Flood E NSW SE QLD East Coast Rain Event 11 Dec - 20 Dec 2020

Artisan

Hard Yards
Dec 8, 2020
487
213
63
North West of Brisbane
Intercepted this beauty just outside of chinchilla last night at about 6.30pm. Was very suprised with the structure seeming there was a lack of shear. It dumped 45mm in 30mins and caused some minor flooding in town. I will post the edited pic later when i get home.
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45mm over the stubble. Now, thats a beautiful thing..:cool:
 

Mush

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Jul 6, 2019
53
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Fernvale NE NSW
Morning gang, been absent for a while down on the Central Coast attending to family issues. (Thanks for the welfare check Mega ) Left the day before the 1 in 100 year flood arrived (the 2nd one for this year around the Tweed) and just can't believe that after that prolonged dry we were all so distressed about it, will go down as one of our wettest years.I see its still teeming down up there this morning.
Anyway, got a nice rumbly treat fr
IMG_20201217_094847.jpg
om this almost stationary storm over the hills just west of Gosford yesterday.
Have a goody folks.

Mate do us a favour and let us know before you go wandering off next time, everyone was worried about you.
 

Steve777

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Jul 4, 2019
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Artarmon, Sydney North Shore
Sydney's experienced the Southern fringes of this "event". It's been warm, humid and fairly cloudy with mostly light showers, building up to some useful but not big totals. A chain of storms moved Southwards to our West yesterday, affecting the outer Western suburbs and Blue Mountains.

Sydey "event" totals so far:
  • City: 31 mm
  • Penrith: 30 mm (outer West)
  • Mt Boyce: 57 mm (Blue Mountains, 1080 metres, 91 km WNW of City)
 

Bello Weather

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Jul 12, 2019
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Another slow moving storm system dropping massive totals - this one on the Qld NSW border - going to be some serious flash flooding just inland from Tweed and Goldie if this keeps up. From the BoM:

The Bureau of Meteorology warns that, at 10:10 am, very dangerous thunderstorms were detected on the weather radar near Coolangatta and Miami. These thunderstorms are moving towards the southeast. Very dangerous thunderstorms are forecast to affect waters off Tweed Heads by 10:40 am.

Intense rainfall that may lead to dangerous and life-threatening flash flooding is likely.

42mm was reported in 30 minutes to 8:55am at Oyster Creek (Gold Coast). Another 45mm has been observed in 30 minutes to 10:20am.


download (1).png
 

PlumbBob

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Jul 5, 2019
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Molendinar
Yep, not giving up in the Numinbah area, scoring 100+ last 24hrs to 9am

Snip Dec 17.JPG

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Also have some Qld Dam Level comparisons, from Dec 13th to 17th. Highlight - above 10% increase !
Sure some will continue to rise over the next week or so

SEQld Dams Dec 13-17 cStchWeb.jpg

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I'm sick of chasing readings from shed weather gauge, estimate another 50mm middnight to now.
More to come throughout today, and for many more days right through to xmas and possibly till New-Year ?

La-Nina has sure Kicked in - plenty of annoyed campers I assume ?
 

Flowin

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Jul 5, 2019
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Pinjarra Hills, QLD
Yep, not giving up in the Numinbah area, scoring 100+ last 24hrs to 9am

Snip Dec 17.JPG

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Also have some Qld Dam Level comparisons, from Dec 13th to 17th. Highlight - above 10% increase !
Sure some will continue to rise over the next week or so

SEQld Dams Dec 13-17 cStchWeb.jpg

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I'm sick of chasing readings from shed weather gauge, estimate another 50mm middnight to now.
More to come throughout today, and for many more days right through to xmas and possibly till New-Year ?

La-Nina has sure Kicked in - plenty of annoyed campers I assume ?
Another 50mm since 9am also over Tweed catchment in last few hours.... perhaps too much for already wet catchments
 
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PlumbBob

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Jul 5, 2019
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Molendinar
Another 50mm since 9am also over Tweed catchment in last few hours.... perhaps too much for already wet catchments
Tipping 100 now, 3.1 hrs & 188mm in last 12hrs, thats similar rates as recieved from Trop Cyclone Debbie 2017
They get some big wets down there every now & then,, two in row backin 2008 & 9.

Mate had a big Tinny on the tweed Rv near Murwillumbah back then, warned him to get it out a few days prior, he eventually realised the idea was varified, parked it in yard, next day it was floating around the yard doing 20meter circles around the trailor ,,,,,

Snip Dec 17bcWb.JPG
 

Weathertraveller

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Jan 23, 2020
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Northern Gold Coast
Received the EWN text just before 10 this morning for heavy rain in the Logan, Cleveland, Beenleigh Coomera, Southport over the next several hours. We've had some heavy showers here this morning, and the ground is already really soaked from the 200+ we had over the weekend and Monday. Looks like some areas like Coolangatta, have received over 150mm since last night, other areas much higher. The Springbrook totals will be well over 1.2 metres now.
 

Gleno71

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Jul 4, 2019
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Gold Coast, Queensland
Morning gang, been absent for a while down on the Central Coast attending to family issues. (Thanks for the welfare check Mega ) Left the day before the 1 in 100 year flood arrived (the 2nd one for this year around the Tweed) and just can't believe that after that prolonged dry we were all so distressed about it, will go down as one of our wettest years.I see its still teeming down up there this morning.
Anyway, got a nice rumbly treat fr
IMG_20201217_094847.jpg
om this almost stationary storm over the hills just west of Gosford yesterday.
Have a goody folks.

Hope all is well
 

Eddy

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Jul 4, 2019
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Port Stephens
A nice little storm rolled in not long after lunch today. Nothing severe about apart from the potential of some very heavy rain.
I recorded 19mm in about the 45 minutes the storm lasted, radar may have imo over read.
Early stages
IMG_2580 by Eddy Groot, on Flickr
Getting organised
IMG_2614 by Eddy Groot, on Flickr
Not a lot of Cgs observed but plenty of anvil thunder, once the storm hit there were a few embedded Cgs.
IMG_2640 by Eddy Groot, on Flickr

IMG_2645 by Eddy Groot, on Flickr

IMG_2654 by Eddy Groot, on Flickr
 

Flowin

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Jul 5, 2019
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Pinjarra Hills, QLD
Does anyone know if the models had forecast this amount of rain on the Gold Coast today ? I didn't get a chance to have a look
Gleno this was this morning Access C run from 4am total to 10am.
That 4am (18Z) Access C run then did not have much more after 10am. But the subsequent 10am run (00z) did show rain continuing another 3hrs 10am to 1pm.
EC 18Z had rain a bit furhter south over the border - less at the GC.
None were predicting totals over 150mm.

upload_2020-12-17_15-11-47.png
 

Long Road Home

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Aug 7, 2020
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Gleno this was this morning Access C run from 4am total to 10am.
That 4am (18Z) Access C run then did not have much more after 10am. But the subsequent 10am run (00z) did show rain continuing another 3hrs 10am to 1pm.
EC 18Z had rain a bit furhter south over the border - less at the GC.
None were predicting totals over 150mm.

upload_2020-12-17_15-11-47.png

That's actually pretty impressive, albeit the timing was a bit off still did pretty well there with the convergence.
 

Ken Kato

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Jul 13, 2019
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Brisbane
Does anyone know if the models had forecast this amount of rain on the Gold Coast today ? I didn't get a chance to have a look
This sort of highly convective setup is another great example of how it's never good to pay too much attention to forecast rainfall amounts. Instead, it's better to look at the overall nature and characteristics of the setup to see whether locally extreme rainfall amounts are realistic
i.e. for this setup, no major synoptic system providing a strong focal point for precip + weak steering winds + plenty of deep moisture = scattering of very slow moving showers and storms with quite "random" rainfall distribution but good chance of locally very high falls here and there.

One of my friends actually put it quite well in a fb post he made the other day:


The one thing that can be useful re the QPF from models especially one like ACCESS-C is to see if it's hinting at locally hefty amounts. If this is also consistent with the overall setup, it puts even more confidence into the potential for very unevenly distrubuted but locally intense falls with flash flooding potential.
It's a bit of a different story for model forecasts for many other setups where the setup's less "random" in terms of rainfall distribution though.
 

Flowin

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Jul 5, 2019
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Pinjarra Hills, QLD
This sort of highly convective setup is another great example of how it's never good to pay too much attention to forecast rainfall amounts. Instead, it's better to look at the overall nature and characteristics of the setup to see whether locally extreme rainfall amounts are realistic
i.e. for this setup, no major synoptic system providing a strong focal point for precip + weak steering winds + plenty of deep moisture = scattering of very slow moving showers and storms with quite "random" rainfall distribution but good chance of locally very high falls here and there.

One of my friends actually put it quite well in a fb post he made the other day:


The one thing that can be useful re the QPF from models especially one like ACCESS-C is to see if it's hinting at locally hefty amounts. If this is also consistent with the overall setup, it puts even more confidence into the potential for very unevenly distrubuted but locally intense falls with flash flooding potential.
It's a bit of a different story for model forecasts for many other setups where the setup's less "random" in terms of rainfall distribution though.
I agree about rain amounts being hard to judge.
When I saw the EC12Z forecast this morning, I did think the CAPE was a possible sign of more instability, but wasn't sure if that alone would be enough.

upload_2020-12-17_15-51-35.png
 

Warlock_01

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Jul 7, 2015
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Gold Coast, Bonogin
What actually caused this significant amount of rain to absolutely annihilate the GC. Total white out driving to work this morning from Burleigh, I just got home and our creeks were over the road and to top that off we received another 250mm with today's drenching, so the total overall is 875mm!

Any reports how much rain dropped in Springbrook?
 

TweedStorm

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Jul 6, 2019
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Banora Point
Hope all is well
All good thanks Gleno. I should be asking you this haha. Strike me that weather up there since I've been gone, has just been beyond belief! Down on the Central Coast it was a nice warm humid sunny one again with some towers developing on the ranges and also visible from Sydney toward the evening with some distant thunder. Gee a place called Davis Town is a great scenic spot to watch afternoon buildup.
IMG_20201217_192628.jpg
 

Ken Kato

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Jul 13, 2019
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Brisbane
just can't believe that after that prolonged dry we were all so distressed
Many people still are actually @TweedStorm ... most of the recent very heavy rain was really coastal as far as QLD goes.... and even then, mostly the southern coast..... to the point that even areas only slightly inland of the coast such as the Lockyer Valley missed out on the higher amounts.
There has been some good rainfall since then about the ranges and western slopes but a lot of that's been very uneven due to much of it coming from storms.
 

Gleno71

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Jul 4, 2019
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Gold Coast, Queensland
The 33mms over night has gone to 54 till 9am, well over 300 now. Is there a convergence just inland SEQ, rain bombs seem to start just on the north side and build as they head south?

im trying to work that out, on the news they said it was a coastal trough but i thought that went from the rain event we had a few days prior. I still dont get the term "severe thunderstorm warning for heavy rainfall" a thunderstorm should only be classed that if there were lightning detected. though some of the cells had limited lightning, some had none but were classed as a storm. Im unsure if this rule applies worldwide , or it's just BOM terminology.
 

Gleno71

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Jul 4, 2019
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Gold Coast, Queensland
All good thanks Gleno. I should be asking you this haha. Strike me that weather up there since I've been gone, has just been beyond belief! Down on the Central Coast it was a nice warm humid sunny one again with some towers developing on the ranges and also visible from Sydney toward the evening with some distant thunder. Gee a place called Davis Town is a great scenic spot to watch afternoon buildup.
IMG_20201217_192628.jpg

That looks awesome, nice towering clouds, i missed a beauty of a storm in sydney a few weeks back, was stuck on the Harbour Bridge while this epic shelf cloud came across the city, i need to learn to give myself more time when doing storm chasing in Sydney lol
 

Gleno71

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Jul 4, 2019
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Gold Coast, Queensland
Hardys Rd and Gunsynd Drv Bonogin GC. Haven't seen Gunsynd Drv go under for a very long time. All this flows out to Mudgeeraba creek which inundates the sports fields and road in town which has gone under also. Hardys Rd causeway looks like it reached the 2m mark sometime today.
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wow thats insane, i was worried there for a minute if i would make it home from work.
 

Auzza

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Nov 12, 2019
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Grafton, NSW
Had another 52mm here today, almost all of which fell in the hour between 2:30 and 3:30 for a total of 115mm in the last two days and 380mm for the event so far. Storms to our west look like they might add quite a bit more to that. Just keeps on delivering in Northern NSW.
Up to 83mm. Looks like radar has cleared up now. Have to say, considering we're usually one of the driest places in Northern Rivers region was not expecting over 400mm for this event. Grafton Research Station over 475mm month to date. 95th percentile rainfall for December is 228mm, already been doubled and then some! And I thought February was insane.
 

Homer

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Aug 3, 2005
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Castle Hill - Sydney
im trying to work that out, on the news they said it was a coastal trough but i thought that went from the rain event we had a few days prior.

Please mate, forget and ignore what you hear on the news. Seriously.

There are but 1 or two actual weather people who actually know what they are talking about. Graham Creed is the best by a country mile. That David bloke on 7 in Sydney knows a bit, but dumbs it down so much for his stupid audience. The rest are hacks who have no meteorological background and put together evening forecasts on their channel that they don't really understand themselves.

The standard of getting weather information out in this country is appalling.
I can't wait for the next mini-tornado report.
 

Warlock_01

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Jul 7, 2015
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Gold Coast, Bonogin
wow thats insane, i was worried there for a minute if i would make it home from work.
I was surprised when I had seen the sign up near The Mill on Somerset Drv which read Gunsynd Rd flooding, my thoughts were that the pelting rain in the hinterland when I left for work did not give up for most of the day. I got home around 4.30pm and my brother said the rain didn't ease up until 3pm. Numerous of times since living out here, Gunsynd Drv goes underwater when heavy rain is consistent. A few days ago it was about a metre under the bridge, goes to show how quick flood waters can rise so rapidly after heavy rain.
 

Warlock_01

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Jul 7, 2015
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Gold Coast, Bonogin
These photos are from March 2017. As you can see, it has been alot worse, due to the fact of consistent heavy downpour that caused the banks to bust. One of the worst I've seen in the suburb. The water level sign on the last image is underwater, which read 2m
 

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Falling_Droplet

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Jul 7, 2019
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Ferny Grove, QLD
fernygroveweather.com
A light to moderate shower in the late morning (4.2 mm over 30 minutes) and a light shower with another 1.2 mm in the early afternoon. 5.5 mm since 9am.

The temperature was near average in the morning which was a little variable then fell in the half-hour before the late morning shower becoming cool before rising in the middle of the day after the rain. The temperature fell in the early afternoon with the shower before rising afterwards but didn't rise much further than the maximum of 27 C reached in the middle of the day. From later in the afternoon the temperature fell and returned to near average before falling slowly tonight and became slightly warm late tonight. Dew point remained moderately high from the morning as the dew point generally rose in the morning but was quite variable before falling in the afternoon and eased to slightly above average from the late afternoon. Tonight the dew point have been stable and returned to moderately high late tonight. The dew point reached a high of 25 C in the middle of the day.

Relative humidity fell rather slowly in the morning, then rose later in the morning and became very high. After reaching 94% the relative humidity generally fell slowly in the afternoon but rose and fell a few times while remaining very high. The relative humidity eased to moderately high in the late afternoon and to slightly below average later tonight as the relative humidity rose quite slowly from the late afternoon. Light N to NNE winds in the morning became E to NE from the mid morning, ENE to NE from the early afternoon, became NNE to NE tonight and N to ENE later tonight.

Last 24 hours:
rain 2020-12-17.PNG
temp 2020-12-17.PNG
hum 2020-12-17.PNG
wind dir 2020-12-17.PNG
 

Gleno71

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Jul 4, 2019
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Please mate, forget and ignore what you hear on the news. Seriously.

There are but 1 or two actual weather people who actually know what they are talking about. Graham Creed is the best by a country mile. That David bloke on 7 in Sydney knows a bit, but dumbs it down so much for his stupid audience. The rest are hacks who have no meteorological background and put together evening forecasts on their channel that they don't really understand themselves.

The standard of getting weather information out in this country is appalling.
I can't wait for the next mini-tornado report.


Yeah i like Graham Creed . Up our way we have a Jenny Woodward from the ABC and Tony Auden from ch.7 . I have always believed that a weather presenter should have some meteorology experience, otherwise everyone on this forum would be candidates to present weather on TV
 

Falling_Droplet

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Jul 7, 2019
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Ferny Grove, QLD
fernygroveweather.com
Some light showers between 2am and 3am - 0.7 mm of rainfall. Rainfall since 9am yesterday of 6.2 mm. Event total is 131 mm.

Warm from early today as the temperature was stable or fell slowly in the early hours before starting to rise this morning. Dew point was stable in the early hours and rose a little this morning while remaining moderately high. Relative humidity have been near average as the relative humidity rose slowly in the early hours and started to fall this morning. Light N winds at the start of the day became NNE to ENE before calm winds from later in the early hours, and then N to NNE winds this morning.
 
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Kazza47

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Jul 28, 2019
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Starting to feel like someone's put a target on us here; these storms creep up in a big arc; but I can already see it will probably split as it hits the mountains.

Looks impressive though.
Screenshot_2020-12-18 Gympie 256km weather radar loop and lightning tracker.png
 

Kazza47

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Jul 28, 2019
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and 2 hours later .... it's still coming, lol At least we can hear something rumbling away ; best tuck in & fall asleep - I slept through the last decent one . If it's moving this slow, we may be floating in the morning. (Not really looking at those totals)
Screenshot_2020-12-18 Gympie 256km weather radar loop and lightning tracker(1).png
 
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Falling_Droplet

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Jul 7, 2019
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fernygroveweather.com
Slightly warm temperature in the morning eased to near average from later in the morning as the temperature rose more slowly. The temperature was a little variable from the mid morning to the mid afternoon. Slightly warm early tonight and became warm as the temperature fell more slowly tonight that then became stable later tonight. After the dew point briefly fell the dew point rose during the morning fell in the afternoon slowly while remaining moderately high becoming slightly above average in the late afternoon before rising slowly tonight and have been moderately high.

Relative humidity fell quickly in the morning that became generally stable from the mid morning. Near average relative humidity became moderately high from the middle of the day, eased to slightly above average later in the afternoon. Tonight the relative humidity have been near average. Light NNW to NE winds in the morning became E to NE from the late morning, ENE to NE from the late afternoon, then N to NE early tonight and N to NNW with some W to NW winds late tonight.

Last 24 hours:

rain 2020-12-18.PNG
temp 2020-12-18.PNG
hum 2020-12-18.PNG
wind dir 2020-12-18.PNG
 
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glenesk

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and 2 hours later .... it's still coming, lol At least we can hear something rumbling away ; best tuck in & fall asleep - I slept through the last decent one . If it's moving this slow, we may be floating in the morning. (Not really looking at those totals)
Screenshot_2020-12-18 Gympie 256km weather radar loop and lightning tracker(1).png
When you look at that screenshot, its hard to believe we missed most of it here. South eastern tip just vanished?
 
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