THUNDERSTORM T0099 Date: Friday 15th May 2015 Time:
04:40-06:30 Local Location:
Norman, Oklahoma. USA. Path: Overhead
Rearward sloping cold front with MCS Duration: about 2 hours Type: Rearward sloping Multicell Squall line Average lightning type: CG/GC and Anvil Crawlers Footage Quality: Full HD / DSLR
An early morning
squall line approached Norman Oklahoma in the early hours of the 15th May
2015 whilst I was working over there, so
I set my cameras up against the hotel window for some potential lightning
shots (albeit through a triple-glazed window - so a bit of ghosting on
The clicking noise you hear in the video is the lightning trigger on my
This was a classic example of a rearward-sloping squall line, a linear
storm-mode thunderstorm covering hundreds of miles progressing slowly
eastwards across Oklahoma. The most intense part of the storm was along the
cold front, itself whereby ahead of this, warm humid air travelled northwards with
low cloud and "silent" lightning of increasing frequency, then the squall
hit with torrential rain and negative C-G lightning.
Then, a clearance to the
cold air and a backward sloping anvil. The latter is a lightning
photographer's playground, as the discharges are large and pretty (Anvil
Crawlers and Ground to Clouds), whilst receiving a clear view of the show in
the colder, drier airmass, often without much rain.
A distant radio mast got struck (or more accurately, IT struck the cloud) 5
times upon the storm's departure with Ground to Cloud lightning, often
spraying into an Anvil Crawler.
A possible rare bi-polar stroke at 3:41 in the video was captured, where
the initially positive channel seems to get reused by one of the branches
from a possible negative region.
Storms like this rarely happen in the UK, especially as intense and
large-scale as this, as the airmass structure and properties are different
in the US, and unachievable without living in a big well-mixed continental
airmass. We can sometimes see these rearward slopers in Spanish Plume
events, but more often than not they forward-slope.
Here is the radio
mast that kept releasing lightning this night...