NSW - RAIN DEVELOPING FROM LATE THIS AFTERNOON IN THE WEST.

And that rainfall is going to be marching east today with a strong cold front lifting moisture through the middle and upper levels, producing widespread light to moderate rainfall by tonight.


Note the system has started to stand up from yesterday where the cold air mass has consolidated into a low pressure system on the front. There is moisture surging southeast through the interior, denoted by the high cirrus and middle clouds.

This morning it is frosty and clear, but that warming northwest flow will see off the frost quite quickly with above average temperatures returning for central and northern parts. The weather though expected to turn this afternoon.


The cloud will increase during the afternoon over the north and west with patchy rainfall developing. Scattered showers and thunderstorms will also develop ahead of that rain band further north near the QLD border with moderate falls there as well.


Another band of rain will form from that convection tomorrow night while the rain band along the cold front and further south will move east and eventually merge to form a large mass of rainfall that will sweep over the GDR. Patchy light rainfall may make the coast in certain pockets, a bit like today.


GFS 12Z - Rainfall for 3 days. Note the rainfall builds rapidly as the front runs into the higher PW values moving southeast.

Then from Tuesday afternoon, showers remain through southern inland areas of the state with a moist and gusty westerly wind that will moderate. The rain will clear the northeast of NSW during Tuesday morning.


Farmers and Graziers for Tuesday through Wednesday.

It will be a noticeable shift in temperatures as well with the risk to stock elevated inland due to the temperature change. The risk is not long duration and should resolve by about Wednesday throughout.


Showers will gradually decrease over the course of Wednesday over southern inland areas before we see full clearance over inland NSW from Thursday with the showers being handed back to Victoria.


A dry few days over the weekend, may be followed by another front mid next week.


Lets look at modelling


12Z GFS Surface Pressure Pattern for the coming 16 days

Rainfall is still anticipated to be the most widespread during the next 2 days with the final wave passing over. The weather will clear the inland areas from mid week and by the end of this week most of the state should have returned back to dry and clearer with a milder northwest flow. The weather looks good for the weekend, but another wave of frontal weather is expected to bring another batch of cold fronts to southern Australia with the rainfall not as extensive as this event running over the nation, however it is over a week out and will likely change. The high pressure belt is slowly moving south over the southern states during this period and may deflect the cold fronts further south than where they have been during recent weeks.

12z GFS Rainfall for the coming 10 days

No change from last night with the most widespread rainfall coming up today and through Wednesday for southern inland areas before it begins to clear southwards later this week ahead of a dry weekend. Then we are looking at more frontal weather developing next week through WA and SA with moisture streaming in ahead of these systems, there is a chance of further areas of rain/showers for southern NSW. But the north should remain dry for now.

12Z GFS Precipitable Water Values for the coming 16 days

Elevated PW values continue to surge southeast ahead of the front today with that helping to develop a cloud band with showers and thunderstorms developing. Then the PW values will come down as a dry southwest flow moves into the eastern inland. The moist air in the lower levels will persist over the inland leading to cloudy skies and light showers until about mid week and then drier and more stable air under high pressure clears the state from later this week into the weekend as the winds turn northwesterly. Another wave of tropical moisture coming from the Indian Ocean accompanies the next front passing over WA through SA next week and that needs watching if that brings another band of rainfall.

12z Euro Surface Pressure Pattern for the coming 10 days

The surface pressure pattern remains unchanged on the Euro for the coming few days, the last of the strong fronts passing through today and tomorrow bringing the most widespread rainfall and a shift to colder weather for the southeast states. The high over WA ridging in will move over much of the nation from mid to late week bringing clearance and a nice weekend of weather. Next week we have another wave of frontal weather to deal with however the frontal weather may be further south than this lot coming through this week, meaning that rainfall could be more coastal early next week. We have to watch the moisture streaming in on the northern flank of this wave as another band of rainfall may develop, as was the case on Saturday with 15-30mm falling over much of VIC.

12z Euro Rainfall for the coming 10 days

No change from last night, really good agreement and guidance on the rainfall over the coming 24 hours. A few spots along the ranges and the east coast will see light falls. In fact the further east you go towards the coast, most areas will stay dry. The better rainfall will develop over the northern tablelands tonight through Tuesday with moderate falls possible The rainfall then contracts back through to VIC on Wednesday and then the showery weather for southern and mountain areas of the southeast during Thursday. The weather turning clear for the inland areas from Friday and weekend. That will be where the weather turns milder.

12Z Euro Precipitable Water Values for the next 10 days

You can see that Indian Ocean influence in the coming 2 days with the moisture streaming across the nation northwest to southeast. That will trigger more light to moderate inland rainfall. For coastal areas, the rainfall is connected to the frontal passage this week and again next week. Another burst of moisture rushing through the jet stream early next week may produce another band of rainfall for WA and SA in around about a week or so.

Rainfall for the next 10 days

The rainfall is mainly for the coming 2 days with the bulk of it out the door by Wednesday. Though lingering low cloud and light showers may persist for southern and central inland NSW and along the divide during Wednesday before decreasing Thursday. The weather greatly improves over the weekend with more sunshine and milder weather, nowhere near the record temperatures of last weekend. The next rainfall chances come with the frontal systems it appears early to mid next week, again watching that moisture surging in ahead of the system, which could broaden over coming days.

The rainfall for the northeast may increase tonight in the forecast packages with there being a signal to lift rainfall further west towards Moree and Narrabri, but will wait for the latest data sets to come through before I increase the totals.

More weather details to come today including the latest on the moisture in the medium term.



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