Storm Australian Severe Weather Forum
Severe Weather Discussion => Australian Severe Storms, Weather Events and Storm Chasing => Topic started by: Antonio (stormboy) on 16 August 2009, 06:56:39 AM
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I have just recently been looking on a few websites to compare weather reports and I have come to a decision as to whether I should create a new topic. Monday 17 August looks like it might be a good day for some storms with mild temps and also humid. Weather zone states possible afternoon showers and thunderstorms. Northwest winds ahead of a milder south easterly change.
Now I don’t know much about the below charts but here is the storm cast and soundings for Monday.
Happy chasing
Storm boy :)
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Hi Stormboy,
Definitely looks like forecasts have something on the cards, though maybe only marginal for the moment?
I'm holding out a small hope for some minor storm cell development as the trough passes over my area on Sunday afternoon/evening.
See what eventuates..
Regards,
Shauno
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We shall see what happens because last week it was only a possibility but a few severe storm cells developed. By the way, in what region is Lightning Ridge?
storm boy
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We are pretty easy to find. There aren't many towns out this way.
We sit pretty much at the top part of NSW right in the middle, around 40k's South of the QLD border. We are easy to find if you follow the Castlereagh Highway straight up North from Dubbo on a map. Or you can just look us up on google maps, that's easy to do also :)
We are in the general area where the good storms build, then head over towards the Northern Rivers via Moree, Mungindi and Inverell and become severe monsters! (MB, Jason(pato) and Rodney Wallbridge will be chuckling at that) ;) lol.
Take care and all the best with the weather on Monday!
Shauno
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Where's all the CAPE in that sounding? Looks very sparse guys?
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Yeah the outlook is not the best, hence my 'marginal' statement. Ahh well, I'd be happy to see a decent cloud formation at this point? :)
I still hold out on a late September season kick-off. Going back through our last 6years work seems to offer a more late Dec./Jan. start for our area but anything is possible?
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If you re-plot the sounding at 29/19 you get a more impressive outlook: -7 LIs and 2400 CAPE, which you know is pretty good actually.
BUT! As I have learnt over the years, don't take the storm cast as a single point of reference for storm forecasts. There is just so much more than what meets the eye.
A basic thunderstorm set up (well in NE NSW / SE QLD anyway) consists mainly of:
- Moisture
- Heat
- Upper level winds / wind shear
- Cold air aloft
- Trigger / trough
Right so lets take a look at the synoptic chart.
(http://img29.imageshack.us/img29/7361/idg00074.gif)
Great, we have a trough at our doorstep by 10am which means that the trigger is there. However my only concern I guess is that the trough might go through too quickly as the 10pm chart anticipates it to be around the Capricornia region.
Wind shear is actually really good, very strong in the upper levels.
Temperature, well once again it is forecast to be unusually warm, but just remember these temps are coming from the Westerly winds. You will need a NE'ly to feed moisture into the region or else it's bye bye storm chance. The upper levels are OK for cold air, although significantly warmer at the lower levels in SE QLD than anywhere else. But I don't think that's going to be much of a problem.
Again, moisture is my primary concern. Things could very well change by Monday, but all I can suggest is look at the observations to determine whether any moisture is coming into the region (the DPs in particular). The BoM is pretty sceptical and I think they are right to do so at this stage.
Hope I got it all right.
So yep, marginal to fizzer set up indeed. :P
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We have a forecast tomorrow of the chance of isolated thunderstorms developing and strong gusty winds throughout the day. Also a temp of 22 degrees so it might be interesting to see what comes up in the afternoon.
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The forecast for someone about 300kms to your SE is for gale force winds, rain developing with possible thunderstorms from mid morning.
Big Pete
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Victoria looks set for a wet, windy stormy day with most areas forecast with the chance of thunderstorms from early morning to evening.
There are already numerous warnings out for Vic:
A severe weather warning for damaging winds for almost all of Victoria and several current gale warnings and a strong wind warning.
There is also a severe weather waring for areas in NSW for widespread damaging wind and a sheep graziers warning.
Western and South Eastern NSW look set to get some light rain and possibly thunderstorms, gusty winds and above average daily temperatures, along with areas of raised dust.
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Rechecked the weather outlook just now.
"northern rivers - Monday showers and thunderstorms with a cooler southerly change.
SE QLD - Monday isolated shower and thunder developing later."
By the way Steven during the storm event a few days ago, my cousin was in Logan and they had some large hail. (Edit JD: I have edited the concept of huge hail and changed to large hail. No exaggeration is allowed on the forum. Please confirm before posting.)
stormboy
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Stormboy,
Can you confirm large measured hailstones in Logan? This means your cousin actually saw and perhaps even measured hailstone sizes.
Regards,
Jimmy Deguara
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Whilst its encouraging to see a forecast for storms for this area, it does look rather marginal to say the least. Looking at the forecast CAPE chart for Monday, it would appear that the best instability will be off the coast by 4pm. Even the forecast sounding for Monday 4pm looks dodgy to me with a pretty strong CAP in place and moisture near the surface could be better. There also looks to be a strong Westerly component in the shear, so I'd imagine there isn't going to be a big injection of moisture that we need (ie from the NE). When I replotted with 29/14 the CAPE went up quite nicely to 1200j/kg but there is still a CAP in place so its going to be difficult for anything to get going. If something by chance does initiate it'll probably be quite high based given the LCL is at around 800mb (on the replotted forecast sounding).....mmmm long strobing bolts.
By the way Stormboy, I think that sounding you posted was for the 14th of August so that would explain the lack of instability.
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Those soundings are a little better and the lapse rates are a bit more enticing but you'd have to keep a check on the actual temps and DPs during the day to confirm the soundings accuracy unless you get them hourly from BoM (cough). Still it's early days and a lot can happen. will watch this thread with interest over the forecast period.
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Hi guys,
Boy it's a shame the atmospheric moisture is low (for the time being) as there's certainly no lacking in the driving heat/convection department today! It reached 30c by 11am here and now (2:25pm) it's sitting at 34.2c! I have another thermometre across town at my mums place and it too is sitting at 33.9c currently.
Russ and I will wait out the day and see if we can catch anything weather wise this arvo or tonight. The trough is almost upon us now, just waiting for frontal cloud development to push in from the W-SW with the change.
Is this our first heat trough? Surely feels like it.
I'll keep you guys posted on what happens throughout the arvo.
Kindest regards,
Shauno
EDIT: Just a quick adage here: There is a small isolated cell already firing off a few stikes between Tibooburra and Bourke as of 2:40pm. I really wish they had a decent radar install out that way.
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JD my cousin told me that when she held a $1coin on top the hail was bigger. hope that helps. Monday tomorrow and weatherzone predicts pos storms for NR, NT, SE QLD
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Storms firing just this side (East) of Bourke currently, still quite warm.
We'll be ready for anything that comes our way!
Regards,
Shauno
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Whilst I would love to see DP's of 14 around Lismore and Casino today, the reality is that mixing of the drier air above down the surface will probably lead to DP's in the single digits by mid afternoon. There will still be storms and showers about however bases are going to be mighty high possibly up towards 10,000 feet. If storms can get nice and close to the coast there maybe a bit more moisture to give some more structure.
Nice day for lightning at least.
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Well, the DP's are holding up ok so far, better than I thought! Over the last hour there has been a slight increase at Lismore and Casino, may have something to do with the cloud cover present. Will be interesting to see what happens once it clears again in the next hour or so.
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Well quiet hot here right now 30.6C and a north easterly freshly blowing. It is very cloudy now and the radar indicates some mild rain developing in the northern parts of the northern tablelands. Hope to see some action. BSCH storm cast has improved too.
stormboy
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I'm not impressed with what I'm seeing at the moment. I think once the cloud band rolls over, it will just be light rain throughout the night. Hardly any severe activity at all.
We just had our maximum of 28.1 in the last hour but it has dropped to 24 with a shifting NNE wind change. Humidity has gone up too.
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Hi Stormboy,
Don't use the BSCH LI and CAPE maps as a true guide to what is happening. Click on the map and look into the sounding for a true reflection. There is some instability and small CAPE in the mid levels however thats about it. It's awfully dry and warm in the lower and upper atmosphere at the moment meaning mid level convection only.
Some small showers have popped up on the change down near Coffs. Something worth keeping an eye on as it moves north.
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Thank you james for explaining the above to me by the way steven mentioned earlyer DP’s what exacly is that because i am not so familiar with these weather/stormchasing tools
Storm boy
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Well at least the storms have formed some ware today. The first few are around Ipswich and Marburg at the moment with the full heaviness colour on the radar. It is also rumbling extremely light thunder here now and drizzling.
storm boy
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DPs is the dew point which forms part of the calculations found in skewT's which are used as part basis for predicting and chasing your storm.
Some skew T's allow you to recalculate with current DPs and Temps. Some good sights are available to help understand, and Michael Bath started a brilliant thread in which others contributed called " Understanding Aerological diagrams" (skew T) ( Understanding Aerological Diagrams / Soundings « 1 2 »)
http://www.australiasevereweather.com/forum/general-weather-all-topics-that-are-not-current-severe-weather-should-be-posted-here/understanding-aerological-diagrams-soundings/ (http://www.australiasevereweather.com/forum/general-weather-all-topics-that-are-not-current-severe-weather-should-be-posted-here/understanding-aerological-diagrams-soundings/)
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Thank you coltan i will look at that topic and learn more about DP’s. Some nice storms in both the Ipswich area and the Coffs harbour area. As for here the light thunder stopped and its very windy. Tonight might be a warm one as the temp now is 23.7C.
stormboy
See : 64km Radar Loop for Brisbane, 05:00 17/08/2009 to 10:00 17/08/2009 UTC
(http://www.theweatherchaser.com/radar-thumb/IDR664/2009-08-17-05/2009-08-17-10/300.s.png) (http://www.theweatherchaser.com/radar-loop/IDR664-brisbane/2009-08-17-05/2009-08-17-10)
EDIT: You can change the radar loop times to show just the hours you want rather than a full 24 hours - try the "Date Range (UTC)" control on the weather archive page. MB
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We did not get any storms up here, what may have appeared as storm cells on the radar moved over quickly and just gave us a brief shower, we overlook Moreton Bay and the ocean from our place and cant see any lightning to where the clouds have moved. A few more showers are on the card, and that is about it. The wind from the cold front moving through is making itself felt now.
Cheers
Col
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No storms locally for me. Some formed along the coast south of Coffs Harbour and moved east very rapidly. I saw one flash of lightning from the cell east of Brisbane about 7.15pm and that was it.
The radar again seemed to be overdoing the intensity. At one stage there was solid precipitation showing for my location yet zero rain was reaching the ground. The sounding attached here gives some indication why - very dry air in the boundary layer up to about 800hPa. Rain and any storms would have been above this layer and any precip would be partly evaporating through the lower layers - ie.virga.