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  Weather events
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Above: Radar images each 20 minutes from 4pm
(06.00UTC) to 7pm (09.00UTC).
Below: Hourly rainfall gaugings between 4 and 8pm.
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QLD: Hailstorm
causes chaos in Brisbane
An unseasonable May hailstorm swept across Brisbane's western and northern
suburbs late this afternoon bringing extensive small hail and some flooding.
A deep upper trough lay over inland eastern AUS today, with cold upper air
enhancing
instability.
The
entrance to a strong jetstream east of the SE QLD coast also increased
uplift across the region, resulting in the development of many small shower
and storm cells.
While the storm was small, precipitation was prolific with several locations
reporting over 30mm. Indooroopilly, just SW of Brisbane CBD, received 37mm
in the hour to 6pm and Gordon Park, 6km N of the CBD, recorded 34mm in the
hour to 7pm. The temperature at 850hPa (about 1.4km) was about 6C, so that
much of this precipitation
remained
in
a frozen
state
as
it fell
to
ground level resulting in a heavy fall of mostly pea-sized hail, though one
western-suburbs resident reported golfball-sized hail to the Courier-Mail.
Hail completely covered the ground to ankle depth in some areas. Deep drifts
of accumulated hail blocked drains and roof guttering, flooding roads and leading
to 200 SES
callouts, mostly to deal with blocked gutters overflowing into homes.
Over 7,000 properties lost electricity as Energex recorded about 200 lightning
strikes on power poles across the city and a downed tree brought down five
powerlines at Kedron. Brisbane Airport was closed for over an hour. Peak-hour
traffic
on
many roads,
including
the Inner
City
Bypass,
Coronation Drive, and Gympie and Sandgate Roads, was brought to a standstill
by icy conditions, local flooding and poor visibility. Fire crews were brought
in to clear ice from some roads. About 20 motorists were stuck in ice at Milton.
Flooding damaged the ABC studios at Toowong and the Fourex Brewery at Milton.
Twenty
stores
in the
Toowong
Village
complex
were flooded when hail blocked drains on a rooftop car park.
Houses were also damaged at Kedron, Red Hill,
Wavell Heights and Bardon.
Hail was reported from Darra, 12km SW of the Brisbane CBD, at 5.30pm and Indooroopilly
at 5.45. At 5.50pm traffic along Coronation Drive and the Inner City Bypass
was brought to a halt by rain and hail. These times coincide with the bright
red pixels in the radar animation above, which suggest hail began falling
from the storm shortly before 5.20pm, then moved to the NE crossing the coast
north
of Brisbane Airport about 6.40pm. The development in one of many small shower
and storm clusters caught the Bureau off guard, with a warning not issued
until 5.58pm. An unfortunately-timed server problem at the Bureau was blamed
for the lack of warning, however even with the radar it would have been
difficult to predict such a
heavy hailfall
given
the
small
size and
relatively
low
intensity of the radar returns from the system.
 NSW: Heavy seas
and showers along the coast
A complex and unusual set of low pressure systems has been operating in the
Tasman Sea for the past week. A low formed off the SE QLD coast on the afternoon
of 12 May, then drifted southeast into the central Tasman, reaching a central
pressure of 991hPa during the morning of 14 May. As the main low approached
the North Island of New Zealand on the afternoon of 16 May, a secondary low
formed to its northwest, then proceeded to dumbbell around the parent low until
today. The result has driven a strong SE to southerly airstream onto the NSW
coast for a week, resulting in seas up to 4 to 7m and a steady stream of heavy
showers.
The rainfall map for the week
ended 9am shows that much of the coast has received over 50mm, but several
locations, mostly right on the coast, have received much more including:
209.3 NELSON BAY (NELSON HEAD)
181.4 JERVIS BAY (PT PERPENDICULAR AWS)
174.6 WAUCHOPE (COMMERCE ST)
154.4 FORSTER BEACH CARAVAN PARK
146.8 NORAH HEAD AWS
144.0 WOOTTON
136.4 ULLADULLA AWS
132.4 COFFS HARBOUR MO
132.0 PORT MACQUARIE AIRPORT AWS
130.0 LORNE (LORNE ROAD)
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