Topic: Coral Sea Lows - Major Flooding NE NSW / SE QLD (incl Kyogle, Lismore, Coraki): 29 Dec to 7 Jan 2008

[Mike]

Seeing how this low is expected to strengthen to about 997hpa and become an extra-tropical low during the weekend and it's hugging the east coast I've pre-empted a thread in case some severe weather comes from it.  So those who are in that region might want to stick all their posts here...

Mike

[Michael Bath]

Have had fairly regular gusty showers in between areas of drizzle since Sunday afternoon.

24.2mm to 9am 31st, 47.0mm to 9am this morning and 24mm so far today.

The models now seem to be agreeing on an increase in the showers to rain by Thursday and Friday over SE QLD and NE NSW as the low moves south and closer to the coast.  The creeks are primed by the 150mm or so we've had since the 29th so it wont take much to cause some flooding.

[Gambit]

There is some water sitting on ovals and low lying areas in Lismore, as Michael has said everything is primed so a couple more days of rain like we have had and floodage!

Most of the Storm water culverts in town are at least 3/4 full and flowing quite fast, the Wilson river is also up noticeably.

I did see the SES out in their boat on the river this afternoon; perhaps making an assessment?


Also, is a flood considered a Severe Weather Event? Please go to the following link for further discussion on the definition of severe weather and severe thunderstorms:

http://www.australiasevereweather.com/forum/index.php?topic=685.0


Cheers

Mathew

[Michael Bath]

Yes - flooding is severe weather.

Up to 130mm for the month already.

47.0mm to 9am 1st
37.6mm to 9am 2nd
42.0mm to 9am 3rd
and 7mm already today (in the past hour) - looks like the rain has set in with radar showing deep convective clouds well out to sea moving towards the SE QLD/NE NSW coast.

Going to be an interesting 48 hours.

[Steven]

37mm to 9am, thats a nice total from the intermittent showers we've had, though they have been very squally.

Wind has died down slightly from yesterday though.

[Michael Bath]

NSW BoM have updated their warning.  Have had the local SES on radio this morning warning of flooding as well. Edit - BoM have a flood watch for the Wilsons and Richmond rivers too (Lismore area).


NSW SEVERE WEATHER WARNING
for Locally Damaging Winds, Damaging Surf, Flash Flooding
For people in
Northern Rivers and Midnorth Coast,
Issued at 11:00 am on Thursday 3 January 2008

Synoptic Situation: 9:00 am EDT Thursday
A complex low over the Coral Sea is expected to move west towards the Queensland coast during the day. Steady rain, heavy at times, over the area is expected to continue during the next twenty four hours. Winds are also increasing, with the exact strengths dependent on the location and strength of the low.

This is an update of the warning issued at 4:10 pm Thursday

Winds may average over 65 km/h with peak wind gusts in excess of 90km/h along the coastal fringe north of Yamba this afternoon and overnight.

Continuing rain over the Northern Rivers region is likely to lead to local flooding.

Damaging surf conditions, with waves exceeding 5 metres in the surf zone, are likely to produce significant beach erosion between Tweed Heads and Smoky Cape later today and overnight.

[Michael Bath]

Flood warning for the Wilsons River now. Had another 40mm here since 9am though nothing heavy - just constant light to moderate falls.


MINOR TO MODERATE FLOOD WARNING
For the Wilsons River at Lismore

Issued at 4:16pm on Thursday the 3rd of January 2008

Flood Warning Number : 1

Up to 150 millimetres of rain has fallen during the past 48 hours to 3 pm Thursday [3/1/2008]. Further heavy rainfall is expected over night which will result in minor and, possibly, moderate flooding at Lismore during Friday.

River Height Predictions


Lismore  - exceed minor flood level [4.2metres AHD]  Friday [4/1/2008]
           morning - probably around 6am to 9am
         - reach moderate flood level [7.2 metres AHD] Friday afternoon
           or evening with further predicted heavy rainfall over the
           next 24 hours
         - further rises are possible if recorded rainfalls are heavier 
           than predicted

[Michael Bath]

108mm in the 24 hours to 9am with some places (in the flood warning network) getting over 200mm. It's going to be very interesting if the next rain "blob" east of the Northern Rivers impacts here later today. Will be in for major flooding. Some BoM rain totals to 9am:

NORTHERN RIVERS:
Alstonville 106 Ballina 139 Ballina Ap AWS 153 Byron Bay 149
Cape Byron AWS  95 Casino  37 Casino Ap AWS  44 Evans Head AWS   9
Grafton  21 Grafton AWS  24 Green Pigeon 175 Kyogle  89 Lismore 100
Lismore Ap AWS  62 Mullumbimby 137 Murwillumbah 101 New Italy  42
Nimbin 158 Tweed Heads 105 Woodburn  43 Yamba  28

A few flood photos taken within the past hour in my local area - McLeans Ridges to Eltham and the creeks feeding into the Wilsons River (which I could not get close to due to all the flooded roads).

[Mike]

Not good for the poor souls who are selling their stately four bedroom home eh?!  A lot of water in the area there, what is the peak height of the river mentioned there Michael?

Mike

[Michael Bath]

The Wilsons River at Eltham (about 2ks west of those last few photos) was 9.17m at 11am - about 8 metres above its normal level. That is classed as moderate flooding I think for there - but close to major. It has not peaked yet.

You can check the river levels here - under the Wilsons River heading:

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDN60140.html

[Mike]

Eight metres above the normal level?  I would class that as major!  What about your specific area Michael, has there been significant stream rises that you have seen?  Does this runoff of water affect your area close to home?

Mike

[Michael Bath]

It is all very close to home - these are my 'local' creeks - within a few to several ks. You can see the river in flood on the webcam (between showers which block the view somewhat)

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

Click on the left image to see the Wilson River just east of Eltham.

We live at the top of the ridge and have a few small streams at present running down into the valley you see on the webcam.

The levels at which the rivers reach major flood varies quite a bit. In Lismore itself it's 9.7m. Lower downstream on the main floodplain major floods may be around the 5m mark. Depends how deep a gully the river normally flows through.

This is the one to watch - two rivers meet in the Lismore central business district. The Wilsons River comes from the NE on that Google map. Lismore is one of the most flood prone cities in the country.

http://www.bom.gov.au/fwo/IDN60231/IDN60231.058176.plt.shtml

Check here for more info and pics of major flooding that happened in June 2005

http://australiasevereweather.com/storm_news/2005/docs/200506-03.htm

MB

[Peter J]

To all those in northern NSW getting all that lovely rainfall, can you send some to the Central North East and Western region of Victoria (especially the catchments) - we could do with a drenching. We have had no rainfall since Dec 20th floods.

PJ

[Richary]

MB

I used to live at Coraki years ago (1979-1981), then my parents stayed there then Lismore near the Showground for a while. So I know all about north coast floods. At Coraki it was only a problem if the Richmond and Wilsons peaked at the same time. We were a bit out of town and had to row the boat in for supplies!

[Mike]

Let's hope that it does not cause too much damage farming wise.  The catchment areas will benefit no end one would think.  It's been a varied and around-about season has it not for this area?

Mike