We continue to see widespread rainfall and thunderstorms impacting large parts of NSW, spilling over into VIC as the upper low starts to open up today. The instability also extending into southern QLD leading to scattered showers and thunderstorms for southern areas. Thankfully along the coast of NSW where there has been significant flooding, the rain has eased with the trough axis and upper low shifting a little further west and beginning to weaken.
Across inland areas, after a batch of showers and thunderstorms Thursday, the showers and storms continue to spread across the southern parts of QLD, through much of inland NSW and into northern VIC with some storms dropping heavy rainfall and small hail, some areas could see large accumulation of hail as well. That coverage should increase this afternoon, especially in areas where the skies are clear and stable.
For the west of the nation today, it will be a warm and dry start to the day with a northwest to northerly flow establishing, and freshening about the southwest. A cooler southwesterly change along a cold front is forecast to move through the southwest this evening, with a band of showers and thunder. The band of showers should begin to break up with interaction of the land mass so only light falls getting into the SWLD for now.
A cloud band forming along the cold front will begin to broaden and thicken up and could form further areas of light rainfall as the front drags in moisture from the Indian Ocean and begins to be lifted by the clash of airmasses over the Bight. This will be in response to the clash of airmasses that will take place over southern WA and SA. We can see that unfolding this morning to the southwest of the nation.
This sets the stage for a chance of rain spreading over southern SA and into the southeast of VIC with widespread cloud and hopefully extensive rainfall to follow for large areas of southern and southeast Australia next week. There is a chance this system could begin to process of the Autumn Break which we have profiled throughout the week, but once again the confidence is low.
The cold front will strengthen as it moves through eastern SA and crosses into VIC and NSW. There may even be a low pressure system form along the front, with modelling placing that low anywhere from Tasmania, through VIC or into NSW and then an ECL in recent times. That represents the uncertainty around this system. This will continue to have large impacts on temperature and rainfall distribution.
We need to get the current system off the board in the east, before we look at this feature in greater detail and as mentioned last night, this won't be possible with any great accuracy until about Saturday night or Sunday.
Tropical weather also needs to be watched for the medium term impacts, as that too could send follow up rainfall events across the nation. Starting to see significant rainfall projections for the north of the nation with above average falls likely with a Rossby Wave.
Lets take a look
Rainfall Next 10 Days
Rainfall has been heavy to very heavy in various locations overnight with some areas seeing moderate to severe flash flooding and riverine flooding for many areas as well. The rainfall with some luck should begin to ease about the coastal areas today, though showers remain through the weekend. Over inland areas of NSW, extending south into northern VIC and north into southern and perhaps central QLD east of Quilpie through Wilcannia through Kerang, scattered falls over 20mm possible and isolated flash flooding with strong to severe storms remain possible until Saturday night. Out west, we have a cold front today that will send in mainly light falls, though if thunderstorms become more northern focussed, a few moderate falls over 10mm cannot be ruled out. The rainfall clears eastwards during the weekend with drier weather returning for WA. Across the Bight and south of SA during the weekend and into Monday, a deepening pre frontal trough, a cold front and that moisture surge setting up a cloud band we can see over the southwest, will mix together and a low pressure system/wave may form on the front and this may thicken up the rainfall production under the cloud cover over SA then expand as the system moves into left over moisture through VIC and NSW/ACT. Some areas could see moderate rainfall over the thirsty areas of the southeast inland but further heavy rainfall is possible over the eastern inland of the nation through NSW and the ACT. An east coast low cannot be ruled out at this time. Looking into next week, the severe weather potential should be on by during Thursday and Easter looks reasonable for many areas away from the coast. Over northern Australia we may see increasing rainfall and thunderstorm activity with a Rossby wave moving through during early next week.
SHORT TERM CLIMATE DRIVERS
SOUTHERN ANNULAR MODE - SOUTHERN OCEAN - ANOTHER POSITIVE PHASE MAY DEVELOP NEXT WEEK
This is providing me some concern as to another wet phase developing for the eastern third of the nation through the second half of April. With any system that emerges through SA and VIC next week, it could bomb into another east coast low or inland feature driving heavy rainfall under such guidance. This would keep the same pattern of the past few months going, rainfall for the east, drier weather for much of the south and west.
MJO - TROPICS - CLIPPING THE WESTERN PACIFIC WHICH MAY INCREASE FALLS NEXT WEEK.
We do have a Rossby Wave forecast to pass through the northern region next week which could enhance rainfall and moisture throughout the region however the MJO may also pop into the Western Pacific for a brief period lifting the rainfall frequency mainly north of Australia under current guide, but the humidity values will be back to early March levels and above average.
Thunderstorm Forecast Friday
Not much change in the forecast from Thursday with strong to severe storms once again with heavy rainfall leading to flash and riverine flooding. Thunderstorms, mainly isolated to scattered inland could also drop a large amount of small hail with slow storm motion near the upper low.
Hail Risk Forecast Friday
Thunderstorms will be able to produce hail from later today through Friday with the coverage of thunderstorms peaking during Friday afternoon. Thunderstorms carry a low chance of producing large hail (> than 3cm) during the day and evening. The risk of hail continues on Saturday. Up to a 50% chance of hail developing within 25km of a given point in the high zone and dropping to 30% in the moderate zone and 10% in the low zone.
Thunderstorm Forecast Saturday
Thunderstorms may continue into Saturday but contract inland a little as the upper low opens up into a trough and that trough moves west a little as the flow turns northerly. Storms unlikely to be severe at this time and should decrease in coverage for the coastal areas. Isolated thunderstorms possible through most days over the northern tropics but many areas going dry.
Thunderstorm Forecast Sunday
Thunderstorms are forecast to clear eastwards from the nation. We could see a scattering of thunderstorms clipping southwest SA and over the tropics, just a scattering of coverage yet again during the afternoon and evening.
Thunderstorm Forecast Monday
Thunderstorms are possible with a prefrontal trough and low pressure system forming over the eastern and southeastern inland with some storms possibly producing damaging winds and heavy rainfall through the east of Victoria and across inland NSW in advance of the colder shift. Thunderstorms are possible over the northern tropics, the coverage increasing a tad as the moisture deepens.
Thunderstorm Forecast Tuesday
Low confidence forecast for the southeast however instability moving through with a deepening trough or upper low moving through the region. The air ahead and with the system is quite humid and the colder air in the upper levels will support scattered storm development near the troughs. Over northern Australia, the showers and thunderstorms may begin to increase with the tropical wave moving in from the east.
SEVERE WEATHER REGIONS
Severe Weather Watch - Heavy Rainfall and strong winds - Monday through Thursday Next Week
Keeping a very close eye on the system next week and I will have more details on this coming up tomorrow and Friday then across the weekend. This system carries low confidence and you may see major weather events on the charts in the coming days and that may be cause for excitement for some and dread for others, however, be aware that the forecast is dictated by what happens with this current event and so we have to wait for this event to conclude by Sunday and then we will get a clearer picture.
A closer look at the southeast, and this remains a relatively low confidence forecast so pay attention to forecasts in the coming days.
DATA - Refer to the video for further information and it is critical to keep check of the data sets to understand where the next major weather events are emerging from outside of this period. It may be quiet now but I am all about preparation and ensuring that information is shared with you as soon as it is available.
MEDIUM TERM FORECAST - April 15th-22nd 2022
Moisture Watch Next Week
Moisture continues to be a huge feature for northern Australia and I am of the belief that it could sweep south or southeast through the nation. Where that occurs will be in relation to the long wave troughs passing through Southern Australia and the turn to the south of that moisture may occur through the NT then into western QLD (GFS) or it could extend across into the Indian Ocean and then turn southeast into WA then Central Australia (CMC and Euro). There will also be moisture building through westerly wind belt but overall, the biggest take away is that waters around Australia are above average which is leading to widespread rainfall every time we see major low pressure across the nation.
Still running high over northern and eastern Australia with mixed odds elsewhere with some of the rainfall heavy at times over northern Australia. The east coast may see above average rainfall with a positive phase likely to unfold. I will have more on that throughout the weekend because I think that may see yet more flooding potential for the east. Spill over from the northern tropics will likely be seen into Central Australia, but models struggle to connect that with frontal/trough weather moving west to east through the southern states. So there will be some wild rainfall projections in the medium term to watch across the nation, which will chop and change, but it is likely the wettest weather would be found over northern and eastern Australia.
Temperature Anomalies Next Week
These temperature projections are quite volatile in terms of the data sets being observed, however I am keeping it largely unchanged with warmer weather for most of the interior of the nation, cooler back in the southwest, over the northern tropics and east of the Great Dividing Range through QLD into NSW with the wetter weather over the north and east dominating the weather and the cooler southwest to southerly winds with high pressure anchored southwest of WA keeping the cloud cover in the region in the onshore flow.
DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.
12Z Euro Surface Pressure Pattern and Rainfall Distribution - Next 10 Days
The pattern remains dynamic over the east today but that low should start to weaken over the weekend. However eyes are now shifting to the southwest of the nation with the front approaching today. Behind that front, colder air surging north may start to interact with the warmer and moist air that is being drawn in ahead of this feature, and as it meanders in the Bight south of WA and SA over the weekend, it will likely be picked up by an upper level low and this will see more rainfall develop later Sunday into early next week over southern and southeast Australia, while conditions ease over the east. Northern areas will need to pay attention to the tropical wave moving through open waters over QLD and NT with enhanced rainfall with locally heavy late season rainfall and severe storms. Fine and dry for a while over central interior Australia and that could also cover much of western QLD. Now as the system moves eastwards from the Bight next week, it could develop into a formindble rainfall event for parts of SA and VIC before covering NSW. Some modelling has the potential for 1-2 months of rainfall along the path of the system, but as outlined over the past few days, there is uncertainty in placement and timing of this feature. There is potential for an Autumn Break but the data can only be taken far more seriously once we get to Sunday and the current upper level system over the east is out the door and we can see what the atmosphere looks like over SA and points east with this next system. Looking into Easter, the weather is looking volatile up north and a positive SAM may lead to rain increasing for the east of the nation once again! Drier weather may return to inland areas but watching the moisture over northern Australia and whether that can turn southwards and form more rainfall chances for the nation over Easter-ANZAC Day.
12z Euro Precipitable Water Anomalies - Next 10 Days
Moisture content is elevated for much of the nation's east and north and this is where we continue to find higher rainfall chances for much of these areas. The moisture in association with a front moving into the southwest of the nation looks to deepen a bit more with a rain band developing in the Bight before it sweeps into the east and south for much of next week. Drier air continues to dominate the inland but watch that moisture over northern Australia very closely. If you are living over inland areas of the NT, QLD, SA, NSW and northern VIC, this could provide some chance of rainfall events towards the end of the month.
12z Euro Rainfall Accumulation - Next 10 days
Refer to video for more information
12z GFS Rainfall Accumulation - Next 10 days
Refer to video for more information
12z CMC Rainfall Accumulation - Next 10 days
Refer to video for more information
12z Euro Rainfall Accumulation - Next 15 days
Refer to video for more information
12z GFS Rainfall Accumulation - Next 16 days
Refer to video for more information
I will have a Climate Update for the coming 6 weeks, later this morning but I am on holiday schedule for the coming days (which has not been as successful with the severe weather about) with another update during this afternoon.