FRIDAY NIGHT WEATHER - A QUICK WRAP AHEAD OF RAIN BUILDING.

Thank you all for your kind emails and support while I like many of you, battle this thing called Covid. Makes it very hard to get to all your requests as well but I do endeavour to look at them throughout the weekend. Thank you for your patience.


Now lets have a look at all things rainfall across the nation very quickly, as we do have severe weather potential and flooding also possible over large areas of inland Australia with a series of rain events coming in from northern and northeast Australia through Central Australia and into the southeast and eastern inland over the next 1-2 weeks.


If you are planting, I would be ramping up your operations this weekend and Monday ahead of a period of prolonged rainfall and severe weather risks.


Lets see the forecast first.


FORECAST

Rainfall Next 10 Days

Not a whole lot of change to the guidance, as mentioned this morning, it was best to just adjust that heavier rainfall band a little further east through SA, into QLD, NSW and VIC as the frontal weather over the Bight does look to push the moisture and instability over these areas. There looks to be at least 2, maybe 3 rainfall events through the sequence which could provide some flood issues for inland areas of the east. We probably need the 3 events to verfiy over 2 weeks to see the flooding extend into NSW at this time. The hot spot for heavier rainfall is most certainly northeast QLD, but this laden airmass is forecast to shift south and west this long weekend, leading to a significant increase in showers and storms by Sunday night and Monday over Central Australia. This is then forecast to shift into the southeast and east next week with repeat troughs of low pressure likely to reinvigorate the moist airmass into follow up rainfall for the same areas during early May. There is some interest in the tropical weather being very active to kick off dry season and with the seasonal shift, you have to watch this influence very closely as we can sometimes get late Autumn flood events over the Outback as the mid latitude westerly wind belt begins to get involved in the weather. So this can wrap up some very productive rain producing low pressure systems and severe storm outbreaks so large areas of the east are already on notice and this could extend further south. If you are west of a line from Mount Gambier through Adelaide Hills to about Woomera and points east, this is where the heavier of the rainfall should be, to the west patchy falls expected. This is subject to change and one wobble to the west or east will change the spread. The rainfall in the southwest connected to fast moving frontal boundaries which will come up again the blocking in the east and slide away to the southeast.

Severe Weather Watch - Flooding.

This is the preliminary chart for the period and will change over the weekend and next week but a heads up for friends in western QLD. Some of this may clip eastern NT and northeast SA. Right now I am leaving NSW out but this is on a knife edge. Any heavy rainfall and flooding will roll over the border, but it could be the residual flooding from this event that impacts NSW from the north, rather than direct heavy rainfall over the state.

DATA

00Z GFS - Synoptic Pattern Next 2 Weeks

The pattern looks to be amplified over the east and northeast for the coming 10 days or so with multiple bouts of rainfall. How they evolve and where the heaviest of the rainfall will occur comes down to how much of a knock to the east the fronts will have on the upper system that will be stuck over the northeast and east of the nation with high levels of tropical moisture. This will mean the same areas will see repeated bouts of heavy rainfall while 100km to the west, some areas missing out all together. So it is a tricky forecast on that topic so keep watching. Over the northern tropics, very much above average humidity and rainfall continuing for QLD, some of that may run across to the eastern NT but dry further west. SA sits in the wild card zone with the band of rain and thunderstorms forming from there northwards during Sunday and where that occurs will determine rainfall for the Ag Areas. That is yet to be determined but I am going with my gut read and placing heavier rainfall east for now. Fronts in the west keeping conditions cooler than normal with gusty winds and showery periods but north of this frontal wave, there will be warm dry weather with above average temperatures.

00Z GFS - Precipitable Water Anomalies - Next 2 Weeks

The moisture content through the atmosphere is really high over much of QLD, the eastern NT, eastern SA, through NSW into northern VIC and the ACT this leading to above average rainfall returns on the forecast packages for the southeast and eastern inland. But it will come down to timing of the frontal weather to the west, where the upper system gets stuck and how strong the low pressure is in the east. All of this to be ironed out over the weekend.

00Z GFS - Future Satellite Next 2 Weeks

Shows you where the cloud bands form this weekend and subsequent moving of that initial cloud band as it moves into the southeast and east. Also understand that this initial system will have impacts on the follow up rainfall events so do not get to caught up on rainfall beyond about a week right now, but models pinging away with moisture trapped in the east with multiple large scale rainfall events possible through the first week of May.

00Z GFS - Future radar Next 2 Weeks

This gives you an idea of where the rainfall will be and how it moves with the upper level troughs in the east. Now the radar will not look like this as the week rolls on but you can see the persistent signal for rainfall over large parts of the southeast and eastern Ag Areas of Australia. So pay attention to the forecasts.

00Z GFS - Rainfall Next 2 Weeks

This model is showing significant rainfall across the southeast and eastern inland but west of the divide where other modelling has the rainfall further east. I just want to show you the GFS tonight as putting all the data together shows you how fickle forecasting the rainfall will be and not to get excited/disheartened by forecasts at this time. Stay close to the information through the next week.

00Z GFS - The full spread of members.

You can see the various scenarios through the period from the model itself. Which one do you choose? Well you dont, but you can see the amount of information I look at so you don't have to, so I come up with the assessment and diagnostic rainfall up the top. But you can see lots of members going for a wet central, southeast and eastern parts of Australia and SA is covered in some of these solutions, just my gut read right now is to place the rain a little further east at this time.

Have a great night, more coming up during Saturday. I am going back to my soup!