OK let's take a look at the BOM. Firstly the big wet coming is dragged from Vic up through the Central Tablelands -our trip is inside of Newcastle, we are just on the edge of it.

MetEye is the better of the long term BOM forecasts for our purposes: http://www.bom.gov.au/australia/meteye/
Type in "Mandalong" which is pretty much the closest town to our trip.

Wed 60% chance of rain; 0-2mm
Th 30% of rain; 0-0.4mm
Fri 50% chance of rain; 0-4 mm
Sat 95% chance, 5 to 10mm.

Statistically that is something less than 2mm-4mm of rain during the week prior to the trip - almost enough to dampen the dust.

Saturday is raining, but if you look through the hour by hour forecast, it is 25% to 50% in each time band with it looking more likely in the middle of the day and to the north of our trip.
Note that the long term forecast takes a jump to better accuracy at -3 days (they use local datapaks at that stage). For now the weather looks fine but we will know better from Thursday. We will check wind and storms as we get closer (I don't like to have to deal with too many fallen trees, so wind tends to be more important than rain.) And also any zealous Park response with track closures.

You'll be washing off the mud on Sunday, think about boots, waterproof jacket and umbrellas for the trip, but we are looking good to go. If it is greasy we will avoid Creek Road, but the rest of the trip should be fine.

Stay in touch! We are on weather watch!