Australian Severe Weather Forum

Just noted a severe weather warning on the Bureau site that talks about some very heavy rain between Coffs Harbour and Wooli.

Top Priority for Immediate Broadcast
NSW SEVERE WEATHER WARNING
Flash Flooding,
For people in
Northern Rivers and Midnorth Coast, especially around the Wooli to Coffs Harbour region.

Issued at 8:50 pm on Saturday 2 February 2008

Synoptic Situation: 6:00 pm EDT Saturday

Very heavy rain is expected to cause flash flooding in the Wooli to Coffs Harbour area, where local automatic rainfall reports have reported nearly 100 mm of rain in the past hour. Further heavy rainfall is likely over the next couple of hours at least.


The river height page shows the following 3 hour rainfall figures for some of the Wooli River.


 
Station Name
   
3 hours to                          12am   3am   6am   9am   12pm   3pm   6pm   9pm
Wooli Caravan Park               0.0     0.0    0.0    6.9     2.5     4.6    26      136
Wooli (Browns Knob)             0.0     0.0    0.0    1.4     1.6      2.0   3.9      61


Don't know if this was forecast. Not storm related looking at StormTracker, just a localised area of very heavy rainfall that from the radar is moving in from the NE.

Given the rate of rainfall and probably the slow movement, this is a thunderstorm/cumulonimbus as it does take a large volume of moisture aloft to substantiate such intense rainfall rates. You do not necessarily have to experience thunder or lightning locally. At night time, the same cumulonimbus may create lightning flashes.

Having said this, I did see radar and some areas of consistent rainfall blobs that were moving from the east over the Mid North Coast and I think also Central Coastal districts as well. Incidently, there was some instability in northern NSW generally yesterday.

Regards,

Jimmy Deguara

A very coastal event which happens now and then with these coastal troughs creating an area of convergence. Many locations between the border and Coffs Harbour have received 100mm to 150mm with the highest appearing to be Wooli caravan park with 254mm to 9am.  Just 38mm at my place though much more within 10ks.



Conditions were generally cloudy yesterday afternoon with low cloud and large cumulus moving in from the ENE initially then more from the NE later. I didn't observe any thunder locally though there was a thunderstorm cloud to the far north late arvo.

Marrickville has just received 72mm of rain in the last hour , it has been hammering down and has flooded local streets ,
at one point i noticed strong scud upmotion , probably the local escarpments . it must have been fairly local because no where else has recorded anything like that..........hmmmmmmm maybe bird been urinating in my rain guage

first photo shows Illawarra Rd


the second shows the area of upmotion in the centre , a light microburst a couple of kms to the NW mave have interacted with it?

nick,

We have just had the first main heavy rain area though not prolonged. I did see the heavy rainfall associated with the slow moving cumulonimbus over the eastern parts of Sydney.

However, at 11:50am, I see the development and intensification of a major core to my northeast. With all this moisture pumping in and uplift due to instability, widespread heavy falls are inevitable.

More for the catchments?

Regards,

Jimmy Deguara

Great photo of the flooding Nick.

33mm here in the past hour to 1pm EDT. Coming straight down, no breeze at all. There was hardly any rain 9am till noon.

A bit over 50mm in about 2 hours and you can see the effect on the creek in the valley below my place:





The Wilsons River at Eltham has risen 4 metres since the rain started last night. Eltham is on the right side of that webcam view.

http://australiasevereweather.com/video/webcam.htm

Rain event Sunday 3 February 2008

I was at Castle Hill and I observed a few lightning flashes (within cloud) and heard occasional rumbles of thunder around 11.30 am to 12 noon.

The storm / rain cell was very slow moving and appeared to weaken over NW Sydney after 12.30 - 1 pm. Looking at rainfall figures for Sydney at least to 5 pm 3/2/2008:-

Marrickville 79 MM.
Avalon 76 MM.

Highest totals in the city.

This would have occurred from separate storm cells or intense rain cells.

Castle Hill, Baulkham Hills and vicinity scored 30 to 31 mm, Seven Hills 24 MM.

Falls were lighter elsewhere and in many far western and southern suburbs, very light falls occurred.

While doing this observation, I have noted a large rain cell containing embedded storm cells in an area just north of the Hunter Valley that appears to be producing significant rainfalls in the affected areas. Moving in a southerly direction. This might be of interest to anyone in that area.

I have also identified several other storms with significant rain near Corowa, NSW / Vic state Border indicating that this system is also producing rain in parts of inland New South Wales as well.


Harley Pearman

We had some heavy rain for a while near Parramatta this morning. Looking at the radar it was all from onshore winds from the NE so figured I would go west towards Penrith for some bushwalking. Well it certainly got that far as well, and I got soaked. Oh well. Brief heavy showers in between continual light drizzle/showers for most of the day.

The news reports that a 15 yo kid has been washed away while using a boogie board at a flooded creek at Woolgoolga near Coffs is annoying. Knowing my ex girlfriend's 14yo son he would have been quite likely to be one of those doing that sort of thing there. So it could well have been one of his mates.

Storm Report & Photos. 3rd Feb. 2008 Upper Western/North West Region
Hi guys,
Well we finally had some luck excitement last night with numerous storms in our vicinity. If you happened to see the lightning tracker yesterday evening around 7pm you would have seen the masses of activity kicking off around the Bourke and Moree area. We were definitely in the middle of it just as the activity kicked off in the late afternoon/evening with several large, highly active storms visible around us.
We seemed to be right in the centre of all the weather as cells built, broke into HP cores and became highly active with a nice flurry of CG activity. These were all moving rapidly away from us with the strong N-NE winds but we still got a few shots due to a bit of back-building from a very moist inflow.
The photo below was a typical scene in any direction around town after 7pm. (there were a couple large, dark & nasty looking storms earlier on in the day but were all pushing the 40klm mark in distance from us.


This was a large storm developing somewhere between Collarenebri and Moree at 8pm. I contrasted this photo a little to bring the structure out somewhat. I did notice a few CG firing out of this monster now and again.

 
The two photographs below were taken from Snowy Brown's opal fields not too long after each other at 8:34pm. This is looking generally South from town and basically in the direction that the storms were traveling away from us. It is great to see some decent activity AT NIGHT and not during broad daylight as has been the case for the last couple months!



As per usual, Russ and I did miss several brilliant, and quite close CG that emitted from a cell that formed just behind us. It was one of those evenings where you just didn't know where to point the camera!
I'll get confirmation and collaboration of a few rain totals from the system asap.
Cheers and take care.
Shauno

Rain event Monday 4 February 2008

The rain event across Sydney is beginning to produce some significant rainfalls for the city. From 9 am Sunday morning 3/2/08 to 6 pm Monday evening 4/2/2008, the highest rainfall totals across Sydney include:-

Avalon 125 mm
Avalon Beach 129 mm
Arncliff 117 mm
Terrey Hills 86 mm

These are the highest cumulative totals for Sydney for this period.

Other healthy totals include

Seven Hills 66 mm
Castle Hill 56 mm
Penrith 55 mm

Areas around Blacktown, to Baulkham Hills have had 60 to 70 mm. This region has received the second highest cumulative totals for the metropolitan area for this period.

The remainder of the city has received falls of 30 to 50 mm but varies between localities. With the cumulative totals as they are and with more rain falling, this is becoming a significant February rainfall event.

I have also looked at rainfall totals on the North Coast as well and some localities have had up to 175 mm and I am aware of a flood warning at or near Coffs Harbour.

Further, anyone reading the Brisbane newspapers eg Courier Mail on the web site would have become aware of a flood emergency in portions of southern Brisbane from heavy rain as well. There is a severe weather warning for flooding near Brisbane as well in addition to what is happening further south.

Harley Pearman

Hi all,
Yesterday (4th Feb.) was very interesting to say the least, even though the shear and steering winds were supposedly low? A storm that formed just to the NE of town around 1pm was severe to say the least and very long-lived! It hit the cap not long after forming and threw out the best anvil I've seen in years due to extremely strong updrafts. Lightning was constant and I don't think there was a break in the thunder at any one point in time! This storm would've caused significant flooding between here and Collarenerbri (it was only 25k's or so from the edge of town). It was still present and very HP at 3pm but shifted off to the SE with the next line of storm activity to roll in around 4:30pm. These cells were typical of the recent patterns, but, were holding structure throughout their duration, so this lead me to believe the shear and steering winds were not so weak in this region? Storms were converging right in front of Russ and I while out photographing and dropping massive totals of rain in short periods, also seeing ACTUAL hail for once, though only about 3mm in size lol!

I have a few shots that I will post of an interesting development 20k's North of where we were photographing that looks very intriguing, it may only be scud cloud but it's the most funnel like structure I've ever noticed out this way, it was definitely turbulent enough and lasted 3minutes or so. 

The lightning was everywhere as usual and I almost thought we'd lost Russ at one point due to a powerful cannon-like CG that must've only been a few hundred metres or so from him. He was between myself (standing 50mtrs back behind him at the time) and the bolt so it looked to me like he was hit! My heart was in my mouth at that point, I headed towards him but to my relief I soon saw him quickly get up and start walking towards me.

A storm cell that came directly across town at 5:20pm dropped 40mm in 40mins and caused some minor flooding. I'll post photo's and full report asap as our site being a little stubborn in the upload department today.
Cheers guys.
Shauno

Hi,

I must say that I was surprised yesterday morning in regards to flooding - well anticipated flooding. I had to drop something off and also get to school for an early meeting. After setting off on another route, the road was flooded. So turning around I decided on my usual route. On top of the hill I could see some water in areas not normally flloed -w ell when it is flooded here the road is normally cut off. Having only received 21mm of rain overnight, I felt the road should not have been flooded. A car flashed me but regardless I wanted to see for myself.

Well the road was flooed but it was quite high - higher than I have seen on my whole time seeing the Grange Avenue flooded. And it was flooded in to regions including the bridge itself. Explanation?

Well the rainfall statistics speak for themselves. The rainfall had falledn in the upper reaches of Eastern Creek with as much as 130mm of rain and even more in some areas. This would explain the above average flood level despite the far lower totals in our region. The floodwaters would have taken a few hours to peak downstream. Quite impressive I must say!

Regards,

Jimmy Deguara

Hi Jimmy,

I know the area well from way back, something to consider is the build up as Sydney expands, there used to be fields, it is not surprising to see creeks and rivers going up quickly, some in normal times are hard to find/spot. I have lived on the Prospect Creek Lansvale, the Hawkesbury River and traveled extensively in those days, the Georges and Nepean Rivers systems I am familiar with, including back roads and detours.

 

4th Feb. 2008 Upper Western, North West Area. Storm Report & Photos

Hi guys,
The 4th started off with a nice looking storm building around 12pm then breaking the cap at 12:35pm to settle down and reach full phase at 1pm-ish. This storm had the best anvil I have seen in a very long while. The structure held up well and lasted for well over 3hrs as it continued to cut a path of torrential rain just North of the Ridge. I ended up taking 10 photos and a 30sec. movie capture just as my battery died (my spare was still on charge from the night before) but luckily I did catch the anvil mammatus before it spread out over a wide area.


Once the next line of active/squally storm cells moved in at 4pm, Russ and I positioned ourselves to the NE of town. These cell came with rain and lightning abounds! Many cells dropped rain in the area of 1mm per minute which is substantial as they stuck around for an hour or two but moved fairly quickly with a strong south-easterly push. The panorama below was one of the first cells of the afternoon moving across town in a SE to NW line and also brought tiny, 3mm hail for a brief moment.


The next two photos are the most interesting. The first, I took at 4:34pm when I suddenly noticed a formation on the rear base of a large storm to our North. This seemed to be around 20-25k's distant (I so wished it was closer!). I watched it closely over the next minute or so as it became larger and seemed to rope out with a long extension curving towards the ground (I contrasted up a little it in the inset of the second photo). This feature lasted 2-3minutes before blending in behind the heavy rain core of the closer storm.
Moderators: I had to show these at 1000pxls wide to see the details. Please let me know if this is too large!)



I'd like to know a few thoughts on these shots, any info or comments would be very helpful
A few more photos and panorama's from the day here- http://www.ridgelightning.com/gallery2/main.php?g2_itemId=1823
Kindest regards,
Shauno