QLD & NSW significant rain event: 2 to 6 September 2008

[Jimmy Deguara]

Models are indicating a very exciting scenario with a deepening trough and cyclogensis occurring in central eastern NSW. The end result is for a significant widespread rainfall event. Certainly worthy of discussion - perhaps someone with a bit of time could post some rainfall charts in this thread.

regards,

Jimmy Deguara

[Peter J]

This event may be preceded by one due over this weekend - that could provide some nice falls in QLD NSW and VIC. Temps are a bit too high for snow development though.

Big Pete

[Shaun Galman]

[Michael Bath]

GFS and EC are going for significant falls over wide areas. GFS sends a coastal low very quickly SSE during Friday while EC keeps it near the NSW/QLD border. LAPS doesn't go out that far but has a stronger ridge up the east coast so may not form a coastal low at all.

An interesting few days ahead.


GFS 20080901 12z





EC 20080901 12z

[Steven]

GFS has progged for falls up to 100mm in SE QLD on Thursday and Friday and up to 50mm for the catchments. Bring it on!

MB edit: Already had this topic Steven which covers all areas the rain will affect.

[Michael Bath]

Today's model runs suggest a low is likely to form close to the SE QLD coast north of Brisbane late Thursday. The question will be where exactly - and how quickly it will move away....
Expecting about 100mm for here over 48 hours, double that if the low gets in the sweet spot

[Rodney Wallbridge]

Gasp and Laps, both playing with a coastal ridge with an offshore surface trough this  morning. GFS and EC have taken the turn towards a fairly sharp little ECL .The  high parked in the Tasman sea may be a bit on the weak  side to sustain anything in a position for very long. All models have a very swift motion of this system.
I have been failry impressed with the warmish SST's right along the QLD coast and out off to the ditch around here....Coral sea etc has been fairly cloud free leading up to this event too. Lots of moisture a possiblity if this system can feed off it. Thursday night looks very wet over SE Qld and inland areas.
I'd like to see the bulk of this Low/Trough if it can happen, north of Brisbane on friday 10am. Totals of up to 200mm for Nrth NSW would be certain then . I agree with Michael watching with interest. Moisture has been building in the Sky here the last few days as well.

[Michael Bath]

Here's a comparison of the three models for future reference. As Rodney mentioned the Australian models are quite difference to GFS and EC. The shape of the Tasman High will be a important factor: whether it strengthens a ridge up the coast, or instead cradles a low.


GFS 20080902 12z






EC 20080902 12z






LAPS 20080902 12z






GFS develops the low inland of the QLD coast and crosses it over the NSW/QLD border. It will be an interesting situation if this occurs. Events like this in September are very uncommon.

[James]

Both 0z LAPS and MLAPS have joined the party so to speak. In fact both LAPS models are now going for a low to spin up over central QLD overnight tonight and continue moving S towards Cunnamulla during Thursday before losing puff Thursday night. However the trough continues towards the coast Friday before developing into a low again off the coast during Saturday. Comparing LAPS to GFS/EC it delays the ECL 24 hours. Interesting how the LAPS models have a low developing inland tonight. I will be impressed if it comes off however EC/GFS looks a little more realistic.

[Rodney Wallbridge]

Gyday all, surface Obs over the QLD interior right over to the coast in the southern areas show a fairly broad trough this morning.I'd really hope the Low if it forms delays forming untill as late friday as possible when it has the potential to form over water. The potential of coastal falls reaching in to Brisbanes dams looks increasingly positive.All Models have boosted Precip totals which is a good thing. Sat image perhaps could have kept the cloud in QLD more its allready well into northern NSW. I think maybe this shows the nature of how fast this system may move?

[Harley Pearman]

Significant rain event 5/9/2008

The east coast low moving down the New South Wales coast has delivered some heavy coastal rainfalls for New South Wales especially in areas between Newcastle and the New South Wales / Queensland border.

On 4/9/2008 Seal Rock received a fall of 100 mm.

On 5/9/2008 the heaviest rainfalls in New South Wales occurred in 2 regions being the Richmond Tweed and the Coffs Harbour region. For the period 4/9/08 to 5/9/08 some of the the top falls for this region to 9 am were:-

Richmond / Tweed:

Doon Doon 112 mm, Limping Wood 105 mm, Huonbrook 93 mm, Green Pidgeon 89 mm, Dunoon 80 mm, Eungela 78 mm, Alstonville 75 mm, Nimbin 74 mm, Coolangatta 68 m, Ballina 62 mm and Tumblegum 58 mm.

Rainfalls tapered off for this region after 9 am.

Coffs Harbour:

Dorrigo has had the highest fall being 143 mm, Dorrigo Alert 132 mm, Bowra Sugarloaf 130 mm, Lowanna 130 mm and Girralong 106 mm. The hills behind Coffs Harbour and areas around Dorrigo are the wettest areas in New South Wales and this has been demonstrated again.

Lower totals include Thora Post Office 86 mm, Belibrook 70 mm, Lower Creek 62 mm and Red Hill 58 mm. Coffs Harbour urban area had 63 mm.

Since 9 am to 5 pm 5/9/08 rainfall totals for this area include Girralong 130 mm, Thora 100 mm, Bowra Sugarloaf 81 mm, Lowanna 70 mm, Upper Darkwood 61 mm and Red Hill 58 mm.

Orographic rainfall is common along the eastern escarpment of the Great Dividing Range which has occurred during this event, especially in this area.

During the period 9 am to 5 pm 5/9/08 the highest rainfall tally for Sydney include Sydney Olympic Park and West Pennant Hills 18 mm, Parramatta 16 mm, Kings Langley and Terrey Hills 15 mm. Falls of between 10 to 15 mm have been common with heavier totals north of Sydney.

The most significant totals for 5/9/08 are restricted to the coastal strip from Sydney north to south east Queensland.

Harley Pearman

[Richary]

Hi guys

17mm from this event at Rydalmere to 5pm today which is consistent with the Olympic Park and Parramatta figures. Dont really want to walk outside and check the guage now as it is consistent showers though not heavy rain all evening so far. Was planning on camping near Newcastle for a night away tomorrow but might leave that until a dry weekend I think.

Some good falls though, Dorrigo certainly gets it! The waterfalls would be running nicely on the drive down to Bellingen at the moment.

[Jimmy Deguara]

The latest models indicate the potential for heave falls from Sydney to Seal Rocks. The low should venture further south than anticipated in previous models and that should continue the rain for at least say another 12 hours or so. @3 have had 26.4mm of rain up until this morning.

We'll see what happens today as the low deepens.

Regards,

Jimmy Deguara

[Michael Bath]

Received 56mm of rain here at McLeans Ridges from the event. 35mm of that fell in the 12 hours to 6.30am 5th Sep before a band of torrential rain passed through the region during the following hour. Many of the locations mentioned in Harley's report would have picked up close to half their totals during that morning deluge. There was some flash flooding as a result.

It appears that a region of convergence with very large cumulus and embedded storms was the cause.

Later in the afternoon some weak thunderstorms formed with isolated showers around the Northern Rivers.

Michael

[Shaun Galman]

Hi all,

We received a nice rain total here of 36mm between Thursday the 4th and Friday the 5th adding to the much needed 26mm we received during last weeks rain & isolated storm event.

Seems like the usual change of season weather flurry, lets hope it continues over the coming weeks and on into the higher temperature regions of late spring, early summer and make for a few decent storm setups!