Your weather: Southerly storm brings massive 8m swells and plummeting temperatures

Cooler temperatures have arrived after a run of warmer-than-usual weather. Photo / File

A series of southerly storms are sweeping the country whipping up giant waves over 8 metres and causing temperatures to drop.

Yesterday brought waves approaching 8m to the west of the North Island thanks to a powerful southerly flow kicked up from below Australia.

WeatherWatch NZ forecaster Philip Duncan said autumn was "waking up" with gale winds in the usual exposed and marine areas, and more dangerous waves.

The strong winds would whip waves exceeding eight metres to the southeast of New Zealand.

The windier weather, despite being much colder than the sub-tropical flow a week ago, was still bringing warmer-than-average weather to a number of places by day.

However, colder-than-average nights were in the mix now too.

MetService meteorologist Kyle Lee said Tuesday was on a slight easing trend with waves in the 5m range, before kicking in again tomorrow with waves as big as 7m metres in the far south.

Below 20C across the board. See what your weather is here https://t.co/Yjbq0jxdqz. GK pic.twitter.com/EKxQqTctuE

— MetService (@MetService) May 13, 2019

Tuesday was looking relatively quiet compared to the start to the week, where wild wind and rain wreaked havoc in central parts of the North Island.

Temperatures had dropped slightly with the southerly change from the above-average conditions last week.

Auckland was in for a day of southerly breezes and a high of 17C.

Thunderstorm outlook for tomorrow (Tuesday). There are Severe Weather Watches and Warnings in place from broadscale wind and rain. More information at https://t.co/qHyE5zhh6X. ^Lisa@NZTACWC pic.twitter.com/ky1LWeRY3m

— MetService (@MetService) May 13, 2019

Later today another front would arrive on the West Coast bringing periods of rain there, and strong northwesterlies in the east.

Lee said the front would bring "unstable conditions" to western areas with a high risk of thunderstorms in the South Island.

↗ The arrows and colours 🔵 below give you a pretty good idea of the weather flavour for the week.
🌬️ Windy and unsettled weather is here to stay and the prevalence of W to SW winds will make it feel cooler then it has been lately. pic.twitter.com/3YB9cLjXMp

— NIWA Weather (@NiwaWeather) May 13, 2019

That front would reach central New Zealand by tonight and Wellington overnight but would have greatly weakened with just a few showers remaining.

While conditions would settle from tomorrow a southwesterly flow would remain for much of the week keeping temperatures relatively low.

Today's weather

Whangārei

Cloudy at times. Westerly breeze from afternoon. 18C high, 11C overnight.

Auckland

Cloudy periods, with the odd light shower along the west coast. Southerly breezes, turning westerly in the afternoon. 17C high, 12C overnight.

Hamilton

Cloudy at times. Westerlies developing this afternoon. 17C high, 9C overnight.

Tauranga

Fine. Light winds. 17C high, 11C overnight.

New Plymouth Cloudy at times. Westerlies. 17C high, 13C overnight.

Napier Fine, afternoon high cloud. Northwesterlies developing this morning. 18C high, 10C overnight.

Whanganui Cloudy at times. Northwesterlies gradually strengthen. 18C high, 12C overnight.

Wellington Fine then becoming cloudy this evening. Strong northwesterlies. 16C high, 13C overnight.

Nelson Fine, but chance evening shower. Northerly developing this morning. 17C high, 9C overnight.

Christchurch Gradually becoming cloudy. Northerly winds. 18C high, 4C overnight.

Dunedin Cloud increasing. Brief rain late afternoon or early evening as strengthening northerlies turn strong southwest, then ease. 18C high, 8C overnight.