Victoria: Trough/Front - Storms and rain - 17th -19th Nov

[Jake Smethurst]

Nice write-up Meso.

The day does appear to be probably the best for the coverage of thunderstorm activity probabilities for the outlook period. These northeasterly winds we have been experiencing over the last day or so are gradually filtering in the moisture and we will really be able to feel the mugginess tomorrow in the temperatures that will be 30+ degrees across the majority of the state. The trough is likely to move into western Victoria during tomorrow afternoon and evening, not reaching central districts until late at night or overnight I think. However the environment will be quite unstable, there is reasonable inflow through all areas, very good outflow particularly in the west, and obviously our other variables; surface temps, upper temps and moisture values will be very good. At this point the entire state is at risk for thunderstorm activity, with a reduced risk in the northwest and southeast. Areas of focus will be in the west near the trough and perhaps near the ranges thanks to the extra uplift. Flash flooding and damaging winds the largest concern in activity tomorrow, but these are more likely in the Wimmera/Southwest.

Will be an interesting day nonetheless. And I have updated the AWF TS chart/discussion.

[apocalypse]

Interesting fact - the colours of the second and fainter rainbow are opposite to the first. I actually learnt something in Physics.

[Macedonian]

What a difference a day makes...
yesterday morning we had calm clear conditions with light frost in low lying areas and 4C ,today it is windy ,quite unpleasant and 21C . I know which one i would rather have.

[Meso]

Already storms along the trough line nudging the SW coast. Should be an interesting afternoon/night.

[dry]

Not even 8:30 and it's a tad unbearable outside. Hoping for an entertaining afternoon/evening like everyone else.

[Jake Smethurst]

Its 25/17 degrees here!! Very sticky!! We have had lots of altocumulus ahead of the trough system which is currently near LSE of South Australia. As I mentioned last night though, the trough wont enter Victoria until the afternoon and evening, so its a fairly slow mover initially. As Meso said, some shower and thunderstorm activity already developing with the trough, particularly in the stuff in the Bight.

Going to be an interesting afternoon and will have the AWF forecast out shortly, and the TS charts later this morning.

[aussiestormfreak]

26C and still climbing, feels quite sultry out there, and almost as blustery as September

Thought I'd put the satellite link up so that we can monitor the situation with each passing hour...

http://realtime2.bsch.au.com/vis_sat2.h ... art=&stop=" onclick="window.open(this.href);return false;

That thunderstorm activity just off the Southwest coast looks impressive, I'm sure we'll get sometime this afternoon and evening, another after-dark lightning display or two would also be a bonus!

[Supercellimpact]

28/14.5 here at 10.30am

[Jake Smethurst]

I'm going to be at work until 10pm, when is the trough due to arrive in Melbourne?

Hi Wilstar. It is currently a hard one to pin-point regarding timing, but at this stage will most likely be entering or crossing Melbourne by about 9 or 10pm. It could be later with the latest data suggesting it has slowed a bit.

Otherwise lots of small Cu about the place here even underneath this higher cloud thats in the region. Probably a couple of showers here until 1pm before hopefully some thunderstorms this afternoon. Its 28 degrees with a DP of 17!!

[Jake Smethurst]

I've updated the chart and discussion. Still looks like a good day on the cards, for reference sake, here is the discussion, but please see http://www.theaustralianweatherforum.co ... mchart.htm for full details and chart.

Discussion for Friday:
Issued at: 11:30 AM Friday 18th November.

Atmospheric conditions across Victoria are expected to become quite unstable this afternoon ahead of an approaching trough of low pressure which is expected to move into the western districts during the latter part of the afternoon and evening, before central parts at night. Latest guidance does suggest that the trough may be slower moving than anticipated, and could become stationary at several points for short periods as it moves into the state. Moisture levels are expected to be very good across most of the state, although the northwest may experience slightly drier conditions. Ahead of the trough, a freshening northwesterly flow will cause surface temperatures to be in the low 30's, and combined with the moisture profile will cause nice instability through the majority of Victoria, with both modest Lifted Index and CAPE values. Already the growing unstable conditions has been causing isolated thundery showers in the southwest of the state this morning. In relation to the shear variables, the 0-1km layer looks generally fine, allowing reasonable inflow, however the 0-6 km section looks rather good overall for outflow. Due to these variables, isolated thunderstorm activity is likely across the majority of the state during the afternoon and evening, with activity expected to be more scattered near the trough in the west and possibly about the ranges. There is only a chance for thunderstorms in the northwest due to those drier moisture levels, and also only a chance along the southeast coast due to being further away from the trigger. Severe thunderstorms are most likely in the Wimmera and Southwest districts, however are not restricted to these areas. Damaging winds are the biggest concern, however flash flooding does appear it could be a problem thanks to the higher moisture levels. Large hail is not ultimately ruled out, however it does appear to be the least likely severe phenomena to occur. Restricting factors for today appear to be any cloud cover that may cap temperatures, however at this stage looking at the visual satellite imagery, there appears to be good clearance through the majority of areas, but it is not expected anyway to cause much of a problem. The directional shear of the thunderstorms is expected to be towards the southeast.

Next Update is due by 3:00 PM Friday 18th November.

[Dc449]

Yeah i finish work at 10PM as well so hoping it holds off!

[I_Love_Storms]

Right...for Melbourne BOM have 30% chance of rain 0-1mm and Weatherzone 90% chance of rain 20-40mm haha big disparity there!

[Supercellimpact]

BOM is very conservetive these days, they need to loosen up and stop covering there ass so much. For Melbourne it's more like 20mm-30mm and 90% as weatherzone say.

[Riz The Weather Wiz]

Hey guys

Latest Melbourne Atmospheric Sounding has an LI figure of -4.1

Looks like we would have to reach 32degC to really get things going

Currently in Melbourne, 29.7degC, Dew Point 16.1

Cheers

[Jake Smethurst]

And there we go, action developing from the southwest all the way into South Australia!

[crikey]

Howdy all.. Just been snooping around the BSCH weather variables
http://forecasts.bsch.au.com/stormcast? ... #stormcast" onclick="window.open(this.href);return false;
Thought this looked like a pretty wicked front line change.A north to south westerly change. Looks to be a strong gust front.???
This is the 925mb wind stream chart for 11pm. Looks pretty intense in the n/west of the state


and also checked out a parameter called relative storm helicity from BSCH for the same time period. I believe it is related or linked in some way to potential storm rotation,' tornadic' activity.. or at least one of the variables that is considered.


Noticed the s/west wind change was near Eucla this morning , so wind change, cool change still a long way off. The cold pool behind it had temps in Collie in s/west WA st 8 deg C at 6.00am this morning.A bit nippy!! Looks like the cold pushes into the interior parts and NSW in the coming days..
Will be interesting to gust fronts if any and significant temp differences in front of and behind the change

[I_Love_Storms]

Have to admit, before I saw weatherzone forecast and radar I wasn't that confident...radar looks very good at the moment though!

[TheFishmanAU]

We have burst through 33. 33.3 15.3 here.

[solcampbell]

35/15 down here

[rikjpool]

Looks like the action has started in the west as was mentioned. I'd expect this to grow and thicken out into a nice line of heavy hitting storms cells. A very Multicellular line today. If you get under a core, expect a good 10-15mm in quick time. Also be aware of cells firing in the clear air ahead of the main band. Horsham at the moment is 36/9. Whilst not the best for storms to develope, it can certainly happen. Id expect that main band to hit Central Vic (Bendigo/Maryborough) around 5-6pm. Right when im caught up in stuff..... grr. Haha. Ah well. If anyone did manage to get out and in front of it. I'd imagine some nice structure out there today. Clear air, plenty of viewing out west... get on it people who can.