Topic: Cold snap through the Northern Territory

[Mike]

Well it's official.  June 2007 the coldest in 40 years and yesterday the coldest day on record.  Our maximum temps for the week ranged from 24- 20C.  BoM reports that a slight shift in the Tropic of Capricorn by a few metres is the cause.

 Normally with the Easterly high pressure dominance during the dry we get lovely warm weather and cool nights, but with this NW cloud cover blanket associated with the jet this has capped any warming.  We have not seen the sun in three days and we've had significant rainfall in the NW NT and the previous two nights very light constant 'rain'.

I can tell you that every Territorian is shivering and have gone out and bought jumpers and jeans - and believe it or not - Ugg boots!

Mike

[Jimmy Deguara]

Mike,

BoM reports that a slight shift in the Tropic of Capricorn by a few metres is the cause.

Please elaborate further?

Regards,

Jimmy Deguara

[Mike]

This is a quote from Blair Trewin, Climatologist with the BoM.

I know what you are asking and the answer is that I paraphrased 'shift' for 'axis'.  No harm done.

'I've done a search for sub-10 maxima in the tropics - haven't looked in detail at site records yet. Defining the 'tropics' is trickier than I thought because the Earth's axis wobbles a little over time and the position of the Tropic of Capricorn moves at a rate of a few metres per year - and Longreach is so close to the line that, on its present position, the current site is in and the old site is out, but the old site was probably in at the time it got its sub-10 in 1908. For the purpose of this exercise I've used the current value (quoted in Wikipedia) of 23 deg 26 min 22 sec.

There were 13 sub-10 maxima in the tropics yesterday, 8 in Queensland and 5 in the NT. Before yesterday there had only been 12 in the entire record (and no more than 2 on any day), all but one of them in the NT (5 of them at Yuendumu, which also scored yesterday).

Tennant Creek Airport's 8.0 is the northernmost sub-10 max ever in Australia, albeit only just (the old record was at the old PO site, 900 metres to the south). Camooweal's 9.8 is the northernmost recorded in Queensland.

Three sites broke Yuendumu's old record (8.2) for the lowest max ever recorded in the tropics, with the lowest being 7.7 at The Monument (near Mount Isa).

Outside the tropics, Applethorpe's max of 4.9 is a Queensland record for June.'

[Geoff Thurtell]

Mike,

Quote: "Well it's official.  June 2007 the coldest in 40 years and yesterday the coldest day on record.  Our maximum temps for the week ranged from 24- 20C.  BoM reports that a slight shift in the Tropic of Capricorn by a few metres is the cause. "

May I suggest that you be more careful with your wording. In your initial submission it appears that you are implying that the slight shift in the position of the Tropic of Capricorn was the cause of the low temperatures. This is obviously not the case. Blair was just referring to the slight shift in the Tropic as a criteria for which maximum temperatures were included as being "in the tropics".

There have been some amazing low maximum temperatures in tropical Australia last week. I saw on the news that Cairns had a maximum of only 17 degrees on either Thursday or Friday. I am not sure which day it was as I am just recalling a fleeting glimpse that I saw on the TV.

Hopefully this change in weather pattterns is further indication that more rainfall is on the way for the drought affected areas.

Geoff

[Mike]

Thanks Geoff, albeit i did refer to my paraphrasing of the words used to correct my statement.  Tis done and over with and will not, as in the past, take any critique personally - yet take onboard replies to my honest mistakes as reminders to correct wording to express an opinion.

All good.

Mike