The seasonal shift is underway with humidity returning this week, starting tomorrow, the noticeable shift to humid weather gets underway. This will lead to increased heat levels and unsettled weather for the northern Top End.
The unsettled weather will stick around for much of the week with the humid layer of air likely to lead to showers developing through the morning over coastal areas and thundery showers over inland areas as well.
Then later this week into the weekend a trough will begin to move in from the south and this slow moving boundary could kick off showers and storms for the southern Barkly and Tanami/Lasseter districts with moderate falls possible.
Lets take a look at the latest details.
Rainfall for the coming 10 days
Showers and thunderstorms developing for some locations from Wednesday afternoon in the east, becoming more widespread from Thursday and into Friday before drier air moves in over the weekend up north. In the south, the chance of rain increases from Friday into the weekend with a stalled boundary, there is some indications the rain could be heavy at times over the outback with thunderstorms. That moisture then moves on by to the east with a high ridging in bringing drier air back next week.
00z Euro Surface Pressure Pattern for the coming 10 days
The pressure pattern remains unchanged in the short term with high pressure dominating the east and sending in that very warm airmass. We then watch the strong cold front passing over the southwest of WA tomorrow and track that through the Bight Thursday and then into SA Friday an VIC through Friday night into Saturday and then into NSW Saturday with a few heavy falls along the journey from VIC into southern NSW. The band of rain extending back over the outback as well with the colder air surging north. Then a large high pushes in and noses out the colder air surging over the east out to the Tasman Sea, stopping the formation of follow up rainfall next week over QLD. The rain band likely under this scenario exits with the cold front, and I would be cautioning you to this outcome with a positive SAM phase possibly in play, this could see rainfall return to the east coast of NSW and QLD and possibly hang up the rain event over the east next week. For the remainder, once the front is through high pressure keeps you dry and cooler. The tropics see the odd shower and storm this week before a return to dry air.
00z Euro Rainfall for the coming 10 days
Rainfall is likely to become widespread over the south with a northward moving trough which will run into moisture and see showers and thunderstorms break out in response. There will also be a pulse of moisture run across the Top End with showers developing and a few thunderstorms also possible. Next week a dry surge could bring in the last pop of dry season weather before moisture returns and hangs about for a longer duration mid month.
00z Euro Precipitable Water Values next 10 days
The moisture over QLD is drawn west over the tropics and part of the moisture is drawn south into the cold front passing over the southeast and east. The moisture coming in with the front from WA is modest and sufficient for a rain band to form during tomorrow. The moisture will also follow the front but for SA the lifting mechanism to bring rainfall falls to the southeast as feared last week as one of the options due to the Tasman high. Then the trough over SA gets new life over the eastern states, invigorated by the deeper moisture layer leading to widespread rainfall reforming on the boundary as it moves throughout the southeast and eastern inland. Dry air likely to surge through following the front with a colder airmass to sweep the moisture north and east. The tropics will see a moisture increase mid to late week ahead of drier air surging north next week, perhaps the last dry surge of the season.
Temperatures are expected to be well above average as well through this period, but the colder weather next week is still very much on the table and this volatility in the high amplitude pattern will continue for a number of days on the models. So look for trends!