A CLOSER LOOK AT THE RAIN EVENT NEXT WEEK.

As mentioned yesterday, I will focus on the rainfall sweeping the nation in greater detail this today as it has the chance of being a high impact event for many people across the south and the east ahead of harvest.


Lets take a look.

FORECAST CHARTS - Refer to the video for more analysis for each region.


I will focus on the rainfall as that is the major concern.


Severe Weather Zones.

Flood watches are likely to be issued for parts of the region and I have drawn in my areas of concern well ahead of time, these areas may see minor flooding at least, of creeks and river systems mainly west of the divide. But properties that are low lying, bogged/saturated will be dealing with a lot of run off, especially when the thunderstorms kick off Tuesday evening into Wednesday. Storms could be severe with flash flooding a major concern. Some areas with the presence of thunderstorms, could score 40-50mm in a couple of hours.

Rainfall Zones

NSW and VIC - Clearly the bullseye for the event this week.

Central West

Soaking rainfall with some areas already recording their September average, may see another months worth of rainfall this week and most of Octobers rainfall taken care of in the first week of that month, so a heads up for a wet phase to be protracted through this period. May start to do more harm than good.

Tristate

Light falls generally, but as mentioned for the southern areas, if the trough over SA can stall out over that region, then rainfall totals could increase for this region a tad. But it is a tight rainfall gradient.

Southeast NSW and Eastern VIC.

Bullseye for the two rainfall events over the coming 10 days, with flooding a higher chance over this area. Wild card system will be if a trough can lay east west and run parallel to the easterly flow pattern to see coastal rainfall increase over 100mm in the outlook period, some models show this but it is low risk at this time.

Northeast NSW - Southern QLD

Rainfall totals are creeping up for inland parts of QLD and I will issue a chart for the state later, the focus today is the higher probabilities of widespread rainfall for the southeast inland of QLD with multiple rounds of storms.

Southwest NSW and Northwest VIC

Reasonable chance of light to moderate rainfall for thirsty areas of the Mallee but as always and to be expected, the better rainfall is further east as it should be at this time of year.

Southeast SA and Southwest VIC

Best of the rainfall is likely further east through VIC, but the rainfall gradient could creep further west if the trough stalls out over western VIC from mid week.

Ag Areas of SA.

This area could see the numbers come up in the coming days if modelling continues to strengthen the secondary event. This area remains a low confidence forecast, not to receive any rainfall, but it could be higher falls than what is being shown here for some locations.

SWLD of WA.

A months worth of rainfall likely under this guidance over the course of this week for some areas, especially as we head into October which is trending drier throughout the region.

DATA - Again refer to the video for more insights.


18Z GFS - Surface Pressure Pattern and Rainfall Distribution - Next 2 Weeks

With the high heat and extra moisture content, the air is more unstable and we will see low pressure begin to dominate the synoptic scale for the best part of 10-14 days, which could see some areas get a months worth of rainfall in a sitting, some areas two in NSW but lighter falls accumulating over large parts of the nation will be welcome for areas such as SA and QLD hanging out for a drop and for those wanting to get their crops over the line in NSW and VIC. But I do warn famers in NSW and VIC, it could be a case of far too much by this time next week as we stare down even more rainfall.

18Z GFS - Precipitable Water Anomalies - Next 2 Weeks

The moisture content is starting to return today as we lose the dry air field from last week, and it is all tracking as we were discussing throughout the week with a continuation of the moisture dominating the outlook period into the second week of October.

18Z GFS - Rainfall Accumulation - Next 2 weeks - HIGH CHANCE.

This is quite a wet spell for the south and east, which is traditionally the wettest time of the year, but falls over the course of this week could trend damaging with flooding possible in some locations over northeast VIC and southeast NSW.

Significant rainfall in excess of 100mm for parts of NSW. Some areas could exceed 150mm through this sequence. Widespread 50mm throughout the southeast and east and across parts of SA and WA.

12Z Euro Ensemble - Rainfall Accumulation - Next 2 weeks - MODERATE CHANCE

Come back in terms of rainfall in recent days but still running a bit too dry for interior parts of SA and WA.

12Z CMC Ensemble - Rainfall Accumulation - Next 2 weeks - HIGH CHANCE

This model has been very consistent in the approach for this wet phase and continues the wet phase beyond this period as well, so something to think about as we look at this system is do we get a break in the east, and do others area pick up on rainfall such as QLD and SA?

Rainfall Anomalies for the coming 2 weeks

GFS 18Z

Some areas up to 6 inches (125mm+ above normal) for the coming 2 weeks.

Euro 12z - Much more conservative as we track through the coming 2 weeks, but that is a wet look off this model. Even 50mm above normal for some areas (which are in the wettest time of the year) is significant.

The SWLD also looking for rainfall totals of 20-30mm above normal for this period, which would be a nuisance for many coming into harvest out west after some brilliant warm days.

More in your state based forecasts this afternoon.