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This is short image report documenting two days of nice convection over Maghera, N. Ireland. The forecast was the same for both the 28th and 29th of April. Wide spread convection with a risk of thunderstorms. There was enough instability however the wind shear was weak so all we could expect was single or multicell pulse type storms which I was happy enough with. On both days the weather was pretty much the same with hot sunshine and diurnal driven convection. I will start with the 28th.
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The main highlight of the day was this beautiful cumulonimbus with wonderful wispy anvil slightly sheared in the direction of travel. This was the dominant cell in a line of multicells. The cell was many miles away above the northern horizon so must have been of tremendous size and contain very strong updraughts. You can see other anvils to the L and R of frame. The cell was moving extremely slowly to the R (NE). This was captured from the countryside.
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Mid level cloud and velum began to obscure the mid and high regions of the cell however the base was still visible. As I watched this abrupt lowering descended from the cell base under the main updraught area. It looked for all the world to me like a wall cloud. Persistent wall clouds can produce tornadoes, especially if they are rotating. I couldn't see any obvious rotation here due to the distance involved however the lowering did change shape in a regular fashion. You can see precip curtains behind the lowering and to the right. The main precip area is to the left which made me very suspicious. An expert suggested to me that this 'could' be the edge of a gust front observed from an oblique viewing angle giving the appearance of a wall cloud. I was told that a good rule of thumb is that the lowest part of a wall cloud will lean towards the area of most intense precip, however a gust front will lean towards the area of least precip (inflow and outflow features). If this is the case then this might be a gust front, however I observed it for one hour easily and it looked like a wall cloud to me. If you know your subject and can tell me in no uncertain terms which is correct, then please contact me.
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Zooming in for a closer look. At a first glance that feature on the ground looks like a tornado forming from the ground up into the wall cloud with no condensation funnel. It looked more brown with the naked eye so I could tell that it was smoke rising into the sky. It's location under the lowering was an exciting coincidence.
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Full zoom here. You can see that this is definitely smoke. Pity there wasn't a tornado, I would have had a perfect view of it. I took many more images during the afternoon but these are my favourite.
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There was plenty of sferics over Ireland and N. Ireland but none seemed to happen in my area. During the late evening my Uncle asked me to do some photography for him so I was on the road with my family heading to the base of Slieve Gallion to spend a couple of pleasant hours taking images of Geese, Ducks, Chickens, Herons, Robins and dogs. This image was taken through the rear car window on the Tobermore road looking N. This was a big dark chunky cell with looked like a storm brewing, it produced heavy precip but didn't become electrified. I really liked its menacing form though. It later produced a mammatus display.
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Now on to the late morning of the 29th. Taken from a country road just E off the Coleraine road and looking E. Unlike yesterday when the cells approached from the SW, today they where arriving from the E due to a rotating low pressure system in the NW Atlantic Ocean which had been producing fronts and troughs bringing showers and thunderstorms for the last three days in a row. This cell had 'the look'. It was slow moving, dark, with a well defined updraught base which indicated some early unexpected shear. It sported this nice precip core which produced long duration rain and small hail. I felt sure I was going to get lightning at any moment so I took many images and video clips hoping to catch my first bolt of the year. After a long time the cell decided to behave itself and quietly crept over the Sperrin Mountains making me feel disappointed. I still liked this image though.
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The early afternoon was a very hot affair with strong sunshine. There was plenty of fabulous convective towers with crisp tops firing up forming cbs with mainly soft cirrus tops. The highlight was this cell miles away in the NE with a small overshooting top which was visible for a long period of time. I watched this cell for hours. It's moving toward me here and to the left. Overshooting tops (OSTs) indicate extremely strong updraughts which punch through the top of the flat anvil. If the OST is short lived or rises and falls and rises again then this indicates a pulse type storm which can produce brief periods of severe weather such as strong wind gusts, heavy hail, lightning and even tornadoes. An OST which persists for longer than 10 or 15 min's is certainly a danger warning. This will indicate a high chance of sustained severe weather and powerful tornadoes and may even indicate that you are in the presence of supercell.
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This at 17.30 BST on the same day. I'm in the town of Maghera now looking S towards the bank. The entrance to St. Patrick's College is to my left. I wanted to catch this nice anvil crossing over my home town. It's moving R to L with nice striations on the anvil. It also had nice well formed white mammatus under the down wind side of the anvil and a flanking line of towers behind.
Back at home I logged onto the UKWW and checked the recent convective reports. I was shocked to read that someone had seen two funnel clouds over Lough Neagh 20 min's ago which worked out to be just after 18.00 BST. I couldn't believe it, my view in this direction was blocked by Slieve Gallion so I missed it. I checked the sferics and rainfall charts which confirmed the activity in this area. There was lightning above and near the Lough at this time and the satellite images showed a number of big cells. The BBC news line weather forecast on televison mentioned the 'beefy showers' in that area. The sferics showed a ling of c-g and I-c lightning on the E coast of Scotland. The wind direction had veered and was now heading from the NE so some of this action could come in this direction.
Conor Mc Donald had been following the events also and rang me. We decided to go on a chase in a SEly direction to see if we could catch anything. By 19.00 we where on the road. We picked up Christina (Conor's girlfriend) and decided to head for Slieve Gallion. During our speedy drive up the twisting country roads we spotted a number of cells a great distance away. One of them was a complete monster with a wide girth and bulging updraught. It also had a sinister black vertical tower to its rear exploding upwards with convection. We got quite excited by what we saw and couldn't wait to get to the mountain top!. We lost it from view for a period due to the tall hedgerows zooming past but during brief clear sections I saw a superb overshooting top (the 2nd of the day!) to the rear of the main updraught area. This was the best dome I had seen to date. It pulsed up and down then formed two domes which seemed to rise and fall quickly so this was a pulse storm and we felt sure it was a good candidate for a funnel or tornado. I couldn't get any still images of these domes however if you have a keen eye and patience you will spot them on the video clip.
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This was the view from the top of Slieve Gallion looking S. It was cold and windy up here despite being calm and warm on the ground. Here's the cell which caused all the fuss. It still has a hint of a small OST to the L. Note the dark tower in shadow. I took many images of this but one is only needed here. There was a long anvil to the right out of frame and a new young line of convection to the L. Those dark horizontal strands are Velum. It was a real challenge to get images due to the distance involved. This was a big object in the sky and an incredible distance from us so it must have been a sobering sight from 'ground zero'. I'm amazed that no one else in that area took images of this cell, at least I haven't heard about it anyway. If you are reading this and did so, then please contact me. Lough Neagh is the largest inland lake in the UK and is located away out of frame to my L. From this great height it looked like a large puddle and using this for comparison it was obvious that this cell was as long as, or longer than the Lough which makes it over 200km long!. Note the chimney smoke to the lower L?. The smoke is blowing away from us to the S, yet the cell is moving to our R (W) indicating that the wind not only changed speed with height but direction also. This may have created some kind of local convergence zone and could have been the reason why two funnel clouds formed here over one hour earlier. It was near sunset now.
This is a video clip showing our journey up the mountain while I try to keep the cell in view, with much difficulty.
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This was located L of the big cell. We watched this crispy cumulus tower grow and begin to glaciate. Vertical wind shear has tilted the tower to the R (W) where the Sun is illuminating the updraught area. The mountain blocked some of the sunlight so the base is in shadow.
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There was a row of insignificant cumulus in a boring region of sky. Within min's this tower erupted upward like a bomb and rapidly grew in height.
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Expanding up big time. It's beginning to flatten out and form a young crisp anvil.
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Big mounds now on top. Note the tiny mammatus under the right anvil sector. This was taken through the windscreen of the car. That's the wiper to the right. Conor was leaning out the driver's window taking his own images. This was a great sight!. There was a van parked away to our right with one of those small black rotating ventilators on the roof. We had a good laugh joking about how it was a doppler on wheels lol.
This is a very short slide show presenting a number of the above images in sequence. It shows the tower rising up from a congestus to cg. I don't know if this works or not. An animated gif would have been much better.
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This is the base of the mountain before sunset. We stopped at this junction to get some more shots and got very strange looks from all the cars passing by. It didn't bother us though, we are well used to it by now. Looking S down a main road. Above is a nice line of cumulus lit red by the low Sun.
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Taken through the front windscreen while heading home. This truck had an amazing selection of white and blue lights flashing in a strange sequence which looked very cool. Unfortunately you can't make out the sequence here but you can see the lights over various sections of the cap and trailer.
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We stopped again on flatter ground because the sunset sky was getting very atmospheric. These clouds looked like they were on fire. A single crep ray is present.
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I couldn't help catch this nice Lenticular spaceship!
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I just love this vivid pastel scene in the W. Very fine virga to the ROC.
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Just when I thought it couldn't get better! There was also red mammatus to the L of frame. It was not under a thunderstorm anvil but instead formed from cool sinking air through the atmosphere.
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The final image of the day and a perfect end to an enjoyable chase. We caught no storms, however we did see some great convection and a powerful cell and I'm sure I would have missed this sunset if at home. This year I have already seen half a dozen OST's which I think is a good sign of activity to come. At the time of writing there is more convection forecast for the next two or three days so it looks like busy times ahead!
Martin McKenna