NSW - RAIN IN THE EAST, HEAVY ALONG THE COAST TONIGHT. SHOWERS DECREASING INLAND. DRIER LATE WEEK.

OVERVIEW

What a wild few days it has been and the weather still wet and windy along the coast, but the overall threat of severe weather is starting to ease as the low-pressure system responsible moves away, but the showers won't totally clear the coast, in fact still some moderate to heavy totals possible about the central and northern coastal areas in the days ahead.


The inland will start to dry out post the cloud and patchy rainfall today and colder nights are also set to return with a large-scale high nosing in from mid-week.


SHORT TERM

The pattern is starting to ease, but the calmer weather pattern may be brief, as we have the threat of another trough developing along the coast later this week, interacting with another pool of colder air and this could see another low forming offshore the south of central coasts of NSW.


In this scenario, we could have another batch of showers and areas of moderate to heavy rainfall for some in the southeast but more likely south of Wollongong at this time, but definitely an area to watch. For areas west of the divide, generally dry weather through the weekend under ridging and a chance to dry out, remaining dry over the far west.


LONG TERM

Watching the risk of further low pressure developing offshore QLD and NSW with this persistent signal of rainfall hugging the coast. All the ingredients are seemingly there, not clearing away as what was being modelled say a day ago, so we must be on the lookout for further rain over the east coast of the country.


That means that the drier bias would continue over the interior, from the west of QLD/NSW through northern VIC, SA and over much of the interior and back to the west away from the SWLD. This pattern would support the suppression of the Winter Westerly regime and lead to drier than normal weather for large parts of the south.


AREAS TO WATCH

Can the SAM turn back towards negative values and the positive phase that is currently underway ease, helping to dry out the east and end the risk of more above average rainfall.


Will the moisture content over the Indian Ocean begin to influence frontal weather into the medium term over the SWLD of WA? Signals are that it may be the case of a gradual increase in the rainfall spread for WA that may translate eastwards.


But some areas over southern Australia, especially SA, could go rain free for the coming 2-3 weeks bucking the trend of all the guidance that has been available this year.


WEATHER VIDEO PM - MONDAY 4TH JULY 2022

FORECAST

Rainfall Next 10 Days

Rainfall is expected to ease gradually along the coast through the coming 48hrs with the trough and low slowly moving to the east with a drier airmass trying to move in. The rainfall over the state will be focused over the eastern seaboard and clear the inland for the remainder of the week. Another system wafting through VIC on Friday has a pool of cold air attached to it and as it moves over NSW, will be drawn into the broader circulation of low pressure sitting over the Tasman Sea. This will see widespread showers return to southern and southeastern parts of NSW with the risk of another deep low forming offshore with this system later in the weekend. The remainder of north and central parts of the state should avoid additional rainfall from this and rainfall should be nil over the western areas.

Additional rainfall in the shorter term could be quite heavy at times over the coastal fringe, but that should ease mid-week ahead of another burst of showers over southeastern inland areas from the weekend with that running north up the Great Dividing Range and then heavier rainfall possible in the presence of an east coast low forming this weekend. I will have more on that later on.

A broader look shows how unusual the rainfall spread is for this time of year, where the heavier rainfall should be in those areas exposed to the westerly wind regime and not the easterly wind regime.

Frost Risk Forecast Tuesday

Frost will return to the southern inland but not severe at this time as a ridge starts to nose in. Southeasterly winds and cloud cover clearing over the inland north and to the east will save the region from frost, but it will return mid to late week but not at the levels we saw last week.

Riverine Flood Risk This Week

Very high chance of flooding remaining an issue over areas that have seen heavy rainfall over the past week. This will continue for some time and be reminded, this rainfall is setting up a dangerous Spring flood season that may stretch into Summer 2022/23.

MEDIUM TERM FORECAST

July 11-18th 2022

Rainfall Anomalies

The wet bias hanging on over the east coast with troughing in the region and the moisture profile deeper in the easterly flow of this week, lagging into this period. The drier signal is now starting to strengthen over the southern parts of the nation as the SAM struggles to get back to neutral territory meaning that frontal weather is retarded to the south.

Temperature Anomalies

Not a whole lot of change from yesterday though a warmer tongue of air could be established over inland WA as a northwest flow becomes persistent ahead of frontal weather further to the south over the SWLD. Colder signal continues for much of the east and north as the persistent cooler air is trapped under ridging and the landmass slowly recovers from the week of cloud and rain we have experienced. Cloudy with wetter weather potential in the east could bring temperatures to near seasonal.

DATA - Refer to the video for more information and to cut down your reading time.


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

More details are found in the video at the top of the page with a lot of weather in the short term and possibly once again this weekend in the east and far west.

00Z GFS - Precipitable Water Values - Next 2 Weeks

High amplitude pattern means very high levels of moisture and dry air with that being drawn around a large low-pressure system in the upper levels in the east. The drier air will keep the west dry and the east will remain wet with excessive rainfall reflecting the excessive moisture load that is present. The weather will slowly mix out over the coming week and the airmass becoming less humid over the east and less dry of the west and that will bring more settled and seasonal conditions across the nation. But the moisture does look to hang on over the east for now.

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 wet weather in the east is somewhat persistent but will ease in intensity over the coming week. But watching the threat for another east coast low. Showers over the southeast and southern states very limited for now but as you can see the rainfall is expected to increase in the medium term.

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



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