The NINO3.4 index is one of several El Niņo/Southern Oscillation (ENSO) indicators based on sea surface temperatures.
NINO3.4 is the average sea surface temperature anomaly in the region bounded by 5°N to 5°S, from 170°W to 120°W. This region has large variability on El Niņo time scales, and is close to the region where changes in local sea-surface temperature are important for shifting the large region of rainfall typically located in the far western Pacific.
An El Niņo or La Niņa event is identified if the 5-month running-average of the NINO3.4 index exceeds +0.4°C for El Niņo or -0.4°C for La Niņa for at least 6 consecutive months.
Sydney-siders have been spoilt for choice in the surf department over the past few days.
Severe thunderstorms sparked up just to the west of Lochington yesterday late morning, tearing through many parts of southeast Queensland into late last night.
A very cold airmass coupled with vigorous a low pressure system caused snow to fall to low levels in Tasmania last night and into this morning, leading to road delays and closures.