Quick Update SA Low with cold air
Quick Update SA Low with cold air, squally winds and rain September 7th-8th 2023
G’Day everyone, even though I have just issued the September outlook, I figured it was important to push out a little update to show the changes that have happened with this system.
In short, it certainly is going to pack a punch with already some nice falls from the initial frontal band. This band thickened from showers to rain about 80km further west than it initially appeared which is a great thing for rainfall. Some heavy totals and minor flooding already through the Adelaide suburbs this morning.
Currently as of Midday on the 7th, the low is rapidly developing in response to the strong temperature gradient from ahead of the low with the warm air advecting SE across NSW/VIC and the colder air rapidly barrelling NE up from the deep south and this colder air is already beginning to push in across the agricultural areas with convective cells and short but sharp showers developing. With some solar heating these will gain more inland penetration and vigour with small hail and isolated cold air thunder.
However, the main purpose of this update was for the back side of the low, the sting in the tail which is winding up with a lot more vigour than it appeared a couple of days ago. The low is currently located south of Kangaroo Island however some smaller centres or meso lows and shortwave troughs will rotate around the main low and sling back around the back side, compressing the flow and increasing the winds with it. Damaging winds associated with this meso low or meso lows will begin by the evening and extend NE across most districts east of about the Spencer Gulf however with a particular focus into Kangaroo Island, the Fleurieu Peninsula, Southern Yorke Peninsula, Mt. Lofty Ranges and the Coorong areas. The Adelaide metro is also likely to see damaging winds or near damaging which certainly could bring some trees down.
The main trajectory of damaging winds will focus in a corridor up from the Coorong into the SE Districts and Mallee through the early hours of the 8th. Showers and areas of rain with some handy falls for the affected areas will be associated with this band and certainly the potential is for gusts in the 90-100km/hr bracket and likely to 110-120km/hr about exposed coastlines, then tapering off inland but still in the 70-80km/hr bracket which will blow crops around a fair bit.
Rainfall so far has been good with 10-20mm in some locations from the rain, chiefly around Adelaide and the Mt.Lofty Ranges, with totals up to 10-15mm across parts of the Lower North and Yorke Peninsula. East of the ranges so far it has been light on due to the rain shadow effect but that is expected. A little better effort for the east tonight with the wrap around band with 5-15mm generally and isolated 20mm totals. The main focus of the wrap around rainband seems to come up through the Fleurieu and into Adelaide and the Mt.Lofty Ranges and I can see potential for 20-30mm extra on top of what has already fallen, with some isolated 30-40mm in the hills.
The frost event after this is looking similar in intensity for the Upper and Lower North and the Riverland however a weak front passing below the state will just add some light wind to the areas south of about the Adelaide latitude as well as some cloud over the Lower SE so the edge of the cold may be taken off here by 2-3C. But very frosty north of this unfortunately.
Link to temporary blog website: https://farmweathersa.blogspot.com/
Happy Farming and Cheers from The Weatherman
*Note – For interest only, all thoughts are of The Weatherman and may not be reproduced without my consent.
Comments
Post a Comment