weather and Sydney-Hobart

tweaker

Member
My Aussie Mates help a San Diego Anarchrist out. I haven't done a Hobart race yet, but it's on my list of races to do. So I have been studying the weather down under right now, preceding the race, so as to get a feel on how the systems of lows, etc. move through the racing area. Just in case I get a chance to do one in the future.

I see persitant Highs that build and then are pushed east in the area just to the south of mid continent and also east of Tasmania @ 40-45S . These seem to set up

Mostly S-SW prevailing winds off SE Australia. The strong lows that push east from Below 45-50S Knock these highs east and weaken them alowing some of the low pressure to settle over SE Australia setting up a good NE-NW wind for a run down to Hobart.

My questions are?

1. How close are my observations to what You know are the general patterns of the weather down there in December?

2.Does a persistant low settle in over SE Australia in Late December regularly to make a Good run down to Hobart likely? Like the one I see forecast for Dec. 7 on the mean seal level pressure chart. http://www.bom.gov.au/cgi-bin/nmoc/latest_...00030&number=28

3. What are some good weather links and any links about the SE Australia Current? And how big a factor is the current?

I have been using this one . www.bom.gov.au/cgi-bin/nmoc and a US Naval one for some of my study.

4. I see periods of light winds as high pressure stays over the race area for several days followed by some strong Southerly - SW winds for many days and then the possibility of a few days of good NE-NW winds. So my question is what condition historically is most likely? What odds are there for a good run for AAPT and the KiteShip kite? I know it depends on what system is happening at the time.

You guys are going to have to show me how to work my GPS upside down when I get there as I haven't raced below the equator yet. I have found my way to Mexico a lot which is south and out to HI a couple of time, so that's got to help.

 
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Hey Tweaker,

You think that those guys are going to let you go down there and steal their women?? Hah!

Pretty good weather analysis though.

Sticker Schock

 
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duncan (the other one)

Super Anarchist
5,401
426
Siderney
That weather of Dec7 is atypical for a Hobart race.

Generally, the tropical lows will stay further north, and the dominant lows south of the mainland. This will accelerate the NE sea-breezes before the breeze swings W/SW when the front comes through.

Fronts are usually 25-35 on the NSW coast, grading up to anything like 50-60kn on the tassie coast. Seas of southern NSW suck, as you want to be where the East Australian Current is strongest (2-4kn). So you've got Strong southerly wind waves and swell against 2-4kn.

Once the low has passed through (assuming it doesn't sit in Bass Strait 'ala '98, and it may hang in the W/SW for anything from 1/2 to 4 days if the low is far enough south), the breeze will clock SE and weaken, then E and back to NE sea breeze.

If the breeze hangs in the W/SW through Bass Strait, expect mountainous seas.

Basically, in a typical Hobart, AAPT may be able to fly their kite for 1 day... but that may also take them 3/4 way down the racetrack.

Have a look at the BOM Chart Archive, for the Hobart dates (26-30th Dec). Years like 2001 are not uncommon.

 
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tweaker

Member
That weather of Dec7 is atypical for a Hobart race.
Generally, the tropical lows will stay further north, and the dominant lows south of the mainland. This will accelerate the NE sea-breezes before the breeze swings W/SW when the front comes through.

Fronts are usually 25-35 on the NSW coast, grading up to anything like 50-60kn on the tassie coast. Seas of southern NSW suck, as you want to be where the East Australian Current is strongest (2-4kn). So you've got Strong southerly wind waves and swell against 2-4kn.

Once the low has passed through (assuming it doesn't sit in Bass Strait 'ala '98, and it may hang in the W/SW for anything from 1/2 to 4 days if the low is far enough south), the breeze will clock SE and weaken, then E and back to NE sea breeze.

If the breeze hangs in the W/SW through Bass Strait, expect mountainous seas.

Basically, in a typical Hobart, AAPT may be able to fly their kite for 1 day... but that may also take them 3/4 way down the racetrack.

Have a look at the BOM Chart Archive, for the Hobart dates (26-30th Dec). Years like 2001 are not uncommon.
DTOO thanks for the feedback.

So I take it that depending on the pattern most of the race is usually a close reach to reachy?

I was looking at the SST charts for the EAC but the PIC is over such a large area it is hard to see any detail for the current.

Where do the racers check for good East Australian Current info?

 

greasy al

Anarchist
982
53
I think you'll find that the weather for the race especially over the last few years has been a bit random. I don't think you want to make any assumptions or lock yourself into any plan until a few days out, especially this year given the yes/no/maybe el nino pattern. The weather over Oz currently is quite unseasonal.

 

duncan (the other one)

Super Anarchist
5,401
426
Siderney
So I take it that depending on the pattern most of the race is usually a close reach to reachy?
I was looking at the SST charts for the EAC but the PIC is over such a large area it is hard to see any detail for the current.

Where do the racers check for good East Australian Current info?
Hmm... the reachy part (from the W) is usually short-lived.

Although the systems say SW, the breeze on the NSW coast tends to be more southerly (fronts tend to slow on the coast due to land effects whilst still moving quickly out at sea).. so the race usually involves at least a day or two or beating into strong headwinds. You may get a good westerly across Bass Strait, but if its blowing from the west, you've also got a large swell/sea coming from that direction with a fetch all the way back to Africa. The rhumbline is also west of south.

It is a little difficult to find good EAC charts.. govco wants us to pony up our dough (twice) to get our hands on that information.

 
O

OzRick

Guest
Ain't done a Hobart, but my observation of watching it for the last few years is:

Midday 26th - negotiate harbour, avoid all the camera boats and spectator craft, finally get out of the Heads, hit the fairway mark, turn right, pop big kite.

Evening 26th - Listen to weather report that a southerly buster is due, see wind increase, change down to heavy kite or jib top.

Night 26th - Listen to more buster forecast, talk about how you're going to handle the southerly when it arrives and have decided nuthin when it does - all hell breaks loose, shit goes everywhere, you finally settle down to a tuck in the main and a heavyish number 2, or the 3.

Early hours 27th - Fucken forecast is for more! Take second tuck in main, change to 3 or 4, clean up lotsa shit that's going on. In middle, discover that HF radio is on the blink - half the crew are pist it looks like Eden for a quick fix (ignore rule 41) other half wants to head for Eden NOW!

27th daytime - radio fixed (who's the f'whit who pulled the coax out and stuffed it back in the hole?) - wind eases enuff to warrant a change up, but angle gets worse and seas get bigger.

Late 27th / Early 28th - have a fabulous blast reach down coast of Tassie - sail into huge hole! Park for about 10 hours, watch every bastard you wanna beat sail past in a breeze line half a mile inside you. Get going again, then park in the Derwent.

Finally cross line - 3am - no bastard in sight to pay up on rum bets - have a drink, finally get tired and really looking forward to sleep, and all the SA bastards turn up to party!

You thin and say? .... f'inf A1 - Best race ever - wouldn't miss it for quids!

 
Oz Rick pretty much hit it on the head.....

Surf first day, on the nose through the night and building for second day.

More of that shit through to late pm.then pop the womper for the 28th .

followed by the derwent shit fight

and we do this year anfter year :blink: :unsure:

 

duncan (the other one)

Super Anarchist
5,401
426
Siderney
yeh.. they seem to move them about.. that link of yours was what I was looking at the other day and all you end up with are $$$ dead ends. I only just rediscovered the other one myself.

not much set on the northern south coast this year... its all down off Eden and even a fair bit into Bass Strait.

 

Eventually

Super Anarchist
not much set on the northern south coast this year... its all down off Eden and even a fair bit into Bass Strait.
That should be fun for some nice big waves in the Strait.

Odd to see so many cold core counterclockwise eddies right now.

 
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tweaker

Member
So I take it that depending on the pattern most of the race is usually a close reach to reachy?

I was looking at the SST charts for the EAC but the PIC is over such a large area it is hard to see any detail for the current.

Where do the racers check for good East Australian Current info?
Hmm... the reachy part (from the W) is usually short-lived.

Although the systems say SW, the breeze on the NSW coast tends to be more southerly (fronts tend to slow on the coast due to land effects whilst still moving quickly out at sea).. so the race usually involves at least a day or two or beating into strong headwinds. You may get a good westerly across Bass Strait, but if its blowing from the west, you've also got a large swell/sea coming from that direction with a fetch all the way back to Africa. The rhumbline is also west of south.

It is a little difficult to find good EAC charts.. govco wants us to pony up our dough (twice) to get our hands on that information.
You guys are getting me straightened out. I guess I am kind of an optimist. ( me to the rest of the crew)"Hey guys we are only going to have this shit on the nose for a few more hours and then it's gona clock back for some running."Me I live for the RUN! I want the wind from the beam and back. You know let's hook up and "haul the mail".

In my first post #4 second sentence? I think I said "mostly strong S-Sw's for many days" . That's like a bad dream and I want to block it out.

Also "So I take it that depending on the pattern most of the race is usually a close reach to reachy?" kind a optimistic.

DTOO thanks for the hook up on the Sea Temps.

 

tweaker

Member
Ain't done a Hobart, but my observation of watching it for the last few years is:
Midday 26th - negotiate harbour, avoid all the camera boats and spectator craft, finally get out of the Heads, hit the fairway mark, turn right, pop big kite.

Evening 26th - Listen to weather report that a southerly buster is due, see wind increase, change down to heavy kite or jib top.

Night 26th - Listen to more buster forecast, talk about how you're going to handle the southerly when it arrives and have decided nuthin when it does - all hell breaks loose, shit goes everywhere, you finally settle down to a tuck in the main and a heavyish number 2, or the 3.

Early hours 27th - Fucken forecast is for more! Take second tuck in main, change to 3 or 4, clean up lotsa shit that's going on.  In middle, discover that HF radio is on the blink - half the crew are pist it looks like Eden for a quick fix (ignore rule 41) other half wants to head for Eden NOW!

27th daytime - radio fixed (who's the f'whit who pulled the coax out and stuffed it back in the hole?) - wind eases enuff to warrant a change up, but angle gets worse and seas get bigger.

Late 27th / Early 28th - have a fabulous blast reach down coast of Tassie - sail into huge hole! Park for about 10 hours, watch every bastard you wanna beat sail past in a breeze line half a mile inside you. Get going again, then park in the Derwent.

Finally cross line - 3am - no bastard in sight to pay up on rum bets - have a drink, finally get tired and really looking forward to sleep, and all the SA bastards turn up to party!

You thin and say? .... f'inf A1 - Best race ever - wouldn't miss it for quids!
Gotta love it.

 
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