Two tropical systems have their sights set on New Zealand this coming week and WeatherWatch.co.nz continues to monitor their progress and the latest computer modelling.

What we know now:
Vania was downgraded to an ex-tropical cyclone Saturday.  The system doesn’t look dramatic (or even that clear) on the satellite map but it has tapped into some very moist air.  Often it’s what can potentially happen with these systems that drives the numerous weather updates, as opposed to us saying stormy weather is definitely coming.

While Vania was being downgraded Zelia was doing the opposite – bumping up three categories in just 36 hours the storm is now classed as “severe tropical cyclone”.  Using the American standard for measuring hurricanes this would now be a “strong Category 1 ” tropical storm.

Severe Tropical Cyclone Zelia continues to strengthen this morning and for a time she may even hit category 4 status out over the very warm waters of the Coral Sea, predicts WeatherWatch.co.nz.  The cyclone currently has winds averaging 150km/h (up from 120km/h earlier today) and gusts are now up to 205km/h.

The tracking of both these systems takes them in to the central and upper Tasman Sea and merging on Tuesday.

What we don’t know:
We still don’t know just how rough this system will be for New Zealand however WeatherWatch.co.nz doesn’t believe it has the same aggressive hallmarks as other cyclones (think Drena, Fergus, Bola).

There is still potential for damaging winds and flooding in some regions though.

The models:
The models are picking the two systems merging during Tuesday and crossing New Zealand on Wednesday.  While some isolated areas may receive damaging winds the overall set up does seem to suggest rain will be more of a feature.

Worst hit:
One positive about the two systems merging is that it appears it will spread the energy over a greater area.  That lessens the severity of the wind in many instances.

We believe the Nelson region could be in the firing line for some of the heaviest rain however all northern, central and western regions remain at risk (of both islands).

Still developing:
Severe Tropical Cyclone Zelia still needs to lose her tropical cyclone status and start to fall apart before she reaches us, so there are still a lot of physical changes expected in the coming days.

Your plans:
WeatherWatch.co.nz is not advising people to change their holiday plans, we simply ask that you keep up to date with the latest weather news and forecasts and have a back up plan should you need to move from your location.

We also suggest now is a good time to check on your emergency survival kit (or get one).  Go to www.getthru.govt.nz for more information.