Easterlies and clouds are already picking up in northern NZ today ahead of a sub-tropical low that will bring days of wind, rain and showers to the North Island in particular.

Gales are possible across the North Island, developing overnight and into Monday and lingering from the easterly quarter (NE, E and SE) for the days ahead. The low itself looks to sit around Northland, blocked from tracking southwards due to dominant high pressure.

This set up means rainfall totals across Northland, Auckland and Coromandel Peninsula may be high enough to cause localised flooding. For Auckland dealing with water shortages for the past 12 months the rain is critical and could make a big difference. Totals are not 100% locked in but it looks as though, at the lower end, Auckland may get 40mm and at the higher end some parts may reach 100mm. Coromandel Peninsula which is even more exposed may see over 150mm of rain possible.

But be prepared for some shifting of the rainfall totals. Lows that hover in one spot for days in a row do bring repetitive weather (helping lift the rainfall totals), but if the low shifts just a little further south or north it can dramatically lower or increase the totals. Keep an eye on your local rainfall totals at WeatherWatch and RuralWeather as we use IBM’s Watson supercomputer. The NZ Government told us in November 2020 our rainfall data was the most accurate in New Zealand.

Speaking of rainfall forecasting – most people only take 2 of the 7 steps required to get the most accurate rain forecast for your area. This recent article gives you tips on finding more accuracy with rainfall forecasts and to give you fewer false alarms.

Not everyone will get helpful rain. Those in the west have lower totals from the Bombay Hills southwards.

Even some regions exposed to heavy rain may still find the month of February ends with them receiving below normal rainfall. But, this is a positive event for many of those who need rain in the North Island.