The weather is leaning more and more towards a humid and unsettled spell not just for northern areas, but extending for a decent period over inland NSW and QLD with a deepening trough mid week. The instability is also set to seep over into VIC as well with moderate rainfall expected over a large area of NSW and VIC.

The trough placement over the east is critical, as is the timing of the ghost of Seth and all that moisture being pulled into the trough coming out of SA. If this can line up over central parts of NSW and VIC, then some big rainfall is likely to emerge. If the sequence is decoupled the falls will be more patchy.

Over the north, we have seen the return of very hot build up conditions with isolated showers and thunderstorms about, that in the wake of Seth that brought that widespread rainfall and gusty cool conditions through Christmas. Thankfully some relief is on the way for locations over northern Australia this week with the risk of severe weather Tuesday through Thursday for the NT and northern WA.

For SA and much of southern and southwest WA, the weather not changing a whole lot. Will have to keep watch of the monsoonal weather perhaps returning from mid month, offering the next chance of rainfall for these regions, but it is not unusual for rainfall to be patchier in La Nina Summers through these areas while the east and north remain very humid and unsettled.

Lets take a look


Rainfall Next 10 Days

Rainfall continues to build across northern Australia with deepening heat troughs and lows and the presence of a developing low or two north of the nation at the end of this sequence which may introduce a very wet second half of January for the north and then spreading southwards. The other major area of rainfall is in the short term, over the southeast inland with a slow moving trough, cradled by high pressure to the south and being fed by the remains of Seth via northeast to easterly winds. Heavy showers and thunderstorms are expected to form near the trough with areas of rain developing over parts of VIC and southeast NSW. Some locations in southeast NSW and the ACT through the Riverina could record more than one month's worth of rainfall from this event. More rain and storms build through the nation as we track from this time next week with another trough deepening over SA and pushing into NSW and VIC once again at the end of the period. Showery weather for QLD continues with inland thunderstorms on most days, the coverage and location of the storms random and scattered. And for WA and SA, more of the same, sitting on the dry side of the trough nearer stable high pressure, so limited rainfall opportunities for southern areas of these states into the next weekend, but your fortunes may change as we track into mid to late month.

Thunderstorm Forecast Monday

Thunderstorms continue over the northern tropics, some of these could be severe as mentioned below in the thunderstorm outbreak chart. Thunderstorms also possible over the western interior and about the southeast of NSW and the ACT near a stalled boundary. There may be some thunder along the NSW and QLD coast depending on the proximity of the low to the coast.

Thunderstorm Forecast Tuesday

The trough over southern NSW will lift to central and northern NSW on Tuesday, but stall out, resulting in storms relocating out of the southeast of NSW for a period. The trough over the north is set to deepen with multiple heat lows involved over the interior sparking showers and thunderstorms over a wide area of the NT and WA. The storms could be gusty over the north with damaging wind gusts.

Thunderstorm Forecast Wednesday

Showers and thunderstorms become more widespread during Wednesday with storms tending severe with heavy rainfall leading to flash flooding the main concern. The storm coverage over the north and northwest also on the increase with storms tending severe, gusty damaging straight line winds are possible. Thunderstorms may also produce heavy rainfall.

DATA - Refer to the video to see GFS comparison and to see how they differ.

Euro 12Z - Surface Pressure Pattern and Rainfall Distribution - Next 10 Days

The pressure pattern remains dynamic and complex over the next week with a few troughs on the board, very deep moisture being pulled into these features via easterly winds over QLD, NSW and VIC resulting in widespread rainfall and flood potential. The northern tropics after baking the last week, will see a more routine weather set up develop, with strong to severe storms about today and throughout much of this week. Out west and across much of SA, the weather dry and fairly benign under sinking air motion so conditions stable and warm to hot. As we move into the weekend and next week, a new trough will emerge from SA and into the southeast and east, tapping into moisture once again leading to widespread showers and storms returning. The more interesting feature will be found over the northern tropics, with odds favouring a deepening low near Cape York or in the Gulf Of Carpentaria, expected to move west over the NT this time next week, with another very wet phase developing. How far west that feature comes will determine how much of the nation ends up getting wet as we move into the second half of January.

Euro 12Z - Precipitable Water Values - Next 10 Days

Note the deepening moisture through northern Australia is a feature of this outlook with the development of tropical lows within the developing monsoonal trough offshore a key to introducing heavier moisture loads throughout the nation. It will be the pattern evolving over southern Australia that will dictate whether the moisture moves south or southeast/east throughout the nation. In the short term, the remains of Seth can clearly be seen being ingested into the trough moving out of SA and into QLD and NSW/ACT as well as central and eastern VIC with moisture pooling near and to the east of this feature. The moisture content near seasonal out west.

Euro 12Z - Rainfall Accumulation - Next 10 Days

More information can be found in the video.

CMC 12Z - Rainfall Accumulation - Next 10 Days

More information can be found in the video.

GFS 12Z - Rainfall Accumulation - Next 10 Days

More information can be found in the video.

Euro 12Z - Rainfall Accumulation - Next 15 Days

Note the tropical moisture being dragged by upper northwesters away from WA and SA, this is one of many ideas on the table, but additional heavy rainfall is likely for the east and southeast as well as over northern areas.

GFS 12Z - Rainfall Accumulation - Next 16 Days

More information can be found in the video but once again, the rainfall signals are increasing from mid month.

More updates coming up today on the heavy rainfall potential for the east and southeast and the increasing tropical activity and how that impacts mid month..