NSW - CLOUD THICKENING BUT NO RAIN JUST YET, DOES THIS CHANGE AS WE MOVE THROUGH THE WEEK?

OVERVIEW

We can see that cloud band developing through the northern and northeast parts of the nation today with that kicking off a fairly sizeable and anomalous rainfall event over the northern parts of the nation.


For us, we are dealing with excessively cold conditions tonight with some areas into freeze territory (<-5C for much of the evening) with severe frosts possible over large areas of the divide and southeast inland. But sunny days are forecast to emerge throughout the week, though as mentioned, high cloud will visit from the north mid-week with rainfall chances coming up for the back of the week.


SHORT TERM

The pattern is very complex and there are multiple upper level disturbances that are set to tap into moisture surging southwards from the tropical waters north of Australia, leading to widespread cloud we can see here today over northern Australia, and rainfall increasing in coverage over large parts of the nation’s northern and northeast.


Another upper level trough is forecast to deepen over the southeast during mid week and this too is likely to move northwards into the moisture leading to showers developing over much of NSW and possibly eastern VIC. Some of the rainfall could become heavier later this week into the weekend.


Models have also been flirting with the idea of a low pressure system forming along the trough as it slowly moves eastwards with the upper feature driving showers and storms over the inland of the NSW.


Severe weather potential is also coming up in chance over the weekend and into this time next week and will be monitored.


LONG TERM

The low pressure system will begin to move eastwards and the trough responsible for dragging the large amounts of moisture through northern Australia will pop off the east coast leading to drier air returning for inland areas and a resumption of seasonal weather.


A series of strong cold fronts west of the nation may start to approach WA and this could bump high pressure further eastwards and lead to a pattern flip and see conditions dry in the east and drier back in the west with conditions forecast to start shifting wetter as we start to track a series of cold fronts across the nation’s southwest.


AREAS TO WATCH

The weather over the nation is forecast to shift in the first week of July once we move the large scale upper trough over the east away to NZ. The weather over the west and south of the country is forecast to remain fairly changeable, not seeing a large swing to large scale cold fronts just yet but this could change as we move forward throughout the period ahead.


WEATHER VIDEO PM - MONDAY 27TH JUNE 2022

FORECAST

Rainfall Next 10 Days

Rainfall is hard to pick for the state, but we are looking at more widespread rainfall developing throughout the period, especially over the east coast where onshore winds coupled with troughs and low pressure over QLD dipping into NSW will continue to push further southwards as we move into the week and weekend. This will set up a wet period for the east coast with the onshore winds producing showers with the potential for heavy falls along the coast. An upper low over the southeast and eastern inland is expected to produce widespread showers with small hail and thunder over the course of mid week into the weekend, but rainfall coverage is expected to be not as widespread as the coast at this stage, but this could change so keep watching during the low confidence forecast period. Out in the far west it should remain mostly dry and that may also be the case for the southern areas near Victoria.

You can see the coastal areas will certainly see a decent chance of rainfall with the focus of heavy rainfall moving around in relation to where models place the low-pressure trough/centre along the coast and the upper low over the inland so this forecast will become more refined through the week.

Frost Risk Tuesday Morning

Frost is possible about the ranges and extensive areas of the central and southern inland where frost too could be severe. Frosts may start from as early as 8pm tonight about higher terrain and 10pm along the plains. It will clear from around 8am on Tuesday morning.

SEVERE WEATHER WATCH

As mentioned this morning, if you are in the yellow zone, make sure you check back daily and even if you are near the area drawn in but not included, the weather doesn't care about where I draw the line, still pay attention. This risk zone could be drawn further west or trimmed back further north into QLD. But for now, it would be wrong to not flag this as a risk developing for the region, really from the weekend into Monday. Flash flooding and riverine flooding the main issue and some locations on current modelling could see 300mm from the event. That will become clearer as we move through the week.

MEDIUM TERM

July 5th - July 12th, 2022

Rainfall Anomalies

Rainfall anomalies are still leaning above normal in the east and northeast and seasonal elsewhere after a dry spell over southern and western Australia. Rainfall will return but not enough for southern areas to make up the deficit just yet, but that will come with time. No outrageous weather systems are forecast during this period but keep watching that moisture north and west of the nation. You can see where things are heading as we move into Spring.

Temperature Anomalies

Warmer bias in the east with left over humidity and easterly winds keeping temperatures up to 1C above normal overall. In the west and central areas and over northern Australia, the cooler bias continues under cloud and moisture circulating through the region and onshore winds over Southern Australia. Frontal weather returning to WA will also lead to cooler air being projected through the state.

DATA - Refer to video for more information and the model comparison and context about all the forecast products you see from me.


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

More details on the rollercoaster ride that is the short term forecast and a detailed look at the medium term in the video at the top of the page.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The moisture profile is quite deep over northern areas of the nation and remains so for much of this week into the weekend, before it merges into the upper low and trough over QLD and NSW with the chance of widespread rainfall emerging as a result. The weather is expected to be more humid than normal for many areas of northern and eastern Australia for much of this week and won't resolve until early next week when the system moves off. The southwest and west of the nation is expected to be drier for the next week or so before we see moisture returning via the upper level northwest winds and bringing some moisture back via the Central and Western Indian Ocean. The rest of the nation at seasonal values.

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 GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - the rainfall spread in the short term over the southeast inland is expected to be connected to the position and strength of the upper low that forms later this week and how much moisture gets drawn into the upper low as it meanders along during the weekend and whether we see an east coast low also remains to be seen. Otherwise, dry weather for much of the southern coastal areas before rainfall returns from mid to late next week.

More coming up from 8pm EST with a look at the models and rainfall.


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