Thursday, March 28, 2024

PULSE: Polar vortex moderates La Niña

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Weather forecasters have been talking about La Niña with growing certainty, and this month La Niña conditions developed with greater intensity. However, a chaotic weather pattern in the lead up to summer and a polar vortex generating more storm activity in the Southern Ocean is limiting the strength and length of this year’s La Niña.
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This spring, the weather has been very haphazard. Early highs stirred up unpleasant memories of a drought that some farmers had only just put behind them. The low pressure systems of the past two weeks freshened up pastures across the North Island with much-needed rain. They also installed low temperatures in the South Island, with the potential for frosts in the next few days.

According to WeatherWatch’s Phil Duncan, a chaotic weather pattern is preferable because it creates more variant weather across regions, and that has the potential to reduce, or limit, summer droughts.

So far, the traditional La Niña pattern of more clouds in north-east areas and drier conditions in the south-west appear to be coming to fruition, but forceful southerlies are mitigating the severity somewhat. In fact, early lambing country like Hawke’s Bay is in need of some hotter days to harden feed, as soft grass and cooler temperatures hinder lamb growth.

The last time a La Niña weather system dominated New Zealand was summer 2010-11. There was no polar vortex to soften the blow, and both islands dried out significantly before receiving rainfall in January.

Less feed availability weakened the store lamb market and schedules in the summer of 2010-11. Throughout summer, ram lamb prices deflated in the face of dry conditions, until rainfall recovered pastures and the market bounced back in February. At the time, heavy ram lambs sold for $3/kg, and greater confidence in lamb growth lifted the price of light ram lambs to $3.20/kg.

After lending itself to a depressed market, the La Niña of 10 years ago trounced the trend of the past five years, when heavy ram lambs have devalued by 24c/kg from the start of December to the end of February. This trend is to be expected because demand dips once early lambing country exits the market. Last week, most North Island store lambs were selling for $3.50-$3.80/kg.

AgriHQ observed that the frenzied lamb trading earlier in the season left North Island store lamb prices overcooked compared to schedules. Farmers are now focusing on finishing the lambs they have on hand and have less interest in re-entering the market, so it is widely expected prices will decrease to better align with slaughter values, regardless of La Niña’s impact.

A moderate La Niña, with less drought potential, should not aggravate price drops and could maintain buying power in north-eastern areas, which normally dry off earlier. However, let’s not count chickens before they hatch.

All farmers should take heed of the La Niña prediction, if only to be on a greater lookout for facial eczema (FE). Warm, moist conditions create an optimal environment for spore growth in pastures. Farmers who face an outbreak of FE this summer will have more to worry about than any upsets that may eventuate in the store market, particularly if last year’s mild season has resulted in some complacency around FE management.

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