Weather Watch: Welcome to the end of winter

Photo / Dean Purcell

Here comes the rain - as one low and frontal system moves onto New Zealand another one is already gearing up to move in on Tuesday bringing another belt of strong winds and heavy rain.

In a significant shift to the weather pattern this week will see a strong change to lows and fronts moving in from the western Tasman Sea. Breeding off the east coast of Australia, the lows will quickly move towards New Zealand then slow down as they cross the country, bringing periods of heavy rain.

The second low, which should move on to our shores during Tuesday and Wednesday, will be centred far enough north in the Tasman Sea to pull down moist, sub-tropical air over northern New Zealand. It may not exactly be singlet weather but it's not going to be mid-winter conditions either, with overnight lows unlikely to drop below double digits until the end of the week for many centres across the North Island.

The South Island will also see more rain and wind but the next belt of rain does look to be more focused on the North Island.

Windy conditions will remain from the northerly quarter - when I say that I mean anywhere from north westerlies to north easterlies. While that doesn't sound like much, it can actually have a dramatic affect on our weather.

Case in point - the West Coast this weekend. Winds shifted to north-north easterlies and gales quickly moved in and gusted to 100km/h. A north westerly there can be windy and wet...but a slight shift to the NNE direction and all of a sudden you're talking damaging gales. It's not a common wind direction for Coasters so it can be quite damaging to trees and buildings, which grow/or are built to withstand constant westerlies. It's like the opposite affect of Canterbury's famed nor'wester.

In Canterbury the difference between a no'rwester and a nor'easter can be the difference between shorts and a t-shirt or lighting the fire. Canterbury's nor'easter is often considered 'miserable' with low cloud and chilled air coming off the cold south Pacific Ocean. Highs can often sit around 10 or 11 degrees...but a few kilometres inland, where the wind may be more of a nor'wester, and it might be sunny with 18 degrees.

The nor'easter is generally not a warm wind for most of us - but it can bring in much warmer overnight temperatures. Overall the nor'wester is our warm wind - for almost the entire country.

This week sees plenty of nor'westers, northerlies and nor'easters... but as the week progresses the winds will tilt more westerly then south westerly. The week will end chillier but still not what I would call cold. Welcome to the last month of winter.