Victoria: Strong cold fronts and winds 23rd-27th April 2010

[Karl Lijnders]

With a TC wafting off the NW coast - I suspect the refining on Tuesdays complex is unclear but 20 mm would be acceptable.

Still anticipating 20-40mm across the state tomorrow into Saturday with another period of rain in the south Sunday AM.

[droughtbreaker]

10.8C to 20.3C is the average for Melbourne in April. We are way above it atm and if it wasn't for the significant cold week that we have ahead to finish the month we would be threatening the April maximum record. Still, the fact is that we are going to see this cold week which is a textbook scenario for this time of year where you get a lengthy 'Indian Summer' period mid month and then a cold outbreak sort of a week to finish it.

If the BOM forecast temps for the next 7 days end up correct then Melbourne will be on 22.9C average for the month with a day to go. This is 0.1C lower than April 1993 and 1.1C cooler than 2005 (Pretty sure that was the record month). Assuming a mximum of around 19C or 20C on the last day of the month (which is a rough guide from the models) then that average max should be around 22.8C. A very warm month but nothing exceptional.

[Jake Smethurst]

Don't think I have posted in this thread yet.

Looking at the start of the colder weather from later tomorrow, with a frontal system approaching the state and a pre-frontal trough moving into the west of the state later in the day. Should see some showers and isolated thunderstorms develop at first from the west, but gradually increase to rain areas during the day from the southwest and extend through most localities by midnight. Fresh to locally strong northwesterly winds developing across the state, particularly the western half during the day.

Further rainfall, colder temperatures due on Saturday with the actual cold front reaching the state early, and another overnight Monday into Tuesday.

[Harley34]

Question.

If i remember last year, specifically during Winter, we had a decent amount of cold fronts pass Melbourne overnight.

Is this a coincidence? or are should we be calling these Cold Fronts "Nocturnal"?

[Ken]

I thought the average for melbs in april was 10C min and 19.something max?

The mean April min for the Melbourne Regional Office site (it's not actually right at the Regional Office but still in the city) is 10.8C while the mean max is 20.3C.

P.S. the cold air field behind the front south of WA is looking fairly impressive on satpics as it surges up through the longwave trough in those longitudes. Will be an interesting weekend as it starts interacting with moisture streaming down from the Indian Ocean. Precipitable water values off the WA coast northwest of the Gascoyne district were >40mm according to this morning's 00z analyses.

[Harley34]

I thought the average for melbs in april was 10C min and 19.something max?

The mean April min for the Melbourne Regional Office site (it's not actually right at the Regional Office but still in the city) is 10.8C while the mean max is 20.3C.

P.S. the cold air field behind the front south of WA is looking fairly impressive on satpics as it surges up through the longwave trough in those longitudes. Will be an interesting weekend as it starts interacting with moisture streaming down from the Indian Ocean. Precipitable water values off the WA coast northwest of the Gascoyne district were >40mm according to this morning's 00z analyses.

Goes to show rank means nothing Ken's full of valuable knowledge.

Yea, i would really love to see the front maintain a SW-direction towards Victoria. I mean it could all change tomorrow, however we still have the 2nd front to consider

[Macedonian]

Thanks guys, i didnt think that 23C or 24C was the average fo Melbs in April ( well not yet anyhow )
Hope it cools down significantly over the weekend.
Would be interested to know how far above average we are here in Macedon for April. still shorts and t-shirt at the minute. kack.

[droughtbreaker]

We are usually pretty close to Kilmore Gap (near Wallan). Same elevation and only 40-50km away. Ballarat AWS is about 100m lower than Macedon township I am pretty sure so it is fractionally warmer. Kilmore Gap is currently running 2C above average for maximums. By the end of the month it should end up about 1.5C above average so I say we would be similar. Significant difference to Melbourne which should end up about 2.5C above average.

Excellent period of weather ahead. A bit of a NW cloud band developing and the very cold air that could get dragged over us mid next week. This weekend though we should see some very showery weather with the fronts coming through although models aren't all that keen on anything significant past Saturday but hopefully that will change.

[Karl Lijnders]

I expect the system to come back for next week with falls of 20-40mm across the state. This is dependant upon the TC off the NW coast and the timing of the front.

Anyhow tomorrow still looks very useful. Plenty of rain developing from late morning over the SW and spreading NE through the state.

[Anthony Violi]

Sorry Macedonian my bad. Getting a little carried away! Was thinking of the minimum for Melbourne!

[tizza]

OMG @ the sunrise, if you're up get outside NOW

[Lily]

It was spectacular - absolutely, gob-smackingly beautiful. And do you think I could find the camera in time?

[daviescr]

OMG @ the sunrise, if you're up get outside NOW

was stunning indeed, 'Red sky in the morning.....'

[Karl Lijnders]

Still looking good for 20mm widespread through southern VIC with falls locally of 30-40mm near the ranges. Chance of a mid level storm in C and E areas.

The rain should break back to showers tomorrow with another burst of rain Sunday AM with winds shifting SW through the morning.

EC has around 25mm or so for this system as does US. Some uncertainty as to next week but still fairly confident in a follow up if 10-25mm atleast. Another front Thursday could drag dome real cold air and deliver mor rain.

Quite warm overnight with a record likely to fall in the CBD. Latest 20C+ minimum ever.

[Harley34]

Good Morning Guys.

I have noticed some members making reference about the Low/Cyclone in the NW affecting us in some way?

Can someone explain the connection, in which this depression might have on us?

[I_Love_Storms]

Good morning Harley,

This Weatherzone summary should explain it a little better:

"A trough is crossing from WA into SA, drawing in tropical moisture, leading to patchy rain. This trough extends into the southeast, causing rain and storms."

If you look at that latest BOM weather map: http://www.bom.gov.au/cgi-bin/nmoc/late ... E=IDY00050 this also clearly illustrates the trough extending from NW WA down through SA and then on towards offshore Tasmania. This trough will push east on or near the rain band. Hopefully we can get some decent heating in before it arrives The atmosphere is well positioned at the moment for a few sparks later if things go right, there are already some sparks near Cape Otway.

[rikjpool]

Morning all.

Looking at the Satpic and the Radar, I dont think i've seen such a low riding frontal passage!? Is it literally following the upper Jet atm or something? Its sitting below Melb, Adelaide, and most of the Nullabor? When/Is this going to head up onto the coast?

P.s. Random piece of information, this weekend last year it rained as well. A good 15-20mm fell over the Dandenongs. I know Cause I was bowling in a Competition for 24hours in Dandenong, and everytime we went outside to jog across the road to get some maccas we got soaked... haha

[I_Love_Storms]

It definitely did Rik. I remember last Anzac day it was terribly windy as I was down in Williamstown and it was blowing a gale! Quite a chilly day though, it only got to 19 and then that cold front ripped through and the following day only got to 13.6 and remaining under 15 for the following 3 days!

Back to the topic, what are the chances of an upper low forming off the coast?

[Harley34]

Good morning Harley,

This Weatherzone summary should explain it a little better:

"A trough is crossing from WA into SA, drawing in tropical moisture, leading to patchy rain. This trough extends into the southeast, causing rain and storms."

If you look at that latest BOM weather map: http://www.bom.gov.au/cgi-bin/nmoc/late ... E=IDY00050 this also clearly illustrates the trough extending from NW WA down through SA and then on towards offshore Tasmania. This trough will push east on or near the rain band. Hopefully we can get some decent heating in before it arrives The atmosphere is well positioned at the moment for a few sparks later if things go right, there are already some sparks near Cape Otway.

Ahh ok thx. I knew that the pre-frontal trough would indeed give us some rain before the front, i just wasn't sure about the depression off the far NW coast.

Like you said, good to see the sun is out, giving us some heat, and the wind is picking up aswell, which means things are going to plan.

Do you think we could experience some decent storms this afternoon before the front?

[I_Love_Storms]

I'm not very confident at this stage for anything big. If temperatures can nudge 30 again we may be in for a slight chance, I think the northern ranges will have the best shot today for some half decent convective activity.

Think we are more of a chance for some isolated weak storms with pockets of moderate rainfall, only my opinion though.