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Hail Storm, Thunder & Gust Front - April 11th 2008

I'm delighted to say that the 2008 thunderstorm season in the UK has began!. This was the third day in a row which thundery activity had been forecast. So far, the Republic of Ireland and Britain had been getting the very best action with several funnel cloud reports, a possible tornado, and wide spread observations of giant cells, gust fronts, mammatus, and lightning. On the 10th from Maghera no thunderstorms were observed although we did see a beautiful gust front at sunset which made the day a success. On the 12th my friend John McConnell from Magheraberry, N. Ireland got a good brief thunderstorm which produced several cloud to ground (c-g) bolts. However, back to the 11th from Maghera. The day looked promising with plenty of turkey towers bubbling up developing anvils and combined with the intense ground heating it was only a matter of time before something kicked off. After a long photo session in the country I returned home and checked the sferics websites. I was delighted to see a line of lightning activity to the west of me stretching from N. Ireland, across the border, and into the Republic. Considering that the storms where moving very slowly in from the SW I felt pretty sure I would see something. Now it was time to stop looking at a computer screen and get outside. I decided to walk up to the 'site' near my home at Willow Glynn where there was a good vantage point. I just wanted to survey the sky and make a plan of action but once I glanced at the sky I knew it was already too late to relocate to a better location because the storm was already here!.

I knew the moment I seen this structure that there would be action. This is facing south towards Slieve Gallion mountain. Stretching across the sky from SW (R) to NE (L) was this very dark cell with a long silver hail curtain. Even though the system was moving slow it did seem to creep over a substantial distance in a very subtle manner. The area from the outskirts of Maghera to near the bottom of the mountain are probably getting battered by hail at this moment in time.

It was at this moment that I heard a very loud rumble of thunder!. (the video starts from this moment). There has been lots of t-storm activity in Ireland lately and despite seeing amazing convective cells for months on end I haven't actually heard a rumble of thunder since July 2007 so hearing this got my adrenaline pumping. I felt like a child hearing thunder for the first time. I never seen any lightning so it must have been of the intra-cloud (IC) type as I'm sure I wouldn't have missed a c-g. That hail curtain is getting quite severe now. The 'burnt out' region to the right is not a gap or cut off point to the hail. The curtain extends to the right out of frame for a considerable distance but bright sunlight caused this area to overexpose. That's a very well defined dark updraught base to the right. I kept an eye on it incase a funnel formed.

This is a more natural exposure showing how dark the storm cell was. Excellent structure within the hail curtain below. Strong wind shear meant that updraught/downdraught separation was well defined allowing for a long duration updraught to develop. Unknown to me at the time, this storm was forming large hail.

The hail is getting closer, bigger, with much more dense shafts. The outskirts of Maghera is definitely feeling this now. You can tell the hail is falling between me and the mountain. The tower to the left belongs to a local bakery.

A few minutes later it got much worse as the storm got closer. Look how dense those hail curtains are now. I would say the hail was of a decent size already.

Feeling the first few hit my head and sensing that things were going to get nasty I retreated home. Then it was like a switch had been flicked and all hell let loose. From the kitchen I heard a sound which reminded me of a hand full of pebble dash being thrown against the windows and roof tiles. I opened the back door and stood within the frame and watched as a full blown hail storm occurred straight above my home. It was not the speed which got my attention but the size of the hail stones. At first they were as large as frozen peas then after minutes it got even worse as they grew to the size of marbles. I heard a non stop 'pinging' and 'clanging' sound as the stones hit everything around me. Looking up into the NE I could see a section of the cell and the tremendous hail core which looked stunning. To the lower left of there was a clear slot where a section of blue sky could be seen, it was here that I was amazed to see the large icy stones falling through the air without any difficulty. I had never seen such a big hail storm like this from here in all my life. There must have been very decent convection and updaughts taking place within the cell to keep these stones suspended within the cell in order to accumulate more ice and produce these bigger stones. I have been up close to plenty of hail showers during the Winter and I could easily see the cool looking mottled texture of the hail within the falling sheets but never before had I seen something like this!. Another loud rumble of thunder ripped through the heavens which I actually caught on the video footage below.

I quickly ran into the back garden and got a few snaps of the hail on the garden. Some of the stones are well formed but the larger ones seemed to have three or four stones merged together. There must have been serious updaughts within this cell. I was getting really hurt. The stones whacked off my head and arms so I ran back to the safety of the back door where I resumed taking video. You can here me making strange noises due to the large hail hitting me from even inside the door. I looked out the front window and could see the hail bouncing back off the ground to a height level with the bonnet of our car. I felt sorry for anyone who was caught out in the open under this severe hail storm. Conor Mc Donald was watching the storm with just as much excitement as I was. We had a quick phone call during the fall then decided to hang up and get some images.

The storm went on for at least 15 minutes then it began to slow over my location and sensing that the slow moving cell was drifting away I decided to run up the road to my original location at the site. Facing east I could see the storm retreating. The tilted base on the left and monster hail core to the right was breathtaking!. This is facing NE. Willow Glynn is to the lower left and Crewe Drive to the right. There was still a few stones bouncing off my camera lens and LCD screen as I took this and my head was quite sore. I actually had a migraine all night after this. The stones melted pretty quickly, however along the sides of the path sheltered from the Sun I could see hail drifts which looked like snow. Here the stones where still visible 30 min's after the storm. At this stage I text John McConnell to inform him that there was a monster hail storm heading his way. He never did get it as I suspected the storm moved further north from his position.

This was taken with a slighter longer exposure to pick up the white colour of the hail. I love the tilted cloud collar above the core.

About 20 minutes later Conor Mc Donald appeared and together we watched as the storm retreated at a very slow speed. This image was taken a good half hour after the event at my home and it was still visible. To the lower right of the hail core you can see a long horizontal ridge of cloud with a fold on bottom above the distance rooftops. I believe we were looking at the underside of a shelf/gust front from behind as it moved forward. Conor and I had a very excited chat as we talked about our own experiences with the large hail. This must have been the same event which turned the roads white near Tobermore earlier so overall we reckon this hail storm was active for at least one hour which is some feat for this country. This was without doubt the most spectacular hail storm we had ever seen. It was exciting stuff!.

We relocated to a hill in the same area and realized the show was not over. Looking to the SW we could see this huge gust front with stacked shelf showing nice structure heading towards us. You can see the curved edge to it.

A little later with a brighter exposure. That looks to be a dense hail core over Slieve Gallion. Some scud beginning to dance along the edge of the shelf.

It looks like Maghera was in the firing line. We decided to stay and watch what it did. The gust front actually passed to the left of us so we missed the hail core however on the western side where we stood the sky turned dark grey and showers began. We decided to call it a day and went home. The rain never stopped for hours, it was only as the sky got dark (after sunset) that it began to stop!. I consider this a very memorable day. I got my first brief thunderstorm of the season and I experienced my largest hail storm to date. My instincts are telling me that we are in for some great thunderstorms this Summer!.

This is the YouTube video I made. It's 7 min's 12 sec's in duration. It begins from the site just after I heard the first rumble of thunder. You can see the dark cell and hail curtains approaching. Then it moves to my back door where the hail storm takes place. Turn your volume up loud for the full effect. You can hear a rumble of thunder at 1 min 17 sec's. After this you can see the large black stones falling from the sky to the centre and right. Give the the video time to run because the best hail takes place from 2 min's 36 sec's onwards. You can hear the rumble of our washing machine in the background. My mum can be heard near the end as we call our dogs over to see the hail. They never went out the door that's for sure!. The video then moves back to the site where you can see the retreating hail core then there's a short clip showing the gust front, Conor was with me at this time. I have added a few still images at the end. I hope you enjoy it.


Martin McKenna

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