Niwa is urging beachgoers to get out of the water as cloud-to-ground lightning strikes pepper the Waikato and Bay of Plenty.
Nearly 80 strikes have been recorded in eastern Waikato and Bay of Plenty, however the thunderstorm was making its way north up the Coromandel coast about 1.45pm today.
Big increase in cloud-to-ground lightning strikes just west of Waihi pic.twitter.com/KD38YvS3rp— NIWA Weather (@NiwaWeather) December 18, 2017
Initially there were only 10 strikes recorded between Waihi Beach and Tauranga before the storm spread east into Waikato.
Seventy-seven strikes were recorded around Te Aroha, Paeroa, Ngatea and Waihi.
However, by 2.15pm today, the MetService was reporting more than 800 lightning strikes over a two-hour period.
Lots of instability over the upper North Island (image at 14:15 local time) both with and ahead of the cold front this afternoon. Around 800 lightning strikes were reported in 2hrs. MetService have a Severe Thunderstorm Watch in force. For the details https://t.co/GZIq9Jlbrw ^AB pic.twitter.com/bOsIV6TjJy— MetService (@MetService) December 18, 2017
The storm moved north a slight distance before veering east out to Whangamata.
Niwa urged people to stay out of the water and off beaches when there is lightning nearby.
Cloud-to-ground lightning flaring up over/west of Whangamata pic.twitter.com/Qgg3vFeAGS— NIWA Weather (@NiwaWeather) December 18, 2017
Some cloud-to-ground lightning from near Waihi Beach to Tauranga. Be sure to say off the water/beach when lightning is nearby! pic.twitter.com/397JZnt7ak— NIWA Weather (@NiwaWeather) December 17, 2017