On this blog we are going to take a look back at the rare thunderstorm event that impacted the Western Isles. I hope you enjoy this look back and it hopefully brings together all the aspects of the event.
So the best place to start was why am I calling this event rare? We get a lot of out thunderstorms occurring in the winter months. These mainly caused by the differences in between the temperature of the sea and the land. Since living on the island since 2004 there have been a number of thunderstorm events but this was by far the most significant and the sheer volume of lighting strikes. We get summer time thunderstorms but they are a lot rarer and usually a lot more short lived.
So moving back to the start of the week. I got a message from my friend Dan Holley. Owner of the excellent convection weather website. He gave me the heads up early on the week that there was going to be a risk of thunderstorms later in the week. By this point, the Met Office had also started mentioning the risk of thunderstorms in their text forecasts for Thursday and Friday. On Wednesday morning the Met Office issued a yellow weather warning for thunderstorms for Thursday and Dan issued a Moderate risk for us including a severe element for large hail.
A more in depth and technical forecast from convection weather can be found here http://www.convectiveweather.co.uk/forecast.php?date=2020-06-25
So by this point, my excitement had really started to build up. Ask any of my friends I was really hyping things up. So I was working on Thursday until 1700 so this was going to really limit my ability to storm chase. But the very worst of the storms where forecast here for the late afternoon and evening. I had weather radar from Netweather.tv on from 0900 which showed the storms already across Tiree, Mull and moving along the West coast Mallaig and Oban. At just before 10 am a flood alert was issued by the Scottish Environment protection agency which covered the entire Western Isles.
Into the afternoon and the storms started firing across the Uists and Barra and the first reports started coming into my page from the islands. I went down to the beach on my lunch break and experienced my first rumbles of thunder of the day. Around 1600 things when utterly crazy. With huge amounts of thunder and lightning as multiple storms rolled across my location bringing thunderstorms to Lewis and Haris. This result in large hail stones being reported and multiple lightning strike. Alongside flooding which resulted in a road being washed away in Harris.
I was working at the time of the first main wave of thunderstorms but lighting bolts rained down and heavy rain which resulted in the flooding above and damage to the road surfaces in Stornoway.
We then had a lull followed by more thunderstorms building across Skye and moved across to North Harris and right across the middle of Lewis and back out in the Atlantic which resulted in a barrage of lightning strikes as multiple cells brought heavy rain and lightning bolts that came crashing all around. Outside of the USA I had never seen anything like this before. I counted 30 strikes in about 20 mins. My phone went into melt down with notifications from friends and across my social media platforms.
The next few photos are from me showing a radar grab of the storms at one point and also my view on the Point peninsula watching the storms roll past. I spent in total 2 hours watching these storms this is not an event I will forgot in a hurry.
This resulted in some stunning thunderstorm photos. Many of which were shared to the page. Further thunderstorms occurred during the early hours of Friday morning. I managed to sleep through those.
Friday we had the aftermath of the storms with the road out to Rhenigidale washed out. The council and road teams in Harris quickly got the only road in and out of the village repaired
Dan Holley from Convection weather explains exactly what happened for the Western isles –
A plume of warm, moist air over Scotland drifted slowly northwestwards towards the Western Isles during Thursday, becoming engaged and destabilised by a shortwave lifting northwards. This resulted in elevated thunderstorms erupting in the vicinity of the Hebrides, their slow movement and a very moist airmass (precipitable water of 30-35mm) producing some localised flooding. Furthermore, the magnitude of instability and more specifically wind shear mean that the thunderstorms became organised and long-lasting, producing large and potentially damaging hail, as well as frequent lightning.
I hope you have enjoyed this look back at the storms last Thursday and Friday. I had done my best to ensure all images are credited correctly. Any issues let me know. Thank you for reading.