The rain events however also continue to cause a stir in the coming week over in the east and northeast and across the southwest of the nation with a deepening trough and moisture in feed into a strong cold front moving in from the west.
The weather is cold though in the short term, I have given ample heads up on the frost and grazier issues over the course of this week into the weekend and now the focus shifts to the rain event potential over QLD/NSW and then into WA with the next strong cold front. Does that western event bring some rainfall through to SA and into the southeast states later next week as well?
There is a lot of weather on the board so let’s get straight into the forecast, no video this morning as I am flying through the sky across the country.
Rainfall Next 10 Days
Rainfall is forecast to remain scattered over the southeast with the cold outbreak today, some of that could turn moderate over VIC and possibly heavy over TAS with a low pressure deepening over Bass Strait. The low itself will begin to move away with rain easing over the southeast of the nation this weekend. The showery weather over the northeast tropics is forecast to continue this weekend as well and there may be a few showers and thunderstorms over the QLD coast with onshore winds. The rest of the nation is forecast to be quiet. Now the rain event of interest to kick off the new working week is the upper trough deepening over inland QLD. This upper-level system will tap into the northeast flow with areas of rain and thunderstorms forecast to break out in response to this. The rain will start to seep southwards and impact northern and central NSW, possibly eastern parts of SA and this could meander through to later next week. There is a low chance of rain making it to the southern border of NSW with this system but what falls should be light. The rainfall over inland QLD and along the coast from NE NSW through to FNQ could be heavy to torrential along parts. Some of the rainfall could exceed 300mm for the sequence here. Flooding is possible. Out west while this rainfall event is going on in the east, a strong cold front is forecast to move eastwards and tap into the moisture coming out of the Indian Ocean leading to a large rain band emerging across the southwest of the state. This system could provide some heavy falls for the SWLD. The rainfall from this event is forecast to move east, but how much reaches SA and VIC is hard to determine but there is some better signs today.
Thunderstorm Forecast Friday
A pool of cold air on the northern face of a low in Bass Strait will continue drive stream showers which could spit out a clap of thunder and small hail. A weak upper trough over parts of inland WA which will strengthen to the rain event in the east next week, may trigger a few thundery showers. A thundery shower or two over the northern coast of the tropics in advance of the dry southeast surge and a few thunderstorms possible over the southeast of QLD and northeast NSW with a stalled boundary.
Thunderstorm Forecast Saturday
A stalled boundary over QLD will continue to trigger showers and a few thunderstorms, no severe weather is expected. A few thunderstorms possible about northeast Arnhem Land. A departing low may send up another trough with the risk of hail and thunder in the showers.
Thunderstorm Forecast Sunday
Thunderstorms may start to develop through a large portion of inland QLD as an upper low begins to move towards the east. Thunderstorms at this time not expected to be severe but will watch trends. The severe weather threat from storms increases from early next week.
Thunderstorm Forecast Monday
Thunderstorms are forecast to become more widespread and extend south through the day and overnight into Tuesday through to NSW with heavy rainfall leading to flash flooding the main concern over inland QLD. The rest of the nation sits in stable air.
Thunderstorm Forecast Tuesday
Thunderstorms are forecast to continue over much of QLD, with storms possibly severe with heavy rainfall leading to flash flooding and damaging winds and large hail also quite possible given the sharp upper low. Heavy rainfall along the coast with thunderstorms may also lead to flash flooding. There is the chance of thunderstorms Tuesday night with the approach of a front over the southwest.
Severe Weather Watch - Tuesday through Friday
Flash and riverine flooding is possible next week as widespread rainfall falls over relatively wet catchments following months of above average rainfall. Rainfall rates could be heavy enough to cause renewed moderate flooding in some of the disaster zones.
Severe Weather Risk - Tuesday through Friday
A deepening upper trough which will likely cut off into an upper low will combine with deep moisture to produce widespread rainfall, some heavy through the inland with the risk of riverine and flash flooding. A separate trough over the coastal areas between Cardwell to Hervey Bay may trigger torrential rainfall through this period but the confidence is not high.
Flood Risk - Next Week
The flood risk is expected to increase through the middle to latter part of next week, especially the closer you are to the coast between Ayr and Bundaberg along the coast. A low to moderate risk extends well inland and will be connected to where heavy thunderstorms emerge.
Severe Weather Watch - Tuesday through Thursday
A large cold front with a tight thermal gradient, deepening moisture profile and strong upper-level trough will lead to widespread rainfall and strong to gale force winds moving through the region identified Tuesday night through Thursday.
Frost Risk Friday through Sunday Morning
Cold air trapped under high pressure combining with clear skies, dry air and light winds will assist in the formation of the first frost event of the season. No severe frosts are expected at this time.
SOUTHERN ANNULAR MODE - PEAKING CONTINUES TODAY.
The SAM is expected to remain at positive levels through the coming days before heading back towards neutral values but in recent days, there are more members than not, suggesting the positive phase could persist into the back half of the month which could increase rainfall chances for the east and north again.
MEDIUM TERM - May 12th-19th 2022
With the bulk of the heavy rainfall event with the upper low now moving into the short-term forecast, the anomalies are looking less dramatic for the east though lingering heavy rainfall early in this period will continue for the east before easing and clearing. The north of the nation likely to see further above average rainfall potential with the SAM remaining positive sending in more humid northeast winds. Over in the west, the rainfall should be leaning above average through this period with the long wave trough settled over the region if not offshore producing cold and showery weather. Most elsewhere should be seasonal with a mixture of rainy days but mild sunny days too.
The cooler bias is unchanged over in the west with the persistent onshore flow with windy weather and showery conditions. The east warms up following the widespread high impact rainfall event. With the winds out of the northwest in advance of cold fronts and a ridge to the southeast and east of the nation, a warm tongue of air could become established over the north and east for a good chunk of this period.
DATA - No video this morning as I am flying across the country. I will try to get one up and running this evening. Thank you.
12Z Euro Surface Pressure Pattern and Rainfall Distribution - Next 10 Days
The pattern is largely unchanged this morning from the evening suite of modelling. Overall we are looking at the the conditions in the southeast beginning to warm up from about Sunday with the peak in showery weather forecast today through Saturday before clearing. The upper trough over the inland of WA will move into the NT and then into QLD producing widespread showers and storms over QLD as the instability interacts with the moisture being drawn in from the east. Widespread rain will emerge as an upper trough deepens into a low pressure system resulting in above average rainfall for much of QLD and into northern and eastern NSW. There is some issue around how far south the system does spread the rainfall but overall the signs are reasonable for that rain to come south ahead of a front next week. Speaking of fronts, likely to see widespread rainfall and a severe weather chance (although it is low) for SWLD of WA. This is routine weather for the west and will break the back of the dry spell there. This system will help to pull moisture south and east into the eastern states. SA may sit between it all but some chance of rainfall does emerge later next week with the frontal passage.
12z Euro Precipitable Water Anomalies - Next 10 Days
Excessive moisture levels are forecast to return after the drier than normal weather that has been seen over the south and south east with this colder weather. The moisture thanks to the improving easterly wind regime and that moisture is forecast to move west into much of QLD and then divert south into NSW leading to above average rainfall potential. The next moisture surge to watch is over WA with the jet stream lofting in large amounts of tropical moisture. The issue will be around whether we can get that moisture to link up with a frontal passage leading to widespread rainfall traversing the nation’s south. Models are playing hokey pokey with that and will continue to do so over the coming days. Overall this trend of above average moisture over the north and east continues for large sections which has lead to the severe weather so far this year.
12z Euro Rainfall Accumulation - Next 10 days
Not much change from yesterday, we are seeing a lot of rainfall for this time of year through QLD extending south into NSW and then into VIC. This is largely thanks to the upper low and trough shearing moisture south and east ahead of an approaching front next week. Above average rainfall, local flooding problems for many districts in QLD may extend into NSW. A front in the west of the nation later next week will also trigger widespread rain and thunderstorms with moderate to locally heavy falls. A much wetter period coming up throughout the nation.
12z GFS Rainfall Accumulation - Next 10 days
Reasonable shower coverage over the southeast continues today but as mentioned above, the rain events to watch remain over QLD into NSW and then possibly VIC later next week with a very active area of low pressure and high moisture content. The moisture over the west builds ahead of a developing cold front which will lead to widespread rainfall developing over in WA, the question remains, how much of that skirts across southern Australia later in the period.
12z CMC Rainfall Accumulation - Next 10 days
Certainly showing more rainfall than the other models along the front coming into WA and then over southern Australia later next week and most models have had this and then dropped that idea, so something for the southern states to watch. The rainfall in QLD would be classified as intense under this guidance with dangerous flooding possible if that was to verify, but the idea is the same, widespread rainfall spreading south and southeast through the nation ahead of a large scale upper low and then a front through the south and east.
12z Euro Rainfall Accumulation - Next 15 days
Rainfall continues out west in the medium term with follow up frontal weather and more moisture looks to pour into the northwest and west of the nation on the northern flank of that frontal weather leading to more widespread rainfall developing. The east may dry out but not completely sold on that idea given the SAM could remain positive.
12z GFS Rainfall Accumulation - Next 16 days
Similar to the Euro, the rainfall looks to continue through the medium term via the westerly wind belt and the frontal weather grazing the South. The moisture surging in via the jet stream the key to widespread rainfall developing across the nation and whether this is in phase with the frontal weather. The east looks quieter for now.
I will have more weather information throughout the day. Have a great Friday!