NSW - SHOWERS DEVELOPING ALONG THE EAST COAST, DRIER FOR MUCH OF THE INLAND UNDER RIDGING.

OVERVIEW

An upper-level trough that moved into far western areas overnight is on it’s way through the inland QLD today and should start to emerge as showers and thunderstorms moving through areas just north of the border tomorrow afternoon. Some of this may start to drift over into northern parts of the state with moderate falls possible in a narrow band extending back north into QLD.


Along the east coast, onshore winds may start to assist in showers developing with moderate rainfall developing mainly north of Sydney.


The rest of the inland is expected to be dry for now, but there is a developing trough approaching from the west later in the weekend which may begin to trigger widespread cloud and areas of rain over SA which could move into the west of the state.


SHORT TERM

So the wet weather once again is to stack up in the easterly winds with moderate falls developing. The light falls are forecast to drift into far northern NSW tomorrow, but the heavier rainfall is most likely to be found in QLD. The rain and showers along the east coast will begin to ease during the weekend as the blocking pattern in the Tasman begins to break down.


Once that happens, that will bring a batch of showers from SA into the eastern inland of the nation and so the current dry spell over the western regions may come to an end through Sunday into early next week with mainly light falls for now.


LONG TERM/AREAS TO WATCH

So, the longer range is of interest to many over southern Australia with the chance a more traditional belt of westerly winds to start moving northwards towards the mainland over the course of the end of the month into early August.


The main axis of moisture in association with the frontal weather passing through from west to east will be over WA with moderate falls to continue in the SWLD. The rainfall will approach the south and southeast with mainly light falls for now but that is subject to change.


The prevailing wind conditions will likely clear out the eastern inland of the nation with a drier airmass moving through. Those same westerly winds will bring back hopefully the wetter weather signal into the south of the country.


WEATHER VIDEO PM - TUESDAY 18TH JULY 2022

FORECAST

Rainfall Next 10 Days

Rainfall is now forecast to develop along the eastern seaboard with light falls for the southern coast and tending more moderate into the central and northern coastal areas. Some of the showers could be heavier through later this week as a trough deepens offshore then the wet weather should ease by the weekend as the easterly wind regime begins to ease and the trough offshore moves away, and the block breaks down. There will be a weakening trough coming through the westerly wind belt which will be giving the SWLD of WA a fair chance of rainfall throughout the period but for the south and southeast, these fronts will be struggling against the weakening easterly wind regime. A stronger system emerging out of WA towards the end of the period offers better rainfall chances through the medium term (first week of August)

Watching the amount of thunderstorm activity that lurks close to the northern border in the coming 24hrs to see how much of that drift southwards over the border and into the Upper Western. Along the coast, the persistent easterly winds will bring daily moderate rainfall with the chance of thunder Friday and into the weekend before the trough moves away. Then we see rain drifting into the far south early next week with a shift to westerly winds.

WEATHER ISSUES

Frost Forecast Wednesday Morning

The frost risk is contracting south through the state thanks to the upper trough rolling through QLD and the wind regime tending more easterly. Severe frosts are possible along the Victorian Border tonight and tomorrow morning and once again on Thursday morning.

Thunderstorm Forecast Wednesday

A sharp upper trough will move into QLD during Wednesday and collide with warm moist air leading to scattered showers and thunderstorms forming throughout the afternoon and evening with some of these possibly drifting into far northern NSW later tomorrow into Thursday.

MEDIUM TERM FORECAST

July 26th-August 2nd, 2022

Moisture Watch

Moisture is still expected to feature through WA and offshore the east of QLD and NSW with the appearance now that the weather could be tending back towards what we should be seeing at this time of year. Moisture running through the westerly wind belt and extending back to the northwest of the nation will likely be the feature to watch. Rain impacts from that strongest over WA but it may creep further east into SA and VIC. Dry weather at this time throughout much of the north and east of the country.

Rainfall Anomalies

Rainfall anomalies are starting to ease in terms of that drier bias over the southern parts of the country as we see frontal weather passing through from west to east through the period, but given the SAM forecast, the neutral phase at this time, should see the fronts further south. But it is the moisture running through the westerly wind belt that may see rainfall return to more widespread levels for Southern Australia, we just need to see the block leave the east of the country for this to unfold. Dry weather to continue up north which is normal.

Temperature Anomalies

Temperatures not changing a whole lot from yesterday with the cooler bias continuing over the northeast of the nation and the warmer bias maintained over the western interior of the nation. The seasonal weather is forecast to continue over the southeast and east of the nation where the warm burst of weather will be knocked back west, thanks to the return of frontal weather and the potential rainfall.

DATA - Refer to the video for further context and information in this low confidence forecast period.


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

Refer to the video for further context and information in relation to the low confidence forecast period.

00Z GFS - Precipitable Water Values - Next 2 Weeks

The moisture profile in the short term is deeper and much more widespread over the northeast of the nation with a western branch of moisture coming through QLD and drawn into the trough passing through in the coming days. A southerly flow developing on the western face of the low that forms offshore this weekend will pull in dry air to the eastern inland into early next week. Out west, frequent intrusions of moisture coming out of the Indian Ocean is apparent on the charts, but also on the satellite this evening. That pattern will continue over the course of the next week or two. The question will be how much of that comes further east in the week ahead? There is plenty coming through, and you can see that by the end of the period the moisture is very deep in most areas.

00Z ICON - Rainfall Accumulation - Next 7 Days

Refer to the video for more context and analysis

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 - rainfall confidence across the nation is far higher along the east coast with the onshore winds but for the interior of QLD and NSW, where we have a deep trough forming tomorrow into Thursday and this may see rainfall nose into northern NSW. How far south remains to be seen. Otherwise, the confidence of the GFS capturing the system coming out over SA into VIC on Sunday into early next week is poor and other modelling has broader rainfall developing with this feature so expect numbers to change.

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


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