Michael Thompson's Australian
Storm Chase Diary
Thunder Downunder 2005 - Day 8, 2nd December 2005
Crows Nest, QLD to Grafton,
NSW
All photos
clickable for larger size
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The
inflow interface on the north flank of the storm near Lismore is
almost on the ground
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When time
lapsed, video of this cloud shows clockwise rotation of the cloud
on left side ( small gap in inflow line )
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The scene at Crow's
Nest ( Toowoomba ) in the morning was not that inspiring. Overnight, large
storm complexes had developed over the plains westwards. This had resulted
in complete overcast for much of south eastern Australia. The wind had
also turned a less humid NW. Victorian chasers had to be back in Melbourne
at end of the next day - at this stage they were close to 2000km from
home. This ruled out a trip NW back into Queensland to intercept a clearing
line aligned to a fast moving longitudinal trough.
We decided to head
south not expecting much. At the New South Wales ( NSW ) town of Tenterfield
the scene was very similar to Toowoomba, complete and utter overcast and
cool. The AM radio however suggested some weak discharges, we took a gamble
that these were storms developing on the north coast of NSW. From Tenterfield
on the northern tablelands to the coast is a two hour drive - but two
hours of restricted speed corners and mountains. The occasional glimpses
east that we did get however revealed clearer patches in the overcast,
and better yet some healthy cumulus cells.
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From
the western flank the storms appeared high based and slightly moisture
starved, contrast this the the NE flank in the first picture above.
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What appears
to be a gust front or shelf cloud is actually inflow across the
NE flank of the storm. The low cloud is moving parallel to us
from right to left.
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From the western flank
the storms did not look that impressive. We pushed NE into the storm only
to find torrential rain and flash flooding. This continued from the town
of Casino to Lismore. At Lismore the western suburbs of the town were
in heavy rain and some nuisance street flooding, whilst the eastern side
of town was still dry. The NE edge of the storm was in utter contrast
to the western flank. The inflow interface was almost at ground level
and the air saturated.
We proceeded off the
plateau and down onto the sugar cane flats for some photos. From the pictures
it would appear that a gust front was hurtling towards us, but in fact
the cloud marked a line of inflow along the NE flank of the storm. At
one stage weak cyclonic rotation could be seen, but no funnels.
The storm passed south
of us and out to sea. We then proceeded to Grafton where we spent our
last night. At 10pm a squall line passed through town with brief rain
and some lightning. This was the remnants of a much larger squall line
that affected much of inland NSW earlier in the evening and afternoon.
The next morning for
our trip home the entire state of NSW was under dry W/SW winds and clear
skies.
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More
of the storm near Lismore
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Only a
vague remnants of the trough line can be seen on the far eastern
horizon. Nambucca Heads, NSW
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