 |
 Hourly infrared satellite images for SA from
8.30am to 6.30pm. The animation opens with the passage of a frontal cloudband
through Adelaide that brought record June rain to the city. An area of
strong convection approaches the southern Eyre Peninsula during the morning,
and the animation pauses at 1.30pm when a suspected tornado and violent
storms were experienced in the Wangary area, marked with a red rectangle. Weatherzone, BoM |
 SA: Damaging wintry
storms bring record rain
One of the most powerful winter systems in years crossed the SA coast late
this morning, bringing hail, storm-force winds, record rain and a possible
tornado. Damage and
disruption
were widespread in Adelaide
and occurred elsewhere
in
the state. Preliminary estimates of damage have been placed at $700,000 from
about 300 insurance claims, whilst Charles Sturt Council has estimated damage
to its 11km of foreshore between West Beach to Glanville at over $4m.
 |
 Above: Adelaide rainfall for the 24 hours to
9am. BoM 
 Below: 500hPa analysis for 10am shows the upper cold pool and closed low
pressure system at about 5.5km. Temperatures at the core of the cold pool
were below -30C, setting up a vertical temperature difference that produced
dramatic
instability
and uplift. Weatherzone, BoM |
 |
Torrential rain from the frontal cloudband fell in Adelaide during the early
morning peak, causing widespread local flooding and traffic disruption. 23.6mm
was
recorded
at the
Bureau's
Kent Town office between 5.30 and 9am, adding to yesterday's heavy falls (see
report for 20 JUN) to produce the city's highest
ever one-day June total of 54.6mm. The previous record, in 168 years of inner-city
observation, was 53.6mm on 1 June 1920. Rain was even heavier in the Hills
to the southeast of the city ( )
where Sutton Creek flood alert gauge registered 121.8mm, Torrens Gorge 88.0
and Cherryville 85.8. Other falls are in Wettest below.
Very cold and unstable air followed the front, resulting in a broad field
of winter cumulonimbus storm clouds, which are the white speckled clouds in  above homing
in on the Eyre Peninsula, Kangaroo Island and Adelaide. The strongest of these
can be seen approaching the Eyre Peninsula
and making landfall at 12.30 at Port Lincoln. The classic comma shape of this
small system suggests it was formed in the area of maximum vorticity (or "spin"
or curvature) of the advancing upper low seen in  .
The egg-shaped low has its sharpest curve at the top, just to the south of
Port Lincoln, where the system, a cyclonic vorticity advection maximum (CVA),
formed.
As this system moved through at about 1.30pm a suspected tornado
toppled powerlines, flattened fences and blew apart a shed at Wangary, 40km
NW of Port Lincoln, cutting power to 6,000 Port Lincoln users and the lower
Peninsula generally for between 2 and 7 hours. A resident who saw the shed "disintegrate
before his eyes" told the Port Lincoln Times "It
got real dark and black and then it hit, a big swirly thing, spinning as
it went." Strong winds also unroofed a house at Coffin Bay, 10km S of
Wangary.
The highest wind gust reported, 119km/h, was at Neptune
Island, 70km
SE of Port Lincoln, at 2.21pm. It, and many other gusts reported in Highest
gusts below appear from their timing to have been associated with
the CVA. Neptune Island's average wind speed for the 24 hours to 9am Wednesday
was 62.7km/h, with galeforce average windspeeds reported at all observations
from 6am to 9pm today. The strong westerly winds drove seas into the
narrowing waters of the Spencer
and
St Vincent
Gulfs
and combined
with
a
king
tide to produce
high tides nearly a metre above normal, bringing a sea flood threat to
Port Pirie and Port Augusta during the evening.
In Adelaide, SES responded to over 240 callouts in the 30 hours from 2pm yesterday,
over 85 of them in southern suburbs which were worst hit by the passage of
the CVA between 4 and 5pm. Seaford Rise, McLaren Vale, Coromandel Valley, Flagstaff
Hill and Silver Sands were worst hit, with
windows blown in, at least one roof ripped off, and one home struck by lightning.
Trees and branches littered roads and fell on cars, and isolated blackouts
occurred
from Adelaide to Victor Harbor. Hail fell intermittently around the city in
the cold air behind the front, but during the late afternoon was heavy enough
in the Hills to turn the summit of Mount Lofty white and bring residents out
for snowball fights.
 VIC,
NSW: Snow season off to a good start
While the snowfields began the official skiing season on the Queen's Birthday
weekend with bare slopes (apart from man-made snow), substantial snowfalls
have been recorded across both the VIC and NSW Alps since last Wednesday afternoon.
Level snow depths recorded at 9am at the Kosciuszko Chalet in the Snowy Mountains
were Wednesday 0cm, Thursday 20, Friday 29, Saturday 31, Sunday 38, Monday
55 and this morning 60cm. The melted equivalent of the 24-hour fall to 9am
was 52mm. Nearby Perisher Valley reported a melted equivalent of 100mm, which
would be a June record, but has yet to be confirmed. Falls in VIC were lighter
over the past 24 hours, but all main resorts are reporting an excellent snow
base of half a metre or more.
|
