A few more days of more of this benign weather with a high pressure ridge extending over the state, dry air also in place allowing for temperatures to be near seasonal and rainfall chances near zero.

That is all set to change through the weekend however, with a deepening pressure trough over the central portions of the nation, this likely to link up with deep moisture throughout the atmosphere bringing the next round of showers and thunderstorms during the end of the weekend and through a good chunk of next week. But let's see who gets what at this stage on the latest guidance.

Rainfall next 10 days

Dry weather for the most part this week with a dry airmass. There is a very low chance of a thundery shower for the southwest districts tomorrow with an upper trough passing through but dynamics are marginal, and if anything falls it will be light and patchy. From the weekend, all eyes will be on the southern NT and northern SA where the next chance of rainfall is developing for our region. Model divergence means the confidence in rainfall forecasting is quite poor, however I am leaning towards soaking rainfall for southern Ag areas of the state, possibly central areas through into the medium term. More regional based rainfall forecasts will be drawn once we get better clarity on the data sets and more consistency in the global modelling as a whole.

Thunderstorm Forecast Wednesday

The southwest corner of the state may see a isolated high based thunderstorm tomorrow afternoon rolling along the upper trough, but falls less than 2mm expected. The 'better' dynamics are further south.


Euro 00z - Surface Pressure Pattern and Rainfall Distribution - Next 10 days

The models are well place on the short term forecast package with a front passing through the southeast of the nation Wednesday and Thursday bringing a burst of showers. Maybe some thundery showers and gusty winds over the outback of SA, western NSW and southern NT into QLD with this feature later tomorrow. Now the nation remains quiet until the weekend when we have the deepening low pressure trough over Central Australia combining with deep moisture throughout the interior, this allowing a large scale shower and thunderstorm event develop. The areas of greatest impact likely to be southern NT, northern SA and western NSW and QLD at this stage. This area of low pressure likely to slowly creep through to the east. The placement of this event is what the models are struggling with and I will have further to say after 9pm, but at this time the rainfall looks heaviest through southern QLD, NSW and northern VIC. Out west another strong cold front is expected to bring a further burst of colder than normal weather with showery periods early next week. IF this front comes in from the west earlier than GFS, than we will see a clearance of that system over the east quicker, but there is not great guidance upon that idea. Therefore the trough over the east may take the best part of next week to lift off the east coast but the moist unstable airmass may continue if the front does not arrive. Up north, baking weather with showers and thunderstorms in the afternoon and evening, in random scattered locations.

Euro 00z - Precipitable Water Anomalies - Next 10 days

This again paints the picture such as the GFS with the movement of moisture through the nation being repeated multiple times during the coming 7-10 days but if you watched the video, you see this trend continue. That supports the forecast bias of rainfall in the short and medium term with higher chances of above average rainfall through northern and eastern Australia. For the west, dry air behind cold fronts, will suppress rainfall for inland areas of the state and while keep temperatures colder than normal in the southwest inland, it will also stop rainfall developing for the medium term in that northwest corridor.

Euro 00z - Rainfall Accumulation - Next 10 days

Rainfall accumulation across the nation carries a low confidence from the weekend and as outlined in the video surrounding the GFS, it comes down to placement, scale, intensity and speed of the systems progress through the nation. The higher chance of rainfall can be found in the shorter term with this weakening cold front.

A closer look in

GFS 00z - Rainfall Accumulation - Next 10 days

Refer to the video surrounding the crazy outputs from the GFS over the past 24 hours and where do we go from here and can we take it seriously?

I will have the full model wrap on all things rainfall and severe weather potential coming after 9pm. As you can see the confidence is not especially high in this outlook which is normal for spring.

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