Thunderstorms and Convective Potential

rc28

Torrential downpour now.

ch750536

http://www.metoffice.gov.uk/weather/uk/radar/index.html



Rarely see red there, looks like the Rathkeale reports may be correct.

Hal1

Malin Head reporting rain/thunder, thats the first report I've seen on met.ie today of storm related activty, it must be near the station. Drizzly here moderate at times, feels really heavy in the air.

Sierra Oscar

There are some astonishing black clouds coming our way from Limerick City at the moment.

nacho libre

I've been taking some pictures of what looks to be a developing thunderstorm to the west of me. These cb clouds are impressive!

Snowbie

Snowbie wrote: »

This is it BB i dunno. Mentioned myself earlier of a threat to the S and SE from the 06Z but i don't see anything as yet to pose a risk to the rest of the country. Havin looked at 12Z yet.

This is the thing that annoys me about met.ie lately.
Their sheer guesswork.
the amount of times they chop and change on the same day (I wouldn't mind if they changed 24-36hrs and stuck to that change)
We are doing a better job with all due respect and we are amateurs/enthusiasts.

Anyhow...now they've had a look out the window and at the radar... :rolleyes:

They say the following "Further heavy or thundery showers tonight, with all areas at risk. Lowest temperatures 9 to 12 degrees, with some mist or fog developing." No mention of where it's spreading from..

ch750536

Sierra Oscar wrote: »

There are some astonishing black clouds coming our way from Limerick City at the moment.

Was looking at that during dinner. Very imposing, very black.

nacho libre

False alarm on that developing thunderstorm.:o All there was out of it was a downpour.

Are these thundery showers that are forecast for tonight spreading across the country from the South East? Or has that weather forecast now changed?

Hal1

Just had a look at the forecast from Estofex.

"Latest GFS and WRF indicate quite strong instability in the range of the trough axis due to daytime heating, and showers and thunderstorms are forecast to form. Given weak vertical wind shear, some spouts :eek: may form especially over Ireland during the day."

Tomorrow could be our day in the east.

Supercell

Hoping so, am off work tomorrow and am gonna go chasing i think:)

Snowbie

From the 12Z output, the vertical wind shear speed is very weak at 3 m/s.

A bit better than today in terms of directional shear to tilt a storm but with little vertical speed shear, no severe storms.

Cape and LI pretty much same as today.

Cloud cover put a dampner on todays convection with the upper trough pepping up the showers only. With no convection it just didnt get that final push.Orographic lift played it's part in building congestus.
High level cirrus moving up from the south and with the unstable air with convective cloud meant that no sun could heat our land sufficiently enough to build widespread Cb's.

Tomorrow should be a bit clearer.

Cbstar

Met have to account for the whole country which is far more difficult than small areas

StratoQ

Good TS over Kilkenny City now. Went for a walk about 10 mins before hand but quickly ran back when I saw what was about to arrive!

Several stikes and some very intense rain (My rain gauge logged intensity at 136mm/hr).

Seems to be heading slowly north. You shud be next Danno!

Snowbie

Speaking to Danno now on MSN and he stays "looks like its between ballyragget and freshford"

Danno

One fork lightning here a few minutes ago.

Danno

Watched it from the attic velux. I thought it would fire up when it hit the east nore valley - the ridge from Ballinakill to Jenkinstown. Nothing still.

Danno

StratoQ wrote: »

Good TS over Kilkenny City now. Went for a walk about 10 mins before hand but quickly ran back when I saw what was about to arrive!

Several stikes and some very intense rain (My rain gauge logged intensity at 136mm/hr).

Seems to be heading slowly north. You shud be next Danno!

Hmmm, looked close enough to me here, but then again it was getting a bit darker. The edge of the rainfall area just clipped me here and headed more towards Castlecomer.

StratoQ

Well, Danno. I can vouch for the accuracy of your lightning detector anyway. The 10pm strike here (green triangle) was spot on. Green I take it means "negative"?

Snowbie

Another upper level trough will cross Ireland early on in the morning, once again.Showers from the word go through the south and SW will become widespread.
Depending on cloud cover, surface heating(if sun is out) will enhance convection and allow cloud tops to build up high. In any case slow moving heavy showers can be expected throughout the country but the south midlands and later east and north are at risk of a storm or two.
Showers subsiding by mid evening.

Although vertical and directional wind shear is slightly stronger than Wednesday, it is still very weak so storms be weak pulse type in nature.

Attach:Cape(SB and ML) LI and instability again favourable for hefty showers.

Storm risk a cautious 50%
Convective rain across the region at 15Z

Danno

StratoQ wrote: »

Well, Danno. I can vouch for the accuracy of your lightning detector anyway. The 10pm strike here (green triangle) was spot on. Green I take it means "negative"?

Negative intra-cloud. Good to hear that! Myself and Snowbie were concerned about the angle of placement one night. I made an educated guess for 175 degrees south, later a compass backed it up as 170. So we re-adjusted it and accuracy seems quite good since.

Mind you the further away storms are the more relevant the degrees become.

Snowbie

Attach are cloud cover across the region.

Wind shear speeds which are low and is an important ingredient for severe storms.

Atmospheric winds at different heights

Surface overview displaying Temp RH and DP. Depending on cloud cover, the surface temp will be affected. Otherwise borderline for storm development.

Snowbie

Still the threat also tonight for the south coast and SE where there are heavy showers in the Celtic sea. They are moving north and then west and in the last half hour, north again. A couple of strikes from them too.

Danno

I spy with my little eye something heading for Wexford... http://sat24.com/frame.php?html=view&country=gb

Deep Easterly

Nothing thunderwise this side, although plenty of shortlived "mircrobursts" as BB calls them on and of all day. Could see some pretty impressive cloudscapes towards the west midlands this evening driving back from Claremorris looking blood red in the setting sun. Beautiful.

Total of 3.2mm recorded today, more than I was expecting.

forkassed

Deleted User wrote: »

On what are the Met basing their forecast of heavy showers and thunderstorms moving up from the south east tonight?

I have no clue how the met predict this stuff but it doesnt look like a bad forecast judging by the radar

http://www.metoffice.gov.uk/weather/uk/radar/index.html

Snowbie

Lightning out on the Irish sea. I say somewhere along the east coast will see some in the next while in that clump. Sat pics has embedded CB's within it.

http://www.sat24.com/frame.php?html=view&country=gb&sat=vis

rc28

Very heavy rain for most of the morning here but it's now a complete downpour. Is Fridays/Saturdays rain still on?

Snowbie

rc28 wrote: »

Is Fridays/Saturdays rain still on?

Atm yes.

With deep cloud cover here in the east from that surface LP, convection atm is woeful here.

The SW W and NW have showers there getting heavier.
If that clump moves on northwards the sun will get to work on the ground and showers will break out in the south and east.

Orchard Rebel

Recent thunderstorm down here south of Cork City. Several bolts of sheet lightning followed by moderate thunderclaps and a brief downpour to finish. Temp 15.8.c and dropping I think.

Sat up in my attic office watching the storm pass. Love the conditions after a storm.

Edit @ 14:10 - second thundery downpour underway.

Edit @ 14:35 - a third very heavy fall has now begun - the previous one lasted 15 mins or so. Looks like a succession of heavy showers is passing west to east over Cork right now.

Snowbie

Looking at the Satpic over the last hour and some CBs have formed over the Celtic sea moving towards the Cork and Kerry coastlines. GFS picks it up with some energy(CAPE) and instability from 18Z output.

http://www.sat24.com/frame.php?html=view&country=gb

EDIT: Just added the ML Cape and Theta wet bulb temps, there seems to be more energy in the midlevels suggesting more humid air in that region. Also are elevated. Some quite heavy showers are likely if they make it onshore.