Cold n Wet

Tawa’s weather for the three weeks to June 21st has been colder and wetter than last year.

Whilst we have been spared the snowfalls that have bedevilled many parts of Otago and Canterbury, we have had several southerly blasts that have lowered temperatures and brought steady rain with occasional bright sunny interludes.

So far this June, 92 mm of rain has fallen and the average temperature has been 8.4°C. Last year, we had 48 mm of rain during the entire month, and the average temperature was 9.7°C.

The recent cold snap caused a new record in electricity consumption to be set on the evening of June 19th when nationwide consumption reached 6630 MegaWatts (MW) between 5:30 and 6:00 p.m., 2% higher than the previous record set in August 2004.

Every cloud has a silver lining, and the South Island’s spell of bad weather has helped to improve hydro lake storage. Whilst storage on Fri 16th June was still below average at 2471 GWh (88% of average), inflows have been above average in the week to June 16th, reversing a trend of below average or negative inflows that applied during most of May. It is expected that the accumulated snow will boost wintertime inflows as it melts. Provided, of course, that the beleagured residents of parts of the South Island get a chance to thaw out.

The National Institute of Water and Atmospherics (NIWA) forecast for the three months to August 2006 predicts that in “the main South Island hydro catchments, near normal seasonal rainfalls are the most likely outcome.” If so, this would dramatically improve the hydro lake storage levels.

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