduce the size (original is 2274x1704) as the resulting file is around 4-5GB. The upload to flickr then reduces the frame rate to 25 or 30 fps I think.

Hopefully there will be plenty more storms to capture over the summer

Snowbie

Monday afternoon looks likely to be turbulent again with the south and SE at high risk atm. A sea breeze front could be created close to the south coast overland with a wind convergence then later transfering into Wexford and Wicklow where lift will aid in developing some explosive development from the mtns.

pirelli

Loud thunder in Leinster over wicklow mountains SAT Night

Supercell

Whats up with the Irish radars?, show nothing currently yet there is a front tracking accross the country, and even with thunder it seems.

Any on the ground reports from the midlands ?

nilhg

Met Eireann radar shows front fizzling out over Cork, presently absolutely clear over West Kildare

Weather BOFH

Pretty much clear here too. Nothing of much interest on the satelite either, front breaking up over the west.

Danno

Scandy high is building, along with a splitting jet - one north and one south - taking place off west scotland.

Snowbie

pirelli wrote: »

Loud thunder in Leinster over wicklow mountains SAT Night

Nah, must have been something else.

ninebeanrows

Yea Danno, looks like winters finally arriving:eek:

Might not be too bad, cool, feeling warm in the sun kinda stuff with some nice convective activity

Danno

WC, Where have you been this long time?

Hal1

Cape seems good around the midlands later today maybe 300 J with small amount of lift.

Snowbie

Hal1 wrote: »

Cape seems good around the midlands later today maybe 300 J with small amount of lift.

Not great for development according to the 0Z on a widespread scale. But the air is indeed humid and with slight surface warming, a localised downpour might be triggered.Low risk atm.

CAPE not great but the trigger is there albeit slight.
Let you know what the 6Z brings, I think a slight upgrade

Danno

Currently 18.0c here. DP of 14.0c. Humidity of 78%. A bit of surface heating would spark one in those conditions.

Snowbie

Chance is Low of Ts activity today.

Tomorrow risk remains high in the same areas (SE) as i mentioned yesterday and GFS is consistent on that.
Convergence is still there but a little slighter today.
Air Temps upto 23C with Dp at 16C-18C
Rh 80-85%
Met.ie dont seem to agree and are going for dry warm and sunny. I beg to differ from the below attach atm.

Hal1

Those charts look significantly better for tomorrow. I was looking at the earlier chart here. Thanks for the update Snowbie.