NH Fall/SH Spring 2021 Discussion Thread

So far, a max temp of 6.6° C here. I note a rather high LCL—of about 900 m (I'm only barely inside the cloud base). Steep lapse rates as a result: Cabramurra mostly 5+ °C cooler than here today (max 1.4° C), so approx. 1° C / 100 m.

[UPDATE as of 3:50 PM]: temp spiked to 7.5° C here and 2.8° C at Cabramurra recently, but dropped back down.

Significant atmospheric river event moving through southwestern BC, began yesterday evening and lasting through tomorrow afternoon.

48hr rainfall totals throughout the Vancouver region will be in the 100-200mm(4-8") range by tomorrow evening. Potentially higher amounts, up to 250mm(10"), in the eastern fraser valley and north shore, along the coast mountains.

Already seeing flooding, rockslides and mudslides in some areas in the region.

SNOWVEMBER! Mountains coated in white two weeks out from summer
( Source: weatherzone )

Image: Thredbo on November 15, 2021, five days before mountain bike season, not ski season! Source: Simone Griffin.

A strong cold front has lashed southeastern Australia, bringing strong winds, cold temperatures, hail, rain and yes, even snow to the mountains.
Weatherzone meteorologist Chris Matthews told us yesterday that a dusting of snow had sprinkled the ground, but that dusting has turned into a "dump", with locals reporting around 20 cm up high and 10 cm or thereabouts down in the valleys in places like Thredbo Village.
Snow is, of course, far from unknown in the Australian High country in late spring or even in the summer months, as Southern Ocean cold fronts can push northwards in any season. But it's far less likely at this time of year, and especially in this quantity.
But if you take a look at the current satellite image overlayed with the synoptic chart, you can see the cold southerly flow at work, with the tell-tale speckle cloud that usually accompanies a strong cold front.


As you'd expect, temps were frigid across the Australian Alps, and when you factor in the wind chill, the apparent temperature (effectively what it feels like to be outside factoring in air temp, relative humidity and wind speed) some of the readings were pretty extreme, and still are.

For example, as we write this at 10:30 am on Monday morning (AEDT):
Thredbo top station (NSW, elevation 1957m) was sitting on -4.3°C with wind gusts approaching 100 km/h and an apparent temp of -20.1°C
Perisher Valley (NSW, elevation 1720m) was -2.0°C with gusts around 80 km/h and an apparent temp of -13°C.
Mt Buller (Vic, elevation 1707m) was sitting on -3.5°C with gusts around 50 km/h and an apparent temp of -11.7°C.
Several minimum temp records appear to have been broken in Tasmania, and Hobart's low of 2.9°C was its coldest November reading since 1953.

Unsurprisingly with such cold temperatures, the snow level in Tasmania was low for any season, let alone November. This was the scene at Mountain River near Hobart, at an elevation of just 360m.



The mountain weather should start to clear tomorrow in Tasmania and on the mainland. That’s good news for hikers like Simone Griffin, who is currently undertaking the Australian Alps Walking Track (a 670 km trek from the ACT to southern Victoria) who is currently holed up in Thredbo waiting for the snow to melt. The pics of Thredbo village in this story are hers.

Image: They don't call then snow gums for no reason: Source: Simone Griffin.

Meanwhile the strong winds that have lashed Tasmania, Victoria and southern NSW should start to ease across inland areas today, although parts of the NSW coast, including Sydney, have gale warnings in force today, and strong wind warnings in place for Tuesday.

Aside from the strong winds, the southeast will stay cool and mainly dry for the first part of this week, before warmer unstable weather arrives around Thursday.

High was 72 (22 c) today with mostly sunny skies so I guess I was wrong about last Sunday being the last 70 f.

Mild night, still 63 (17 c) at 8 PM.

Record-breaking late-season cold spell hits southeastern Australia
( source: Weatherzone )

If you think it's been unusually cold in southeastern Australia during the last few days, you're not imagining it. Some places just endured a late-season cold spell not seen for more than 160 years.

A mass of cold air has been driven over Australia’s southeastern states during the last few days by a strong low pressure system. The satellite image below shows a large mass of speckled clouds within this cold air mass on Monday.

Image: Himawari-8 satellite image captured at midday AEDT on Monday, November 15.
This weather pattern is more typical of winter than late-spring, and it has brought a string of cold days that are rarely seen this late in the year.
Melbourne’s maximum temperatures during last four days have been well below the long-term November average of 22ºC, reaching:
Friday: 14ºC
Saturday: 14.6ºC
Sunday: 15.3ºC
Monday: 13.5C (running max. as of 6pm AEDT)
This is the first time in 167 years of records that Melbourne has had four days below 15.5ºC this late in spring.

Further north, Canberra’s last three days have been around 10ºC below average for this time of year:
Saturday: 13.4ºC
Sunday: 14.0ºC
Monday: 13.9C (running max. as of 6pm AEDT)

Image: Canberra's minimum and maximum temperatures during the last five days, as of 6pm AEDT on Monday.
This is the first time in 99 years of records that Canberra has had three days at or below 14.0ºC, this late in spring.
Temperatures will warm up during the next couple of days as the low pressure system moves east, towards New Zealand.

The 9am reset should sort out that low max yesterday. 

Coldest day so far in Riga, min -2.2C, high 1.2C. Fog all day and massive hoarfrost on grass, trees. At least one flight, the flight from Copenhagen could not land in Riga and was redirected to Kaunas.

Down to as low as 0.2° C earlier this morning. Yesterday maxed at 7.2° C, and the day before at 7.5° C; precipitation for the event (11–15 Nov) totalled 142.6 mm, bringing my monthly and yearly totals up to 206.2 mm and 1,786.3 mm respectively.

High was 70 (21 c) today, now probably the last one of the year.

Down to 48 (9 c) at 9:40 PM, actually the one time the 7 PM-7 PM “day” is good as it preserved last nights low.

Looks like the first real cold night of the year coming up Wednesday with forecast lows in the 10s. Still no real cold days and snow though.