Developing — This past week WeatherWatch.co.nz forecasters have been closely watching various computer models which are now agreeing there is a moderate to high risk of a tropical cyclone either directly hitting, or brushing, the upper North Island late next week.

“Latest data shows the potential tropical storm heading south next week and then directly impacting the upper North Island anywhere between next Thursday and next Sunday at this stage” says head weather analyst Philip Duncan.

The last significant ex-Cyclone to hit New Zealand was Wilma in January 2011, which had the strength of a Category 2 tropical cyclone (out of a scale that goes up to 5).  Wilma was fast moving but caused millions of dollars of damage in the 6 to 12 hours it blasted through.

Previous to that many would say it was Cyclones Fergus and Drena over the La Nina summer of 96/97.

This storm may well weaken as it approaches Northland – tropical storms must transition from a warm core to a cold core as they head south out of the tropics and towards the Southern Ocean. This transformation often happens around New Zealand – which is why predicting strength and specifics is so incredibly hard this far out, the storms change shape dramatically as they leave the tropics.

WeatherWatch.co.nz will continue to monitor the progess of this potential tropical storm.

“If it weakens as it moves in then the rain will be hugely welcome – some parts of northern New Zealand are as dry as they were in last years drought” says head weather analyst Philip Duncan. “If it doesn’t weaken then wind damage can be added to the list of risks from this low”.

Maps:  Above – European wind maps for Sat March 15th.  Below – NZ/American rain & air pressure maps for 1am Sat March 15th.

– WeatherWatch.co.nz