RaVeNStOrM

THUNDERSTORM T0018
Date: Wednesday 9th September 1998   Time: 1230BST (1303BST for CG)
Location:
Macclesfield, Cheshire UK
Path: Overhead, travelling northeast

Synoptics:
Returning polar/arctic maritime airmass near centre of deep low
Duration: 35 minutes
Type: Open-cell Multicell
Average lightning type: C-G
Average discharge rate: n/a (no footage taken)
Footage Quality:
None

 

I was at school during the passing this storm, so there is no photogenic footage unless I draw a sketch. The only reason I kept a log of it here is, at the time, I wanted to log every storm that had happened in Macclesfield that year. I could delete it now but it would mess up the sequence of the proceeding storm numbers.

In fact, I had set the camera up at home ready to film as I was expecting a storm risk given the late-summer returning polar maritime airmass, heavily unstable with long-land track to Macclesfield. The hope was that a swift phone call to mother at home would have the camera switched on at the right moment, however the phones at school were out of order and only the extreme privileged had a mobile phone! So I stood under shelter from the splintering rain watching it with my friends. There was actually no lightning activity until the rain had stopped and it had trundled off. The first thunder to be heard was a substantial bass-boom that sounded crisp and clear without the noise of the rain. At that point the inevitable happened and everyone who was stood outside cheered in unison. Everyone loves a thunderstorm, glad it isn't just me...!

At that point I started watching it as it went off into the distance. A distant C-G struck from the backside of the storm where there were a few strong towers in development, which in turn gave another distant thunder. Other cells were visible around it to the
NW and SE, all of which appeared to be sharing the same anvil.

The torrential rain almost flooded the school again, as T0014 did in June, but not quite. If it had rained much longer at the same intensity it would have been close. There was also a mini tornado reported in south Derbyshire today on the news.

Synoptic Analysis
The showers in the were associated with an active trough hanging from a parent Low, post-cold front in the returning polar (or even arctic) maritime air. The low was deep at 980mb with a dart-board isobar pattern. All this suggests the air over the UK would have been easily unstable to both September-sea (warmest seas) and land temperatures. However, the Sferic diagrams indicate it was only the land-generated showers which were unstable enough to produce thunder, as the strikes were largely inland and east of the country.


CHARTS (Credits)




SFERICS (Credits)


SATELLITE IMAGES (
Credits)
VISIBLE 09.09.1998 14:15

INFRARED 09.09.1998 14:15

VISIBLE 09.09.1998 14:15 + Grid
INFRARED 09.09.1998 14:15 + Grid


 


 
Mark Seltzer  www.electricsky.co.uk

 

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