RaVeNStOrM

PASSING STORM PS0001
Date: Friday 12th September 1997   Time: 20:15 BST
Location:
Macclesfield, Cheshire UK
Path: ~20-25 miles away to the north (over Manchester)

Synoptics:
Polar maritime airflow
Duration: 30 minutes
Type: Open-cell convection, aided by land convergence
Average lightning type: P-F
Average discharge rate: 180 seconds
Footage Quality:
VHS/Hi8


 

This was a late season unstable polar maritime situation, basically plenty of showers. The Cheshire gap in this situation is often good at coming up with some convergence-enhanced shower bands. Not expecting any big thundery activity, I briefly filmed a belt of anvils forming along the northwest horizon about 45 minutes after sundown. A few minutes later I filmed them again to record how much they grew (bear in mind I didn't have a still-camera at this age, only video). This time, as I was panning anti-clockwise I saw a brief flash in the corner of my right eye. I then positioned the camera at a large multicell, which was still developing.

Unusually I had a clear shot of the entire cumulonimbus cloud and its thunderhead along with the surrounding atmosphere, and as a result I got some fantastic displays of Positive Flashes (P-Fs) and Cloud to Airís (C-As), which I was not expecting, especially from a cold air thunderstorm. The footage is a little rugged as it was ripped straight from VHS/Hi8 but it is still relatively impressive.

The only thunder heard was from two P-Fs. The strangely spider-shaped C-A in the still images above connected to the ground for the first P-F. Then another one in direct view occurred a little later (shown below). Despite being over 20 miles away to the north (calculated from the delay to the thunder) the two P-Fs it gave were heard as distant bassy rumbles, showing how powerful they were.




SATELLITE IMAGES (Credits)
VISIBLE 12.09.1997 17:16

INFRARED 12.09.1997 17:16
COLOUR 12.09.1999717:16

CHARTS (Credits)


 
© Mark Seltzer  www.electricsky.co.uk

 

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