Once again, we are looking at the risk of rainfall returning to large areas of the coast from later this week as another trough links up with moisture fed in via the warmer waters of the Coral Sea and Pacific Ocean at top a high in easterly winds. The same pattern we have seen play out time and time again is likely to play out once more, and as a result further inland rainfall is likely and showery coastal conditions as well.

How far west the easterly rainfall event comes remains to be seen because we have another promising rainfall event passing through WA then moving into SA, this is expected to push into western parts of the state during the late weekend, likely merging with the easterly moisture, seeing a better chance of widespread rain unfold early next week.

So, this sets the scene for more above average rainfall to end the month.

The rainfall is not wanted in some areas with crop damage already underway from the heavy Summer and Autumn rainfall, this is likely to continue for the months ahead. Some are struggling to get crops in! It is a tricky time and headlines a period of difficulty in the months ahead looking at trends.

Let's take a look


Rainfall Next 10 Days

Rainfall is forecast to remain coastal in the coming days with a few showers along the north coast above about Taree with the lingering moisture associated with the onshore flow. The remainder of the inland should be dry and pleasant for a number of days, a chance to dry out as temperatures move towards above average levels. Higher moisture levels, more active low-pressure systems lifting the moisture and we have warmer air as well, all of this combining for major rainfall events to persist through the weeks and quite probably months ahead. The rainfall event to pass through mid to late week should not bring any further flood problems but keep catchments wet for eastern areas and isolated to scattered falls are forecast further west.

Northeast Rainfall

The rainfall is expected to be more extensive later this week along the coast with some areas possibly seeing more than 50mm (more than what is being shown here) but certainly the rainfall focus does look to head back towards the coast from mid to late week.

Inland Rainfall

A much drier look throughout western areas of NSW with some areas expected to be somewhat rain free which falls into the seasonal barrier for this time of year, but off the back of well above average rainfall it should be welcome news for those planting. Note that the rainfall will be close by to the northeast and east of the divide and could spill over once again this weekend, but that remains to be seen. Overall, much drier this week with colder nights returning.

Southeast Rainfall

Strictly coastal in onshore winds and really does not quite increase as we get towards the end of the weekend and into next week with the flow turning more unstable northeast to easterly. Inland areas west of Canberra look mostly dry with just a few showers possible later in the weekend with a weak front passing through VIC.

Thunderstorm Forecast Monday

Thunderstorms are forecast to become scattered along a weak trough and deep moisture profile passing through northeast areas during the afternoon and evening. Thunderstorms could produce some moderate rainfall.

Frost Risk Forecast - Tuesday through Friday

A drier airmass is forecast to settle in from Monday and with clearer skies and the high-pressure ridge moving in, there is the chance of frost developing. The peak of frost is forecast from Wednesday and Thursday before easing later this week.

Medium Term - May 22nd-29th 2022

Rainfall Anomalies

Northwest cloud bands look to continue over the nation with moderate rainfall extending underneath the cloud band. The moisture may merge with moisture from easterly winds in a warm airmass leading to widespread rainfall above the average once again a decent chance over parts of eastern QLD and through NSW. The SWLD with persistent onshore winds and frontal weather moving through bringing bursts of showers and colder conditions. Generally seasonal rainfall is forecast over southern parts of the nation with light to moderate rainfall.

Temperature Anomalies

A warmer phase looks to be in place over much of the nation with a broad area of high pressure in the east directing warmer than normal weather from northwest Australia into central and eastern areas of the country. Higher humidity values over the nation will support warmer nights as well. The cooler bias looks to continue over western parts of the nation with thicker cloud and the chance of further influence from the Indian Ocean. But the position of the high-pressure system over the southwest of the nation will continue to pump in onshore winds.

DATA - Refer to the video at the top of the page for further details on all this data below and to place it into context.

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

The high-pressure system that is set to develop is forecast to become the dominant force for much of the nation leading to a drier eastern and southern inland. The wettest weather will be found on the periphery of this large scale high with rain forecast to be above average over in the west of the nation with a few events on the board as mentioned and the possibility of another event developing over Central and SE QLD, chiefly near the coast with moderate to heavy falls. Elsewhere, it is looking much drier through this week which may start to shift in around a week. A strong cold front moving through WA during the early part of next week could bring a band of rain into the Bight mainly south of the mainland. Medium term shows more moisture feeding across the nation and further rainfall chances in the eastern inland of the country. This is fairly typical for this time of year as the high-pressure systems move northwards to their Wintertime location.

00Z GFS - Precipitable Water Values - Next 2 Weeks

Moisture that is feeding across the nation from northwest to southeast via the jet stream is forecast to lift northwards early this week with dry air undercutting this very anomalous moisture spread that has driven the high rainfall across the country. High pressure is forecast to dominate the synoptic elsewhere and trap the drier and cooler air that comes in from Tuesday onwards with frosty nights and fine days for the east. But all the action with the higher moisture levels will be found in the west with a large-scale system moving in from Tuesday through Thursday and yet again later in the weekend into next week. Another burst of moisture is forecast to be drawn into a trough over QLD with the better rainfall along the central and southeast coasts for now, this then spreading to the NSW coast with moderate falls developing later this week. In the medium term, the moisture should begin to spread throughout the nation with better rainfall chances moving into southern Australia towards the end of the month.

00Z GFS - Rainfall Accumulation - Next 10 Days

Refer to the video for more context and analysi

00Z GFS - Rainfall Accumulation - Next 2 Weeks

Refer to the video for more context and analysis

A closer look in - rainfall numbers will start to bounce around as we start to track some systems in the medium term, so while it is looking drier this week for most in the region, your numbers beyond about the 24th will start to change after a warmer and drier spell.

More coming up from 8pm EST with a look at the models and rainfall, where we have some interesting signals in the medium term to consider, but the broader modelling will help answer a few of my questions and hopefully some of yours as well.

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