EVENING RAINFALL UPDATE FOR NSW

Not much change in the model guidance so will keep the preamble short and sweet and get straight to the raw data this evening.


00Z GFS - Surface Pressure Pattern and rainfall next 16 days - Valid Monday 12th of July 2021.

A vigorous pressure pattern this week is largely unchanged with two major fronts to pass through, the coldest of the two coming in during Thursday into Friday through NSW with the chance of more dynamic weather moving in, so be sure to keep up with the warnings and forecasts. A high pressure system will move north of SA during the weekend and could open the door for more frontal weather by the weekend. Then in the medium term there is more rainfall and strong winds possible with moisture spreading into another wave of fronts. But this is low confidence and a signal but one we will talk about every day this week.

00Z Euro - Surface Pressure Pattern and rainfall next 10 days - Valid Monday 12th of July 2021.

A fast flow pattern with multiple waves expected this week, no change from this morning, though the precipitation continues to bounce around a tad for the later system Thursday and Friday, but I am sticking with GFS given it has gotten the trough correct today over the southeast and better falls for southwest Australia today as well. Then next week, the follow up rainfall from the Indian Ocean is moving more east than south tonight, doesn't quite phase correctly with the front, but it is now moving the system further east which is a good sign.

00Z GFS - Precipitable Water Values and pressure pattern next 16 days - Valid Monday 12th of July 2021.

Impressive moisture anomalies coming across the country for July and being lifted by fast moving cold fronts. So widespread rainfall should break out in response and that is being reflected in the modelling for the coming week or so. Again the models repeat this process next week, but the configuration of that event is still up for debate. Follow up rainfall is likely for many areas of southern Australia but how much is yet to be determined.

00Z Euro - Precipitable Water Values and pressure pattern next 10 days - Valid Monday 12th of July 2021.

Very high PW values means a lot of moisture coming down the pipe into the central and eastern inland this week. Even once the rain band clears through on Wednesday afternoon, the airmass is moist with the ability produce widespread showers on Thursday over inland areas as another shortwave passes through. Some of those could be heavy, not just about coastal areas. A stronger front arrives on Friday with a cold dry airmass and you can see that sweep out the moisture. BUT in this climate, it doesn't take long for the moisture to recycle through the tropics and have another crack, more rainfall potential at the end of the run is evident for WA and SA to begin with.

00Z GFS - Rainfall for the coming 10 days - Valid Monday 12th of July 2021.

Rainfall totals are starting to come up with 3 events being picked up in the coming 2 weeks, but for the most part I will pull the events apart, so focus on the two fronts this week first and then the event next week tonight in a later post. Rainfall in a westerly wind regime again looking very promising for anyone living on and west of the divide through NSW with moderate falls up and down the divide. Those falls could turn heavy and snowy through Alpine areas down to 700m during Saturday. Conditions ease Sunday throughout NSW.

00Z Euro- Rainfall for the coming 10 days - Valid Monday 12th of July 2021.

Rainfall numbers a lifter softer than GFS but productive and welcome for many in western NSW and SA, through northern VIC. I am sitting half way between GFS and Euro at the moment in my forecasts as in these situations the truth often lay somewhere in the middle. We wait and see what the morning update brings but it is essentially unchanged tonight so that is good news for those planning.

Rainfall for the next 10 days - Valid Monday 12th of July 2021.

Rainfall is largely unchanged for the sequence, adding a little more back to the northern tablelands and adjacent plains with a little bit more moisture streaming through now. I do think with high PW values the rainfall totals should get above 15mm for the region. Elsewhere numbers are largely the same, note the coast is near dry through this sequence, very normal for these winter setups, it is traditionally the driest time of the year for the NSW and QLD coasts, running into the fire season starting next month

Rainfall for the next 10 days - Valid Monday 12th of July 2021.

Rainfall looks to stack up along the western face of the Great Dividing Range with the best of the rainfall expected through the Southwest Slopes, bordering onto the eastern Riverina with most of this falling as rain before Friday. Rain will largely thin out the closer you get to the coast, very normal. Light to moderate rainfall over a number of days looks to bring 8-20mm over much of the inland this week.

Rainfall for the next 10 days - Valid Monday 12th of July 2021.

I have lifted the rainfall up to the QLD border again this evening with 15-20mm possible now through to about Stanthorpe. These numbers may be raised further if the guidance continues to strengthen the moisture profile and rainfall output over the region which has been subtly increasing during the last 36hrs.

Next week as mentioned there are significant areas of rainfall likely to develop over the west of the nation with moderate to heavy falls there, some of that may drift eastwards, I will update details on that after 9pm.

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