Convective/Thunderstorm Discussion : Spring/Summer 2017

pad199207

GFS wants to push some welsh imports into leinster early tomorrow morning. Has also increased the potential for Eastern parts for tomorrow. Wicklow Mountains could set off some storms tomorrow evening.

Even though its all decent cape its still very low risk.

Oscar Bravo

an update from MT UPDATE on Isolated Thunderstorm Risk (1800h to 0300h and a second round tomorrow afternoon)
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A few showers that may contain brief thunderstorms will approach west Munster this evening and track northeast through parts of east Munster, south/central Leinster, the midlands and south Connacht overnight. Chances appear to be about 30% for isolated thunderstorm activity, so only a few locations are likely to see any lightning, but it can't be ruled out.

There is probably a somewhat better chance for thunderstorms to develop during the day tomorrow, when a cold front pushes east across the country late afternoon and early evening. There will be about a 40-50 per cent chance of thunderstorms breaking out ahead of and during this frontal passage, but it will be warmer than today in Leinster as winds veer back to the southwest eliminating the sea breeze that has kept it relatively pleasant today (in eastern counties that is, as the west has warmed up considerably due to today's easterly flow coming across the land).

Further updates may appear for more specific thunderstorm information as things develop later. Watch for some development across west Munster into south Galway this evening, and later on tonight, moving through central to inland southeast counties, with the best chance of seeing any activity, but it may not be intense so perhaps a couple of flashes of lightning and some sporadic rain as this moves in.

The heat will diminish in stages Thursday to Saturday and a much cooler, fresher interval is still expected from Sunday to the following weekend.

pad199207

Is that some interest I see near Cork City ?

Oscar Bravo

Sparks out to sea, south west of Bantry.

chris2007

Is Dublin included in seen any thunderstorms tomorrow?

Oscar Bravo

Belfast aldergrove forecasting thunderstorms overnight and pretty much all day tomorrow with very heavy downpours forecast also

squarecircles

continental style CAPE across the uk tomorrow,

glightning

Super annoying (as always). Why can it never be the reverse??? (Don't worry, I don't need an explanation as I'm aware of the mechanics lol)

Meteorite58

All the activity off the W / NW coast atm

glightning

How familiar is that activity? You know what's going to happen...
Storms fire well off shore to the W / NW as the trough initially engages the plume - activity tracks off NE towards far west Scotland.... Nothing else fires further east.
Large shield of cloud and muck tracks up over Ireland and gives either a few and zero sparks. Just disappointment...
Tomorrow then has max temps suppressed due to more extensive cloud than you would want with such a warm airmass. further disappointment...
Meanwhile, across the water the temperatures soar.... the streets melt.... the CAPE goes through the roof.... the lifted index through the floor.... then BOOM! 40,000ft CB's with overshooting tops, MCS (with possible embedded supercell), prolific lightning, and all this continuing well into the evening and overnight as it tracks NE.. Everyone gets to see the light show - nobody misses out. Unlike here!!!

Gaoth Laidir

Ignore the GFS in these situations. It's been consistently overheating on the CAPE, suggesting near 3000 J/kg over the UK tomorrow. The Arpege and Arome are much more realistic at about half that.

squarecircles

glightning wrote: »

How familiar is that activity? You know what's going to happen...
Storms fire well off shore to the W / NW as the trough initially engages the plume - activity tracks off NE towards far west Scotland.... Nothing else fires further east.
Large shield of cloud and muck tracks up over Ireland and gives either a few and zero sparks. Just disappointment...
Tomorrow then has max temps suppressed due to more extensive cloud than you would want with such a warm airmass. further disappointment...
Meanwhile, across the water the temperatures soar.... the streets melt.... the CAPE goes through the roof.... the lifted index through the floor.... then BOOM! 40,000ft CB's with overshooting tops, MCS (with possible embedded supercell), prolific lightning, and all this continuing well into the evening and overnight as it tracks NE.. Everyone gets to see the light show - nobody misses out. Unlike here!!!

the forecaster said on rte one,we cant rule out an odd rumble of thunder,
woop di bloody doo,the excitiment...spain is lit up like a christmas tree,as will the uk tomorrow,

Danno

Alot of will it/won't it - the models are chopping and changing with regards to TS activity, heck this extended warm spell wasn't forecast either - we were supposed to be back in the high teens today IIRC from the charts last week.

http://convectiveweather.co.uk/ has unusually left off tomorrow from their homepage. They usually update around 8pm, so keep an eye there.

glightning

I'll be amazed if all that cloud spilling over Ireland doesn't seriously suppress temperatures tomorrow. Some models only show maxes of 20c to 22c, whereas others go for upper twenties. Someone's got it wrong that for sure!

Danno

Big drops of rain here, light though, so far.

Meteorite58

Rain approaching Galway / Mayo Coast and the Kerry coast ( maybe a few sparks from that after it moves inland if it lasts of course , AROME cloud prediction shows sporadic Convection overnight into tomorrow.





Cloud seems to clear enough during the day to let temps build up, I'm siding with the HIRLAM




Warm 850hPa Temperatures as well

Meteorite58

Can see the line of convection off the W / N/W that is producing the latest sferics.

glightning

The view south from my location in County Antrim right now (towards Newry, Dundalk, Dublin)....
Appears to be mid level convection going on. Seems to be developing quickly too. It's now larger than it was when I took the photos a few minutes ago. One to watch...





MOD EDIT: resized and rotated pics

glightning

Sorry, don't know why they came out like that. Anyway, it's the white stuff to the right of the roof

redsteveireland

Looks like some active cells moving towards the Kerry coast.
Edit: last strikes were over 20 mins ago.

Cork Lass

Is it likely that we might get some lightning tonight on the south coast?

Reckless Abandonment

Radar coming alive over the north Midlands

Meteorite58

Cork Lass wrote: »

Is it likely that we might get some lightning tonight on the south coast?

A few more off the SW coast now, hard to know if they will come closer to the coasts but there is a slight chance I would think.

Rougies

Reckless Abandonment wrote: »

Radar coming alive over the north Midlands

Strange differences between Met E radar and Netweather/Raintoday

Met E have plenty of precip around the N. Midlands, and very little around Dublin/Wicklow/Kildare, while raintoday and netweather are showing almost the opposite.



Met E is more accurate for my area of Dublin anyway, bone dry here while netweather shows rain.

Meteorite58

A cluster of strikes on the Beara Peninsula just now.

glightning

I think there is a lot of anaprop showing up on the radar (i.e. false rainfall).
I must say however that skies to the west and south of here in South County Antrim continue to darken. Also interesting 'streams' in the clouds like you see with hail shafts. But, I don't actually know what it is to be honest. It's difficult to determine the vertical extent of any of them as they are elevated and the sky is covered enough to not be able to see tops.
However, the stuff I saw at a distance earlier to the south of here definitely appeared to be towers

Danno

Rainfall radar looks lively off the Kerry/Cork coast... a few strikes on our detector showing up from the region. The clump to the NW is some interference that I cannot find the source for.

Rougies

glightning wrote: »

I think there is a lot of anaprop showing up on the radar (i.e. false rainfall).
I must say however that skies to the west and south of here in South County Antrim continue to darken. Also interesting 'streams' in the clouds like you see with hail shafts. But, I don't actually know what it is to be honest. It's difficult to determine the vertical extent of any of them as they are elevated and the sky is covered enough to not be able to see tops.
However, the stuff I saw at a distance earlier to the south of here definitely appeared to be towers

Definitely a cluster of anaprop around NW Cavan alright.

Gaoth Laidir

The GFS is grossly exaggerating dewpoints and hence SBCAPE values. Comparing tomorrows GFS CAPE chart shows over 4000 J/kg over a wide area of England. The GFS sounding for the area with the red dot shows an unrealistic surface dewpoint of 24 °C. The ARPEGE sounding for the same location and time shows just 17 °C. The corresponding CAPE is a much more reasonable value of around 2000 J/kg.

I would totally ignore the GFS in this setup.

glightning

How do you interpret a skew-t diagram properly? I always have trouble understanding how to work out what level convection begins, what the level of free convection is, and what the cloud top height might be?

So how do you interpret these charts to determine if a storm  is possible??