A fine end to the working week is expected for the state, a stray shower or two with a possible thunderstorm may develop later tomorrow along a weak cold front passing through the Victorian region.

The southeasterly change that follows with the ridging high pressure over SA and VIC will begin the process in shifting conditions over the eastern half of the nation, moisture will be allowed to pool over the inland and a trough from QLD, and another moving in from WA will likely converge over eastern areas of the nation, this leading to extensive shower and thunderstorm activity.

Rainfall could be heavy at times on CURRENT guidance, but lets see what probabilities we are looking at and the timing of the event.

Rainfall for the next 10 days

Not much apart from a few showers and thunderstorms over VIC, creeping over the border into the Southwest Slopes and Alpine areas on Friday. A southeast to southerly change will move up the NSW coast on Saturday and become marginally unstable for showers for coastal areas during Saturday afternoon and evening. The showers reach the North Coast during Sunday. Next week, the moisture from easterly winds will transport into the western plains of NSW and QLD and be drawn south through the state ahead of a trough moving in from the west. Showers and thunderstorms developing from Tuesday afternoon onwards. I will have regional based charts in the next day or so for those areas under heavy rainfall - waiting for another few sets of data and then will start issuing those once again.

Thunderstorm Forecast Friday

Thunderstorms are a low to moderate risk with a weak cold front passing through Victoria. With moderate forcing and topography aiding in line with the day time heating process, non severe thunderstorms may develop over the region. The jet stream aloft may see storms IF they form, become gusty at times. Small hail is possible over higher terrain. Storms diminish in the evening but may form offshore the South Coast with a nice light show for some.


Euro 00z - Surface Pressure Pattern and Rainfall Distribution - Next 10 days

The pattern remains mostly dry and settled for the coming days, despite a fast moving cold front passing through the southeast with a burst of showery windy weather and a few storms. The weekend is where the weather starts to shift nationally. Firstly in the west with a trough deepening over the inland triggering scattered showers and storms, moisture improves the coverage of showers offshore the SWLD generally, the circulation broad but the wet weather will be about. Over in the east a trough will develop over the eastern inland of Australia with a stalled boundary off the east coast of QLD sending easterly winds and that moisture along the coast inland to help produce showers and thunderstorms through inland areas. The moisture will be taking a journey south as upper level northerly winds develop between the high in the east and the approaching trough out of the west with the moisture over NSW and VIC being lifted by that WA trough and low into a multi day rain and storm event. It still appears the best of it will fall east of SA. The rainfall heavy at times and could lead to areas of flooding through NSW and northeast VIC. There is another system to follow later in the period which I will cover off later on this evening. The north hot and becoming humid with showers and storms developing. Showers and storms will also move into QLD during the mid to latter part of next week, especially through southern and central inland areas.

Euro 00z - Rainfall - Next 10 days

Rainfall distribution is largely unchanged from last night with the bulk of it falling over the eastern states and across the SWLD of WA with a trough passing through this weekend. The event over VIC and NSW appears to be the most productive on the board, but keeping an eye on the follow up system over in WA later next week which could tap into deeper moisture coming in from the Indian Ocean. There should be a good coverage of showers and thunderstorms during the coming week over QLD but the falls more scattered and patchy, where the rainfall much more widespread over the southeast inland. Lighter falls for SA, surrounded by all the potential but the second system coming out of SA may provide better rainfall opportunities in that configuration. The northern tropics will see showers return once the upper high breaks down next week, but isolated falls are possible.

Closer look - the sharp edge of the trough quite evident. If the trough can move further west with the moisture through the outlook period, this may see rainfall tick up for Western NSW but this is traditional rainfall spread for Spring.

Euro 00z - Precipitable Water Anomalies - Next 10 days

It is all about the available moisture content and where it is travelling in the coming days, and you can clearly see from the chart below and the modelling again tonight that there is good agreement about the moisture over the east being drawn south, the moisture over the west being drawn southeast into the Bight and bypassing SA, however the lifting mechanism runs into the eastern inland with widespread rainfall developing. Then another surge of moisture is expected to approach WA later next week and the moisture over inland NSW and QLD will retrograde back through Central Australia and be held up and primed to be absorbed by the next system coming out of WA, fingers crossed this behaves better for SA. The tropics turning soupy through the outlook but the upper high needs to break down for showers and storms to return.

I will take a look at the full model suite and the rainfall potential in the next week after 9pm once all the data is in.

65 views0 comments