Tuesday, 5 October 2021 - Monthly Climate Summary for New South Wales - Product code IDCKGC15R0

New South Wales in September 2021: Wet inland and warm days

September in New South Wales was wetter than average, with widespread falls in inland areas at the start and end of the month. Daytime temperatures were generally above average across the state, although nights were relatively cool. At the end of the month a slow-moving inland trough generated severe thunderstorms, with a tornado confirmed near Bathurst on the 30th.

Wet inland

• September rainfall was 20% above average for New South Wales as a whole at 42.4 mm, the wettest since the record rainfall in 2016.
• Rainfall was above average in all inland areas except for parts of the far west, although it was below average for most coastal areas.
• The rainfall pattern was consistent with the weak negative Indian Ocean Dipole, where relatively warm water off the Australian north-west coast acts as a source of moisture for inland areas.
• On the 3rd and the 4th a cold front combined with moist tropical air to bring daily rainfall of 25 to 50 mm to southern areas and the Western Slopes.
• At the end of the month a slow-moving inland trough brought up to 60 mm in the 24 hours to 9am on the 30th to the North West Slopes and Central West Districts.
• Some sites, including Moree and Walgett Airports, had their highest September daily rainfall on record.
• The snow depth at the Snowy Hydro Spencers Creek site decreased from 161.1 cm to 122.6 cm during September, comparable to 2016 but less than the 182.7 cm at the end of September 2019.

Warm days, relatively cool nights

• The September mean maximum temperature for New South Wales was 1.42 °C above the 1961–1990 average.
• Cloudy and wet conditions meant that this was the coolest September for the state since 2016.
• Daytime temperatures were generally above average in the west of the state, and in most coastal areas except the Northern Rivers district.
• It was warmest at the start of the month, with the state's highest temperature for September of 33.8 °C recorded at Menindee and Pooncarie in the Lower Western District on the 2nd.
• Broken Hill Airport equalled its warmest September night on record with 21.5 °C on the 3rd.
• Night-time temperatures were close to or below average for most areas except for the south-east of the state.
• Narrabri Airport had its lowest September mean daily minimum temperature on record and three other sites had their lowest since 1994.

Severe thunderstorms at the end of the month

• On the 29th and 30th many inland areas had severe thunderstorms, with damaging winds, hail and heavy rain.
• This was generated by a slow-moving surface trough, with a band of middle to high level cloud across the eastern states drawing tropical moisture south.
• Giant hail (5 to 7 cm in diameter) was reported 40 km north of Bourke on the 29th, with further reports of large hail from Cunnamulla and Eulo.
• Smaller hail (up to 2 cm in diameter) was reported in Canberra and Sydney.
• A tornado on the 30th was confirmed at Clear Creek and Meadow Flat near Bathurst, with damage to houses, powerlines, and trees.
• There were reports of two other tornados on the 30th near Narrabri and Mudgee.

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top

Maps
	Observed	Anomaly	Decile rank
Total rainfall
Mean daily maximum temperatures
Mean daily minimum temperatures

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Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top