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

Bello Weather

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Our local road and river - impossible to tell where the river or road are!

moodys bridge.jpeg
 

Bello Weather

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This is from the BoM Flood Warnings for the Kalang River:

Kalang River:
Below Minor flooding is occurring along the Kalang River.

That has sat there for the last few warnings. I reported it as an obvious error but nothing other than an email saying the warning was correct. Now check the photo of Moodys Bridge on the Kalang from a few posts above. If that is Below Minor flooding then holy moly. Dangerous and wrong from the BoM on that one, and dissapointing that they are not up for fixing it. @Ken Kato appreciate not your area but any idea how to feed this one back so it doesn't happen again?
 

Ken Kato

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This is from the BoM Flood Warnings for the Kalang River:

Kalang River:
Below Minor flooding is occurring along the Kalang River.

That has sat there for the last few warnings. I reported it as an obvious error but nothing other than an email saying the warning was correct. Now check the photo of Moodys Bridge on the Kalang from a few posts above. If that is Below Minor flooding then holy moly. Dangerous and wrong from the BoM on that one, and dissapointing that they are not up for fixing it. @Ken Kato appreciate not your area but any idea how to feed this one back so it doesn't happen again?
I'd suggest try calling the NSW office on 9296 1555 and sending the photo to them as well (if you haven't already done so?)

Oh and interesting point Megamatch, I haven't seen his posts for awhile either. I wonder if it's NBN outage related or something else. I'm not sure.
 

Bello Weather

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I'd suggest try calling the NSW office on 9296 1555 and sending the photo to them as well (if you haven't already done so?)

Oh and interesting point Megamatch, I haven't seen his posts for awhile either. I wonder if it's NBN outage related or something else. I'm not sure.
Thanks Ken, appreciate it. Called the number, emailed in photos..and the warnings still coming out saying no flooding. I've emailed again.
 

Ken Kato

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The forecast totals for the next couple days for Brisbane, are they going to be from very hit and miss stuff like today? Or is there a rain band or such expected to come through at some point to give more widespread rain?
Nah I'd say it'll be like what I mentioned in an earlier post as far as SEQ goes i.e.

" The more favourable (for widespread rain) outer southern and southeastern flank of the upper low is now down around the MNC and areas to the adjacent southwest where some rain areas are occurring and the upper low itself is also starting to gradually lose strength. There's also a localised surface trough near the northern part of the MNC which is helping to enhance the rainfall near that area.
There's still some background upper support from the upper low and we're in the deep NE to N flow on its eastern side but most rainfall over the next several days for SEQ should be more in a convective mode with no strong focal points i.e. day after day of a humid northeasterly flow, a mix of sun and clouds, and some sporadic shower/storm activity that can pop up at any time of day or night. "


In other words, muggy at times here with a mix of clouds and sun with any heavy showers/storms (which can pop up at any time of day or night) being more like interruptions to these dominant conditions.... not the widespread steady persistent rain areas that coastal SEQ just experienced.

Until about midweek, the vertical wind structure in the atmosphere could make it somewhat conductive for training of convection near the coast, moreso during the overnights/mornings..... narrow but intense lines of showers/thunder where those directly under them would experience some persistent heavy downpours while many areas those outside of those lines at the time hardly get anything.

Also, as we get further into the week, steering winds aloft weaken as well storms to become slower moving and possibly causing decent accumulations in the areas they sit over but those heavier falls will probably be quite hit and miss a lot of the time. Weakening shear also means that the threats of large hail and damaging winds will probably become lower.

There'll probably be somewhat of an overall tendency for them to start near the coast overnight/morning before focusing more on inland parts by the afternoon. But in terms of the heavier rainfall amounts, it could be quite a lottery.
 

Homer

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Looks like the 15 - 35/40 mm's forecast for Sydney and surrounds for today is still to come. Radar concurs.
A large rain band is heading towards us from the N/NE. I've been watching it all day and slowly but surely it is descending upon the metro.
Possibly a few hours of moderate to at times heavy rain if it holds together.
Looking forward to the 4.20 pm update. No doubt, it will be the generic computer generated stuff which is always dished out. I'm more curious about how much the forecast will have changed from this morning, as well as the updated projected rain totals.

Today has been a dull, almost lifeless day. Heavy overcast with occasional bursts of very light, misty drizzle. The sun made two brief, short lived appearances here. Very humid though, which is no surprise considering the direction of the moisture infeed.
 
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CirrusFibratus

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Nah I'd say it'll be like what I mentioned in an earlier post as far as SEQ goes i.e.

" The more favourable (for widespread rain) outer southern and southeastern flank of the upper low is now down around the MNC and areas to the adjacent southwest where some rain areas are occurring and the upper low itself is also starting to gradually lose strength. There's also a localised surface trough near the northern part of the MNC which is helping to enhance the rainfall near that area.
There's still some background upper support from the upper low and we're in the deep NE to N flow on its eastern side but most rainfall over the next several days for SEQ should be more in a convective mode with no strong focal points i.e. day after day of a humid northeasterly flow, a mix of sun and clouds, and some sporadic shower/storm activity that can pop up at any time of day or night. "


In other words, muggy at times here with a mix of clouds and sun with any heavy showers/storms (which can pop up at any time of day or night) being more like interruptions to these dominant conditions.... not the widespread steady persistent rain areas that coastal SEQ just experienced.

Until about midweek, the vertical wind structure in the atmosphere could make it somewhat conductive for training of convection near the coast, moreso during the overnights/mornings..... narrow but intense lines of showers/thunder where those directly under them would experience some persistent heavy downpours while many areas those outside of those lines at the time hardly get anything.

Also, as we get further into the week, steering winds aloft weaken as well storms to become slower moving and possibly causing decent accumulations in the areas they sit over but those heavier falls will probably be quite hit and miss a lot of the time. Weakening shear also means that the threats of large hail and damaging winds will probably become lower.

There'll probably be somewhat of an overall tendency for them to start near the coast overnight/morning before focusing more on inland parts by the afternoon. But in terms of the heavier rainfall amounts, it could be quite a lottery.
Thanks Ken, above and beyond as always :thumbs:
 

Seabreezes

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62.0mm in the 24hrs to 9am this morning here.

72.6mm has fallen since 9am. Bursts of heavy to very heavy rain this afternoon.

Minor to moderate flooding warning have been issued for the Hastings and Macleay Rivers:
http://www.bom.gov.au/nsw/warnings/flood/hastingsriver.shtml
http://www.bom.gov.au/nsw/warnings/flood/macleayriver.shtml
The flood warning for the Macleay says the river may possibly reach moderate flood level (5.7m) tomorrow morning at Kempsey. Roads downstream on the floodplain begin to be affected once the river reaches 5.7m at Kempsey (all roads to South West Rocks cross the floodplain).

Sherwood Bridge (upstream of Kempsey)
221.jpg
 

Eddy

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Jul 4, 2019
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Port Stephens
Torrential rain in the short time since my last post. Now on 120.8mm since 9am. Just had 47mm in 45 minutes here. :emoji_swimmer:

And by looks of things a bit more to come.

Its been a pretty dry show here up until an hour ago when 30mm fell in about an hour from some steady rain. Event total stands at 56.3mm but looking at radar and obs from just up the road, slight chance I could hit the ton mark. Time will tell.

Nice reports and images too guys.
 

Gleno71

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The more favourable (for widespread rain) outer southern and southeastern flank of the upper low is now down around the MNC and areas to the adjacent southwest where some rain areas are occurring and the upper low itself is also starting to gradually lose strength. There's also a localised surface trough near the northern part of the MNC which is helping to enhance the rainfall near that area.
There's still some background upper support from the upper low and we're in the deep NE to N flow on its eastern side but most rainfall over the next several days for SEQ should be more in a convective mode with no strong focal points i.e. day after day of a humid northeasterly flow, a mix of sun and clouds, and some sporadic shower/storm activity that can pop up at any time of day or night. But since the vertical wind profile has become a bit more conducive to training, any locations which get under a narrow heavier train of convection could get hefty rain rates.

In other news, here's the "Dorrigo Falls" at the moment:



gee i wonder if they will still be pumping next week, so tempted to go down there for a day trip
 

Homer

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All the pineapple fell off.

But in seriousness, the real heavy stuff for the metro doesn't come til very late/overnight. Fresh convection up north

Haha, yeh, that's what I was thinking. The pineapple stuff (possibly capsicum and onion as well) as well as the overnight rain forecast. Sat pics, lightning tracker and radar still have rain and storms pushing southwards.
Currently, just some disappointing light rain here from that pizza that looked so promising earlier. Must have been a Dominos rain band.
 

Seabreezes

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More heavy showers here since my last update. There's now been 161.2mm since 9am.

A showery / drizzly mix at the moment. The heavy showers may possibly be over. There's still some beefy showers offshore, but it currently looks like those may slide away to our south.

December has also overtaken February as the wettest month of this year here. 529mm has fallen so far this month, compared to February's monthly total of 509.6mm.

Sherwood Bridge (upstream of Kempsey)
221.jpg
The river continuing to rise
221 (2).jpg
 

Gleno71

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I thought i would share a few more pics of the event before the thread wraps up . Thanks to everyone's contributions and charts etc. It's been great to be a part of this weather community. Most of these images were taken with the phone believe it or not, and edited in lightroom so quality will be not on par. A few also are with the camera. The cumulus cloud structure was the best i have seen in this region for a while, like the old days.
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Homer

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I thought i would share a few more pics of the event before the thread wraps up . Thanks to everyone's contributions and charts etc. It's been great to be a part of this weather community. Most of these images were taken with the phone believe it or not, and edited in lightroom so quality will be not on par. A few also are with the camera. The cumulus cloud structure was the best i have seen in this region for a while, like the old days.
_C150053.jpg
20201215_070014-2.jpg
20201215_071143-2.jpg
20201215_091958-2.jpg


Great pics Gleno, as always.
Huh? I'm not sure this thread will wrap up soon. Title says till the 20th and in the title it includes Eastern NSW.
Just because it is somewhat weakening up north, it doesn't mean it will end elsewhere.
Remember, this isn't just a SE QLD thread. It's an Eastern NSW thread as well.

I'm looking forward to seeing more reports re rain and storms, possibly severe, over the next 5 days. Hope everyone stays safe.
There's also continuing flood issues that are ongoing.
Plenty more in this baby yet.
 

Gleno71

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Great pics Gleno, as always.
Huh? I'm not sure this thread will wrap up soon. Title says till the 20th and in the title it includes Eastern NSW.
Just because it is somewhat weakening up north, it doesn't mean it will end elsewhere.
Remember, this isn't just a SE QLD thread. It's an Eastern NSW thread as well.

I'm looking forward to seeing more reports re rain and storms, possibly severe, over the next 5 days. Hope everyone stays safe.
There's also continuing flood issues that are ongoing.
Plenty more in this baby yet.


thanks mate, completely forgot it was a joint thread !!!
 

Ken Kato

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I thought i would share a few more pics of the event before the thread wraps up . Thanks to everyone's contributions and charts etc. It's been great to be a part of this weather community. Most of these images were taken with the phone believe it or not, and edited in lightroom so quality will be not on par. A few also are with the camera. The cumulus cloud structure was the best i have seen in this region for a while, like the old days.
_C150053.jpg
20201215_070014-2.jpg
20201215_071143-2.jpg
20201215_091958-2.jpg
Fantastic photos gleno, I can't tell that they were taken on a phone. I know the photos and video above that I recorded last year aren't from the current event but they just go to show how spectacular it can be around places like Snapper Rocks when the sea turns angry like they just did with this system.
 

AshestoAshes

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Shower activity starting to pick on the Central Coast beginning to pick up, i expected that earlier band that dropped decent amounts on the hunter to make it over here, but alas no. Typical moist NE feed though it's being picked up as showers over the escarpment . Also do we count this event as a Black Nor'easter given the NE flow which has been backed by a strong high + upper trough combo?

EC had a some thunderstorm impacting Sydney around 11pm yet to believe that will happen though. Humidity really has been something though rare to see a dew point of 20 maintained right through the day from 8:30 to now, luckily it only maxed out at 25-26 around the city.
 

Ken Kato

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Mr Miskelly nails the summary of this system in a single Twitter post (apologies if already posted?):
Impressively big area of anomalously high PWAT values extending right down to far southern NSW too and merging with that associated with the front and trough moving across VIC/TAS. In fact, EC has PWAT values approaching 55mm along some parts of the MNC and extending along parts of the central coast although some of the existing convection in the model might be contributing to that. Quite climatologically high nevertheless and would increase flash flood potential under any storms especially around the MNC.
 

Sideny

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Shower activity starting to pick on the Central Coast beginning to pick up, i expected that earlier band that dropped decent amounts on the hunter to make it over here, but alas no. Typical moist NE feed though it's being picked up as showers over the escarpment . Also do we count this event as a Black Nor'easter given the NE flow which has been backed by a strong high + upper trough combo?

EC had a some thunderstorm impacting Sydney around 11pm yet to believe that will happen though. Humidity really has been something though rare to see a dew point of 20 maintained right through the day from 8:30 to now, luckily it only maxed out at 25-26 around the city.

Radar starting to intensify a bit so wouldnt be suprised if we see some storms.
 

Falling_Droplet

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Yesterday's maximum temperature ended up as 26.2 C at 8:36 am this morning as the temperature rose in the morning that was higher than the temperature during the day yesterday. 3.5 mm of rainfall since 9am from light to moderate showers later in the morning.

In the mid morning the temperature temporarily fell with the rainfall and became cool before easing back to near average by the early afternoon as the temperature rose but was a little variable. From the mid afternoon the temperature generally fell close to average before falling more steadily from the late afternoon and became slightly warm tonight. Dew point became moderately high in the morning after rising earlier in the morning, then fell a little before rising later in the morning. In the afternoon the dew point generally fell while easing to slightly above average, stabilised in the late afternoon, rose a little early tonight before stabilising during the rest of tonight, while remaining slightly above average.

Relative humidity was slightly above average in the morning, that became very high later in the morning as the relative humidity rose quickly to a high of 95% before generally falling through to to the mid afternoon. Relative humidity have been slightly above average since the early afternoon. Calm winds in the morning, became light and variable in the mid morning, N to NNE winds in the late morning before NNE to ENE winds in the early afternoon. During the rest of the afternoon and early tonight were E to NE winds before calm winds from 8pm.

Last 24 hours:

rain 2020-12-15.PNG
temp 2020-12-15.PNG
hum 2020-12-15.PNG
wind dir 2020-12-15.PNG
 

Weathertraveller

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Im suprised about the amount of cloud cover in SE QLD. The upper temps are warm and a weakening upper trough in NSW. Normally we get mainly fine conditions in a NE flow when the air is stable upstairs? Am i missing something ?
Thankyou for uploading the pictures Gleno, they are fantastic as always. According to the radar there's lots of rain off shore, been cloudy here since daybreak, and we've had a few showers from the north east this morning and more to come it appears.
 

Ken Kato

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Im suprised about the amount of cloud cover in SE QLD. The upper temps are warm and a weakening upper trough in NSW. Normally we get mainly fine conditions in a NE flow when the air is stable upstairs? Am i missing something ?
Midlevel temps being warm only infers a stable atmosphere if the air below isn't warm and/or moist enough to become unstable and start rising.
In this morning's case, there actually is weak instability along the coast (but much higher offshore) and a fair bit of moisture in the lower levels helping with buoyancy of air parcels. Backing winds with height, some background help from the eastern flank of the upper low, and some wind convergence as the synoptic scale offshore NNE'lies run into the almost stationary air near the coast might also be helping.
 

Ken Kato

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upload_2020-12-16_7-59-46.png


Thanks ken . Does the sounding show this ?? Just trying to understand different weather variables if that makes sense

Yep @Gleno71 - see above for a point around Southport for 6am this morning. Yellow shaded area = CAPE (but only using the assumption that parcels are rising from 1000hpa with that temp and dewpoint and can make it up to the level of free convection. You can see a fair bit of moisture in the lower levels as well as some backing winds with height.
 

Falling_Droplet

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A brief light shower at 4am. Slightly warm temperature that was warm later in the early hours and in the early morning after the minimum temperature was reached at 2am and then rose during the rest of the early hours before warming more quickly this morning. Dew point fell a little in the first 2 hours of the day before rising since then and was slightly above average before becoming moderately high from later in the early hours. Relative humidity have been near average that rose slowly in the early hours to a high of 98% that has started to fall this morning. Wind have been calm.
 

Michael Hauber

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Im suprised about the amount of cloud cover in SE QLD. The upper temps are warm and a weakening upper trough in NSW. Normally we get mainly fine conditions in a NE flow when the air is stable upstairs? Am i missing something ?

The normal NE flow over SE Qld is often ridge dominated as a high pressure system starts to weaken/move away. The next trough is approaching, but it will turn the winds NW by the time it gets close enough to clear the ridge's influence out. So generally quite fine conditions with broad scale descending air under the ridge. The surface might be quite muggy and humid, but descending air from dry uppers makes for a shallow layer of moisture.

In contrast we currently have the remants of an upper low and associated trough sitting in the region, so while the air is not particularly unstable anymore, it hasn't really stabilised. A clue to the difference from the sounding Ken posted is that the dew point drops away quite slowly with height. A more typical fine weather NE sounding would have the dew point drop far more rapidly as height increases, and the wind will usually turn westerly at a much lower level - maybe somewhere near 850hp. Rather unusual not to have any westerly component at all from 500hp and down.
 

Seabreezes

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183.2mm fell here in the 24hrs to 9am. Some more showers fell overnight / early morning. A little bit of thunder about early this morning as well.

The year-to-date total currently stands at 2012.8mm. This now makes 2020 very slightly wetter than 2011 (which brought 2008.6mm). It is the wettest year since 2009 when 2110.0mm fell here.
The river continuing to rise
221 (2).jpg
The Macleay River at Sherwood bridge this morning:
221 (3).jpg


Moderate flood warning current for the Orara River.
Minor flood warnings current for the Wilsons, Richmond, Clarence, Bellinger, Nambucca, Macleay, Hastings, and Camden Haven Rivers.

Three wettest BOM gauges in the 24hrs to 9am were:
195mm Mundays Lane
192mm Maria River
171mm Seven Oaks
All of them being more-or-less under the same train of heavy rain that affected here.

The Severe Weather Warning was cancelled this morning.
 

Auzza

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Grafton, NSW
The weather is favouring us today. Just cracked 50mm since 8am from a continous thundery band. Grafton Research Station has hit 81mm since 9am and about 400mm for the month so far. To put that into perspective, since 2002 our wettest December total was in 2014 when we recorded 209.8mm for the month. Will likely double that by the end of the week if not today.
 
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