Loads of frontal weather moving through in an unstable northwest to westerly flow this week. Cloud band over the interior also making it tricky to pin down rainfall forecasts. So here is the next 3 days.
We already have showers about today in a weakening cloud band that is moving through, light falls of 1-2mm at best today, may increase overnight and into Monday.
18Z GFS - Surface pressure pattern and rainfall for the coming 16 days - Valid Sunday 11th of July 2021.
Active westerly wind profile this week brings showery periods to SA. Not one day will be a total washout with huge rainfall but the rainfall will be widespread at least twice, once on Tuesday/Wednesday with a front passing through with a moisture infeed from the northwest. Another front during Friday/Saturday sweeping the winds into a colder southwesterly may bring another band of moderate rainfall. Showers will be ongoing between fronts. There is a lot of moisture to work with during the following week and will be as you well know, keeping an eye on follow up rainfall potential.
18Z GFS - Precipitable Water for the coming 16 days - Valid Sunday 11th of July 2021.
Reasonable moisture profile coming through with the next 2 fronts this week and in the westerly winds, so showers and rain areas should be productive, particularly for those areas exposed to westerly winds. Next week anomalies of 200-300% above normal means there is a lot of potential there for a front to ride into a very moist atmosphere developing inland rainfall. Fingers crossed that unfolds in the modelling in the short term coming up this week, it currently sits outside the scope of forecasting, looking at signals at this time.
18Z GFS - Rainfall for the coming 16 days - Valid Sunday 11th of July 2021.
Frequent frontal weather and moisture in the air means light to moderate rainfall this week and gradually becoming colder. But look at all that rainfall/moisture off the northwest of Australia. Some of that will eventually filter into the nation. So there is some hope on the horizon for more rainfall after this coming week.
Lets look at SA in general (for SE SA a closer look can be found in the NSW/VIC update).
Monday 11th of July 2021.
Showers light and patchy about the southern coastline extending through the YP and into the Gulf region and then Adelaide overnight and during Monday. The more concentrated falls will be over the southeast with a little cold pool behind the leading front bringing more numerous showers and the risk of some thunder.
Tuesday 12th of July 2021.
A band of rain through WA will spread through SA from the west during the day reaching the YP by afternoon and the Adelaide metro by late afternoon with light to moderate rainfall. More enhanced rainfall may develop over the outback between Coober Pedy and the northwest APY Lands. The rain is expected to clear the west during the evening and increase over the east overnight into Wednesday. Showers will follow the front over coastal areas.
Wednesday 13th of July 2021.
Rain band over the inland will rapidly move into NSW and southern QLD with better moisture in place there producing more moderate falls. Early rain over central and eastern areas contracting east and clearing. Showers to follow about coastal areas, may increase later as the westerly wind becomes more unstable ahead of a shortwave later in the day or at night with the risk of thunder.
I will have more on the week ahead and the potential of follow up rainfall later on this afternoon and a 10 day forecast for the state.