Heaviest rain due this afternoon, early Saturday; forecasters

This afternoon and early tomorrow remain the periods most likely to receive the heaviest rainfall from a low pressure system being closely watched by MetService forecasters and Northland Civil Defence officials.

The MetService today updated its heavy rain warning and gale watch for Northland, with latest forecasts predicting another 150mm to 200mm rain to come for northern and eastern parts of the region until midnight tomorrow. The MetService is also predicting possible severe easterly gales in exposed parts of the region until tomorrow evening.

The Northland Civil Defence Emergency Management (CDEM) Group says while the weather overall is continuing to develop largely as predicted by forecasters yesterday, there's still some uncertainty over exactly how much rain could fall over the next 36 hours.

Group spokesperson Victoria Randall says as of late this morning an estimated 30-50mm of rain had fallen on eastern parts of Northland since about 9pm yesterday, with latest modelling confirming earlier predictions the heaviest was still to come.

"It appears we can expect another 150-200mm of rain on top of what has already fallen in eastern areas, with more than 100mm possible in remaining places. Maximum hourly rainfall rates are still expected to peak at about 25-35mm."

While at this stage officials had no reports of any serious weather-related issues in Northland, if the weather continued to develop as predicted, it could cause some rivers and streams to rise rapidly, with possible slips and surface flooding.

"Typically this would happen in the usual flood and slip-prone parts of Northland, so won't cause locals too many unexpected problems, but visitors and those new to the region – especially those camping in spots they're unfamiliar with – would be wise just to take a little bit of extra care."

"The biggest influences on this will be how much rain falls – and how quickly – during the two heavy rain bands that are expected to affect us this afternoon and early tomorrow."

Ms Randall says for now, there's nothing to indicate people should be unduly concerned provided they kept themselves up to date with the latest forecasts and continued to take basic common-sense steps.

"With so many Northlanders and visitors staying in and around our coastal areas and rivers we're continuing to recommend people take the usual precautions for strong winds and rain."

These included securing large objects that could be blown around in strong winds, keeping a regular eye on river and stream levels and monitoring the latest weather forecasts.

"Civil Defence will continue to monitor the situation and will update the public as required, including through the Northland CDEM Group's Facebook page – www.facebook.com/civildefencenorthland "

Ms Randall says General Civil Defence information is also available from the Northland Regional Council's website www.nrc.govt.nz/civildefence