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Reason for the Season

SATURDAY JANUARY 23, 2010

 

In their June 2006 report the national climate office called June the coldest for 34 years, and in another article they have said it was the coldest for 71 years.  I believe if they looked a bit harder they might find the cycle is closer to 36 and 72 years.  The reason for the cold weather is entirely explainable to anyone open-minded enough to accept the concept that nature does work in cycles, and the weather is no exception.  Readers who purchased Predict Weather Almanac 2006 might want to refer to p41 which says, in the June summary "full moon and southern declination on the 12th, winter may hammer the South island with snow, hail and sleet falling to low levels and making road conditions treacherous in many areas.  Mt Cook may receive snow, also light falls in S Canterbury, Waimate, MacKenzie Country, Queenstown, Ranfurly and Invercargill.  Coastal snow is a rarity in the South Island.."  and in the website ezine... ”the coldest phases this winter will be those days leading up to and during the second weeks of June and July, and the first weeks of August and September.”

 

The entry in the almanac was written two years before and the general gist was that the full moon and southern declination would bring on the June cold event.  Both full moon and southern declination happened on June 12th.  The cold was always going to kick in after Queens Birthday weekend and culminate on 12th.  However, fine weather was around also, especially at the top of the South Island.  May 16 was also the coldest day for the whole country in May.  So what did 12 June and 16 May have in common?

 

Full moons in winter (13 May and 12 June) bring snow to prone areas, but in summer they bring heat-related effects like hurricane/cyclones, such as Hurricane Alberta which formed on 12 June in Florida.  Sporting events on or near summer full moon days can cause heat exhaustion, something the English footballers suffered from on that Monday too.  Believe it or not, the Moon brings both the heat and the cold, depending on the season.

 

The path of the Moon, unlike the reliably annual tracks of the Sun, returns to the same point once every 18.613 years.  This is something called the Declination Cycle, and goes from a maximum situation to a minimum one, which can only be detected if you know what to look for.  Every 27.3 days the moon treks from being over a northern latitude to being over a southern one and back again, crossing the equator twice.  This can be observed by daily watching the point on the eastern horizon at which the moon rises.  This moonrise point slowly progresses 48 minutes later each day along the horizon from due east (lunar equinox) to a northernmost point in the northeast (northern declination), back across the equator (lunar equinox again) to a southernmost point in the southeast (southern declination), then back through the lunar equinox again.  It does that circuit 13 times per year.  The invisible part is that every year over a 9-year period the northern declination reaches to a degree further north and the southern declination to a degree further south.  Therefore at every 18.6 years a Maximum point, north and south, is reached, called the Major Standstill.  The year of it is called the Major Standstill year.

 

If all this is hard to visualise, imagine a very long vertical corridor (world) with an iceberg at either end (poles) and a furnace in the middle (equator).  In this corridor is a movable fan (moon), the source of air-movement in the corridor.  Pretend this movable fan is going up and down every 27 days, one beat or cycle being from a halfway point between top iceberg and furnace (N dec), thence across the furnace (LE), finally reaching a halfway point between furnace and lower iceberg (S dec), and then returning.  This is does continually, without end, the only change being that the fan reaches further towards the icebergs at one time, and recedes to a shallower approach at another .  When - as seen from the northern hemisphere – the Moon/fan is in the southern side of the furnace ((S dec)) it blows hot air all over the place, including back up the corridor towards the upper iceberg.  The warmed air doesn't get very far up and only affects the area up to about halfway (30Ndeg lat).  In summer months it can do heat damage around smaller latitudes on the northern side of the equator.  Witness Hurricane Alberto on 12 June.  When the “fan” is on the southern side of the equator as seen from the southern hemisphere, it blows cold air all over the place, including any regions unfortunate enough to be situated at extreme southern latitudes nearest the “iceberg”.  Witness the snow dump of 12 June.

 

Winter southern declinations always bring snow to the South Island.  But every 18.6 years the moon is the furthest south it ever gets, and as a result record-breaking colder temperatures result and mainly affect those places situated the furthest south.

 

2006 just happened to be the very year of Major Standstill.  On the June south declination day in NZ, the 12th, we experienced the biggest snowfall of the month. The May southern declination was on May 16th and was also the coldest day in May for all NZ.  Tekapo got down to -5.9°C.   At what point does coincidence become predictable rule?  In the ancient past, declination warned villagers of what temperatures to expect because of the moon-influenced air-flows, so state-of-the-art technology then was the erection of a stone circle to keep track of the moon's movements.  The huge immovable marker stones warned you when major standstill years were coming.

 

The last previous major standstill occurred during 1986/87, and a record snow cover occurred in Canterbury and Southland in 1986.  Major standstill before that was 1968, the year of the Wahine Disaster, and 1969.  Two months after Wahine the southern declination was 22 June 1968 and we can go to the Meteorological Gazette, and read:

 

June 1968: “25th - 30th - strong NW to SW winds, several troughs crossing country, snow to low levels..especially around Queenstown”.  July 1968: "In Southland, Otago and inland South Canterbury temperatures 2F-5F below average, the coldest month since July 1938.  The snowfalls on the last 4 days of June on the high country of both islands and to low levels in the South Island persisted for the first 4 days of July.  Frosty conditions, especially during the first half of the month, allowed little opportunity for the snow to melt over the greater part of the South Island.  On the hills to the SW of Mossburn at 2000ft altitude snow depth was 2 ft, and 10 ft in the drifts, remaining frozen there for 3 weeks.  Very severe conditions were experienced, even at quite low altitudes where snow cover persisted.  Tara Hills at 1600 ft (488M) had hard snow lying on the ground the whole month, never less than 5.5 inches in depth.  The mean temp of 23.2F (-4.9C) was the lowest ever recorded in New Zealand below 3000 ft.  On 8 days the temperature failed to reach 32F (0C), the lowest maximum being 20F (-6.7C) on the 14th.  The air temperature fell below 0F (-17.8C) on the 6th, 7th and 14th..."

 

Southern declination was close - on 9 July.

 

There is little doubt it was unusually cold.  Major standstill years before that were 1950, 1931/2, 1913/14, 1894/5.  A new NZ record for lowest temperature was set at Ophir on 3 September 1950, and this was to remain unbroken for 50 years.  25 June 1895 saw a severe snowstorm in Canterbury.  Other bad winter years on cycle halfway points like 1939, 1945 and 1992 also spring to mind.

 

Farmers should always expect cold temperature plunges when full moon and southern declination combine, almost every winter around June through August.  Overlay a major standstill/maximum declination year and you have trouble guaranteed.  A look back through records should confirm this pattern.  Another sure cold time is the true astronomical middle of winter, when the Sun is furthest from Earth, always in the first week of July.

 

Perhaps one day we may see more astronomical regard for the cycles of weather.  This article was written in 2006. It goes on.."until then we can note that further winter southern declination dates for this major standstill year 2006 were July 10, August 6 and September 3.  Civil defence teams and emergency services might also want to keep one eye on the isobars, and at least half the other eye on the movements of the moon.  Following the first week in September, temperatures will rise and spring will take off rapidly.  December will be a pleasant month and may be a good time to take holidays, because two cyclones, in the second week in January and first week in February, will make holiday-planners fume.  In the North Island continuous summer weather may not really kick in until the last part of February, over March and in the beginning of April.

 

It will be a mixed blessing for North island skiers.  Ruapehu will not lack for snow, but winds and visibility may hamper activities, continuous fine spells not clicking in until November, long past the time the mountain will be closed.  South Island ski fields will be better off this winter because skies will be clearer and the cold temperatures will mean snow machines can be effective.

 

It is winter time, and we shouldn’t be surprised that temperatures drop.  The last two years have served mild winters but they have been exceptions rather than the rule.  Milder winters should return around 2012."

 

 

© Ken Ring 2006


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