Rain returning to NSW
Ben Domensino, Wed 11 Oct 2017
Thirsty soils across parts of NSW are enjoying some welcome rainfall this month.
Showers and thunderstorms dampened the state last Sunday, delivering more than a month's worth of rain in a matter of hours in some regions.
Tibooburra picked up 26mm of rain during the 24 hours to 9am on Monday, which was their heaviest rain in a year and exceeded their long term monthly average for October. The bulk of this rain fell during a severe thunderstorm on Sunday night, which produced a destructive wind gust of 159km/h at the airport. This was the strongest gust recorded at the site since wind observations commenced in 2003.
Inverell's 33mm on Sunday night was their heaviest drop since April and close to half of their long-term October average (75mm).
A cold front and low pressure trough crossing NSW during the middle of this week will produced the second round of widespread rain for the month.
A band of rain and thunderstorms will sweep over the state from west to east between this afternoon and Thursday morning. Widespread rainfall totals of 5-10mm are likely across NSW by Thursday afternoon and some areas could see 30-50mm with storms.
With two rain-bearing system delivering healthy totals to inland parts of the state this week, the start of October is helping replenish some of the soil moisture that was lost during the last few months.
NSW registered its ninth driest winter on record and the driest since 2002. Mid-year rainfall was particularly lacking west of the ranges, where the Murray Darling Basin experienced its driest September on record, driest June since 1986 and the driest winter in 15 years.
One factor contributing to the recent rain has been above average sea surface temperatures in the Tasman and Coral Seas, to the east of Australia. Warmer seas enhance evaporation, which increases the amount of moisture in the atmosphere.
Looking ahead, there are no strong signs that rainfall will be significantly above or below average during the last three months of 2017. This is because both the Indian Ocean (IOD) and Pacific Ocean (ENSO) are in neutral phases.
However, some climate models indicate that the Pacific Ocean may warm towards a La Nina-like pattern at the end of this year. If this happens, rainfall may be enhanced across parts of eastern Australia during summer.
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