Thunderstorm/Convective Watch: Summer 2010

Deep Easterly

"So musical a discord, such sweet thunder"
-William Shakespear



Summer is here, so natuarally all eyes and other sensory organs will be homed in on potential pulses, plumes, embeddeds and homegrowns over the next 3 months!


Summer thunder in Ireland.

Not the most reliable or constant weather type in Ireland at the best of times, but chances of thunderstorms do increase during the summer due to the increased heating of the land and atmosphere.

At this time of year, inland areas will warm up quicker that coastal areas which is more likely to trigger off convection overland under the right conditions. According the the met eireann "Climate Averages & Extremes", Midland stations have the highest number of thunder days during the summer months within the 61-90 series. Here are the stats from the various met eireann stations in chart form:





Storms can vary is degrees of intensity over Ireland, although in the main, storms tend to be shortlived. Some showers may bring only a few claps and rumbles while others can bring a lot more. Normal daytime convective showers under slack conditions tend to be a lot less violent than storms that are contained within frontal zones and plumes that can sometimes make their way up to us from the Bay of Biscay or the Continent, which unfortuently is a much less common occurrance than the former. Having said that, homegrowns tend to be much stronger when they are spurred on by a southerly based airflow rather than from a polar maritime sourced flow.

But because this is Ireland, there will always be exceptions to the these fragile rules :)

Heavy rain/hail is nearly always associated with summer thunderstorms over the country, but falls can be very localised with often huge variations in rainfall totals even within the space of a mile or two. Anyone driving through a stormy area will often see the road going from dry to flooded to dry again over a very short distance.


Here are the UK Met Office's convective rainfall rate intensity guide: (in milimetres and inches)

0.1mm to 2.0mm per hour (up to 1/12 in) = Slight.
2.0mm to 10mm per hour (1/12in to 5/12in) = Moderate.
10.0mm to 50.0mm per hour (5/12 in to 2.0 in) = Heavy.
50.0mm + (2.0 in +) = Violent


Nothing to wet the appetite regarding thunder potential on the model outlooks today, although the ECM seems keen to set us up under a slack low pressure area as we move into next week, but all very uncertain at this stage.

Latest forecast:






Please post reports of thunder, or thunder/convective potential that may occur thoughout the summer season here, and enjoy any storms ye may be lucky enough to caught under.

wild handlin

Great job DE,

Lets hope Fermanagh gets a storm or two between now and August, had nothing here since 2009 - although did observe lightning over Donegal/Sligo during the "big freeze" in January 2010!!

paulhac

Thanks Patrick excellent post. I hope to see this thread on fire at some stage during the summer!

wild handlin

Right all,

We have a band of rain pushing in from the west, just visible from the Met Eireann radar now.

Any ideas if this could produce some thunder/lightning? It's pretty muggy here in Enniskillen at the moment...

Su Campu

wild handlin wrote: »

Right all,

We have a band of rain pushing in from the west, just visible from the Met Eireann radar now.

Any ideas if this could produce some thunder/lightning? It's pretty muggy here in Enniskillen at the moment...

I'd say there is a small chance, but it's just arrived at the wrong time (either too late for today or too early for tomorrow). While the surface front is dissipating as it moves northeastward, there is an upper vort max which may sustain convection along and behind the frontal boundary. If there was solar heating present we could be looking at a decent system, but with a cooling landmass after dark, low-level lift will be absent. But upper level cooling will take place overnight, and will be in place to allow some showers to get going with the heat of the day tomorrow.

Deep Easterly

Thunder or nay, tis certainly a seductive, sultry feeling evening out there. Everything is alive!

wild handlin

Cheers guys, will have to see what tomorrow brings!! Here's hoping!!

Min

Looks like there should be some thunderstorms today.

Last summer it was like 'oh another thunderstorm...'

Su Campu

The chance has passed for today. The small upper trough is reaching northern parts of the country now, setting off some convection and light showers in the northwest (including Eniskillen), but upper warming behind it will cause this convection to die out later.

Deep Easterly

Looks like we will be stuck under a col type set up for the weekend, which is not bad for convective activity at this time of year.

Tomorrow is looking increasingly intersting. General forecast seem to be for a weak showery trough to approach the west coast later tonight into tomorrow morning which is expected to hover in or around western areas during the first half of the day, always giving the risk of the odd heavy shower.

This shower trough is forecast to start pushing eastwards from mid-afternoon onwards and meet up with a developing trough that is forecast to push up towards southern and eastern Ireland towards the late afternoon or early evening. Heavy, slow moving showers over parts of east Munster, many parts of Leinster esp, seems to be a high possibility as these two areas of instability merge as we move into tomorrow night. I'd not rule out the odd rumble either.

Forecast chart for 18hrs tomorrow:



Could be more a nowcast situation though.


Sunday also seems to present a risk of showers as a slack and moderately unstable NW airflow becomes established over Ireland:

Forecast streams for Sunday afternoon:



Ulster and leinster most at risk it would seem from this early stage.



Chart source: http://www.meteoblue.com/en_GB/maps/advanced/europe

Takeshi_Kovacs

I do like a good thunderstorm, hopefully there will be a few passing showers this summer, until then , will have to make do with listening to some on the internets..

https://www.youtube.com/watch?v=pJN7Eo3vTt4

Su Campu

The 06Z Valentia sounding gives a deep convective temperature of around 17-18°C, so with temperatures now hitting that value around the country we should see some cumulonimbus kick off in the next hour and the radar should spring to life!

fryup

fairly humid today, should see some activity tonight

wild handlin

Lets hope so!!

Fairly dull here in Enniskillen at present, with a gentle cool breeze blowing from the N/NW

glossy

Su Campu wrote: »

The 06Z Valentia sounding gives a deep convective temperature of around 17-18°C, so with temperatures now hitting that value around the country we should see some cumulonimbus kick off in the next hour and the radar should spring to life!

:D:D hope we get someting on this side of the world

Trogdor

Fairly heavy shower here at the moment, good summery feeling to the rain:)

EDIT: Rainrate peaked at 29.5mm/hr and dropped 2mm in the 7 or 8 mins

wild handlin

Lightning radar has picked up 3 strikes in the past 30 mins or so. 1 over the Dungannon area and the other two on the Northern Fermanagh/South Donegal border, and the third nr. Donegal town.

By looks of the radar I wouldn't be surprised if the strikes were actually L.Neagh, and Dungannon and Cookstown, as these 3 "storms" seem to be the most active looking at the radar here.

The looks of some Convection could be seen which started in the past 2 hours or so (looking north from Enniskillen) but has since died out, with it not quite reaching the 'anvil' stage yet. This could well be the weak system which is currently over Castlederg.

owenc

wild handlin wrote: »

Lightning radar has picked up 3 strikes in the past 30 mins or so. 1 over the Dungannon area and the other two on the Northern Fermanagh/South Donegal border, and the third nr. Donegal town.

By looks of the radar I wouldn't be surprised if the strikes were actually L.Neagh, and Dungannon and Cookstown, as these 3 "storms" seem to be the most active looking at the radar here.

The looks of some Convection could be seen which started in the past 2 hours or so (looking north from Enniskillen) but has since died out, with it not quite reaching the 'anvil' stage yet. This could well be the weak system which is currently over Castlederg.

Yes there is a big black cloud to the south of me, i hope it intensifies and covers me, i havne't seen thunder in ages, weres this lightning radar.

Sierra Oscar

There is a very very dirty looking black sky coming in my direction now from the north west!!

owenc

Theres one forming right over me now. But i think its heading east past me.

Su Campu

Amazing active thundery cell south of Lough Neagh right now while the rest of the island is pretty quiet! :mad: Upper temperatures needed to be just one or two degees colder this afternoon and we might have seen more of this. I'd say this one's formation could be linked to convergence off the Lough, a pseudo seabreeze.

Su Campu

Rain rates have increased in northern Cork/southern Limerick in the last hour as the cell in the north has weakened. Belfast Aldergrove reporting light rain at 2120UTC

[FONT=Monospace,Courier]EGAA 052120Z 32006KT 9999 -RA BKN035 14/10 Q1017[/FONT]

wild handlin

Is this the start of the "front" moving in from the West Su Campu, or is this the sytem?? (streching from Belfast - Killarney?)

Deep Easterly

Got quite threatening looking here earlier on tonight but as usual, sweet fanny adams :rolleyes:. Nice evening out though.

Oscar Bravo

Likewise,very dark/black at times here this evening but nothing.from the met forecasts earlier today the forecast suggested there would be a good deal of thundery showers overnight but not lookin like it now!

Danno

Anyone around Limerick observing a few lightning strikes? My detector is picking up an odd few srtikes near there...

Sierra Oscar

Danno wrote: »

Anyone around Limerick observing a few lightning strikes? My detector is picking up an odd few srtikes near there...

I am on the North Tipp/Limerick border . . . no sign of any lightning as far as I can tell, but there is heavy rain.

Deep Easterly

Quite angry looking sky here at the mo. A couple of very short, sharp bursts in the last 15mins but best of the stuff seems to be skirting just to the north of town. Some builiding cumulus to the west also so hopefully that will explode before it passes completetly.

ch750536

Lovely out, no wind, no rain, enough clod but no threat of rain, has been dry all day

thetonynator

Just came back from Biarritz today.

From about 9 p.m. last night to 10 a.m. this morning there was a lot of lightning on its own, and some thunder and lightning. It didn't form properly into fork lightning, more just flashes accross the whole sky. Lasted all night though.

Deep Easterly

Some isolated stikes in the south over the last hour:




Radar shot:



Those showers could last well into this evening.