Severe storm outbreak brews for SE Qld | Australia weather Mon 2 Nov afternoon | Gus's Weather

Severe storm outbreak brews for SE Qld and NSW; catastrophic fire risk out west

[c06_radar_now]

GUS G'day, I'm Gus, and this is the afternoon bulletin for Monday the 2nd of November.

GUS Here's the story for most of you: heavy rain is falling on Brisbane, Sydney and Canberra right now,

GUS and tomorrow afternoon a serious storm outbreak looks likely inland of the Sunshine Coast and across northern New South Wales.

GUS It's about 4 pm in Brisbane at the time this is uploaded,

GUS and if you want to tell me what the sky's doing where you are, drop it in the comments, I read them through the day.

GUS This is the Bureau of Meteorology's real national radar, not a model, and the newest picture is about ten minutes old.

GUS The heaviest rain on it is inland near Mount Isa in Queensland, very heavy over about 2,600 square kilometres, with more very heavy to top of the scale cells near Roma, Armidale, Toowoomba and Horsham.

GUS Closer to people, heavy rain is sitting over Canberra, Sydney and Brisbane right now, with real storm cloud overhead at Sydney, Melbourne, Adelaide and Canberra too.

GUS Melbourne has lighter rain, Adelaide a touch of light rain, and Perth, Hobart and Darwin are clear under the radar right now.

GUS The model's own simulated radar for this hour has showers over similar parts of Victoria and southern New South Wales,

GUS but it's missing the heavier cells over Toowoomba and Armidale, so trust the real radar over the model detail this afternoon.

[c04_satellite]

GUS Now the satellite, because it measures how cold and high storm tops are, which shows how strong a storm is, and it can see country with no radar coverage.

GUS The strongest looking storm cloud right now sits over the Gulf Country near Normanton in Queensland, with a top near minus 64 degrees Celsius, so expect heavy rain and lightning there this afternoon.

[c07_lightning_now]

GUS Lightning now, tracked by the Blitzortung lightning network, a volunteer network of ground sensors that picks up the electrical pulse each strike sends out.

GUS Nationally there have been about 300 strikes picked up in the last six hours, with the busiest patch near Narooma on the New South Wales south coast, still growing.

GUS There's also a growing patch near Wagga Wagga in New South Wales and another near Swan Hill in Victoria, plus steady patches north of Toowoomba and near Normanton, Queensland.

GUS None of this tells us who's in danger, that's what Bureau warnings are for, but if you're under any of these patches, lightning means get indoors.

[c05_obs_now]

GUS Now the actual measured rain and wind, a different picture from the lightning: this is what's really landed in the gauge since 9 this morning, measured by Bureau of Meteorology weather stations, not a forecast.

GUS The heaviest rain nationally since 9 am: Groote Eylandt in the NT 40.6 millimetres, Normanton in Queensland 32 millimetres, and western Victoria's Mount William, Ararat and Stawell around 15 to 18 millimetres.

GUS The strongest gust nationally is 80 kilometres an hour at Broken Hill, the same dry wind driving today's fire danger there.

GUS Credit to the Bureau of Meteorology for that data, and everything in this bulletin is indexed in the chapters in the description, so jump to the part you want if you're in a hurry.

[c01_verification]

GUS Quick check on how I went yesterday, because that's how you judge how much to trust today's numbers.

GUS Temperatures were close to spot on in most capitals, but my rain calls were shakier, five capitals I'd called for rain stayed dry, so take today's rain numbers as a guide, not a guarantee.

[c02_mslp_fronts]

GUS Because this is cyclone season, I always check the tropics, even on a quiet day for us.

GUS The models are tracking a developing tropical low well out in the Pacific east of the dateline, and a weaker system near Papua New Guinea,

GUS both thousands of kilometres away with tracks staying clear of Australia, so nothing to act on yet.

[c16_index_map]

GUS Fire now, because today's danger is about as bad as the scale goes, in western New South Wales.

GUS About 27 kilometres east-south-east of Broken Hill, the fire danger index is deep into the catastrophic range, the Bureau's top category.

GUS It comes from 35 degrees, humidity near 9 per cent, and gusts to 89 kilometres an hour.

GUS The drought factor, how dry the fuel is from recent rainfall, is very high too, so there's plenty to burn.

GUS If you're near Broken Hill or western New South Wales, any fire today will move fast, check bom.gov.au and your local fire authority for warnings.

GUS Fire danger is also raised in South Australia and WA's Pilbara and Kimberley, though not this extreme.

[c17_temp]

GUS The Bureau has four heatwave warnings out today, and heat like this is dangerous for older people, babies and anyone working outdoors, so I'll keep this plain.

GUS There's an extreme heatwave warning for the Tiwi and Arnhem districts near Darwin in the Northern Territory.

GUS There's also an extreme heatwave warning for the Kimberley, Pilbara and North Interior districts of Western Australia, daytime tops near 44 to 46 degrees for days, overnight lows near 28, dangerous without good cooling.

GUS There's a severe heatwave warning for the Carpentaria district in the Northern Territory, tops near 40 degrees for the next few days.

GUS And a severe heatwave warning covers the Peninsula, Gulf Country, Northern Goldfields and Upper Flinders districts of Queensland, tops around 38 to 40 degrees through the week.

GUS The numbers back it up, the Top End is sitting around 44 to 45 degrees in spots today, and Darwin's forecast top tomorrow is 35.

GUS Drink water, check on anyone vulnerable, and for the full warning areas, that's on bom.gov.au.

[c92_river_gauges]

GUS The Bureau of Meteorology has a moderate flood warning for the Balonne River to Surat and Warkon, gauge near 6.8 metres and steady.

GUS There's also a moderate flood warning for the Bulloo River to Quilpie, gauge near 4.1 metres and falling.

GUS And a moderate flood warning for the Barcoo River to Isisford and Blackall, gauge near 3.5 metres and rising.

GUS On the gauges, the Condamine at Chinchilla Weir is at 8.37 metres and rising, and the Richmond River at Ballina in New South Wales is rising to 1.66 metres,

GUS with the Onkaparinga near Adelaide and the Ord in Western Australia's Kimberley also rising.

GUS The ground under south-east Queensland and northern New South Wales is already very wet from the last month,

GUS so tomorrow's storm rain won't soak in the way it would on dry ground, more of it runs straight into the rivers.

GUS Credit to SILO, the Queensland Government's climate data, and to the Bureau of Meteorology for the river levels, official flood warnings are always on bom.gov.au.

[c03_upper_500]

GUS Moving up from the rivers to the atmosphere above them, because a storm needs moist air, lifting, and fuel, and the weather map shows us the lifting part.

GUS By tomorrow, an upper trough, a dip in the high altitude wind pattern that lifts air like taking the lid off a simmering pot,

GUS stretches from near Sydney to Broken Hill, dragging warm, moist air into southern Queensland and northern New South Wales.

GUS A fast jet stream, winds around 246 kilometres an hour several kilometres up, sits over central New South Wales near Dubbo,

GUS helping organise tomorrow's storms into supercells, so moisture, lift and organisation are all lining up at once.

[c08_skewt]

GUS Now the fuel to go with that lift.

GUS Meteorologists measure the energy stored in warm, moist air that a storm can feed on, think of it like fuel in a storm's tank, they call it CAPE.

GUS Near Armidale that's 2,100 to 2,600 joules per kilogram, a strong tank.

GUS Near Gympie it's similarly strong, 2,000 to 2,400 joules per kilogram.

GUS The lid, a layer of warmer air that stops rising air like a lid on a saucepan, is basically off today,

GUS near zero, so once the afternoon heats up, air can rise straight into a storm with almost no brake.

GUS Timing lines up for storms to fire around 1 pm tomorrow in Queensland, a bit later, about 2 pm, over in New South Wales.

[c11_shear]

GUS Oh, I love this one. Now the third ingredient: wind shear, how much the wind changes speed and direction as you go up, like traffic moving at different speeds on different lanes of a freeway.

GUS Near Armidale shear is about 78 kilometres an hour, strong enough to spin a storm.

GUS Near Gympie shear is similarly strong, about 83 kilometres an hour.

GUS Strong shear tilts a storm sideways so it can organise instead of raining itself out, picture a spinning top getting a proper spin instead of just a wobble.

GUS The supercell number is very high at both spots, strongly supporting rotating storms tomorrow afternoon, and the hail number points to large hail big enough to dent a car.

GUS These are guidance about the environment, not a guarantee, they say the ingredients are there, not that every storm will use them.

[c94_sounding_compare]

GUS One more tool, two model soundings side by side, Gympie and Normanton, a vertical slice through the air above each town,

GUS think of it as a core sample, the line on the right is air temperature, the line on the left is dew point, close together means nearly saturated air.

GUS Normanton's moist layer reaches higher, about 300 hectopascals against Gympie's 400, so Normanton's storms likely wring out more rain per storm.

GUS Through tomorrow evening these storms can also merge into one bigger cluster, forecasters call that a mesoscale convective system, which is why one town gets hammered and the next misses out.

[c19_model_compare]

GUS I always check three models against each other, the American GFS, the European model, and the European AI model.

GUS Near Armidale, GFS wants under 5 millimetres, the European models 12 to 13, leaning wetter.

GUS Near Gympie the models disagree a lot, from 9 to 37 millimetres of rain, so I'm leaning toward the lighter, patchier end there.

[c15_rain_wind]

GUS Taking those model numbers together, here's who's actually under this: towns, not just the two hotspots.

GUS Sunshine Coast, Bundaberg, Toowoomba and Brisbane are in reach of storms off the Gympie patch, 5 to 15 millimetres, spots topping 60.

GUS Off the Armidale patch, Tamworth, Moree and Coffs Harbour expect 5 to 20 millimetres.

GUS The strongest storms, most likely to bring large hail and damaging wind, sit inland where the trough meets the moist air,

GUS closer to the coast it's much more luck of the draw who gets a storm and who stays dry.

GUS If you're in Brisbane or anywhere along the Sunshine Coast tomorrow afternoon, it's worth having a plan ready, somewhere to put the car under cover and an eye on the sky before you head out.

GUS Don't lock in exact numbers for your town yet, placement a day out is the hardest thing to pin down, check the morning bulletin for an update.

[c90_events]

GUS A quick look at events, because thunderstorms don't care about race day.

GUS At Royal Randwick in Sydney tomorrow, there's a thunderstorm risk with about 5 millimetres of rain, and lightning means racing stops.

GUS In Newcastle tomorrow evening, the AFC Elite football has a similar storm and lightning risk, with a bit of rain too.

GUS The Melbourne Cup at Flemington tomorrow looks mostly dry, only about a tenth of a millimetre of rain, though it's a cool day, pack a coat, not an umbrella.

[c21_town_table]

GUS Before the lap of the capitals, here's today's dad joke: why did the high out over the Tasman Sea stop talking to the low near Mildura?

GUS It said the pressure was getting to be too much. I'll see myself out.

GUS Brisbane's top today is 30, tomorrow's low 20, high 27, with about 3 millimetres of rain, nothing to worry about yet,

GUS though with tomorrow's storm risk building inland, it's worth keeping the brolly handy just in case a stray cell wanders your way.

GUS Sydney's top today 23, tomorrow's low 18, high 24, with about 5 millimetres of rain, worth an umbrella,

GUS and that number lines up with the storm system pushing into northern New South Wales, so don't be surprised by a sharp shower.

GUS Melbourne's top today 19 degrees, tomorrow's low 12 degrees, high 18 degrees, and a solid 21 millimetres of rain,

GUS that's a proper umbrella and jacket day, and if you're at the footy or out walking the dog, pack accordingly.

GUS Perth's top today 21 degrees, tomorrow's low 16 degrees, high 21 degrees, with just 2 millimetres of rain, nothing to worry about there.

GUS Adelaide's top today 22 degrees, tomorrow's low 12 degrees, high 20 degrees, and barely a drop of rain forecast, good drying weather, so the washing's laughing in Adelaide tomorrow.

[c21_town_table]

GUS Rounding out the lap of the capitals, the three we haven't covered yet: Canberra's top today is 21 degrees,

GUS tomorrow's low 10 degrees, high 24 degrees, with about 8 millimetres of rain, a cool change is clearly on the way there.

GUS Hobart's top today 17 degrees, tomorrow's low 11 degrees, high 17 degrees, with just over half a millimetre of rain, pretty unremarkable, as Hobart often is this time of year.

GUS Darwin's top today 34 degrees, tomorrow's low 27 degrees, high 35 degrees, with about 2 millimetres of rain, hot and sticky as always,

GUS the air con's earning its keep up there, and with that extreme heatwave warning in districts to its east, take the heat seriously if you're out that way.

[c20_plume]

GUS Now the week ahead, I go further than 48 hours because the models still give useful signal, just with less confidence the further out we go.

GUS Days two and three, Wednesday and Thursday, are a reasonable guide, days four and five more of a guide than a promise,

GUS and days six to eight only a signal that can flip completely next run, because tiny model errors grow bigger every day.

GUS South-east Queensland dries out midweek, then Thursday has storm fuel with little to trigger it, likely to fizzle; central and north Queensland see the same pattern through Thursday and Friday.

GUS Northern New South Wales is more interesting, Saturday brings both energy and a trough arriving to set it off,

GUS that's storm fuel with a trigger to set it off, energy and a trigger together, worth watching closely,

GUS and Sunday looks like a genuine soaking there, the American model alone shows up to 88 millimetres of rain around Newcastle,

GUS the European model much lower, so the amount is uncertain, the heavy rain signal itself is not.

GUS That 88 millimetre figure for Newcastle is a serious rain signal even on the wetter end, so if you're there on Sunday, it's worth keeping half an eye on local creek and river levels.

GUS Beyond those numbers, here's the weekend verdict for four cities. South-east Queensland and Brisbane see possible, fizzle-prone storms Saturday, then a quiet Sunday, so Brisbane's weekend plans should be fine with a backup indoors.

GUS Sydney stays mild and mostly dry Saturday, with a cool change Sunday, so if you've got the barbecue planned, Saturday's the pick of the two days.

GUS Canberra has no storm signal but turns much cooler, and Melbourne has no storm ingredients flagged, but both models agree on showers and a cold Saturday, so pack the jumper either way.

GUS Of the four, if I had to pick the day to watch, it's Saturday in northern New South Wales,

GUS where the ingredients for storm fuel with a trigger to set it off storms are lining up.

[c21_town_table]

GUS A quick lap of the rest of the country. South-west Western Australia stays quiet and mild all week, Perth sitting high teens to high twenties, with only light rain here and there.

GUS What do you call a forecast that keeps changing its mind past day five? Flaky, and not in the good way. That one's for the dads.

GUS The Top End is in its build-up toward the wet season, where steady trade wind rain gives way to hot, humid, hit-and-miss afternoon storms, with the real monsoon rain not due until December.

GUS Victoria and Tasmania see showers push through midweek and again later in the week, nothing severe, just a cooler, showery pattern typical of early November down there.

[c21_town_table]

GUS Overall confidence in today's forecast is high, with the low pressure systems and the upper trough well agreed between the American and European models.

GUS The weak point is rain near Gympie, where models spread 9 to 37 millimetres, so if tomorrow's models shift the trough's timing I'll update it in the morning.

[c06_radar_now]

GUS For all the official warnings, check bom.gov.au.

GUS My next bulletin is tomorrow morning, with fresh numbers on that storm outbreak and on the fire danger out west.

GUS If you've got a weather question, pop it in the comments and I'll get to as many as I can through the day, and thanks for watching.

GUS Homework for today, look west this afternoon from Brisbane or northern New South Wales, if you see tall, hard-edged cloud building, that's today's energy finding its trigger early.

GUS Look up now and then, the sky's the best show in town.

GUS Gus's Weather is a PandaVision production.