Unusual system delivers heavy rain in WA but little where needed

Heavy rain fell across large parts of southwestern WA in the two days ended 09.00 this morning as a deepening low pressure system moved up the coast to Perth, then cut inland dragging a trough across the southern Central Wheatbelt and Great Southern to the South Coast.

The Perth area received the heaviest of the rain overnight Wednesday 21 to Thursday 22 June, with the 61.2mm recorded in the Perth Metro gauge its highest June total since the station began in 1993 and the heaviest June fall in the Perth CBD in 31 years. Perth has not seen much rain since the unseasonal downpour of 114.4mm fell in the Metro gauge on 10 February 2017. Most gauges from Perth to Bunbury also recorded over 25mm in the 24 hours to 09.00 Thursday. The BoM posted this spectacular satellite loop showing the low crossing the coast near Perth, and a radar loop showing the rotation in the rainfall mid-afternoon Thursday.

The heavy rain moved SE, giving the Great Southern district and southern parts of the Central Wheatbelt a very wet Thursday. An area in the Darling Range from Dwellingup to Wandering and southward received over 50mm during the day with Wandering registering 130.8mm and nearby Wilgarra 132.6mm in the 24 hours to 09.00 today. Wandering's total, most of which fell between 10.00 and 20.00WST Thursday, was an all-time record in the station's relatively short 18-year history. More significant was the 77.6mm received at Marradong, 70km ESE of Mandurah, which was its highest June daily rainfall since records began in 1897.

A broad swath of country east through Narrogin and Wagin to beyond Hyden and Lake King received 15 to 40mm, but unfortunately farmers in the Northern, Eastern and much of the Central Wheatbelt looking for rain for winter crops saw little more than a soil-dampener. [ABC News]

Newsbits

 Fog comes with continuing stable weather in Australia: The high pressure ridge that has dominated Australian weather charts for around three weeks continues to produce cold, frosty nights and mostly sunny days. However, a weak southerly change that moved across the southeast over the weekend injected additional moisture that produced little rain but encouraged widespread fog overnight, with a number of places in SE QLD, inland NSW, northern and western VIC and much of southern SA, including Adelaide, reporting visibility down to 50 or 100m. In TAS, the change gave a measly 0.2mm in the Hobart City gauge, ending a record-breaking June dry spell of 17 days.

 Fog follows stormy weather in NZ: The same high pressure ridge pushed across New Zealand on Friday after a series of fronts gave several days of wild weather to the South Island. There was heavy rain on the west coast, snow fell as low as 300m in the far south, wind gusted to 139km/h at Le Bons Bay on the Banks Peninsula east of Christchurch, and a swell, with a maximum wave height of 16m off Banks Peninsula, brought rough seas to the east coasts of both islands on Wednesday, cancelling Cook Strait ferries. As the high ridged across the country, it trapped moisture under an inversion causing fog on Saturday and Sunday mornings, disrupting air traffic at Auckland Airport. Fog there did not lift until early Saturday afternoon, and on Saturday night and Sunday morning caused flight cancellations as well as delays. [Radio NZ, Metservice]

 Dry start to winter for the whole country

It's been an extraordinarily dry start to winter, with most of the country receiving little or no rain over the first half of June. While that's business as usual in northern Australia where the dry season is in full swing, it's far from normal in the south where fronts sweeping up from the Southern Ocean are usually bringing reliable, regular periods of showers, rain or snow.

But those fronts have mostly stayed well away, deflected south of the country by a string of high pressure systems and ridges. The only area to receive significant rain has been the east coast from south of Sydney to around Brisbane, where easteries brought heavy rain and showers early this week and last weekend.

In an average June, most of the settled areas receive at least 25 to 50mm inland grading to 50 to over 100mm around the coast, but this June has produced less than 20% of that so far. Much of SA has had less than 10%. Adelaide was sitting on 0.4mm to 09.00 today compared to a June average of 79mm, their driest start to the season in 60 years. The stable weather under the long run of highs is giving warm days and chilly nights which are enjoyable for fine weather lovers, but exasperating for farmers expecting rain for winter crops or skiers looking for natural snow on the Alps. In TAS, both Hobart and Launceston have had average maxima so far in June of 14.7° compared to their normals of 12.0 and 13.1.

Unfortunately, there is little in the medium term forecast models to suggest relief. A front next week is likely to bring some light showers to the southwest, southern coast and SE Australia, but otherwise the outlook is more of the same.

 A stormy start to summer in Europe

Europe has had a late spring and early summer of dramatic storms, hail, downpours and several tornadoes.

The European Severe Weather Database recorded 448 reports of large hail last month while there were countless reports of colossal falls of smaller hail, such as this one, last Thursday 15 June, at Soria in northern Spain [Severe Weather Europe].

On 13-14 June, thunderstorms dropped torrential rain and hail the size of hens eggs in the Haute-Loire department of central southern France, killing one person and causing 160 evacuations. Landos-Charbon, south of Le Puy, recorded 123mm in one hour late evening, twice as much as would be expected in a 1 in 100-year event. 226mm fell over the full duration of the storm, or nearly three months' average rain for the town. Downstream near Le Puy, the Loire rose from 64cm to 6.10m in two hours in response. [Météo France, Floodlist]

 Do you know your lightning?

Speaking of storms in Europe, here are some recent images and videos from Severe Weather Europe to test your lightning knowledge.

First, here's a stock, standard CG (cloud to ground) lightning bolt, only rather closer than you'd like to be. The bush being vaporised was in Les Estables, Auvergne, France

But lightning doesn't have to originate in the cloud - it can be GC, or upward, lightning as well, originating from some object on the ground. In this case extraordinary things can happen. Here's a still of beautiful upward lightning branching over Trabzon, Turkey last Saturday.

Then there's crawler lightning which, as you guessed, splits into many branches and crawls around the sky like the ones in these slightly out-of-focus videos; the first taken the day before over Trabzon and the second which went absolutely berserk over Valence, SE France last Tuesday.

Finally, there are the really elusive beasts: the sprites, blue jets, gigantic jets and elves. Severe Weather Europe has just put this brief guide to these, along with photos, videos and a guide to photographing them (much patience required!) on its website.

There are many other types as well, including the very rare ball lightning which may or may not exist and for which there is neither credible photographic evidence nor plausible scientific explanation. This list of Lightning Types and Classifications from Dan Robinson is a good introduction to the enormous variety of lightning.

 At least 156 dead, many missing, thousands of houses destroyed in monsoon landslides

At least 156 people have died and many more are are still missing following floods and landslides in SE Bangladesh and adjacent parts of India early this week.

Heavy rain on Monday that accompanied the arrival of the Southeast Monsoon dumped 75 to 150mm in the area with locally heavier falls to 250mm between Monday and Wednesday. The Rangamati Hill District, 50km inland from Chittagong, was worst hit when 300mm produced landslides that killed 100 people and destroyed 5,000 houses early Tuesday morning, with a further 36 reported dying in Chittagong. Landslides have caused deaths in nearby parts of Bangladesh, and over the border in the Indian state of Mizoram and farther north in Assam. Clearing weather on Wednesday allowed relief efforts to begin, though these were reported to be stretched.

This heavily populated area at the head of the Bay of Bengal, at the delta where the Ganges and Brahmaputra Rivers flow to sea, frequently suffers from torrential cyclonic and monsoonal rain. Uncontrolled deforestation and land grabs denude many hills and slopes where the poor have little alternative to live, and are reluctant to leave homes and possessions when bad weather strikes and authorities ask them to. [Reuters] [Accuweather] [Al Jazeera] [Weather Underground]

At the end of May, Tropical Cyclone Mora damaged or destroyed over 20,000 houses in Myanmar as it passed [IFRC] [Democratic Voice of Burma], before making landfall at Cox's Bazar in Bangladesh, killing at least eight and damaging over 50,000 houses in Chittagong and Cox's Bazar alone [IFRC]. Much of the area struck by Mora is the same as that hit by this event. On 25-26 May, heavy rain caused landslides in Sri Lanka that left 203 dead, 95 missing and nearly 10,000 houses damaged or destroyed [AWN 29 May] [ECHO].

Heavy east coast rain eases and moves north

The heavy rain that drenched the NSW North Coast [AWN 12 June] last weekend and early this week has retreated to coastal parts of SE QLD over the past two days.

Yesterday and today the low off the coast near Stradbroke Island, QLD, weakened leaving just a trough. In the 24 hours to 09.00 today on Stradbroke Island, Dunwich Airport recorded 113mm and North Stradbroke Island Flood Gauge to its south had 105mm thanks to the nearby low. Rain eased on Stradbroke Island but intensified on the nearby coast around Brisbane and the Gold Coast during today as the trough brought 12-hour totals of 25 to 60mm to 21.00.

In the flood-weary NSW North Coast [ABC News], heavy showers have continued yesterday and today giving 20 to 50mm between 09.00 yesterday and 18.00 today with the highest 81mm at Doon Doon, in the Nightcap Range between Lismore and Murwillumbah. Flood warnings are still out but, with the rain easing over the past day and a half, river peaks are passing with only minor flooding. Lismore on the Wilsons River peaked early this morning while on the Richmond Coraki peaked late morning and Bungawalbyn during the afternoon. South of Grafton, the Orara River at Coutts Crossing is due to peak this evening.

The heaviest rainfall reports over the whole wet period from 09.00 on 9 June to 18.00 this evening were Terania Creek, N of Lismore, 396mm and Tuckombil, W of Ballina, 388mm.

 Heavy rain brings flood threat to NSW North Coast

Heavy rain has been falling on and off over the NSW North Coast and QLD Gold Coast for the past three days and is forecast to continue. The rain is being produced by a trough off the coast in which a small low pressure system developed today.

The heaviest rain has been between about Ballina/Lismore and the NSW/QLD border with three-day totals generally around 150mm but up to 250mm in places. Maps from the BoM's Twitter page show where the rain fell and the heaviest totals daily to 09.00 on Saturday 10, Sunday 11 and today Monday 12 June.

As of 23.00 today, minor flood warnings were in force for parts of the Brunswick, Richmond and Wilsons Rivers, including around Lismore. The BoM was forecasting the potential for further rain up to 200mm in the Northern Rivers and northern part of the Mid North Coast in the next two days, so flood watches were current from the Nambucca River north to the QLD border.

Australian weather briefs

• Fog was widespread in NSW and VIC this morning. Large areas of both states, from the Hunter to the Southern Tablelands and west to the Slopes in NSW and in northern and central VIC, had fog until mid-morning with several observations coming in of visibility down to 50m. The fog was caused by radiation cooling under generally clear skies after rain. What ABC News described as "a classic pea-souper" fog enveloped much of Sydney causing flight cancellations, delays and diversions at the airport and dropping visibility as low as 100m in parts of the metro area.
• The nights have been exceptionally cold in the Centre so far this month, with Alice Springs Airport reporting minimum temperatures of zero or below on 10 of the 12 mornings so far. The lowest, -2.9° yesterday morning, was the coldest for June in five years according to the BoM. The two mornings with positive minima only reached 1.2° and 2.4°, all well below the June average of +5.0°. The cause of the unusually cold nights has been a persistent ridge of high pressure sitting over SA causing a large area of gently descending dry air and clear skies.

* I link to stories and resources frequently - why re-do what has already been well done? However, a regular problem with the Internet is "link rot". There are two main causes: either the link has ceased to exist, in which case you get the dreaded "Error 404 page not found" or the link exists but the information on it has changed. Where possible, I use "permalinks", URLs which I know are likely not to change in the foreseeable future because the organisation, such as the ABC, has developed a stable link structure. Where I think a link may suffer link rot, I mark it with an asterisk but be aware that there's no guarantee unasterisked links won't evaporate given time.