The Northern Australian Monsoon 2020 - 2021.

[greysrigging 2,221]

She's IN ! At home just now ! The squally showers have done the old 180* turn around streaming in from the Timor Sea to the north west and the Arafura Sea to the north. 
The true indication of our Monsoon season. About a week or 10 days earlier than normal onset, although perhaps a bit later than in a general La Nina year. which might be mid December.
So no excuses now for foolish behaviour, tom foolery, poor decision making, excessive alcohol consumption, and being a bit of a goose.... the 'build up' is done and dusted, mango season is finished, so no more 'mango madness', no more telling the Judge, "sorry Your Honour, but fair dinkum mate, this 'build up' had been a real b****ard....", and the Judge nodding with complete understanding..........
Bring On The Rain !

 

[greysrigging 2,221]

A friend sent some pics from on Darwin Harbour.

A north west squall about to come in....

 

[chinandega81 143]

A trend I noticed this rainy season in Florida was that it tends to be a slow build up.....it starts out somewhat paltry and sporadic and as time progresses, the rains become more frequent as the season progresses. Is it the same for you in N. Australia? Or are you lucky enough to have it full blast from start to finish?

[greysrigging 2,221]

15 hours ago, chinandega81 said:

A trend I noticed this rainy season in Florida was that it tends to be a slow build up.....it starts out somewhat paltry and sporadic and as time progresses, the rains become more frequent as the season progresses. Is it the same for you in N. Australia? Or are you lucky enough to have it full blast from start to finish?

No, our rainy season in the deep north is a completely different weather pattern compared to the early 'build up' rains which revolve around a Kimberley region 'heat low' establishing itself ( usually late August ) in the tropical northern inland of Western Australia. The increasing heat and humidity produces convectional type storms over the Top End, including Darwin. These storms up our way are sometimes associated with 'Gulf Lines' coming east to west across the Top End from the Gulf of Carpentaria, other times 'Hector the Convector'( perhaps the only named thunderstorm in the meteorological world ) and another one known locally as the 'Labelle Cell' to our south west gives us some early rain prior to the onset of the North Australian Monsoon ( Asian actually, as the Trough moves south of the Equator and forms over the Top End at 12*S )
Our 'Dry Season' really is dry, with usually 3 ( sometimes 5 ) completely rainless months, May - Sept.
Some years the Monsoon may only form 2 or 3 times in the season, about a month apart..... these 'break' periods, the conditions revert back to 'build up' type weather patterns, with isolated showers and storms from the east and south east. Often monsoonal weather patterns coincide with the Madden-Julian Oscillation (MJO), which is the major fluctuation in tropical weather on weekly to monthly timescales. The MJO can be characterised as an eastward moving 'pulse' of cloud and rainfall near the equator that typically recurs every 30 to 60 days.
Other influence on the timing and severity or otherwise of our monsoon season is the La Nina - El Nino patterns and the IOD ( Indian Ocean Dipole ) and the subsequent SST's ( sea surface temperatures )

 

[greysrigging 2,221]

Some reading material re 'Hector the Convector'
https://blogs.unimelb.edu.au/sciencecommunication/2020/09/19/meet-hector-the-thunderstorm-that-can-tell-time/
https://www.youtube.com/watch?v=UsOpWeLWgjM

[Tyrone 1,903]

22 hours ago, greysrigging said:

She's IN ! At home just now ! The squally showers have done the old 180* turn around streaming in from the Timor Sea to the north west and the Arafura Sea to the north. 
The true indication of our Monsoon season. About a week or 10 days earlier than normal onset, although perhaps a bit later than in a general La Nina year. which might be mid December.
So no excuses now for foolish behaviour, tom foolery, poor decision making, excessive alcohol consumption, and being a bit of a goose.... the 'build up' is done and dusted, mango season is finished, so no more 'mango madness', no more telling the Judge, "sorry Your Honour, but fair dinkum mate, this 'build up' had been a real b****ard....", and the Judge nodding with complete understanding..........
Bring On The Rain !

 

Nooiceee!!!!

[greysrigging 2,221]

Rained all night, there's another inch in the gauge ( still raining  7.00am )
Lovely cool atm 25c.
!50mm ( 6"' ) in the last week of steady soaking rain....the odd squally heavier burst, but generally great garden rain !

[greysrigging 2,221]

You know you're in Darwin when some bloke is mowing the grass during a monsoonal downpour!....lol

[tropicbreeze 693]

The monsoon went all quiet yesterday, during the daytime. Only got a couple of mm rain over a 16 hour period. Then over night 8 hours of rain produced 160mm. Some other places nearby got more. This month's rainfall is running at 180% of average. There's a good chance there'll be a lot more rain before the end of December. It'll need about 20mm per day to keep the total at the 180%.

[greysrigging 2,221]

42 minutes ago, tropicbreeze said:

The monsoon went all quiet yesterday, during the daytime. Only got a couple of mm rain over a 16 hour period. Then over night 8 hours of rain produced 160mm. Some other places nearby got more. This month's rainfall is running at 180% of average. There's a good chance there'll be a lot more rain before the end of December. It'll need about 20mm per day to keep the total at the 180%.

You mob did well out there in the Outback Appalachians.....
17.3mm in the Northern 'Burbs.... ( sigh ) 246.8mm for the month so far ( 292.5mm av )

[tropicbreeze 693]

I got 164.2mm for the full 24 hours but it was a "mixed bag" around Darwin.

[greysrigging 2,221]

From the BOM ( Weekly Tropical Climate Note )
Monsoon arrives at Darwin

Friday 18 December saw a monsoon trough form across the northern Top End and an embedded weak tropical low develop in the Timor Sea. Monsoonal flow strengthened and extended south-west to the Kimberley the next day. The resulting two days of north-westerly winds from the surface to the mid-levels at Darwin satisfied the 2020-21 monsoon onset criteria, meaning that 19 December is the official monsoon onset date at Darwin for the 2020-21 northern wet season. This season’s monsoon onset date at Darwin is more than a week earlier than average (29 December), and is a month earlier than last season’s onset date (18 January 2020). The last comparable early onset was in 2016-17An early monsoon is typical of La Nina. This season, the onset was also aided by warmer than average ocean temperatures around Australia and the interaction of the MJO and other tropical waves to the Australian region .A deepening tropical low (03U) crossed the Kimberley coast and tracked through the district’s south and is not expected to develop into a tropical cyclone. A weak tropical low is currently located just outside the North-West Australia tropical cyclone region. There is a low risk for it to impact Cocos Islands for the coming week. However, international tropical cyclone forecast models, indicate there is a significantly increased risk for a tropical cyclone development in the central Indian Ocean to the eastern Madagascar at the end of December into early January 2021.

Madden–Julian Oscillation becomes weak in the Western Pacific. The Madden–Julian Oscillation (MJO) has recently been active in the eastern Maritime Continent, assisting the development of the monsoon trough across the northern Top End and the Kimberley last week. The weak MJO pulse is currently meandering from the eastern Maritime Continent into the Western Pacific region. At this time of the year, an active MJO in the Western Pacific is typically associated with above-average rainfall across far northern Australia and the northern Coral Sea. Climate models agree the MJO will be weak this week, with some predicting it will remain so into early January. However, the Bureau’s model indicates the MJO could strengthen over the western Indian Ocean in early January 2021.

[greysrigging 2,221]

Huge storm over Darwin and the rural areas... over 100mm ( 4" ) in a coupla hours at Batchelor and Noonamah ( the Outback Appalachians )
Even Leanyer Heights where I live is more than 50mm ( 2" ) in the hour since it started to rain !
 

[greysrigging 2,221]

3" in three hours.... yeah, I'll take it !

[greysrigging 2,221]

Nigh on 100mm ( 4" ) since 5.00pm Boxing Day ! 

[tropicbreeze 693]

11 hours ago, greysrigging said:

Nigh on 100mm ( 4" ) since 5.00pm Boxing Day ! 

I got 116mm out of that, so now running at 202% of December average. The monsoon took a couple of days break over Christmas. Maybe didn't want to get Santa's presents wet as his sleigh doesn't have any weather protection. Technically, the monsoon has moved back over Indonesia.

[greysrigging 2,221]

5 minutes ago, tropicbreeze said:

I got 116mm out of that, so now running at 202% of December average. The monsoon took a couple of days break over Christmas. Maybe didn't want to get Santa's presents wet as his sleigh doesn't have any weather protection. Technically, the monsoon has moved back over Indonesia.

Measured 95.3mm..... yeah, pretty happy with that !

[greysrigging 2,221]

Bit of activity overnight and this morning......

 

[greysrigging 2,221]

Nice drop overnight and this morning.
A view up and down my street.

 

[greysrigging 2,221]

Darwin, Northern Territory of Australia ( 12.46*S )
2020 Rainfall, Max and Min temps.
Jan - 402.0mm, 32.8c, 26.0c
Feb - 216.6mm, 33.4c, 26.8c
Mar - 278.2mm, 33.2c, 25.4c
Apr - 115.6mm, 33.7c, 25.1c
May - 1.4mm, 32.1c, 22.4c
Jun - 1.0mm, 32.4c, 21.1c
Jul - 0.0mm, 32.0c, 19.2c
Aug - 0.0mm, 32.6c, 21.0c
Sep - 87.6mm, 33.9c, 23.7c
Oct - 162.0mm, 33.6c, 25.3c
Nov - 93.0mm, 35.0c, 25.8c
Dec - 382.0mm, 32.6c, 25.0c

2020 Totals and means
Rainfall - 1740.2mm, Max temp - 33.1c, Min temp - 23.7c. Yearly mean of 28.4c
Hottest day 37.0c on Sept 8th and Nov 17th
Coldest day 25.0c on May 22nd
Hottest night 29.7c on Feb 26th|
Coldest night 16.2c on July 30th
Wettest day 113mm on Oct 8th.

[greysrigging 2,221]

Been quiet in the Darwin region for the last week.....as per usual, a Gulf Cyclone ( Imogen ) tracked East into North Queensland and stole our rain. We have had a run of hot dry westerlies ( although I scored my first 2021 rain this morning 4mm ).
Some local photography from the guys and gals on our local weather FB group.

 

[greysrigging 2,221]

Bit of activity around town the last few days.
Hector the Convector has been going off over the Tiwi Islands to our North.

Groote Eylandt in the Gulf picked up 26mm from this cell.

Good lookin' structure over at Gove on the north eastern tip of the Territory.

And a bit happening around Darwin too.....

East Point.

[tropicbreeze 693]

For a monsoon break period my rainfall totals have been fairly high. These are the daily totals for this month so far
5.8
1.2
0.0
0.0
15.0
0.0
83.2
14.4
0.0
1.0
49.0
35.2
31.4
==========
236.2

In the same period Darwin Airport 65.8, and Noonamah AWS (Weddell) 168.8

Pity Coolalinga doesn't have an official rain gauge, they've had a lot more rain than I have.

[greysrigging 2,221]

^^ 103.6mm here at home in Leanyer so far this month. Was out at Hopewell Rd, Berry Springs this morning.... one can easily see there has been way more rain out that way than in Town.
Nice little drop as I type right now  ( 1.25pm ). 12.5mm so far
From Pilkos's 'Chat on Weather', Darwin.
"A very tropical and quite uncomfortable morning here in the Top End so far.30.9 at the Airport and the “feels like” temp is 37.1 so it’s pushing the boundaries of ones sanity at the moment. Darwin and immediate surrounds missed the action yesterday as a bit of NE steer took over and pushed everything just south of the city. Today tho does look a little better with more favourable conditions for Darwin and hopefully that means free showers for all Models still look keen for a monsoon trough to develop to the north of the Top End in the coming days, but it’s still a bit of coin tossing as to its strength and main area of activity. Off the far north WA coast is looking the best bet for the most concentrated activity, watch for potential low development, but realistically nothing is etched in stone just yet. A strengthening ridge thru central and southern Australia in coming days will push most of the activity to the Top End, especially the NW Top End before moisture again spreads south from next week.

The last few days has seen some pretty impressive lightning shooting about, so please take care out there. Some of these bolts are shooting well clear of the storm front and as such you don’t need to be standing in the rain to get hit."

[greysrigging 2,221]

Look at the filthy conditions yesterday afternoon.....about as bad as it gets !

Then a massive storm last night seemingly right over the top of my bedroom....... when you 'hear' and 'smell' the lightning before you see the flashes you know its close.
I haven't checked my gauge yet, but this is about a mile from me...

[greysrigging 2,221]

Just horrendous !

[Tyrone 1,903]

On 1/15/2021 at 3:25 AM, greysrigging said:

Look at the filthy conditions yesterday afternoon.....about as bad as it gets !

Then a massive storm last night seemingly right over the top of my bedroom....... when you 'hear' and 'smell' the lightning before you see the flashes you know its close.
I haven't checked my gauge yet, but this is about a mile from me...

30.7C dewpoints. Wow. The air has that much heat energy stored in it. So hot and steamy mould would just die!

[greysrigging 2,221]

We whinge about it....but then again it all produces this.....late this arvo.

 

[greysrigging 2,221]

This is about as good as it gets temp wise in Darwin during the 'Wet' 
Only 26c at noon and topped out at 27.6c ( atm 6.00pm ).
Drizzly rain, heavy overcast all day, only 5mm of rain.... wonderfully cool and damp !