One of the coldest June days in recorded history appears to be about to hit the Northern Territory, in the midst of the dry season.
Most important points:
- Cold weather warnings issued by the Bureau of Meteorology
- A senior meteorologist says cold temperatures and rain forecasts are “quite unusual” for this time of year
- The BOM predicts 15 to 30 millimeters of rain, if not more, in regions south of Katherine
The Top End’s typically hot and sunny mid-months have been disrupted by dark clouds and rain in recent days, in what the Bureau of Meteorology describes as “pretty unusual.”
A misplaced cloud band and southeasterly winds combine to bring cold temperatures across the area.
Friday’s reading, from a Katherine weather station at the Tindal RAAF base, could be the second-coldest June day on record, with the BOM forecasting a high of 19 degrees.
Apart from a chilly day of 17 degrees in 1986, temperatures below 20 degrees have never been recorded at that station.
To make matters even more unusual, 2mm of rain was recorded overnight in the Katherine area and 18mm in Tennant Creek.
On Monday, the BOM issued a cold weather warning to farmers and producers in the Katherine, Tennant Creek, Mount Isa and Longreach regions.
“Tempers are expected to be 8 to 14 degrees below average for this time of year and could see 15-30mm of unusual rainfall over a few days with isolated heavier drops,” it said.
“Growers need to be aware that the rapid change in temperature can cause stress on livestock.”
How long will it stay that way?
Billy Lynch, a senior meteorologist at BOM, says a top-floor trough hovering over northern Western Australia is drawing tropical moisture over Indonesia and the Timor Sea, spreading across the Northern Territory in the form of a cloud band. .
“Cloud bands across Central Australia this time of year are pretty common,” said Mr Lynch.
“But cloud bands going to the Top End? Unusual.
As of Saturday, the cloud band is expected to weaken and move eastwards into Queensland, but not before an unexpected shower of rain.
South of Katherine, through the Carpentaria and northern Barkly district, the BOM predicts 15 to 30 millimeters of rain this week, if not more.
It is good news for residents of the region after significant rain shortages.
It is not unusual for Katherine herself to get rain at this time of year.
In any given June, the average point is six millimeters and two millimeters in July, but this week the forecast is a whopping 30 millimeters.
“It would be absolutely unusual to get that much rain at this time of year,” said Mr Lynch.
Depending on how the cloud band develops, Thursday could be a pretty wet day in Darwin, with as much as 10 to 20 millimeters predicted.
Consequences of cold weather
Vet Campbell Costello said the short-term cold spell could go so far as to stress the cows to the point that the birth rate could plummet.
†[There is a] a kind of tipping point where the environmental stress – in this case cold – reaches a point. The cow starts to dig more into her energy reserves and they may lose weight or become immunocompromised,” he said.
Mr Costello said cattle may require more food in cold weather “just to keep warm and keep the ovens up to scratch”, especially with added stress such as collecting or hauling freight.
The unusual weather could also affect pasture quality and quantity for ranchers, according to Dr. Robyn Cowley, a senior pasture scientist with the NT Department of Industry.
“If you have perennial Mitchell grasses they won’t be negatively affected by this rainfall, but you wouldn’t really expect much grassland growth because they respond to warm season rain,” she said.
“If you have annual pastures like Flinders grass, then you could potentially lose most of your pasture…they could spoil with this off-season rain and become distasteful and unavailable for livestock.”
Editor’s Note 29/06/2022: This story has been edited to correct an error. An earlier version indicated that the coldest day reported was in July, rather than June.
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