The weather is pleasant for the most part today for NSW but the temperatures are set to dive away through Monday afternoon and evening with a cold front to pass through bringing a burst of showers and possible thunderstorms for the region. Some areas could see some of the coldest weather come Tuesday, in about 4-6 weeks. And frost is also a significant risk for some locations.
Lets take a look.
Rainfall for the next 10 days
Rainfall is light for the central and northern inland parts of NSW if any falls during the coming 7 days, the biggest event this week is the drop in temperatures and then the rapid recovery to seasonal values come the weekend. Rainfall moderate about the Southwest Slopes and Alpine areas over the coming 24-48hrs. Then we have to wait right until the end of the 10 day forecast to focus on the next rainfall event which bears better chances of more widespread rainfall in a traditional early spring set up.
Thunderstorm Forecast Monday.
Thunderstorms are possible about southeast SA and along southern VIC with small hail and gusty winds forecast with thunderstorm activity. There will also be some brief heavy rainfall but at this stage flash flooding is low with a dry airmass in place and the cells moving through at pace. Storms will fire along the boundary of cold air during Monday afternoon through southern NSW. Over the northeast of NSW and southeast QLD, isolated mid level thunderstorm activity may develop producing gusty winds and brief heavy rainfall. Severe weather is unlikely for all regions at this time, but in spring time expect the unexpected.
Small Hail Risk - Monday.
Cold air showers and thunderstorms will be capable of producing small hail and gusty winds through Monday, extending north through the afternoon into Southern NSW and the ACT where the hail intensity may be moderate to heavy given the day time heating process. The hail is likely to be below severe thresholds.
Damaging Winds Forecast Sunday into Monday
Damaging winds are ongoing in the tightening pressure gradient as the cold air lifts north into the southeast of the nation. On Monday, strong squalls over 90kmh are possible with a front passing north through the state and into southern NSW during Monday afternoon. Conditions should ease later Monday into Tuesday from the west.
Snowline Forecast - Monday into Tuesday
The snowline will drop well below 1000m during Monday into Tuesday, however with the airmass quite dry, this will see falls not accumulate, rather more flurries with the passing showers at this time.
Farmers and Graziers Forecast - Monday to Wednesday.
As mentioned for 5 days now, the event is on the doorstep and this period of cold will place the young animals at great risk, especially through southeast SA, VIC and NSW.
Frost Forecast Wednesday Morning
Frost is expected to widespread, I will add in more specifics when we get closer tomorrow, but this is a preliminary forecast and a heads up on potential frost for large parts of the state.
Euro 00z - Surface Pressure Pattern and Rainfall - Next 10 days
The pattern is in good agreement with the GFS with strong cold front passing through during the coming 48hrs the main weather to watch nationally away from the high pressure. The west will be dry and warm to hot this week, perhaps a weaker change passing through in dry fashion to take the temperatures down by the weekend but at this stage, from WA, through inland SA, all of the NT, much of QLD and into northern and western NSW, dry conditions are expected with a good supply of sunshine. The weather turns more interesting in about one week, we have the SAM likely turning more positive introducing easterly winds over QLD and NSW seeing showers returning and a formidable rainfall event offshore WA may approach in about 9 days time. Northern tropics should enjoy the last week of dry weather before the return of build up conditions.
Euro 00z - Precipitable Water Anomalies - Next 10 days
Precipitable Water values as outlined in the video are way below average this week nation are way below average, hence no rainfall and colder conditions over the south, warmer weather over the west and north. Drier air allows temperatures to rise and fall more freely. The best part of a week shall pass before the moisture begins to creep back in and this is where rainfall chances pick up over QLD and WA. The tropics into October should see more coverage of rainfall. Moisture will work its way back into southern states from later this month lifting rainfall chances.
Euro 00z - Rainfall Next 10 days
Not a whole lot away from the southeast. Once that system is off the board on Tuesday, the rainfall you can see is really for the back half of the period, so not much for the coming week over inland areas, coastal areas of QLD through NSW should see showers return later in the outlook period. Perhaps a few light falls with a weak front Friday over the southeast and then the larger trough and stormy outbreak over WA is the system to watch as we end the month. That system may run into moisture in place over eastern NSW and QLD and see a larger area of rainfall develop for months end into early October.
GFS has more moisture to work with than what it is spitting out in rainfall potential tonight, so watch this space and do not get caught up on the chopping and the changing in the model. Looking at the trends, rainfall chances increase from the 24/25th of this month onwards and in kind from last few days of September.
Model wrap of the rainfall potential in the medium term coming up tonight from 9pm.