Source: NIWA
The Seasonal Climate Outlook for December-February (summer) is attached, along with graphics for your use.
Highlights:
- El Niño has around a 100% chance of persisting through summer and an 85% chance of persisting through autumn. However unusual ocean heat in the western equatorial Pacific and on a global scale has contributed to circulation patterns that are not typically associated with a traditional El Niño.
- Summer air pressure above normal north of New Zealand and below normal to the south is expected to cause more northwesterly quarter winds than normal. However, the effect of a non-traditional El Niño will likely encourage increased variability in circulation patterns and air flows as compared to historical El Niño summers.
- Summer rainfall most likely to be near normal in the north of the South Island, near normal or above normal in the west of the South Island, and near normal or below normal across the remainder of the country.
- Areas of heavy rain are possible in the North Island during the first week of December.
- Strong lows will occasionally deliver heavy rainfall and flooding risk for the western and lower South Island in mid-to-late December.
- Temperatures most likely to be above average in the east of both islands and the north of the North Island, and near average or above average in all other regions. Hot, humid spells look likely during December.
- Despite the non-traditional El Niño impacts, an increased awareness around the risk for dry spells is recommended across several regions.
- Seasonal wind strength is forecast to be above normal across most of the country.
- As of late November, fire danger was low across the country. Variable fire danger conditions are expected in December. For more info: www.checkitsalright.nz
