SA - OVERNIGHT RAIN AREAS CLEARING EAST THIS MORNING - SHOWERY WEATHER DEVELOPING SATURDAY.

The overnight rainfall has been patchy but welcome, many areas recording over 10mm, a few lucky locations recording 20-25mm from the event, one of those locations being Port Lincoln.


Rainfall for the past 22hrs

Some OK falls yesterday with 5-10mm for many locations and some areas surprising with The Plateau east of Leigh Creek seeing 14mm overnight which is nearly all of the July rainfall average in a sitting.


The air has modified a bit today, the heights coming up so with a little more stability between the systems, we can see a drier Friday. But the cloud is set to increase later in the day as will the winds with the approach of a front, which will bring showers to the EP and YP later or at night and the into the east thereafter.


Satellite Imagery

Low pressure and cloud with rain moved east overnight. The weather is dry under sinking air today but those fronts are racing rapidly through the Southern Ocean, showers expected with the lead system about the EP later this afternoon or tonight.


The rainfall will not be as widespread as this event we have just had and quite frankly inland areas should be dry, cold and windy, north of a line from Maralinga-Port Augusta- Broken Hill. These areas should see way below average temperatures and even areas of raised dust.


To the south of here across the weekend, scattered to numerous showers, with gusty winds, small hail over the southeast and thunder possible. Sleet is possible about the Lofty Ranges and Flinders Ranges during Sunday morning before dawn IF the moisture is sufficient inland for showers to form.


State of Play - 730am CST


The showery weather then contracts back to the southeast early in the new week as the wind profile tends northwesterly. Then showery weather increases from mid week with more fronts passing over and a set of cloud bands developing in the moisture in feed coming in from the northwest.


Lets look at modelling.


12Z GFS Surface Pressure Pattern for the coming 16 days

The low has left the state and we sit in sinking air between systems with a weak high over the north. A long wave trough as you can see above, is about to descend bringing a burst of wintry showery weather to the coastal areas. That guidance is unchanged for the weekend. Then we have a few downstream fronts that will slide northwest to southeast along the coastal areas, bringing more coastal falls early next week. Then comes the stronger features which have got moisture attached. That brings up the chance of widespread rainfall with inland areas possibly picking up on some of those useful falls to end the month. Then as you can see high pressure comes in and may flip the pattern opening the door for warmer weather and a drier spell for the south as the westerly wind belt moves south.

12z GFS Rainfall for the coming 10 days

Rainfall largely unchanged in the modelling with the coastal areas picking up the bulk of it as it should in these westerly wind regimes. Frontal weather this weekend will see the rainfall moderate across both days through the southeast dairy country. Then more rainfall for coastal areas early next week as the winds veer into the northwest and weakening fronts bring moderate rainfall once again to the southeast districts. More rainfall likely to develop later next week with stronger fronts rolling through and they contain the better chance for rainfall over the inland areas.

12z Euro Surface Pressure Pattern for the coming 10 days

Pressure pattern largely unchanged from overnight, we have the frontal weather to watch this weekend, with cold squally weather for the southeast, the weather not too bad further north with the cold air not penetrating that far north. Then we have frontal weather coming out of the northwest to the southeast with more showery weather to the coastal areas. The better looking systems for rainfall to become more widespread is definitely later in the period looking at the data this morning and that will be the focus of medium term forecasting across the weekend.

12z Euro Rainfall for the coming 10 days

Rainfall widespread about coastal areas this weekend with some moderate falls over the southeast districts. The southern coastal areas west of the EP will see light falls. Inland areas not as wet over the coming days with the rainfall contracting eastwards out of the state with the low. Next week more rainfall may developing from the northwest and west with those stronger systems. That may bring rainfall back to inland areas to end the month.

Rainfall for the next 10 days

Rainfall largely coastal over the coming week, with the best of it falling from the western parts of the EP through the YP into the southeast districts. Lighter falls as you head away from the coast, that is thanks to west or northwest flow. Better rainfall may exist for areas inland of the coast as moisture increases over WA, I have left the light rainfall areas for inland parts in response to that, but these falls could come up or come down, we just don't have a great handle on the data yet and whether the moisture is in phase with the frontal weather next week.

More updates to come on the Indian Ocean and whether we can see moisture increase later in the outlook and a climate drivers update later this morning.


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