MODELS AND ALL THINGS RAINFALL - THE COMPLEX PATTERN IN THE SHORT AND MEDIUM TERM.

This period coming up over the next week may look fairly routine for this time of year, and by most chances it most likely will be. But as we have seen in recent weeks, when all the ingredients are in play, we get these "black swan" rainfall events. I am moderately interested but not concerned, about the upper level system that is coming into the south and then southeast of the nation next week.


If this system can work its way into the eastern inland, it will kick off yet another large scale storm and rainfall event. With some luck, we can see this impact areas further west, such as eastern SA and into western VIC and NSW and for pockets of QLD that have missed out through the west.


For some, it has been a dry Summer, and these areas do need rainfall. That includes parts of eastern SA and northwest VIC and pockets of Western NSW.


Also areas that have missed out, southern and western parts of WA. It has been a hot and dry season and more rainfall is required very soon as the sowing, growing period gets underway.


And the tropics look to get more active as well, this thanks to the MJO moving around. Now if the SAM can return to neutral or negative values, any increased moisture over northern Australia may be pulled south via the jet stream. Out of these events, we can see Autumn Breaks born.


Lets take a look.


SHORT TERM

The weather in the next few days looking mostly dry for much of the inland of the nation, though there will be pockets impacted by the troughs wafting around, so central and northern inland NSW could see storms this weekend, that will extend into southern and central QLD. We could also see pockets of southern inland WA picking up on hopefully some beneficial rainfall. The tropics seeing routine rainfall in association with the build down conditions. The east coast of QLD and through NSW will see showers, more extensive through parts of QLD and heavy falls over FNQ.


UKMET - Rainfall Next 7 Days - MODERATE CHANCE

The UKMet has started to fall into line with the other global models printing out heavier rainfall for the eastern inland of the nation, but pushing that focus to the western portion of NSW and into VIC plus eastern SA. Showers for the east coast of NSW and QLD. Tropical weather looks routine and seasonal and light falls for now in remaining areas.

ICON - Rainfall Next 8 Days - MODERATE CHANCE

Also showing the feature mid to late next week for the east but has it further east than the UKMet which supports the low confidence forecast period. The weather over the north looks seasonal with scattered showers and storms. Weather along the east coast is also seasonal in terms of what you would expect at this time of year in onshore winds. Light rainfall elsewhere.

MEDIUM TERM

Watching this developing upper trough or low pressure system next week that may form near SA and then drift into NSW and QLD with showers and thunderstorms increasing for southern, southeast and eastern areas of the nation. This will be a feature to watch and it will cause the charts to show all sorts of scenarios of heavy rainfall one moment and nothing the next so pinning down and outcome is impossible right now for these areas. Showers will continue for the QLD and NT tropics with local thunder. The west coast sees drier weather for now, but watching the passage of the MJO over northwest and northern areas of the nation which could lead to significant rainfall chances for tropical areas. Late season cyclone activity may develop in the north as well.


CMC - Rainfall Next 10 Days - MODERATE CHANCE

The rainfall in the east patchy in nature given the series of troughs, but the heavier rainfall does appear to be including more of the Ag Areas in SA. The weather over in the west unsettled this weekend but conditions could turn more unsettled at the end of the period. Wet for the QLD coast with showers and storms in onshore winds but lighter falls further south and into NSW. Does not see an ECL in this solution.

EURO - Rainfall Next 10 Days - HIGH CHANCE

The latest Euro has settled the rainfall down a little from this morning over the eastern inland but none the less still has unsettled weather over the southeast and eastern inland with that trough passing through next week. Scattered falls along the coast with onshore winds, heaviest about the tropical QLD coast. Rainfall is increasing over the northern parts of the nation with the MJO approaching the region.

ACCESS - Rainfall Next 10 Days - LOW CHANCE

The ACCESS has the rainfall more amplified through inland areas of western NSW, eastern SA, western QLD and through the southern NT back to the tropics. Has showers for the east coast but mainly dry conditions for the southeast of the nation. The weather in the west wet over the north but limited falls for the southern areas. ACCESS also has two cyclones on the board in the medium term either side of the nation.

KMA - Rainfall Next 12 Days - LOW CHANCE

The latest KMA also showing more widespread falls over the central inland of the nation extending back into western QLD, NSW and possibly northern VIC. Showers for the east coast with onshore winds, heaviest over the northern portions of the QLD coast. Tropics looking fairly seasonal ahead of the MJO. The west of the nation is expected to be seasonal as well with the trough in the short term offering scattered showers and storms and then perhaps with more moisture being drawn in via northwest winds from the Indian Ocean at the end of the period.

GFS - Rainfall Next 16 Days - LOW CHANCE

This is showing a dynamic system passing through the south and east of the nation next week and seeing an ECL form off the South Coast of NSW with torrential falls. Now the ingredients are there for another ECL given it is the season but whether it forms and whether it forms there remains to be seen but will keep watch in the coming days. Over the east coast, wet, with showery weather continuing. The weather over the north becoming wetter with more showers and storms as the MJO approaches and the west and southwest of the nation seeing a few storms in the short term but moisture floating offshore over the Indian Ocean may be drawn southeast into the western interior towards the end of the period.

ENSEMBLE DATA

These data sets have been increasing rainfall over southern and southeast/eastern inland parts of the nation once again thanks to that system that has emerged as one to watch this time next week. There are also increasing numbers for the north with one of the last bursts of widespread rainfall for northern Australia via the MJO. Otherwise relatively seasonal weather elsewhere, but I am watching the numbers over the north and southeast very closely. If you are living in WA and SA watch the tropics in the next week as this could influence rainfall chances moving into the end of the month.


GFS - Rainfall Next 16 Days (median of 35 members) - MODERATE CHANCE

Note that it is much wetter over the north of the nation than compared to the deterministic data sets so this would impact rainfall spread through the north and east of the nation in the medium term.

CMC - Rainfall Next 15 Days (median of 30 members) - MODERATE CHANCE

Also looking wetter than it's deterministic counterpart.

EURO - Rainfall Next 15 Days (median of 51 members)

Note the moisture building over northern Australia and on the FNQ coast with the trade winds and over the eastern inland with the slow moving trough. Finally the moisture is building offshore WA so that will also need to be watched heading into the end of the month.

LONG TERM

The shift in the pattern is starting to appear, perhaps some Autumnal Break conditions as we move into April.


CFS - Rainfall Next 6 Weeks - MODERATE CHANCE

Seeing that rainfall now spreading around the nation rather than being biased over the north and east which signals that the models see a pattern shift that is smaller than just a short term replacement of high pressure, but more like a seasonal shift. So pinning that down in the next 4-6 weeks will be fun but there is rumblings for that shift in the longer term for all areas of the nation. Note that heavy rainfall over the southeast of the nation and through southern WA.

More coming up from 8am EDT with your next national wrap.