A bit of a spring preview this week with a series of strong cold fronts to pass through bringing showers and windy weather from time to time. The temperatures are expected to warm this week, despite the frontal weather passing through. The variability in temperatures will be noticeable with a warmer northwest flow developing ahead of the fronts and colder westerly winds behind each front.
The rainfall will be heaviest along those areas exposed to the westerly wind regime and the further south that you travel so that will be the same pattern as the past 3 weeks.
Northern areas should remain dry, and getting very warm later this week with some centres in the northwest approaching 30C. Not uncommon but that is a result of the well above average temperatures over the north.
That may set up the a steep thermal gradient through the eastern inland where a cloud band may develop and moisture out to the west may get involved, thus creating inland rainfall.
Lets have a look at modelling.
12Z GFS Surface Pressure Pattern for the coming 16 days
The pattern is still stubborn this week, a few fronts to pass over the region, with the next system to bring the most widespread rainfall on Wednesday. That is starting to carry more moisture in the modelling so light inland rainfall developing for most of the state. Heavier falls of 20-40mm once again for the in the southeast over the Alpine areas and west of the divide up to about Orange. Another system on the weekend is still expected to bring another band of light rainfall and strong winds for inland areas, heaviest over the southeast. Next week you can see the pattern remains the same however the westerly wind belt is beginning to move south. Moisture is beginning to increase over the northwest of the nation and that will come into play for the second week of August.
12z GFS Rainfall for the coming 10 days
The rainfall spread largely unchanged from last night with the wet weather confined to those areas exposed to the westerly wind regime. The fronts with greatest influence will be Wednesday, Friday, Sunday and then next Tuesday. The focus for the forecasts now will be for the weekend and into next week, when can we see the pattern shift? There are signals the high pressure belt begins to move south and shove the westerly winds southwards.
12z Euro Surface Pressure Pattern for the coming 10 days
The pattern similar to GFS for the week ahead, so that makes weather easy to forecast, persistence. What you have seen for the past week you will see this week, with frontal weather to continue move over southern states. The rule for NSW will be the further south you are and if you live along the western slopes, thats where you will find the wettest weather. There will be more variability in the temperatures as a spring preview develops for northern and central areas. Some locations in the far northern inland could get to 30C on Thursday or Friday!
12z Euro Rainfall for the coming 10 days
Similar rainfall spread as per the GFS, connected to the westerly wind belt. The weather will start to shift slowly over the weekend into next week with the westerly wind belt taking a trip southwards. That will allow the strong westerly winds to ease over the state and more sunshine to develop. Keep an eye on the moisture building over the northwest and north with that likely to come down for mid month but that sits just outside the short term forecasting.
Rainfall for the next 10 days
Rainfall spread is largely unchanged. The rainfall over the inland will fluctuate in line with the frontal weather passing through this week. But the rainfall this week will be lighter than last week only due to the long wave troughs peaking out over WA. They will fall apart in the northwest flow, but the moisture attached will not, so this will bring more cloudy skies and light rainfall at times. But overall the wettest part of the state will be the same areas that have seen a wet July. I do think next week we will see a pattern flip that will lead to a drier picture over the inland as the high pressure belt seeps south, however this will also allow moisture to build up in the medium term lifting rainfall chances from mid August for inland areas.
More weather details to come through the day with another look at the moisture and the pattern flip coming up. We will feel hints of that this week with the temperatures starting to bounce around as the pressure pattern begins to break down.