Funnel cloud off South Uist, Outer Hebrides on 9 Aug
Posted: Sat Aug 13, 2016 9:25 pm
The 2nd dreadful summer in a row continues here in NW Scotland, with nearly 3 inches of rain falling over the past week (6 inches since 20 July), and there's been zero sunshine for 5 days-in-a-row now (following a total of only 73hrs in July). We may yet have the wettest summer on record, based on 144-year local series, but let's wait and see.
Meanwhile, attached please see photo zoom (contrast enhanced) into a funnel cloud that I spotted last Tuesday evening (9 Aug) at 17h50 BST, from Kildonan, South Uist, looking northwest out to the Atlantic ocean. Met conditions were not particularly conducive towards funnels at this time (anticylonic ridge, SLP of 1025-6hPa, anticyclonic vorticity). Even so, satellite pictures reveal a thin sliver of deep convection forming close to the leading line of cirrus curving southeastwards (again anticyclonically) outwards from the surface warm front many hundreds of miles to the west. The convection could be seen on visible sat images, as it was casting a shadow on the mid-level cloud deck below. I could see the convection base and tower punching through this mid-level deck from the ground. A prominent dark convection base could be seen, and a heavy shower followed (with a gust front) but there was no thunder. The funnel cloud dissipated over the sea after about 10mins and at no time could I see any disturbance on the water surface.
The Lewis precip radar was out of action at this time, as was the Met Office South Uist weather station (only a few kms distant) prior to the event (based from the later OGIMET reports, only a trace of rain occurred afterwards, with no notable events).
More photos can be seen on my blog: https://uhi-mahara.co.uk/view/view.php?id=5156
Meanwhile, attached please see photo zoom (contrast enhanced) into a funnel cloud that I spotted last Tuesday evening (9 Aug) at 17h50 BST, from Kildonan, South Uist, looking northwest out to the Atlantic ocean. Met conditions were not particularly conducive towards funnels at this time (anticylonic ridge, SLP of 1025-6hPa, anticyclonic vorticity). Even so, satellite pictures reveal a thin sliver of deep convection forming close to the leading line of cirrus curving southeastwards (again anticyclonically) outwards from the surface warm front many hundreds of miles to the west. The convection could be seen on visible sat images, as it was casting a shadow on the mid-level cloud deck below. I could see the convection base and tower punching through this mid-level deck from the ground. A prominent dark convection base could be seen, and a heavy shower followed (with a gust front) but there was no thunder. The funnel cloud dissipated over the sea after about 10mins and at no time could I see any disturbance on the water surface.
The Lewis precip radar was out of action at this time, as was the Met Office South Uist weather station (only a few kms distant) prior to the event (based from the later OGIMET reports, only a trace of rain occurred afterwards, with no notable events).
More photos can be seen on my blog: https://uhi-mahara.co.uk/view/view.php?id=5156