Weather: Thunderstorms and rain to batter western regions, new weekend storm

Polar-laced thunderstorms and rain are set to batter the west coasts of New Zealand as a fresh onslaught of unsettled weather sweeps over the country today.

And a new storm is forecast to sweep across the top half of the North Island this weekend with rain and gales set to lash western and northern regions.

MetService said almost all of the North Island can expect frequent showers today with thunderstorms possible in the west, especially south of Auckland.

“Wednesday morning brings a shift from a northwesterly flow to southwesterlies. This shift brings more precipitation to that previously dry east and clears up conditions in the west by Wednesday night,” said MetService meteorologist Clare O’Connor.

“These bands of rain - with embedded thunderstorms - are relatively short-lived, but there are a number of them that pass over, battering the west coasts of both main islands.”

Westerly winds would blow across northern and central New Zealand this morning, while winds would turn to a southerly direction over the deep south.

Road Snow Warnings Issued 🚗❄🟠

Desert Road: Wed 5pm to Thu 3pm.

Lewis Pass: now until Wed 8pm.
Arthur’s Pass: now until Wed 6pm.
Porters Pass: now until Wed 9pm.
Lindis Pass: now until Wed noon. pic.twitter.com/BbqpgCgs7h

— MetService (@MetService) August 15, 2023

Road snowfall warnings remain in place for Desert Rd and several Canterbury alpine passes with the forecaster expecting up to 2cm of snow to settle on the road early this morning.

Another road snowfall warning is in place for Desert Rd for 22 hours, from 5pm tonight until 3pm tomorrow.

More snow is possible from 4pm through until 3pm tomorrow with up to 4cm of snow settling on the road near the summit.

Wednesday's emojicast:

         🌦
           🌦
             🌦🌦
            🌧️🌧️🌦🌧️
         🌧️🌧️🌧️☁️
             🌦🌧️🌤️
                   🌧️🌦
                      🌧️
 
             🌧️🌧️
          🌧️🌧️
        🌧️🌧️🌧️                   🌧️
      🌦☁️
  ☁️☁️☁️
🌤️🌤️☁️
   ☁️

— NIWA Weather (@NiwaWeather) August 15, 2023

There was a risk of one or two thunderstorms and heavy rain from Horowhenua to northern Wellington shortly after midnight, and again from late morning.

MetService said a “building ridge” of high pressure tomorrow was expected to bring drier weather, but the clearer skies would bring a morning chill.

But the finer weather would be shortlived with a new low developing off the east coast of Australia and expected to reach New Zealand on Friday, bringing rain to western regions and gales for the start of the weekend.

💧A sou-west change for #Australia late this week will reach #NewZealand on Saturday in the form of a cold front, then a low on Sun/Mon for the North Island.

⚠️Rain warnings are likely for some - but not all will have a deluge. 🎥Full details in our weather video out today. pic.twitter.com/x9da9xoBpo

— WeatherWatch.co.nz (@WeatherWatchNZ) August 15, 2023

MetService’s severe weather outlook said the incoming front would bring rain to northern and western parts of the country and strong to gale-force northeast winds to exposed places.

“The front should move eastwards over central New Zealand on Sunday, followed by a change to colder and showery southwesterlies.

“Meanwhile, the front is forecast to slow down as it moves eastwards over northern New Zealand due to a low developing on the front.”

Showers are predicted to develop in the North Island on Saturday, becoming widespread from Taranaki to East Cape northwards.

Rain is expected to develop in the west South Island with possibly heavy falls on Saturday.