Latest news with #LaNina-like
Otago Daily Times
08-07-2025
- Climate
- Otago Daily Times
More drenchings forecast
A truck and a car negotiate recent flooding in Portobello Rd, near Bays Junction. PHOTO: STEPHEN JAQUIERY More significant rainfall and flooding events may drench coastal parts of Otago over the next three months, as moisture from the tropics and low pressure systems flow over the country. Earth Sciences New Zealand (formerly Niwa) forecasting principal scientist Chris Brandolino said global climate models were strongly signalling the possibility of enhanced low-level convergence in the western Pacific and areas north of New Zealand. "This could draw tropical and subtropical air masses into our region, increasing the likelihood of wetter-than-normal conditions over the next three months. "There is therefore an elevated risk for heavy rainfall events, including those associated with landfalling atmospheric rivers." It could lead to potentially significant rainfall and flooding events, he said. However, it also meant seasonal air temperatures between July and September were expected to be above average across all regions of New Zealand. "Thus, while cold snaps and frost will occur, they are expected to be less frequent than usual." Around coastal Otago, temperatures were most likely to be above average, rainfall totals were about equally likely to be above normal or near normal, and soil moisture levels and river flows were about equally likely to be near normal or above normal, he said. "Chances for heavy rainfall events are considered elevated during the three-month period, potentially leading to flooding, particularly in areas with saturated soils." On the West Coast, Southern Alps and foothills, inland Otago, and Southland, temperatures were also most likely to be above average, he said. But rainfall totals were about equally likely to be near normal or below normal, soil moisture levels were about equally likely to be near normal or above normal, and river flows were most likely to be near normal. Mr Brandolino said Enso-neutral weather conditions remained present in the tropical Pacific. Last month, atmospheric patterns in the Pacific continued to be intermittently consistent with weak La Nina conditions, but more recently, ocean temperatures had shifted away from previous La Nina-like characteristics.
Otago Daily Times
01-06-2025
- Climate
- Otago Daily Times
A warmer winter is on its way
Electricity bills may deliver less of a hammering this winter if Niwa's outlook for the next few months comes to fruition. It shows temperatures from June to August are "very likely" to be warmer than average this winter, meaning fewer cold snaps and frosts than usual. Niwa National Climate Centre forecasting principal scientist Chris Brandolino said El Nino Southern Oscillation (Enso) conditions in the tropical Pacific remained neutral at present, but there were "residual signals" that indicated weak La Nina conditions were persisting. Occasional La Nina-like atmospheric patterns might still emerge over the next three months, he said. "However, international guidance indicates about a 70% chance for the tropical Pacific to remain in an Enso-neutral state over the next three-month period." He said higher-than-normal atmospheric pressure was expected to the east of the country, leading to northeasterly flow anomalies that might shift to a more northwesterly direction towards the end of the three-month period. That means seasonal air temperatures are expected to be above average across all New Zealand regions for the winter season. "While cold snaps and frosts will occur, they are expected to be less frequent than usual." On the West Coast, Southern Alps and foothills, inland Otago, and Southland, temperatures were very likely to be above average, he said. Rainfall totals, soil moisture levels and river flows are about equally likely to be near normal or above normal. Temperatures were also very likely to be above average along coastal Otago, he said. "Rainfall totals are most likely to be in the near normal range, and soil moisture levels and river flows are about equally likely to be near normal or above normal." Mr Brandolino said for the remainder of the calendar year, Enso-neutral conditions were expected to persist. "The guidance available, however, suggests the possibility for La Nina conditions to return by summer 2025-2026." La Nina can bring more northeasterly winds to New Zealand, leading to drier conditions in the south and southwest of the South Island.
