Rain here around 7am, only 3.7mm here but BlueSkies weatherman Tony T reported a huge sudden fall at his place near Amberley around 8:30am (see report below). Cloudy morning, rather dull. Calm. Not the weather you would expect any thunder activity. At 9am it was 13.9C. Even though there was no wind, I did see stratus cloud going up as I looked out of my window facing the Cashmere Hills. It was dark and bleak looking to the south of here. Anyway, I was sitting in the toilet, hearing a few spots of rain on the roof, when all of a sudden, I heard a distance roll of thunder. Surprised and "Caught with my trousers down"  I quickly got out of the loo, and rushed outside. Still looking bleak and rather un-thundery looking. Towards the Cahmere Hills however it was raining and if this was a bit of a front, it would move over us very shortly. It could of been a convergence extending way out to ...say,  West Melton ? Anyway, I turned the radio on to my sfreric AM point about 1700kHz, heard nothing until about 5 minutes later about 11:29am which the lights flickered, saw a flash in the cloud towards the Cahmere Hills. The thunder followed about a second later but sounded soft and as if high up in the Cb cloud. Then it poured down with 7.2mm falling to about 11:50am when it cleared up gradually from the south. A light southerly followed and the Cb drifted out to sea to the NE. The storm was non-photographicle from here as the sky was 8/8 grey.

John Gaul
President
NZTS - more than just thunder

With a high (anticyclone) about to move in no one thought thunderstorms were even a possibility but some heavy showers with hail, thunder and lightning did happen. I'm a bit lazy so got up late at around 10:00am (well mayby not so late), unbeknown to me torrential rain and hail had been falling in Amberley about 42 km up the coast while I was asleep! I wish I had of got up because outside I could of seen a nice big Cb to photograph but now I'll never know, although the morning according to John Gaul dawned with an overcast sky so I may have been allright in my bed. TonyT was in the middel of a heavy burst of rain / hail at about 8:30am this morning when he wrote this on the NZweather Forum:

We are in the middle of a terrific cloud burst - the heaviest rain I have ever experienced plus some jagged chunky hail for the last 10 minutes, water cascading down the windows just as if someone has thrown a bucket of water directly at them. Guttters overflowing, ground covered in deep puddles, lawn totally saturated in less than 5 minutes. Winds have swung around through every direction, and the rain is now coming in waves of extreme intensity for about 30 secs followed by just plain heavy for 30 secs.

Thanks TonyT from Amberley.

Tony managed to recieve 27mm from this down pour which took only about 20 minutes to fall! That's a rainfall rate of 81mm per hour! Very heavy rainfall for Canterbury.

Steven Graham in Templeton just SW of Chch had heavy rain, strong winds, hail and thunder at about 11:00am from a cell that had come up the coastline a little later in the morning, here's a few pics from Templeton of some heavy rain / small hail and some mammantis from the back of a Cb. Note the road side gutters overflowing with water.

 

Photo's taken by Steven Graham

Stevens lightning counter recorded the lightning strikes for the day:

The Y axis is the number of strikes (lightning flashes) per minute and the X axis is time represented in hours. This graph is usefull for telling how long the storm persisted for which looks to of been about  an hour but the number of stirkes per minute is unrealistic, especially when the storm was at it's peek. Steven Graham has since adjusted this device and it runs much better now, you can see it here.

At about 11:30am John Gaul got a heavy bout of rain accompanied by a few claps of thunder at Somerfeild, Christchurch. This is what he had to say about this event:

Seriously, I was really caught out by this one
The morning was one of those boring overcast days with the sky looking absolutely like there was no chance of any thunder activity whatsoever.
There was dark cloud over the Port Hills but nothing to stimulate any interest. The barometer had risen overnight. It was calm and rather cool.
We had a bit of rain here around 7am, 3.7mm that obviously intensified when it passed over TonyT's place in Amberley.
I received 7.2mm with the 11am storm in about 30 minutes, no hail.

Thanks John Gaul, President of the NZTS.

That figure of rainfall is about the same for what I got in Southshore Christchurch for the 11:00am storm.

Humble old (well, young really) me here in Southshore got no thunder, lightning or hail and had to settle for some ok heavyish rain plus some cloud structure which wasn't great but I took a few pics anyway.