The weather is forecast to be rather inclement for parts of the south from tonight, we have already seen rainfall developing in association with a large cloud band moving eastwards along a trough and cooler southerly flow that has engulfed Victoria today.

A warm and gusty northwest wind is forecast to remain in place over the northern and eastern parts of the state, the weather will be warm tonight but the cloud and cooler air will eventually drift through with patchy light falls at best, with the bulk of the wet weather forecast to pass eastwards and offshore the southern coastline.

Mid week, most areas should turn dry, though onshore southeast to easterly winds are forecast to develop as we track a change up the coast with a few showers possible but most likely heaviest about the coastal fringe and in the south.

The next system is forecast to develop as we move into the weekend over inland areas of the nation and as profiled, will be due to moisture spreading out of the northeast with the upper northeast flow drawing moisture from the tropics into a trough over the interior of the nation. Scattered rainfall should develop from Friday but more likely over the weekend with a broad area of rain possibly moving eastwards as we move into ANZAC Day.

So we have 2 events in the short term and the potential for another event post this lurking in the medium term.

A lot going on and it is mid Autumn and this should be expected after a warm and breezy week for many.

Lets take a look


Rainfall Next 10 Days

Rainfall is forecast to increase tonight as we see a trough deepen in association with a small area of low pressure likely to form on the trough. Areas of rain with some moderate falls along the western and southern border with Victoria will continue to lift north and northeast with this moving over much of the Riverina and Southwest Slopes into the ACT and Southeast tomorrow before clearing. Only patchier lighter falls forecast further north as we go. Into the middle of the week and a developing southeast change is forecast to develop with bringing a chance of showers and mainly light falls to the east coast and moderate falls on the extreme coastal fringe. Into the end o the week and will start to see scattered showers developing for northwest and northern inland areas of the state with moderate falls possible by the weekend over the Upper Western and through northern inland areas. Some of this rainfall is forecast to drift eastwards as we go through the period with some moderate to heavy falls extending throughout the state west of the divide next week but some of it falls into the medium term window (beyond day 10).

Thunderstorm Forecast Tuesday

Thunderstorms are forecast to develop across the far southeast with a southeasterly change moving northwards but no severe weather is expected. Middle level thundery showers possible in advance of the rainband moving through the southeast.

MEDIUM TERM - April 25th - May 2nd 2022

Deep moisture across the nation looks to spread rainfall and the Autumn Break for many areas. Another moisture surge over northern Australia with a tropical wave passing north of the nation is possible with increased humidity and late season falls for the far north. This moisture too could be drawn south or southeast into the nation lifting rainfall chances. Another wave of low pressure passing through from the south of WA could surge northwards and bring a colder drier airmass towards Australia, which may help to promote another rain band forming in Southern Australia at the end of the period.

Rainfall Anomalies

The anomalies are shifting above average as we move through the period with many areas now leaning towards a wetter bias for the period, thanks to the secondary system on the charts we can see over ANZAC Day and another system lurking out there in early May. Now in pinning down who gets what relating to rainfall totals, that is not possible, but you can clearly see the areas identified as being wetter than normal. And a good chance for many of you.

Temperature Anomalies

Becoming cooler as more rainfall and cloud cover takes over the nation with the warmer than normal weather of this week moving further east and north across the country with a colder shift for the southwest, south and eastern inland quite possible as we move into May. Warmer signal developing for the northwest and west with a persistent easterly flow as the east sits under the positive SAM influence leading to more cloud and rainfall.

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.

00Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

A lot more in the run down in the video but there are 2-3 events to watch in the forecast period that offer some interest for vast areas of the nation. The issue will be the timing, scale and intensity of each of these and because it is a high amplitude pattern, the forecasts will bounce around furiously!

00Z GFS - Precipitable Water Values - Next 2 Weeks

The PW values are really elevated through this period which is not uncommon but what you will find with the extra moisture content means more efficient rainfall events with higher intensity rainfall with thunderstorms and if we do end up with severe weather, flooding would be a feature. Inland areas need to be on alert and follow modelling trends as we go along.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z CMC - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z Euro - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysis

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - rain in the short term more widespread for southern areas, but keep an eye on the follow up rain event from next week! That is the one to watch.

More coming up from 9pm EDT with a look at the models and rainfall, I will only share information that is in reasonable agreement as too much is too confusing and I only want to share what is plausible at this time, so stay tuned for that.

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