Monday, 3 August 2020 - Monthly Climate Summary for New South Wales - Product code IDCKGC15R0

New South Wales in July 2020: heavy rain along the coast

Two low pressure systems in the Tasman Sea brought heavy rain, flash flooding and high seas to the coast this month. In contrast, persistent anticyclones meant that the Riverina and far west continued to see drier than usual conditions. Maximum temperatures were average to above-average across the state.

Heavy rain from two lows

• Two low pressure systems in the Tasman Sea during July brought heavy rain, isolated flash flooding and high seas along the state's coast.
• A trough off the coast deepened into a low pressure system on the 13th, that brought over 100 mm to the South Coast district over 13–14 July, with local flooding.
• The mid-month rain eased short-term deficiencies, since April 2020, that were developing in parts of the South Coast district.
• From the 14th, the system created a powerful sea swell, with wave heights of 5 to 6 m, leading to significant coastal erosion, notably at Wamberal.
• The second low formed off the Queensland coast, before deepening and moving south over 26–28 July.
• The second low was more intense than the first, with many sites in the Illawarra and South Coast districts recording their highest July daily rainfall on record.
• The highest daily total was 223.6 mm at Sanctuary Point on the 28th.
• Flash flooding was reported in several areas, including Newcastle and in the South Coast district.
• As a result of the two lows, the South Coast District received over 400% of its historical July average.
• Many coastal sites had their highest total July rainfall on record while several long-term sites including Bega, Cobargo and Bombala, had their highest total July rainfall since 1922.
• For the state as a whole July rainfall was 10% above the historical average, the wettest July since 2016.
• Much of the Riverina and far west of the state was drier than usual, as has been the case for most winter months since 2017.

Above average daytime temperatures

• Daytime maximum temperatures were average to above-average across the state during July.
• For the state as a whole, the mean maximum temperature was 0.96 °C above average, the coolest since 2016 after several very warm years.
• Mean minimum temperatures were generally above the July average along the coast, but below average in the far west.
• Over inland areas of the state, weather conditions were influenced by the southward extent of the sub-tropical ridge, with clear skies bringing warm days, cool nights and drier than usual conditions.
• Climate models indicate that the weather patterns influencing inland New South Wales so far this winter are consistent with increasing greenhouse gases in the global atmosphere.
• In contrast, cloudy conditions along the coast meant that some sites had their highest July mean daily minimum temperature on record or for at least 20 years.

Snow then rain in the Alps

• The low pressure system over 13–14 July brought snow to alpine regions, with ski resorts reporting falls of over 1 metre.
• However, subsequent rain has reduced the snow cover, with Snowy Hydro reporting no snow at Deep Creek or Three Mile Dam, while at Spencers Creek the 70.2 cm of snow as of 29 July is the lowest since 2013 for this time of year.

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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* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top