Issued by MetService at 08:31 am Tuesday 08 October 2013
Valid until 09:00 pm Tuesday 08 October 2013
This watch affects people in the following weather forecast districts:
Northland
Auckland
Great Barrier Island
Coromandel Peninsula
Bay of Plenty
Rotorua

A front with embedded thunderstorms is expected to cross the upper North Island this afternoon and evening. There is a moderate risk some of these thunderstorms will be severe with wind gusts in excess of 110km/h and small tornadoes over Northland, Auckland and the Coromandel Peninsula this afternoon and over Bay of Plenty this evening.
Wind gusts of this strength can cause some structural damage, including trees and power lines, and may make driving hazardous. If any tornados occur, they will only affect very localised areas.

From Weatherwatch.co.nz:
A front moving towards New Zealand bringing a cold change is also expected to trigger a few thunderstorms as it moves in this afternoon.
While crossing the western Tasman Sea on Monday the front was incredibly active with thousands of lightning strikes detected.
However, as is often the case, the thunderstorms can run out of some of their puff by the time they reach land.
We can see the thunderstorms on satellite maps now, approaching northern New Zealand from the west.
By the looks of the current models for this afternoon, coupled with what we've seen forming out at sea, it looks as though the front will move through fairly quickly this afternoon.
At this stage we believe thunderstorms have the potential to become quite large but they may also be fairly isolated - meaning not everyone will have thunder.
Once the front approaches later today we'll be able to work out where any potential thunderstorms lie.
Not all our models agree that thunderstorms are likely today.  We think Northland will be most exposed with a fairly high risk of thunderstorms. At this stage Auckland and Waikato have a moderate risk for a thunderstorm as the front passes over.
As with any potential severe thunderstorms - which are possible in isolated areas - hail, localised flash flooding and damaging winds are possible.   If you hear thunder remain indoors until the storms have passed.
The front coming in is quite narrow.