Tropical Cyclone Ruby is now a category two tropical storm and has potential to reach 'severe' cat 3 status within the next 24 hours as it approaches New Caledonia, warns WeatherWathc.co.nz

This week New Zealand (and New Caledonia) are experiencing a classic La Nina summer.

"Tropical Cyclone Ruby formed on Sunday afternoon and just over half a day later was already Category 2 and is still gaining power, plus we have numerous other low pressures all linking up - and it's going to produce a lot of rain, cloud, humidity and drizzle for parts of New Zealand," says a spokesperson for the weather organisation.

"The cyclone itself may well stay offshore from New Zealand later this week - but the lows around NZ will connect to it, all linking "arms" to help pull down moisture-rich tropical air over NZ and that brings with it drizzle, downpours and high humidity.

"The rain this week in NZ will actually precede the tropical cyclone (which will technically be ex-tropical by the time it gets closest to NZ - this is because the core of the storm switches from warm air to cold air)."

Some of the bigger rainfall estimates for this week:
Auckland: 50 to 100mm
Waihi Beach: 130 to 150mm
Tauranga & Katikati: Around 120mm
Whakatane & Kawerau: Around 150mm
Stratford: Around 110mm
Taupo: 70 to 90mm
Nelson: 70 to 90mm

A severe weather warning for heavy rain is now in force for the Bay of Plenty.

Meanwhile those in New Caledonia should be paying close attention to Meteo France updates.

Possible placement of ex-cyclone Ruby in the NZ area - remember, the rain NZ is getting this week precedes the cyclone, but is somewhat connected.

Tracking from BoM as of the 7am hour Monday.

Tracking from JTWC as of the 7am hour Monday.

Rainfall totals and other data from www.RuralWeather.co.nz - powered by our partners at IBM.