Michael Thompson's Australian
Storm Chase Diary
Chase Tour 1999 - 1st - 7th December 1999
I
could only join the great End of Year chase for one week, during chase
week number one the crew found themselves in outback Queensland and
on the first two days supercell storms were encountered. During the
rest of the chase upper level winds were light over target areas, and
a ridge of high pressure kept activity much further west than anybody
had anticipated. I waited for conditions to improve and aimed to join
the crew on week two. Week two was also dogged by light upper level
winds causing me to dub the week " The Great Suppercell Chase ".
A supper cell being pulse storm activity that is all over by supper
time. Of course the day after the chase finished a damaging supercell
was recorded in South Australia, and a day later again several in northern
NSW, SE Queensland. After you have finished reading my report, you can
DAY
1 December 1st - Shellharbour to Adaminaby, I was quite confident
of storms today. The day before numerous pulse cells had developed over
the Southern Tablelands of New South Wales, conditions for today looked
even better then yesterday. The main crew had left outback Queensland
and I intended a rendezvous with them somewhere on the Victorian border
where conditions looked good for a major trough in the next day or two.
I left at 11am giving the congestus some time to develop. Conditions
looked good when I reached the tablelands with congestus everywhere.
However by 3pm when none had broken the cap and congestus was weaker
I was disappointed. I continued south to Bungendore from where I could
see two cells glaciating to my west. These were over the Brinabellas,
a high mountain range west of Canberra and also a virtual no-chase zone.
However I had a four wheel drive and tackled the 70km ( 40 miles ) of
poor dirt. A mistake indeed, not only was progress slow but I was mostly
in tall forest and mountain valleys. I could see that the two storms
had matured, one north and one south. I finally emerged from the mountains
near the town of Tumut. Both cells by now were anviling out. A fresh
cell to the SE took my interest, although I doubted my chances of catching
it, I took the only decent sealed road SE, the Snowy Mountains Hwy,
this road is quite good in parts as it rides high on the plateau. Sunset
found me at the little town of Adaminaby, in winter it is a busy ski
base town, but in summer it is dead. I was the only guest at the motel.
The night was cool on the mountains and at 3am I awoke to check the
stars. Being at least 80kms from the nearest town the sight was beautiful.
DAY
2 December 2nd - Adaminaby to Albury. Even before I left home the
models had indicated that today was going to be a poor one storm wise.
The rendezvous with the other chasers was not 'til late afternoon, so
I bade my time crossing the Snowy Mountains and generally playing tourist.
A surprise was that there was still some snow patches on the south facing
peaks of the Snowies. The road from Adaminaby to Jindabyne is fair chasing
standard, but it is not a place a storm chaser would normally find oneself.
From Jindabyne to Khancoban to road is great if you are a botanist interested
in trees. I finally met with the other chasers at Tarcutta, and the
convey proceeded to Albury to await tomorrow's trough. It was a hot
day around 35C ( 95F ) and some of the chasers were already dismissing
tomorrow's prospects, lack of moisture and low dewpoints being sited.
That night the models conformed the worst. A closed low had formed in
the trough and had taken most of the action southwards below Australia.
We would be left with a much weaker trough.
DAY
3 December 3rd - Albury to Mudgee. The morning was a mixed one,
the instruments told of pathetic dewpoints and high temperatures. The
sky looked half promising with streets of castellanus and some cumulus
back to the SW with the trough. We made our way to a lookout, whilst
there a hot NW wind picked up and dust filled the western horizon. It
was not a pretty sight, we decided to move NE to the next town and reassess
the situation. Along the way the radio sent out warnings to farmers
to cease wheat harvesting due to the fire risk. At the next town you
did not need much weather knowledge to realize that the situation was
beyond hope for storms. The bane of southern NSW in Spring / Early Summer
is pre trough NW winds, and this moisture sapping wind was now pushing
past 30 knots at times. We decided that our best option would be to
get as far NE as possible. We expected that overnight the trough would
make the northern part of the state without the preceding NW winds.
We targeted Mudgee as it was an ideal location and about as far as we
could get in one days sensible driving.
DAY
4 December 4th - Mudgee to Tamworth
.

At
last promising signs. The trough had moved NE with us and was approx.
50-100km ( 20-60miles ) southwards. Today we had moister north winds
ahead of the trough. It still was not ideal, the dewpoints were around
15-16C ( 59-61F ), with air temps of 30-32C ( 88-90F ), but it sure
beat yesterdays dewpoints that threatened to go negative. The convoy
of chasers proceeded to Gulgong, a quaint little historic town that
has a great 360' lookout. From the lookout called Flirtation Hill you
can monitor potential in several geographic zones. To the south and
east the central tablelands, to the north the slopes and plains of the
interior, and to the east the upper reaches of the Hunter Valley. The
first congestus started popping in the upper Hunter near 10am. We watched
for another hour or so before deciding that this would be our target
area. At Merriwa two hours later and congestus was everywhere, however
tried as hard as it did it could not break a solid cap. A quick phone
call to Ben Quinn confirmed that a warm layer did in fact lay at approx.
500mb. We knew that if the cap finally went we could have a show. We
drove further eastwards towards the coast. Here the trough caught us
and the winds turned cooler SE. To chasers on the east coast of Australia
the SE wind is called a 'Storm Eradicator' as it means stabilising weather.
The view towards the coast confirmed the well earned name with horrible
patches of stratocumulus. However the SE wind can serve a useful purpose
albeit briefly and that is providing just enough lift to break the cap.
This is exactly what happened. At the town of Scone we were undecided,
to the north ahead of the SE winds was healthy congestus. To the SW
one cell had glaciated, but it was hard to get a decent view as low
junk cloud was coming in with the SE wind. We decided to fill our tanks
and monitor the situation. Whilst doing this an overshoot on the anvil
to the SW left no doubt as to where to head. We eventually caught the
cell near the town of Denman. We watched a lovely rain free base and
some CG's. I even thought that hail may fall. It started to rain and
the road options left us with one choice, to try to get around the northern
flank. The road took us into very heavy rain and through the cell, it
was sheer luck as we were happy to stick with storm 1, but the road
took us away from it, only to be replaced after the rain cleared with
a view of a much bigger an more organized storm to the NW. We pulled
up and took video and photos of several ' lowerings '. I often wonder
what this cell would have done had upper level winds been more favourable.
The concesus with several experienced chasers was that a supercell would
have been on the cards, and this Upper Hunter area is no stranger to
them. At one stage a lowering actually touched a hillside. After about
30 mins a rain curtain developed between us the the flank with lowerings.
We decided to try to get NW of the storm, but the road network meant
that this would be a two hour option at best. For most of the chase
crew this would be the last day, having started a week before me. At
the town of Coolah most of the crew decided to call it a day and start
the long drive home, for some 1200km ( 700 miles ). Myself and three
others still had some days left so we decided to pick up the chase again,
but we were defeated by the road network. We finally caught the storm
again just on sunset a full four hours after first sighting it, by now
it was dying and we had to be content with rainbows.
DAY
5 December 5th - Tamworth to Glen Innes. Today was spent in territory
that we expected to be in at some stage. We also managed to score the
only thunderstorm in the entire SE Australia. The day started with a
field of castellanus and congestus to the north and west. We again bade
our time until midday then proceeded to small town called Manilla, from
here we could see stronger congestus over the New England Plateau to
the NE. We became interested in a cell that showed some weak glaciation,
but being cautious we did not want to commit to the 2 hour drive to
intercept it, as congestus was healthy over the hotter plains west as
well. We had lunch taking our time in doing so. The congestus over the
plains boiled away but as was the case yesterday a strong cap was obvious.
Meanwhile the cell over the plateau started pushing a weak anvil. We
committed to the drive. When we finally arrived the cell had weakened
and I had mixed feelings about our chances. A SE wind had arrived at
the plateau's eastern edge and was stabilising
everything behind it, yet just in front of it there where some very
dark bases. The temperature difference was quite pronounced, from 32C
( 90F ) back on the slopes, to 26C on the tableland before the SE (
79F ), to just 17C ( 63F ) after the SE change. We did not really know
what to do except get away from that 17C air, so we headed to Bundarra,
a town on the western edge of the tableland. When we arrived at Bundarra
30 mins later we could again look back towards the east and we saw another
cell developing rapidly along the SE front, we doubled back and caught
up with this weak storm at the small town of Guyra. The storm propagated
NW ahead of the SE wind, we managed to follow it for about 30 km before
the storm finally died near Glen Innes where we stayed the night.
DAY
6 December 6th - Glen Innes to Inverell. The first priority this
morning was to check the models, Glen Innes library has free internet
access ( thanks ! ). Glen Innes is a recommended strategic stopover
as it is a two hour run to get you into some vastly different geographic
areas. Two hours north will take you towards the Darling Downs of Queensland,
a renown tornado alley. Two hours west and you on the NW plains. Two
hours east will see you on the North Coast of New South Wales. The motels
at Glen Innes are reasonable and the town is just the right size, that
is small enough to be out of in 5 mins, but large enough to have services.
Back to the models and they indicated that the slopes was the area to
be, one model suggested Narrabri, the other towards Tamworth. We decided
to head west to Inverell, then south just off the edge of the western
edge of the tableland, that way we could keep an eye on both the plains
development and that on the tableland. At the small town of Bingara
there was promising congestus in all directions, we kept on south, but
a tower going up just east stopped us. We vectored it to be near Bundarra.
We watched as it glaciated and rapidly grew into a weak pulse storm.
We waited approx 30 mins, as to go any further south would stop us hooking
back to this storm. We rang Anthony Cornelious for a radar update, he
said that there was a line of storms from Tamworth running back to Glen
Innes, but the storms in the north appeared stronger. We therefore headed
back to Inverell. This was a 90 min run and by the time we got there
the storm near Bundarra had died. However we had lost interest in that
storm a while back along the road as to our east near Glen Innes a pulse
bomb had gone off, this cell looked great and had an overshoot. The
other area of interest was right over Inverell itself with a rapidly
developing storm. We again decided sit and wait 30mins. It was time
well spent as the Glen Innes bomb propagated N/NW into territory devoid
of roads, whilst the local storm finally started precipitating and letting
off the odd CG. We followed this storm which also propagated N/NW, not
the usual script, but given the lack of upper winds not surprising.
This storm finally outrun us near sunset so we headed back to Inverell
for the night.
DAY
7 December 7th - Inverell to Home. Left Inverell at approx 9am under
completely clear skies. In fact this was only the second day of the
chase tour that did not have morning castellanus. I decided to head
the long way home via the western slopes of the Divide, rather then
the quicker dash to the coast. Activity was forecast to be well isolated,
but a chance anywhere west of the Divide. ( In true chase tradition
a much larger system that was to produce supercells was also forecast
for 48 hours time. ). By mid morning I had caught up with the trough
remnants again, the trough had appeared to slipped westward and the
castellanus, weak congestus lines where prominent around Narrabri. I
pressed further southwards through Manilla and Gunnedah. Near Gunnedah
at midday some of the congestus was looking healthy, but very similar
to the past few days - well capped ! From Gunnedah I headed to Coolah,
on the way the congestus cleared and completely clear skies were evident
to the east and south east, I thought at that stage that the rest of
the trip home would be a poor affair. A few minutes later and to the
south west horizon a saw a suspicious patch of cirrus, I just did not
look right, small congestus between it and me obscured much of it, which
prevented me from making a proper observation. Out of curiosity I turned
on the AM radio and immediately it began sparking. My interest was high
now ! but I still had my doubts, perhaps it was some congestus back
earlier near Narrabri. I continued southwards, after a few minutes a
knuckle appeared above the cirrus. I knew now I had a storm to chase,
but just where ? My guess was that the storm was 200km distant in the
Orange area. I preceded from Coolah to Gulgong and its wonderful lookout.
From here much closer to the storm I was 100% certain that it was near
Orange, I had two road options. The first was to continue from Gulgong
to Bathurst via the tablelands, hoping that the storm would drift east
over me. Or the second was to proceed west from Gulgong to Wellington
on the western slopes, then south to Orange itself. I rang Jane O'Neill
for a radar fix, she said " Go To Orange " and told me that
this stormwas at peak radar precip' reflect for over the past hour and
that a severe storm advice had been issued for the area. She also informed
that the storm was not moving much. I decided to head to Orange via
the western slopes, a two hour trip. Towers started to glaciate around
the Wellington area as I passed through, the Orange storm looked huge,
by now all I could see was dark blue. As I approached closer I could
see that the big one was weakening, there was a fresh cell going up
to the east in an area without roads, whilst on the western edge of
the big one a line of congestus appeared to to be forming on the outflow
boundary. I targeted this line which involved taking the next SW road
option to Forbes. When I caught the line it was developing into mature
storms, but weakish ones. It was electrically quite active, a change
from the past few days. I noticed signs of very heavy rainfall, flooded
fields and flattened grass, it did indeed look like I was a few hours
late. Getting late I decided to leave this line and head home. Near
Bathurst another suppercell developed which enticed me to do a detour
to Oberon. This storm built and weakened in about an hour, a true "suppercell".
I finally reached home at 11pm.
Other
reports on the 1999 chase tour.
Thunder
DownUnder'99 Photo Album - Jane ONeill
Australian
Severe Weather Association 1999 End of Year Storm Chase, Part 1 &
2. - Matt smith - click on 1999
ThunderDownUnder'99'
_ Paul Yole
- if you want to get an idea on the distances travelled read Paul's
comprehensice dairy.
PICTURES
OF THE WESTERN DARLING DOWNS SUPERCELL, NOVEMBER 22 & BIG CHASE
REPORT
  
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