Golly, we’ve now racked up four consecutive wet months thanks to October delivering above normal rainfall. The Heretaunga Plains, Tangoio and southern coastal parts of the region saw 40% more rainfall in October than usual and the Ruataniwha Plains an extra 30%.
River flows were all above average in October unsurprisingly and so too were the majority of the groundwater levels the Regional Council measures. Soil moisture levels have continued riding high. Spring is when we typically see a steady drop in soil moisture but it just hasn’t had a chance to happen yet. Instead we’re seeing levels either still at field capacity or at least above median levels for the time of year.
Air temperatures were a little grim during October. Daytime temperatures were 0.5°C below average, while overnight and soil temperatures were near normal. As we hit the middle of November, soil temperatures are starting to edge above average and sit between 17-19°C on the Plains, boosted by sea temperatures that recently have been rising above average.
The La Niña event, which has been the chief culprit of our wet weather along with a negative Indian Ocean Dipole, is expected to rattle on through the next few months and then wane to neutral conditions towards the end of summer. At this stage neutral conditions is the most favoured outcome of the forecast models, while an El Niño event gets second rating above a continued La Niña. But for now our La Niña influenced weather isn’t expected to change drastically. That means more easterlies and continued potential for them to bring moisture with them. Hence the seasonal forecast is for normal or above normal rainfall and near or above average temperatures. Heck, northern parts of the region have already received above normal November rainfall while southern areas are making inroads at 50-60%.
Percentage of Normal Rainfall
Dr Kathleen Kozyniak
Principal Scientist Air
Hawke’s Bay Regional Council