MONTHLY WEATHER REVIEW - ARMIDALE NSW

OCTOBER 2012

October 2012 was a dry, warm and sunny month.

The rainfall total of 19.6 millimetres was the lowest for the month of October since 1951 (14.1 mm). Most of the rain (16.8 mm) fell during one event on the 11th and 12th.

It was very sunny month which resulted in higher than normal day temperatures and lower than normal overnight temperatures which in turn meant more frosts than normal. There were two notable temperature extremes on the 12th and 20th - see below.
Winds were mostly light to moderate westerlies, and there were no thunderstorms, which is most unusual for October.

Noteworthy events:
12th - Snow fell on higher parts of the Northern Tablelands with moderate settling falls in Guyra, Black Mountain and Ben Lomond. Light snow also fell in Uralla and Glen Innes. In Armidale there were a few very light snow showers, and some soft hail (sleet/sago snow) during the morning. The showers cleared after 1pm. The maximum temperature for the day was just 7.7C with strong winds reducing the wind chill temperature at 3pm to around zero. This was Armidale’s coldest October day on record (73 years of records).
In Guyra snow was 17 cms deep on the ground at 9am, and it was claimed by some residents to be the heaviest for at least 20 years.
The extreme conditions were caused by cold surface temperatures following the passage of a trough, enhanced by an upper level cold pool, with moisture being added to the system by a low pressure system off the NSW coast.

20th - Very warm air being drawn in from the centre of the continent by a trough created windy and hot conditions over northern New South Wales with temperatures reaching the high thirties over parts of the inland and north coast. Armidale’s maximum of 29.6C was the highest since 15th November 2011 (30.3C), and was the hottest for the month of October for ten years since 19th October 2002 (31.5C).

14th - 27th - A large bushfire burning east of Armidale in the Macleay River Gorges created a thick smoke haze over the Armidale area on a number of days (when the winds were south-easterlies) including the 14th, 18th, 22nd, 23rd, 24th and 27th.

OCTOBER 2012 STATISTICS (long term averages in brackets)

Rainfall: 19.6 mm (68.5 mm)

Rain days: 5 (9)
2012 rainfall total Jan to Oct: 453.8 mm (616.2 mm)

Average maximum temp: 21.7 deg (20.4 deg)

Average minimum temp: 3.9 deg (5.6 deg)

Highest maximum temp: 29.6 deg on the 20th

Lowest maximum temp: 7.7 deg on the 12th

Highest minimum temp: 10.8 deg on the 7th

Lowest minimum temp: -2.6 deg on the 1st

Fine sunny days: 21 (18)

Ideal weather days: 2 (2)

Days with thunderstorms: 0 (4)

Days with frosts: 11 (6.5)

Days with fogs: 0 (2)

Wind direction at 3pm & number of days: W: 15, SW: 8, S: 3, SE: 3, E: 2

Average daily pan evaporation: 4.5 mm (4.1 mm)