For many today it will be the first or second night in the tent or caravan but weather conditions are not favourable for those in the great outdoors over the next 48 hours, reports WeatherWatch.co.nz.

A fairly aggressive weather pattern is moving in from the Tasman Sea and with it – torrential rain for western parts of both islands, with spillover into rivers and streams in the east – where rainfall will be far lower.

Strong to gale force winds are also going to affect many parts of the country.

The Rain:
According to MetService the heaviest rain will be from Waitomo in the North Island, right down the west coast to the glaciers in the South Island.  Nelson, Kapiti and the Tararuas are also in this high risk group.

The heavy rain is predicted to spillover into dry regions such as Otago and Canterbury – raising river levels even in areas that might not even get any rain.

The Wind:
As far as camping goes, damaging winds are expected along most of the eastern coastline from Dunedin in the south to East Cape in the north.  This includes the lower half of the North Island too – from Taranaki to Wellington.

Winds will be strong enough to rip tents and may be strong enough to bring down heavy branches – if near powerlines it might also lead to isolated power cuts.

What about Auckland, Coromandel and Northland?
Three of our most popular holiday destinations will be on the edge of the stormiest weather.  However even winds of 30km/h can make for uncomfortable sleeping conditions in tents and awnings – and winds may be gusting over twice that amount – up to 70 or even 80km/h in exposed areas.

WeatherWatch.co.nz believes the strongest winds will be from midnight tonight until 6pm Tuesday.

The strong winds are mainly due to New Zealand being on the outter edge of a large, very strong, high pressure system rather than a singular low crossing the country.  The isobars between this strong high to the east and some areas of low pressure moving in from the Tasman are being squashed together in a northerly flow over the country.

Is there any good news?
There will be some briefly heavy rain on Tuesday morning for Northland farmers and for other parched farms across the country.  WeatherWatch.co.nz first saw this potential rain band a week ago – so we’re pleased with the accuracy of the long range maps we use from reliable offshore governments and organisations.

The other silver lining is that the system will be fast moving – so conditions will improve by Wednesday for many places – Thursday for almost everyone.

WeatherWatch.co.nz believes the first week of 2011 will be mostly sunny, settled and dry across New Zealand.

MetService has issued a number of severe weather warnings today – you’ll find them here.