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.
ThunderDownUnder'99' _ Paul Yole - if you want to get an idea on the distances travelled read Paul's comprehensice dairy.