Severe storms have been belting parts of NSW this afternoon with damaging winds and isolated falls over 100mm once again reported. The storm activity also drifting into QLD with a humid airmass.

Also strong and gusty storms over the northern tropics, a good sign that the monsoonal weather is set to approach in the coming fortnight.

The west is hotter and expected to get hotter in the coming days with a low to moderate intensity heatwave, I will have more on that tomorrow.

In the southeast, cooler with onshore winds following a cold front leading to a few light showers and drizzle.


00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days

The weather of interest is over the north and east in terms of rainfall and the west and south in terms of clearer and hotter drier weather. It is a tale of two halves across the nation in the short term. The rainfall over the east may increase and become heavy mid week over parts of NSW and into QLD, which may see further areas of flooding developing in pockets. Too early to call where that may be. The southeast generally too far west of this activity so dry weather continues for now. The showers and thunderstorms over the tropics will increase further later this week into the weekend with widespread falls about, some locally heavy and gusty. There is a signal that the monsoonal flow may approach from the medium term, about the 13/14th which may spawn some tropical lows and cyclone potential which will be reviewed this week with the new charts. This activity over the north will impact rainfall potential south and east. The west remaining mostly dry and hot for now.

00Z GFS - Precipitable Water Values - Next 16 Days

You can see the humidity over the northern half of Australia is going absolutely no where with it only creeping southwards during the coming week and deepening further throughout this outlook period. The rainfall chances for the south and west, less frequent, but when it falls, it may heavy, espcially with thunderstorms. The moisture content over the north and east will be supportive of further above average rainfall. The lack of moisture out west will be supportive of below average rainfall, which is not hard through the dry season out west.

00Z GFS - Rainfall Accumulation Next 16 Days

The rainfall keeps bouncing around but the rainfall is expected to be heavy and widespread through the north and east, more scattered over the southeast and central interior extending into the western interior, but mostly dry along the southern coastline and through to the west coast. That idea is reasonable. Where the heavier rainfall occurs will come down to where low pressure systems evolve, deepen and pass through and that is the tricky part, especially up north.

00Z CMC - Rainfall Accumulation Next 16 Days

Note the monsoonal activity strengthening in the broader data sets and the moisture creeping south and east through the nation. Even though you have the deterministic data that is more volatile, the broader data sets support a wet run into Christmas for the east and north of the nation, drier for areas over the south and west.

00Z GFS - Rainfall Accumulation Next 16 Days

The broader data sets from the GFS show drier weather over northern Australia which shows you have volatile the data is from run to run, so I will show you this and compare it with the data tomorrow.

00Z CFS - Rainfall Accumulation Next 42 Days

The signals remain largely unchanged, noting the heavy rainfall bias is stubborn, the CFS placing the monsoon over the Pacific rather than over Australia which I don't agree with.

00Z GFS - Temperature Anomalies - Next 16 Days

The heat is on for the west this week and that will spread heat which is a very regular occurrence before the monsoon arrives up north. Then nature's air conditioner is turned on and the heat moderates. We will see a hot week in WA this week and the following week for SA and VIC and possibly NSW. The weather over the north seasonal, but could become cooler if the monsoon arrives in full force.

I will have a full update mid Sunday morning and a look at Summer 2021/22 as well. Loads on this week.