A colder southerly flow is spreading up and across NZ today bringing frosty weather to inland parts of both main islands tonight, in sheltered areas.

The colder airflow is due to high pressure parked near Tasmania – and this placement will send another, weaker, southerly flow into the southern part of NZ on Friday.

This weekend that high – that’s lingered around Tasmania for the past two weeks – will finally drift towards NZ and cross over the North Island from Sunday into early next week. This means, despite some showers, most places are fairly dry for about another week.

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Meanwhile, we have some jet stream action today!

The polar jet stream is ‘spilling over’ into NZ with pulses of cold air from south of the country moving in.

North-East of NZ the subtropical jet stream is helping invigorate a subtropical low, with rain clouds bursting into life. (well offshore).

Jet streams are high altitude narrow and fast moving wind currents. (They are about the same height as commercial jets fly). Winds can be sustained in them at 130 to 440km/h!

North of the sub tropical jet stream lies tropical air… south of the polar jet stream is polar air. In the middle lies the ‘goldilocks’ belt of temperate weather …and that’s where NZ often is. Both move from west to east and snake up and down around the planet. See the animation below.

🛰️🤓Some jet stream action today! The polar jet stream is 'spilling over' into NZ with pulses of cold air. Note the dry air (dark shading) moving into the North Island.

↗️🌀North of NZ the subtropical jet stream is helping invigorate a low, with rain clouds bursting into life. pic.twitter.com/E5jBFUTGBu

— WeatherWatch.co.nz (@WeatherWatchNZ) May 9, 2024

The @NZComCom and NZ Government lose honest credibility when they issue a report then have redacted areas like this:

"The conduct of MetService and NIWA is … [REDACTED]."

Quite possibly the most important part of the report… pic.twitter.com/icxBXF0pTI

— WeatherWatch.co.nz (@WeatherWatchNZ) May 8, 2024

🌡️#1pm temperatures at the top and bottom of the country really illustrate the difference 1600km makes! pic.twitter.com/U8RrUeJW08

— WeatherWatch.co.nz (@WeatherWatchNZ) May 9, 2024

🥶🌡️A number of places are -5C or colder in parts of the South Island's interior as of 7:30am …. some even -6 to -8C.

It's likely to be slightly colder tonight in the North Island. pic.twitter.com/yk4xJtZa8a

— WeatherWatch.co.nz (@WeatherWatchNZ) May 8, 2024

• WeatherWatch.co.nz – Download our new app now! It’s free to download, has paid upgrades – and the free version is larger than MetService & Niwa (Government Agencies) combined!