A RELATIVELY dry start to 2018 has taken a toll on water storage across western NSW, while the addition of unusually warm weather has resulted in soil moisture levels falling markedly across much of the state.
While rainfall during the final three months of 2017 was near to above average for many parts of NSW, the start of 2018 has seen a drying trend despite weak La Nina conditions in the Pacific Ocean.
The lack of early-year rainfall has been accompanied by intense and record-breaking heat, with NSW as a whole registering its hottest January since 1939 in terms of maximum temperatures.
The combination of dry and warm weather in recent weeks has resulted in the Murray Darling Basin’s total water storage dropping to its lowest level in almost two years.
The accessible volume of the Murray Darling Basin on February 13, 2018, was 14,926 gigalitre, which was 58.9 per cent of its capacity.
This is the Basin’s lowest volume since August 2016 and a bit over 4000 gigalitre below the volume on the same date last year.
In addition to the reduced volume of water in storage catchments, the root zone soil moisture - which is the amount of moisture in the top one metre of soil - has also fallen across most of NSW.
During the month ending on February 13, 2018, most districts in central and northern NSW had below average soil moisture in the root zone.
Parts of the Upper Hunter currently have root zone soil moisture values that are in the bottom one per cent of historical observations and the lowest to be recorded in any month since 2006.
Looking ahead, there are indications that showers and storms may become more active across some some parts of central and northern NSW early next week.
Even if this activity does eventuate, it is unlikely to produce enough widespread and persistent rainfall to make up for the deficits seen during the past few weeks.