Topic: NE NSW / SE QLD Severe Thunderstorms and more flooding : 4 - 8 Nov 2009

[Antonio (stormboy)]

Hey guys yes I know that I have started this topic a little early but have any of you looked through the latest Cape maps? Well if not you will notice that the attached one below has more colour than I have ever seen on a Cape map of NSW usually I see these colours in Darwin region.
 
So I have come to the conclusion that there might be a possibility of some potentially severe thunderstorms possibly in the Grafton area as well as the northern tablelands. Thunderstorms are also forecast for Tuesday but the cape is not that great.

storm boy

[Antonio (stormboy)]

Ok just had a check on BSCH and the maps of Thursday and Friday are also showing instability at a huge level.

[Antonio (stormboy)]

Well folks the BSCH Cape chart has gone down for today’s forecast but Thursday looks to be very promising in the western parts of the northern rivers and also the whole of the northern table lands looks like it will have something good to develop over them. The forecast shows thunder possible right till Friday even Saturday so that will be good.

storm boy

[Clayton]

Hey

I have been looking at the cape for tommorrow and looks promising with high cape levels for warwick-beaudesert QLD and I am most likely going to go to Warick or somewhere near there tommorow.

I was Just wanting to know what everyone else will be doing tommorrow and if I am heading to the right place as this is my 1st time.

Clayton

[DanTheMan]

Hey Clayton

My 1st proper time tomorrow as well, and I think I'll be heading near Wawrick also, looks like its going to be bloody good day! Right where that area of high CAPE is, there is also a bullseye of about 175mm accumulated precipitation!
Keep an eye for silver Mitsubishi Pajero with some guy aiming his camera at the sky!

[Michael Thomas]

I too am looking forward to tomorrow. In my mind, it is actually looking better for SE Qld than a few days ago when it looked like most of the action would be further south. There are a few things I like about this setup but a few things that concern me too.

Pros- Potential for high CAPE - dew points are in the 18C-20C range along the SE Qld coast. If we get temps in the high 20's to low 30's with dp in the high teens we could get CAPE > 2000 j/kg. Potential triple point at the surface and nice deep NE'ly low level flow.

Cons- Moisture is quite shallow at the moment. Despite the high dp's along the coast, it dries out pretty quickly heading west. This is usually indicative that the moist layer is pretty shallow. Last nights Brisbane sounding supports this where only the lowest 50 mbar was moist. Finally, mid and upper level flow is weak.

I am hoping that moisture depth improves tomorrow and that a combination of high CAPE and a favourable surface feature can make up for the weak shear. Fingers crossed.

Michael

Edit: I will say one thing, don't but too much faith in those GFS CAPE charts. They can be way off sometime. A few times this year GFS has forecast CAPE > 4000 for the NSW southern tablelands due to over doing the surface dew points. Conversely, GFS may have low forecast CAPE due to forecasting low surface temps when in reality 30C is likely.

[Jason(pato)]

Hey Dan and Clayton,

Michael T virtually took the words outta my mouth. Warwick and further south look pretty good tomorrow but the shear is only just passable. Going by the forecast sounding for my area tomorrow at 06z it looks like it has better moisture to play with (I use these as a guide only as they are quite smoothed compared to the BoM soundings). Tomorrow mornings Bris sounding should give a better indication of what the day holds. As there has been stuff all in terms of storms here this season I'll be hoping something does fire because I'm starting to get a bit desperate :p. I'll be chasing locally around the Casino-Kyogle-Lismore area. Good Luck tomorrow guys....I reckon the first chase is always the hardest! Follow your instincts and have fun but as always be safe. Hope you bag a good one!!!

[Mathew Townsend]

Nice storm just formed near here with some spits of rain. Theres one nasty cell heading towards Taree in southeasterly direction! No sure if thats a supercell yet with severity looks on the radar.

[Clayton]

Hey

It looks as if the main Point of Interest has moved slightly south back to near casino-tenterfield by looking at the cape, moisture and LI charts

So I am unsure as wear to head but it looks as if the high cape area is moving northward during the day but I may be reading the charts a little to early.

[Macca]

Hi all,

Looks nice for NE NSW and SEQ today.  Shear is lacking but what is lacking in that department will be made up for by some pretty decent levels of instability. 

Its an interesting set up with dry air pushing in through much of the area north of Brisbane, however, the SEly change that moved through NSW yesterday pushed inland far enough overnight to moisten the lower levels over NE NSW and the southern half of the SEQ area.  With DP's on the ranges now being up in the mid-teens, it shows that the moisture depth is at least 1000m deep and I've been following the models and obs closely over the last 24 hours and I think the models have a good handle on the moisture situation - so I'm not as concerned with moisture as I could've been.

As has been mentioned, shear is somewhat lacking.  500mb winds are around 25knts (maybe up to 30knts) from the WNW and 700mb winds are in the 15-20knt range from the NW.  The anvils will be being pushed along by a 35-50knt jet (depending on how high the storms get...but based on the soundings, I'd suggest this will be around 40-45kft).   Of interest is the shear later on in the lower levels - it is forecast to pick up to 15-20knts from the NE (or even ENE) at 850mb which could make things slightly more interesting. 

Instability is quite nice with 500mb temps of -14 and DP's well into the teens we should see MLCAPE of around 2500jkg and LI's of between -6 and -9.  Given this level of instability and the moderate shear, I'd suggest flash flooding and the potential for some very large hail are the two main features today (although damaging winds are often a factor on days like today as big downbursts occur).  Hail size has the potential to get up into the 6+cm range in the strongest storms today (it reminds me quite a lot of Nov 8 2006 where I lost my windscreen near Esk to 8.5cm hail).

I think storms will go up along the ranges today as well as along the dry/moist air boundary which is sitting further west and are likely to move ESE initially before heading NE as they reach severe levels.  I think anywhere from Grafton to Toowoomba could be a target for chasers out there today  (although more cloud further S)  but for anyone heading out for a first time, take care out there today - it should get pretty nasty .  Personally I like the Warwick - Tenterfield - Texas triangle.

Macca

[enak_12]

November 4'th 2009
I went out last night and photographed some nice lighting, the storms were moisture starved but had plenty of nice lighting, I love those storms at night the cg's are long and there's not much rain in your way..I'm absolutley spewing I have to work from 2-5pm today! i'd be chasing Grafton and just north for sure the instabilty looks great  My bet is a severe storms moves through this area this arvo with big hail.. Pics from last night:

[Clayton]

Hey
I've had a change of plans due to the latest cape and LI charts and I am most likely going to head down to casino-woodenbong-tenterfield area as the cape has moved south.

I was wondering if anyone else had the same idea or had different plans. Also if I am heading to the right place.

[Mathew Townsend]

Looking interesting here at Armidale today. Its insanely hot and humid with plenty brewing convection in skies. Lots of RFB's and Cumulonimbus with stratas mixed. Yesterday we had a bit of rain from atomic bomb severe cell formed just north of here and our max temperature was 31 degrees! Today isa  bit cooler but around 25 as to be the maximum with high dewpoints which is good sign.

I wont be surprised for atomic bomb convection today again!

[Mathew Townsend]

Atomic bomb cells firing up with some severe cells near here and Tenterfield yet some more under convection on Moree Plains and Slopes. Severe Thunderstorm Warning is out now.

TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING
for FLASH FLOODING, LARGE HAILSTONES and DAMAGING WIND

For people in the
NORTHERN TABLELANDS and parts of the
NORTHERN RIVERS and
MID NORTH COAST Forecast Districts.

Issued at 1:26 pm Thursday, 5 November 2009.

Severe thunderstorms are likely to produce very heavy rainfall, flash flooding, large hailstones and damaging winds in the warning area over the next several hours. Locations which may be affected include Grafton, Tenterfield and Dorrigo.

Interesting afternoon and evening for us. Its raining here moderately under convective cells. Smell lovely after the stinking hot morning.

[Colin Maitland]

Some pretty intense looking cells over Northern NSW on the radar this afternoon. There have been reports of hail at Stanthorpe from the storm that has passed through the area, just waiting for verification.

Cells are currently building in SEQ just east of Oakey ( 1.44pm QLD time).

Col