The next half of 2014

With half the year gone we might look at what the second half may bring. This recent storm has been due to the approach of July's perigee, the day in any 27.5-day month that the moon passes closest to earth which typically brings extreme weather in winter, especially around full moon. It is the time the moon’s orbital speed increases relative to that of the earth creating more atmospheric turbulence. One can liken the air to the sea, where for more water to fill a bay on a king tide, the currents must increase in speed. For most of the country skies should clear next week.

Because the earth rotates beneath the moon every 24 hours perigees have global effects. Currently severe storms are affecting Philadelphia, South Australia is snowing, rain will soon hit Victoria, and Thailand, Perth, Sydney, Brisbane and much of Ireland may get rain next week. The moon has been getting slightly closer over recent months. June’s perigee was seventh closest for the year and the July’s is fourth closest. Perigee exaggerates any season. The closest perigee for 2014 is 11 August, then the moon starts receding. July and August will be worst for wintry winds but will be the warmest months in the northern hemisphere summer.

June’s storm is still fresh in our minds. Wild conditions on 9- 11 June just 3 days before perigee brought destructive weather that knocked out all power in Auckland. The bad weather wasn't just in NZ - there were tornadoes in Nebraska, a car was hit by lightning in Canada and Australian ski fields went from nothing to receiving ski-able snow within 24 hours. There was a typhoon in Japan, with a repeat typhoon in the same region in the past few days.  Strong weather should happen again for NZ around August’s perigee in the second week.

For much of the North Island It may not get any colder than in June’s last week, except for Taranaki and Wellington. July will be the coldest month of the year for most of the South island. For the rest of winter the North Island may be mild. However Auckland should still be cool enough over coming weeks to run heaters, with temperature swings in the second weeks in August and September.

In August the first and second weeks are both wet in the North Island and the first week brings the most August rain for the South Island.  September is its wettest in the second and third weeks for both islands.  October is relatively dry for all, with least rain in the first week but intermittent rain over the rest of the month.  In November only the north and south of the North Island may receive heavy rain. Overall November is wetter for the South than the North with the exception of parts of Canterbury.  This is reversed in December with heavy falls for the North Island in the second and last weeks, but only in the west and south of the South Island.

A mild autumn and early winter was predicted for the North Island, with not much ski-able snow until mid July. Although snow arrives fairly frequently, alternately mild conditions take their toll. The South island was predicted to be cool enough for snow machines, and for southern snowfields to enjoy a longer ski season than North Island fields. There is another polar blast expected to bring more snow in the last 10 days of July. The North Island may only be suitable for skiing 13-19 July, whereas Queenstown will be worth visiting anytime after 13-25 July, or around 7-12 and 17-23 in August.

In Waikato, Bay of Plenty, Hawkes Bay, East Coast and Manawatu, June was the coldest month and frosts should abate after September. For Taranaki, July may be the coldest month. Wellington receives frosts up to September and August may bring Wellington’s lowest temperatures. In the Central Plateau although June was the coldest month for the year, intermittent subzero minimums may continue until November. In the South Island, July may be the coldest month for most. Marlborough, West Coast and Southland may receive frosts until September, Otago until October, and Christchurch could receive frosts until November.

The reason for milder North Island temperatures are full moon and perigee together this year in winter months which is a 9-year cycle, and the current solar peak that is bringing higher temperatures globally. There is also an El Nino expected in July of 2015 (not this year as most forecasters were predicting).  El Ninos with anticyclones and clearer skies create better conditions for snow storage, less cloud, less low pressure and less runs of milder temperatures.

The cyclone season in the south Pacific and Australia runs from November to April. Cyclone seasons increase in intensity when the moon comes averagely closer to earth which will be from March next year onwards. Cyclones Lusi and Ita were early signs and 2015-17 brings renewed intensity. The coming cyclone season will stronger than last year but not as powerful as the year following.

Potential days when earthquakes are strong enough to be felt are of interest to some.  They often cluster in prone areas before the closer perigees of a year and their associated king tides. There have already been a handful of 3-4-magnitude events in NZ in the past few days, together with a 6M in Vanuatu, a 6M in Japan, and a 7M in Mexico. The next moderate risk dates in July may be 11th -14th and 19th - 28th.  As for larger events in coming months, watch 7 August, 14 October and 8 December. However Christchurch is not expected to receive a significant sequence for another 14-16 years.

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