Down here in Tasmania, we’re used to cold winters, but this last week has been a doozy. For the first time in my 20+ years here, the pipes froze. The frost didn’t lift all day in the shade. The ice we broke off the fish pond one morning was still on the ground, perfectly un-thawed, the next. Notorious as the coldest, bleakest place in the state, the alpine hamlet of Liawenee got as low as -14°C.
It’s been cold.
The driver is the same high pressure system that’s stretching from Antarctica, to WA, to Fiji, dragging up mid-winter air from the frozen continent and freezing the monkeys off us.
Unprecedented high atmospheric pressure is currently being observed across south-east Australia, including a preliminary new national record measured in Tasmania this morning.
The weather station at Sheffield reported a pressure of 1,044.6 hectopascals (hPa) at 10:30am, which if confirmed beats the previous Australian record of 1,044.3hPa at Launceston on June 7, 1967.
Whether it’s indeed a record or not is contentious, due to the changes in how weather is monitored over the last half-century. Equipment is not only more finely calibrated, but takes measurements nearly continuously, meaning previous even higher pressure blips may have been missed in the past. But it’s indisputable that the unusually strong high is having some big effects.
The abnormal pressure is having a significant impact on the nation’s weather, including extreme low overnight temperatures over south-east states and a lengthy stretch of showery days along the eastern seaboard.
The current atmospheric record is due to an intense high-pressure system anchored near Tasmania, which is not only very strong but also exceptionally broad and slow moving […]
The most extreme conditions have occurred near the middle of the high over southern states where clear skies, light winds and very dry surface air have caused icy cold nights.
Although frosty nights are common under a high in winter the additional presence of polar air in the wake of a weekend front has allowed minimums to drop as much as 12 below average this week, even breaking a handful of records in Tasmania and South Australia.
While the southern states are shivering, the record high is leading to a prolonged spell of wet days along the east coast.
The anti-clockwise winds are bringing south-easterlies, blowing showers in off the Tasman and Coral seas, to Queensland and NSW, and warm northerlies to Perth.
Air pressure above 1,040hPa are rare in Australia, these higher readings are a nearly daily norm for the eastern Russian “Siberian High” in winter. The highest recording for the Siberian High is 1,084hPa.
While highs are noted for large-scale physical effects such as lowering sea levels (by about one cm per hectopascal), their effects on humans are less well understood. Is the ol’ ‘bad weather knee’ a real thing?
A 2019 study published in Nature concluded a moderate link between pressure and chronic pain, with the odds of pain lower with an increase in atmospheric pressure.
This research offers hope the current spell of record high pressure could lead to reduced symptoms from arthritis, although the findings are inconclusive to the actual cause since the weather impacts human behaviour.
It’s hypothesised by some doctors and researchers the changed behaviour due to weather, for example staying inside during wet days, is affecting pain rather than the direct impact of the weather itself.
Oh, and you just know they’re not going to let this one go by without banging on about climate change.
Data from the BOM shows both the density and intensity of highs has increased since 1950 around Australia, meaning not only are high pressure systems more frequent, they are also slowly gaining in strength.
The shift towards stronger highs around the mid latitudes is a well researched trend related to shifts in the position of weather systems around the world, including a contraction of low-pressure systems away from southern Australia in winter as outlined in the BOM’s most recent State of the Climate Report.
ABC News
To paraphrase Homer Simpson, “climate change – is there anything it can’t do?”
