Time: 15:25 BST
Macclesfield, Cheshire UK
Storm Stage: Mature
Path / Movement: Core: Overhead, Meso: 3-4 miles NW / SSE
This is the first Supercell-like thunderstorm I have seen (and filmed). Much
to my surprise I was not expecting to see my first one in the UK, let alone
outside my house! With this year being fairly violent so far in terms of
storms, this was the icing on the cake and we weren't even half-way through
storm season yet. Originally I wasn't
on the lookout for storms on this day as there were none forecast for the
north (mainly for southeast), but the calm weather was soon to be broken.
The mini-Supercell came after
a previously developing storm cell that I observed passing through around 13:30.
The first cell had ominous
characteristics that deferred it away from a traditional British
thunderstorm, such as a really dark rolling base and a tremendous downpour,
but no electrical activity. It cleared at 14:15, leading the way for
the Supercell at around 3pm.
I hadn't caught the
lightning on camera from this storm as I was still running home as fast as
possible in the torrential rain. By
the time I got the camera set up the lightning activity had dissipated and
fell silent. My fellow storm enthusiast Matt Robinson reported he saw some
C-C with branches which I missed whilst running and fumbling around for my
door keys as it happened! However the lightning wasn't of any relevance
after I found something else to film...
I had set the camera up facing northwest down the
Cheshire plain, not really taking any notice of it at first as I was still
trying to dry off from running in the torrential rain. Suddenly a piece of
cloud lowering from the base caught my eye and I zoomed in frantically to
get a better shot. It turned out to be a
silhouette of a rotating vortex about 3-4 miles away northwest with a
low-contrast funnel connecting it to the parent mesocyclone above it for
about a minute. Slow but defined rotation of the storm base and cumulonimbus
towers were clearly seen in time-lapsed portions of the footage. The rain
was torrential and persistent with large-diameter raindrops as the core passed
right over Macclesfield, however no hail was reported (even from myself
after I had ran quarter of a mile through it!). The electrical activity was
weak but present with a few C-Cs in the core.
The vortex was subtle but clear near the ground and its parent funnel was
very difficult to see against the same-shade background. See the below photo
sequence for an outline I drew.
I have shown this
footage to the general public including those in the US, and there has been
much debate whether or not this was a tornado or just a funnel cloud. After
studying the footage for many hours, in my opinion it is a tornado touchdown
for sure even if it was only for a brief few seconds. The condensation
funnel can be clearly seen connecting to the ground for a brief second as
the camera focuses in on the footage which qualifies is as a tornado.
Admittedly the visibility was reduced by trees but as the view of the camera
looks downward onto the Cheshire plain it is a pretty flat angle. Also, as
the landscape is predominantly pasture where it would have touched down
behind the houses, trees and pylons, there wouldn't be much in the way of
debris to lift. The mesocyclone was very low-hanging too and judging by the
centre of rotation on the base the funnel could not be more than 3-4 miles
away. It is open to debate but I believe if you stood under it you would
have felt a slight gust of wind at least.
The funnel structure
dissipated 20 seconds after it was spotted and I was left viewing the slowly rotating
mesocyclone cloud-base and towers as
they span towards the south. Every now and then little suction funnels would
appear under the mesocyclone, but none of them
developed into as fully as the first.
This clearance also gave away the back-edge of a very
large arcus cloud to the northwest where the core cell updraughts were as
are a pair of MPEG videos to show the motion of the mesocyclone and tornado.
CLICK FOR 5x SPEED SAMPLE VIDEO OF VORTEX 2.0MB
CLICK FOR 20x SPEED SAMPLE VIDEO OF TOWER ROTATION 2.8MB
As the cloud broke up,
amazing tower growth was spotted over the Pennines to the northeast from
developing storms. The anvils were showing mushroomed characteristics with
no fibrous features.
The heavy rain
during the day from the two cells at 13:30 and 15:00 caused minor flood damage in Macclesfield
and neighbouring Presbury
where a severe rain-burst was also reported on the BBC news. Tytherington
High School just down the road had to
get a fire-engine to pump the water out of the music and reprographics
rooms, and the river Bollin that runs through Macclesfield had suddenly
rose 80cm-100cm in places. The water levels were clearly marked by flattened
grass on the riverbank the following day after the flooding had receded, and
part of the footpath on the Beach Lane road bridge that runs over the Bollin had
collapsed in a landslide (see images below which were taken the following day).
VISIBLE 15.06.1998 15:03
INFRARED 15.06.1998 15:03
COLOUR 15.06.1998 15:03
VISIBLE 15.06.1998 17:03
INFRARED 15.06.1998 17:03
COLOUR 15.06.1998 17:03