Dr Kathleen Kozyniak
Principal Scientist Air
Hawke’s Bay Regional Council
June rainfall exceeded expectations and put any suggestion of a potentially drier than normal winter on very shaky ground. The region received roughly double the month’s long term average, breaking the drought that has plagued us since last November. July has had a cautious start and after the first week we range from 20% of average July rainfall in the region’s north to 5% on the Heretaunga and Ruataniwha Plains.
Soil moisture levels have recovered well and typically sit at or above median levels for the time of year. The levels at our Bridge Pa site even managed to sneak into the top 10th percentile of readings at the end of June. Quite a turnaround from record lows leading into the month. June’s air temperatures were 1-2°C above average, with the night-time temperatures particularly warm due to grim but welcome weather, narrowing the diurnal temperature range – only a few degrees on a number of days. That kept June’s soil temperatures above average and mostly in double digits, which hopefully meant some growth for plants that were previously water limited.
The prospects ahead are mixed. Metservice has a forecast for normal or below normal rainfall for July. NIWA is picking normal or above normal rainfall for the July to September period and above average temperatures. The seasonal forecast models suggest higher than normal sea level pressure to the north and southwest of us. That would favour westerly winds and potentially drier conditions, with the odd icy blast coming from the south. However both NIWA and the Australian Bureau of Meteorology are on “La Niña watch” for our spring and summer and it’s 50:50 whether it will develop or we’ll remain in neutral mode. A developing La Niña might mean we start to get more easterlies than anticipated, as we did during June, which would bring an increased likelihood of near normal rainfall.
June 2020 Rain Map