The humid and unstable airmass that has been in place for much of this week is expected to remain stubborn in the region for this week, combining with an inland trough and waves of middle level low pressure coming out of the west....the pattern wet and thundery for a good chunk of us.
The atmosphere most dynamic through the middle of the week and again as we head into the weekend with a deepening low pressure system which will produce widespread showers and thunderstorms with the chance of these being severe with all modes of severe weather possible.
Heavy rainfall is likely for southern and southeast areas of the state once again, around the ACT and extending north up over the Central West. Scattered moderate falls further north towards the QLD border.
We will need to keep watch of the tropical moisture and to see where that ends up travelling too as we track through the medium term. This could enhance rainfall chances for the back half of the month with the chance of further flood problems if that moisture drifts south.
Lets take a look
Rainfall Next 10 Days
Rainfall is scattered as we have seen in recent days through much of this period, but during this period, most areas should record a thunderstorm with half to one month's worth of rainfall. Some areas may end of up seeing not as much as well, but given the potential within the atmosphere, the thunderstorms will pack a punch. The rainfall will begin to contract north and east through the state as we get to next weekend, there is evidence of a new high ridging through the Bight which could extend a cold front through the southeast, sweeping the humid air northwards for a period. But this may be short lived as the developing tropical low up north starts to move southwards and this could settle into an easterly flow with widespread rainfall developing into the second half of the month.
Thunderstorm Forecast Monday
Thunderstorms will return once again to most of the interior on Monday with the chance of thunderstorms turning severe with heavy rainfall leading to flash flooding, damaging winds and a very low chance of large hail. A new trough approaching from the west will bring up the chance of severe weather Tuesday and Wednesday.
Flash Flood Risk Monday.
The highest risk issue on Monday is the flash flooding with thunderstorms. Slow moving thunderstorms on and west of the divide will likely produce heavy rain rates which will lead to some areas recording 50mm in an hour. These will be few and far between but they will be about under a broad region.
DATA - All the analysis you want is in the video.
00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 16 Days
More details in the video relating to this with the daily breakdown - but note the moisture content remains very high with the high pressure sitting further south leading to easterly winds dominating this period. Also note the tropical moisture being pulled further south as we go along which is very plausible.
00Z GFS - Precipitable Water Values - Next 16 Days
Deep moisture rotating around the nation but covering much of the north and east for the entire period, but there seems to be this idea of the pattern flipping in around a week and the moisture being shared around for the second half of January which has been the advice all along.
00Z GFS - Rainfall Accumulation - Next 16 Days
More details in the video
A closer look in - the same areas to be wet throughout the outlook, this ahead of any tropical incursion from the north.
More details coming up on Monday morning. Have a great evening.