MONTHLY WEATHER REVIEW - ARMIDALE NSW

SEPTEMBER 2011

September 2011 was a mild to warm, mostly sunny month with good falls of rain.

The rainfall total of 73.8 mm was well above the average with the majority falling during the last week of the month.
Day temperatures were close to normal, but overnight minimums were a little lower than normal due to a number of calm clear nights. Maximums exceeded 20.0C on eight days. There was one notable temperature extreme detailed below.

There were thunderstorms on three days. None of these storms produced hail, although there were two falls of small hail on the 29th not associated with storms. See below.

Prevailing winds were moderate westerlies.

Noteworthy events:
9th - A surface trough and an upper level pool of cold air moved through the region during the day and evening bringing gusty winds, low temperatures and moderate rainfall. The coldest air arrived in the evening and early the following morning, but temperatures were not quite cold enough for snow. There were light snowfalls on the higher parts of the Northern Tablelands including Ebor and Guyra. Armidale’s maximum temperature on the 9th was 8.1C, the lowest for the month of September since 12th Sept 1991 (7.4C). Total rainfall from this event was 16.8 mm.
29th September - A strong cold front passed through with moderate rain and strong winds. Total rain from the system was 45.4 mm which caused moderate flooding in Dumaresq Creek. There were two light falls of soft hail (up to 3mm diameter) at around noon and at 4.15pm. Winds were strong during the afternoon gusting up to 70 km per hour between 2 and 3.30pm, and up to 87 km per hour between 6.45 and 6.50pm at the airport.

SEPTEMBER STATISTICS (long term averages in brackets):

Rainfall: 73.8 mm (51.4mm)

Rain days: 7 (8)
2011 rainfall total Jan to Sep: 616.4 mm (547.3 mm)

Average maximum temp: 17.8 deg (17.5 deg)

Average minimum temp: 1.8 deg (2.6 deg)

Highest maximum temp: 24.3 deg on the 19th

Lowest maximum temp: 8.1 on the 9th

Highest minimum temp: 10.8 on the 29th

Lowest minimum temp: -4.0 on the 13th

Fine sunny days: 22 (19)

Ideal weather days: 4 (2.5)

Days with thunderstorms: 3 (2)

Days with frosts: 16 (15)

Days with fogs: 1 (2)

Wind direction at 3pm & number of days: W: 13, SW: 8, E: 3, NW: 2, SE: 2, NE: 1, S: 1

Average daily evaporation: 2.8 mm (3.2 mm)

Thunderstorm details:

8th: 5.30am approx. - thunder heard, no rain
7.00am approx. - thunder heard, no rain

24th: 6.30-7.30pm heavy storm from west

25th: 1.00-3.00am - slight & moderate storms
9.05-10.00am - thunder heard, no rain