The MetService weather radar detected the slow-moving thunderstorms this afternoon and said they were expected to lie in the north Waikato at 3.30pm.
"These thunderstorms are expected to be accompanied by very heavy rain.
"Very heavy rain can cause surface and/or flash flooding about streams, gullies and urban areas, and make driving conditions extremely hazardous."
Some flights were disrupted as some aircraft put off landing in their final approach to Auckland Airport due to the storm this afternoon. Refuelling of aircraft was put on hold briefly due to the threat of lightning strikes.
The Ministry of Civil Defence and Emergency Management advises that as storms approach residents should:
• Take shelter, preferably indoors away from windows;
• Avoid sheltering under trees, if outside;
• Move cars under cover or away from trees;
• Secure any loose objects around your property;
• Check that drains and gutters are clear;
• Be ready to slow down or stop, if driving.
During and after the storm, you should also
• Beware of fallen trees and power lines;
• Avoid streams and drains as they can sweep people away in flash flooding.
The warning is due to be updated or lifted later this afternoon.
- with Rotorua Daily Post