Lightning strike just west of Chch in week before 21st Aug?

tich · Unread post by **tich** » Tue 24/08/2004 22:24

Some of you might know that the Sunday Star Times puts out a map of lightning strikes (cloud-ground) recorded in NZ for the previous week. Well apparently according to the latest of these maps, there was a strike somewhere just to the west of Chch between Saturday 14th and the 21st. But I can't recall any weather here during that time that could've produced a thunderstorm in the Chch area.

03Stormchaser · Unread post by **03Stormchaser** » Wed 25/08/2004 08:15

Yeah noticed that about a week or so ago on meteservices lightning strike site. Probably around tempelton.

I believe we had a Nor'wester that day. Actually it was at night
Aaron you no what day this lighnting strike was?

Thunder · Unread post by **Thunder** » Wed 25/08/2004 09:34

Yes I do, it was the night of Saturday the 14th August (somewhere between 7 and 10 pm to be exact). Me and 03 Stormchaser noted quite alot of flashes coming from the west, and yes it was the night of the Oxford tornado (or was it????, a tornado that is). Some of those flashes that night were quite bright so I'm not surprised one occured quite close. Remeber metstrikeweb doesn't pick up all strikes, only the ones correct in polarity and they have to be Cg's (I think). When I looked at the weatherzone sat image for the hours around then, I noted the anvils from the storms to the west were nearly streatched all the way over to the east coast (this side of the South Island). The SI from West to East nearly looked totally white becasue of the anvils on the sat pics. Where the bases were is the tricky one, maybe it is possible that they came over oxford?

Looking foward to these pics Stephen B!

tich · Unread post by **tich** » Wed 25/08/2004 09:46

Yes I thought it might be Saturday 14th, but I suspected (as it was a northwesterly) that the map might've made an error in placing the strike tooo far east. I can't recall thunderstorm activity nearby that evening, and it's very unusual to get thunderstorms near Chch in these conditions. But if Aaron and 03 Stormchaser observed bright flashes, then a strike must've occured in that location.

NZstorm · Unread post by **NZstorm** » Wed 25/08/2004 18:32

Maybe that isolated lightning strike west of CH actually originated from a storm in the foothills. In the dry NW air I suggest a lightning bolt could travel horizontally quite a distance. There was a case last year in Australia of a roofing contractor being killed by lightning that traveled from a distant storm.

NZstorm · Unread post by **NZstorm** » Wed 25/08/2004 18:43

Where the bases were is the tricky one, maybe it is possible that they came over oxford?

Cloud bases over Oxford, coming off the foothills, would be quite high. Even with a thunderstorm present, it would be middle atmosphere activity.
The clouds would be spillover from oregraphic/frontal forcing over the Alps.

Tornadoes develop within updraughts from ground level under the cb.
The season for funnel clouds/tornadoes in Canterbury is mid spring to early summer when daytime heating/sea breezes trigger t/cu/cbs developments over the plains.

tich · Unread post by **tich** » Wed 25/08/2004 20:18

Maybe that isolated lightning strike west of CH actually originated from a storm in the foothills. In the dry NW air I suggest a lightning bolt could travel horizontally quite a distance. There was a case last year in Australia of a roofing contractor being killed by lightning that traveled from a distant storm.

Scary thought - does it happen often?

Could that Canterbury lightning strike have been a cloud-cloud and then re-routed itself into a cloud-ground after it moved onto the plains?

I've also heard of a strange phenomenon called clear air lightning.

An example being a lightning bolt that killed someone on a cloudless day atop a Colorado mountain.

Thunder · Unread post by **Thunder** » Wed 25/08/2004 23:38

That is one possibility Ben, it could be an error? As I understand Tony said something a while back about how the metservice lightning strike system is on a triangular type system meaning it's more accurate. When I say triangular I mean in laymans terms that three lightning detectors all sense the same bolt and can therefore detect and plot a bolt on the metstrikeweb map more accurately, ah ....bah! I'm probably not explaining this right, hopefully it gives you an idea though. But still, it could be an error.

Steven is also onto something though, the anvils that night were pretty far east, maybe some type of anvil crawler Cg?

And yes Steven, if a tornado did occur in Oxford it would be something really weird to happen in the type of situation that was present on that night (NW etc). Only thing that makes me think though is how a surposed glass house and the peoples own home was close to the garage yet untouched, maybe it was a very crappy garage and the NW simply blew it over from strong gusts

A hunk of garage falling over would make a big sound like the people said they heard. Still, I'm interested in whether this was a tornado or not. Looking foward to these photo's Stephen B. Maybe a talk to the actuall people affected would be interesting next time I go up there.