It was drier than usual in Otago but otherwise it was a typical spring October, consultant hydrologist Dave Stewart says.
Periods of dry, anticyclonic weather were interspersed with unsettled periods bringing fronts, troughs and southwesterly airstreams, which spread some rain to the whole region from time to time, he said.
Rain occurred in the west, with the approach of the fronts and troughs, and in the east with the passage of these rain-bearing systems and their following southwest airstreams.
The wet weather occurred on October 8-10, 16-21 and 27-28, with mainly dry conditions otherwise, Mr Stewart said.
It meant farmers around the region were now hoping for rain to improve soil moisture levels.
The region was also quite windy at times and became quite cold in the middle of the month as a cold southerly brought some snow down to 500m-600m on the hills, he said.
In North Otago, October was generally quite dry, with all sites recording below average rainfalls.
"The combination of drier weather and wind has seen this area dry out quite quickly and this is reflected in the declining river flows."
Rainfall totals at the indicator sites (average monthly totals in brackets) were: Waikoura 15mm (49mm) 70% below average; Oamaru Airport 22mm (39mm) 45% below average; Oamaru 18mm (44mm) 60% below average; Kauru, the Dasher 36mm (63mm) 44% below average; Islay Downs 35mm (49mm) 29% below average; Palmerston 24mm (49mm) 51% below average.
Significant falls were: October 10, Islay Downs 14mm, and Oamaru Airport 13mm.
River flows were below their long-term averages.
Flows improved for a time after the rain on the 17th.
Farmers reported the ground had dried out considerably due to the lack of rain and occasional windy conditions.
In Central Otago, rainfall totals were generally below average but conditions were very good at present, he said.
Total falls were: Lindis Crossing 18mm (45mm) 60% below average; Cromwell 16mm (39mm) 58% below average; Alexandra 18mm (25mm) 30% below average; Merino Ridges 23mm (38mm) 41% below average; Ranfurly 20mm (40mm) 51% below average; Significant falls were: October 8-9, Tima 26mm and October 19, 14mm.
Average monthly river flows were close to their long-term averages as snowmelt boosted flows, which generally declined throughout the month.
Farmers reported good growth as frosts ceased.
In Lakes Wanaka, Wakatipu and Hawea and surrounding areas rainfall was generally well below long-term averages but farmers reported a very good month, Mr Stewart said.
Total falls were: Makarora Station 109mm (252mm) 57% below average; Hunter Valley Station 42mm (103mm) 60% below average; Glenfinnan 128mm (208mm) 39% below average; Hawea Flat 27mm (65mm) 59% below average; Routeburn Station 144mm (245mm) 42% below average; Queenstown 61mm (82mm) 26% below average.
Significant falls were: October 8-9, Makarora 27mm, Glenfinnan 31mm, Routeburn 50mm, Queenstown 31mm; October 16-17, Makarora 41mm, Glenfinnan 36mm, Routeburn Station 26mm; and October 19th, Makarora 22mm, Glenfinnan 28mm.
Average monthly river flows were well below their long-term averages.
Lakes Wanaka and Wakatipu began the month at 277.66m and 310.17m above sea level, 0.20m and 0.05m above average respectively.
Lake levels declined slowly and while rainfalls were well below average, snowmelt later in the month slowed the rate of decline.
By the end of the month, Wanaka had fallen to 277.28m and Wakatipu to 310.00m, 0.2m and 0.13m below average, respectively.
Lake Hawea rose 1m as Contact Energy released only the minimum flow.
The lake level at the end of October was 342.98m, 3m below its full level.
In the Strath Taieri, Lower Taieri and Dunedin rainfall was below average.
Total falls were: Garthmyl Middlemarch 21mm (49mm) 58% below average; Musselburgh Dunedin 28mm (62mm) 56% below average; Lee Flat 59mm (65mm) 9% below average; Maungatua 54mm (71mm) 24% below average; Dunedin Airport 34mm (57mm) 40% below average; Pine Hill 32mm (69mm) 54% below average; Other rain gauge totals were Sullivans Dam 59mm and Southern Reservoir 32mm.
Significant falls: October 10, Lee Flat 15mm and Maungatua 11mm.
River flows were close to or just below their long-term averages in the larger rivers mainly due to snowmelt, while in the smaller rivers and streams flows were well below their long-term averages.
Higher temperatures at times caused more snowmelt and boosted flows occasionally in the larger rivers, he said.
Farmers reported conditions improving after the middle of the month and good growth occurred after that.
In South and West Otago, rainfall totals were close to or above average, the only part of Otago that had close to average rainfalls, Mr Stewart said.
Total falls were: Tuapeka Mouth 60mm (60mm) average; Balclutha 49mm (60mm) 18% below average; Slopedown 137mm (127mm) 8% above average; Moa Flat 71mm (82mm) 13% below average; Clarks Flat 75mm (65mm) 19% above average.
Significant falls included: October 8-9, Tuapeka Mouth 33mm, Balclutha 19mm, Waikoikoi 28mm, Slopedown 35mm, Moa Flat 23mm, Clarks Flat 33mm; October 19-20, Balclutha 19mm, Waikoikoi 32mm, Slopedown 56mm, Moa Flat 18mm, Clarks Flat 19mm.
River flows were above their long-term averages as a combination of close to average rainfalls, very wet ground, and snowmelt combined to create good flows in the rivers.
Flows generally declined during the month to below average.
Farmers reported good conditions and good growth in the last two weeks of October as the weather warmed up, Mr Stewart said.
