NSW - THE DRYING TREND BEGINS

The weather is expected to turn drier from tomorrow with a colder airmass that gave rise to the scattered showers and thunder over southern inland parts of the state today. The weather is drying out tonight as we lose the heating of the sun, the showers decreasing this evening and largely clearing during Wednesday.


Over the northeast, Glen Inness and Armidale have seen about 50mm of rainfall from that moisture plume with that moisture now on the way out.


Low level moisture will return overnight and into Wednesday so expect more thick low level cloud to develop for southern parts of the state, but with a high pressure ridge close by, the sinking air will prevent the cloud from producing much rainfall.


Satellite Imagery

The cold airmass with drier air values is currently moving through the southern parts of NSW this afternoon with a storm risk decreasing tonight. Another sliver of moist air will arrive tomorrow and bring more widespread cloud cover back to the region The cloud band over the northern inland will contract east.

The weather then trends sunnier as we track through Thursday from northern inland areas spreading south, by Friday, dry and partly cloudy with more sunshine expected.


The weekend looks pretty good, no complications other than morning frost about, possibly severe in some areas, but mild and mostly sunny weather to follow.


That should continue into next week as well, there are fronts approaching and moisture is attached to those features, but the high pressure could win out and deflect that frontal weather to the south.


Let's look at modelling.


00Z GFS Surface Pressure Pattern for the coming 16 days

The frontal weather is now clearing the east with high pressure taking over much of the nation so, from WA through SA into VIC and NSW/QLD, settled weather finally starting to dominate. We will see showers for parts of the coastal areas in all states but really this week is now showing that pattern flip I have been talking about in the previous two weeks. The moisture over the north of the nation will be allowed to pool thanks to the dominance of easterly winds, and a lack of dry southwest to southerly surges. The next front will come through WA over the weekend with showers spreading east through the weekend, perhaps reaching the southeast. Over the weekend and next week, easterly winds may develop for the eastern states with showers developing. Then moisture builds up further through much of the inland with rainfall chances increasing from mid to late month. This will be where the bulk of the rainfall will come during August.

00z GFS Rainfall for the coming 10 days

Dry for many areas over the coming 5 days. We have got a few isolated showers for parts of the coastal areas of WA, SA, VIC and TAS. The eastern seaboard dry for now, the inland also dry from now until next week. The winds will turn easterly in QLD and NSW over the weekend and that may bring showers to the coast. Over in the west, a strong cold front will pass through the SWLD with areas of rainfall and a deep moisture source. That looks to break down as we track through next week, the front being beaten down by the ridge over southern parts of the nation.

00z GFS Precipitable Water Anomalies next 16 days

The PW anomalies paint the picture of an active period of weather developing from mid month but before then, the dry air will take about 5 days to mix out over the northern parts of the nation. We do see the moisture levels picking up over WA in line with a strong cold front on the approach this weekend. A band of rain likely to form over the west coast of WA and spread east. But the high will keep the east clear of that weather for now, the high sending easterly winds up the NSW and QLD coasts and bringing showers, but more importantly moisture back through the eastern inland. That moisture will be important, especially the further west it is drawn through NSW and QLD, as it will then be picked up by any frontal weather moving out of the west mid month, this lifting rainfall chances. The tropics also becoming very soupy through the coming 2 weeks.

00z Euro Surface Pressure Pattern for the coming 10 days

Euro is very much in line with GFS in the slow clearing trend over the southeast with a large high slowly moving east. That high already clearing WA and bringing up to 4 more days of settled weather. SA should see that clearance mid to late this week over coastal areas, but the inland should be dry now for another week. The inland QLD and NSW also clearing overnight and essentially dry as the high moves in. The high clearly the dominant system to bring that pattern flip through the nation. The next frontal weather comes through WA over the the weekend with that being the focus of the most widespread rainfall. Onshore winds may introduce showers to the east coast over the weekend into next week. And humidity over the tropics set to increase dramatically as we go through the coming weekend into next week.

00z Euro Rainfall for the coming 10 days

Rainfall largely confined to the southeast states over the remainder of the week with the rainfall contracting south tonight to coastal SA, VIC and TAS. The winds will turn unstable northwesterly over the weekend which will see showers increase over WA with moderate falls possible. The weather becoming more humid over the north and east with a wind shift into the east. That will send some showers onto the NSW and QLD coasts. Morning showers also possible next week over the NT and Cape York. Perhaps some rainfall developing later in the period from northwest Australia with moisture deepening.

00z Euro Precipitable Water Values next 10 days

You can see that moisture over QLD and NSW clearing offshore and being overrun by the dry surge moving through SA, VIC and TAS. That dry air will dominate the eastern inland and shift through the tropics later this week bringing one of the last dry surges for the season. The low level moisture returns for southern coastal areas as the high starts to ridge in. The weather is expected to become warmer over the north and that will coincide with moisture increasing over inland areas which will then combine with some upper features to bring cloudy skies and increased rainfall chances from mid month over northern or western Australia. The east coast could also go into a prolonged period of easterly winds with that impacting northern NSW and QLD more than areas south of about Newcastle. Those easterly winds bringing moisture to the eastern inland.

Rainfall for the next 10 days

Rainfall largely clearing the inland for the coming week. I am leaving it dry for now as if I draw in every solution from the global models surrounding next week, it will drive you spare. So for now dry for the coming week and coastal showers easing for the southeast. Showers developing for the coast over the weekend with mainly light falls.

Friday 13th of August.

Here is an example of the moisture activating into widespread rainfall over the northern parts thanks to a trough deepening. This guidance will come and go but it is a great example of the IOD bringing rainfall through Australia.

I will have more on the medium term outlook coming up tomorrow.

0 views0 comments