ClimateWatch: AUGUST has more BIG highs & lows slowly moving through (+9 Maps & Video)

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ClimateWatch: AUGUST has more BIG highs & lows slowly moving through (+9 Maps & Video)

1/08/2024 2:24am

The winter of “big air pressure” continues around NZ with another massive high pressure zone kicking off the first week of August. In fact some modelling suggests it dominates our weather for the first half of August bringing drier than usual weather across much of NZ.

An area of low pressure lingers for the first three or four days of August though – bringing rain and showers to the upper North Island.

Behind this high pressure zone in half a month might be a low with sub-tropical connections, but at this early stage it’s too far out to lock in.

The general theme for AUGUST is similar to JUNE & JULY with more slow moving, and very large, highs and lows.

The neutral weather pattern we’re in looks to remain in play for the rest of 2024.

Still in NEUTRAL – remaining in a La Nina WATCH (which suggests we’re leaning towards LN).

The model of all models shows NEUTRAL is likely for the rest of 2024 – meaning the weather pattern we have now may continue on into spring.

Pacific Ocean’s La Nina update, and the Indian Ocean’s Dipole are both in NEUTRAL.

**WEEK 1** – A massive high pressure zone lies over Australia and stretches down to almost Antarctica. It’s this anticyclone that brought snow to NZ in the last week of July and is feeding in the colder south-east to easterly flow into NZ for early August. A weak low pressure zone remains over northern NZ for the first weekend of August.

**WEEK 2** – Kicks off with that same anticyclone from Week 1, stretching out and over NZ to the north. This encourages west to south-west winds for a time over NZ. But overall this high pressure zone looks to dominate NZ’s weather for the first half of August. A giant low pressure zone remains south of Australia, also encouraging a westerly flow.

**WEEK 3** – The controlling high pressure zone is now east of NZ and, if this maps holds true, could encourage a mild subtropical airflow down into NZ – and may also help spin a new low pressure zone in the north Tasman Sea Sea. Outside of that, high pressure looks dominant over Australia and coming in from the Indian Ocean, while most other lows remain contained south of both nations.

**RAINFALL** for the first half of August shows a ‘rain shadow’ effect in the east and central areas… this is when the weather flow tends to be tracking from west to east and the mountains and ranges block rain from spreading eastwards. Cantabrians may be the most disappointed with this set-up.

KEY:
Green to Blue 1 to 15mm.
Yellow & Gold: 15 to 40mm.
Red: 60 to 100mm.
Purple to dark blue: 100mm+

MARINE – And thanks to the Moana Project as you can see temperatures are creeping up above normal across NZ from a marine perspective, particularly around the North Island. Outside of what this does to the marine world, from a weather perspective it means slow moving coastal rain/downpours can get more energy and becoming heavier.

**SOIL MOISTURE –** As of 9am July 31 Canterbury remains much drier than average – mostly central and north Canterbury.

WeatherWatch.co.nz / RuralWeather.co.nz / Alerting App

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