Areas along the NSW Northern Rivers, Mid North Coast, Hunter and potentially the Central Coast are set to cop a Winter drenching over at least the next 3 days, but potentially over the next week. Above image HSC Forecast 4-day rainfall (Friday to Monday)
An upper level low pressure system / cold pool is set to track up through Central Inland NSW on Friday, with an upper trough covering much of the State, this upper level low is then set to move into the Northern Inland districts / possibly as far North as Southern Inland QLD during Saturday before remaining in the area and becoming elongated from South-West QLD into the Hunter on Sunday. This upper level system is forecast to combine with a relatively deep onshore South-East to Easterly flow to generate showers and rain periods along the Coastline from Sydney, Northwards. The rainfall expected from this event is expected to cover at least 3 days consistently with falls of 50-100mm possible each day, and grand totals of 150-200mm+ likely for some areas. Widespread falls of 50-100mm are likely from Lismore to Sydney, with lighter falls (but still good) extending inland to the Ranges. The better falls are expected to be directly along the Coast.
These kinds of falls, given the area has already receive 50-125mm, could lead to some minor flooding for creeks and rivers, while localised flash flooding under heavier downpours is also likely. A flood watch may be issued for this potential.
Further inland, and showers / some rain areas, but more importantly… thunderstorms, are expected to surround the cold pool. The colder upper level temperatures are expected to interact with increased moisture to produce isolated to scattered thunderstorms over Central Inland NSW on Friday and Northern Inland NSW on Saturday and Sunday.
Forecast position of the cold pool at 4am Saturday via BSCH/GFS
As stated above, the onshore winds onto the Northern and Central Coastline of NSW may extend beyond Sunday / Monday where further good falls may occur. Another update will be posted for this potential later on.