There may be a sting in the tail for some North Islanders today as a low pressure system continues to cross New Zealand.  WeatherWatch.co.nz forecasters say the cold front, which will pass over the North Island today, will remove the muggy weather with a more refreshing south west change.

For South Islanders more heavy rain is expected across a number of regions, before easing later in the day.

This mix of air masses could prompt thunderstorms, mainly in northern and western parts of the North Island, from Taranaki to Waikato, Auckland and Northland and across to Coromandel Peninsula and Bay of Plenty.

Surrounding regions will also be at some risk.

WeatherWatch.co.nz says while the risk today is considered “moderate” for any severe weather, it will also be isolated.

But the unstable weather conditions, created by the deepening and strengthening low, could again see funnel clouds forming with the potential for small tornadoes – like we saw last week.

WeatherWatch.co.nz head weather analyst Philip Duncan says people should be vigilant as to what is happening around them on Thursday.  “Like last week severe weather is likely to be isolated – but being isolated doesn’t reduce the severity.  We may still see a tornado or waterspout, or simply a squall that can produce locally damaging winds”.

“Torrential downpours may again cause flash flooding and we advise motorists and residents to be aware of any incoming clouds throughout the day”.

Last week numerous reports of tornadoes, waterspouts and funnel clouds came in from the upper North Island – and while some storm cells created isolated pockets of considerable flooding, nearby suburbs and communities often had blue skies and not a drop of rain.

Government forecaster MetService is also predicting a “moderate risk” for thunderstorms along western and northern regions of the North Island today, saying “any thunderstorms that eventuate here are likely to produce locally heavy rain up to 25mm per hour, strong wind gusts around 90 km/h and there is a slight risk of one or two small tornadoes near the west coast”.

But unlike last Friday, when afternoon heating created dozens of large thunderstorms, today’s activity is due to a front sweeping over the North Island – which means rain or showers will be more widespread but embedded thunder activity should be more isolated.

We’ll update you as the day progresses.

– Homepage image / Dramatic clouds at sunset in Palmerston North on Monday / Lauren Gillies

– WeatherWatch.co.nz