Waterspout over Lough Neagh (NI) - 3 June 2014

[Simon Culling]

A beautiful waterspout was filmed travelling across Lough Neagh in Northern Ireland on Tuesday 3rd June 2014.

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

It occurred around 7:30pm and was witnessed by quite a few people.

[Orion]

Very elegant. Do they happen often there?

[Simon Culling]

Orion, waterspouts are not particularly common in the UK with something like 10-15 seen annually, with most of these witnessed on southern and south western coasts of England and the Welsh coast. I am not aware of any others seen over Lough Neagh, but as it is the UK's largest lake, it is possible they have occurred before. This was a particularly well developed waterspout for the UK and there are some good photos in the attached link:

http://www.nightskyhunter.com/Sky%20Events%20Now.html

The feature on the waterspout is halfway down the page.

[NZstorm]

Its an interesting waterspout case as its occurring over a cold lake.

I had a quick look back at the set up and it was fairly typical conditions for funnels with a very cold airmass 850mb 0C, 700mb -8C (very steep lapse rates) and a relatively juicy surface dewpoint of 10C. The convective buoyancy is more the product of the low level moisture than the lake temperature.

[Simon Culling]

Steven, the surface conditions on that day were a slack returning south westerly flow behind an oocluded front which was over the rest of the UK (to the east). The parent low (1003mb) was 200 miles north of Northern Ireland. The surface wind was fairly light over N Ireland, but southerly in Belfast (west of the Lough) and north easterly at Eglington (to the NE of the Lough). The air temperature was 12*C at both stations and there were showers in the area with Cb's reported in the Eglington METARS. I could not find a current temperature for the Lough, but an old paper gave 14-15*C as the average temperature for early June at a depth of 5m.

These conditions look suitable for the formation of a surface vortex (especially if there was a local thermal boundary associated with the Lough) and the developing cumulus would have provided the required updraft/downdraft.

The Lough is quite large - 30km by 15km.

[NZstorm]

Sounding here taken a few hours after the spout had occurred. Castor Bay 040000Z.

The chunk of CAPE between 850-700mb is fairly typical of when spouts occur. See it a lot in NZ.