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Forecast Accuracy

Old 14th Mar 2019, 09:59
  #1 (permalink)  
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Forecast Accuracy

As I sit here I have hail, severe downbursts significantly reduced visibility in a storm that 1 hour ago the TAF had no indications of. 2 hours ago the AWS had SCT 061 when it was actually OVC A017 ( BTW I am an approved Aerodrome weather observer). My point is the main BOM site indicated all day that storms and weather were possible but not the TAF, no inter no nothing. The cells were literally 10nm SW before the TAF was amended, as a response not actually as a forecast.

In winter the BOM will put inter or Tempo for fog and reduced viz in a destination that is known for never having fog. In 30+ years 2 fogs, both from the sea in the middle of the day neither forecast. When MET were located at this aerodrome the worst it got was shallow fog on the flora surrounding the aerodrome never on the movement areas.

So in times of actual prudence there is none and in times of no danger its panic stations. Since Mildura its just become hopeless. Carry the fuel for a no chance event (historically) and have no real reserves when a cell is in the circling area. I think it is outrageous and cannot understand why they believe the AWS when they could just look at the ASA webcam for the aerodrome and take it onboard that their systems are dangerous and don't work.
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Old 14th Mar 2019, 10:08
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Yup. Anybody flying around with min. fuel these days is a clown.
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Old 14th Mar 2019, 10:13
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Originally Posted by George Glass View Post
Yup. Anybody flying around with min. fuel these days is a clown.

Serious question, do you think that this is due to the BOM getting worse at forecasting? (possibly due to an over reliance on computers)

Or is it due to more unpredictable weather?

Or something else?

I agree with you that min gas is a great way to get yourself into trouble.
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Old 14th Mar 2019, 10:28
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Iím not sure if youíre talking about Mildura, however they are scheduled for BOM / ASA cameras. They must be close to next on the list. Installation is complex and there are many parties involved.

The BOM are aiming to have cameras installed at every airport with a TAF.

I on the other hand, am trying to have cameras installed at every airport. 75 and counting thus far, with a lot more to come to reach that goal! Time is spread thin though as Iíve got lots of overseas interest and camera supplies are difficult to maintain at the present volumes.

All of my cameras are in Avplan and Ozrunways. If there is another product that could benefit from them, please tell me which one!
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Old 14th Mar 2019, 11:24
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Not talking about Mildura. But in that case unforecast weather caused a couple of issues for Virgin. The bigger issue is that there appears to be a huge gap between BOM guesses on their website and actual aviation forecasts. I've sent them photos in real time of their AWS saying viz 3000m in fog when its actually cavok. They don't give a sh...... and are unaccountable for their folly. Just look at their initial predicated tracks for Cyclone Oma. As it turned out it went the complete other way and this is assuming many computers were used, where in actual fact a chocolate wheel or a TRS80 could have done a better job.
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Old 14th Mar 2019, 11:31
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I think most knw our WX reports are atrocious here in Oz, you get used to it & source other avenues to seek out the real WX. I never trust any WX produced by the BOM!
I guess that's why they are called 'forecasts' to save their butt!
Camera's are great for short term stuff, I often 'phone a friend' where I am going get a real assessment of the weather if it looks average!
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Old 14th Mar 2019, 12:12
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I think the lawyers have got at the forecasters. What is available is hopelessly conservative. Volatile weather isnít forecast at all, since to a lawyer, no forecast at all is a better strategy that a potentially wrong forecast.

The result? when forecasting deteriorating Wx. they always forecast an hour earlier than predicted. Improving WX is always forecasted an hour later.

Your TS were probably forecast but not issued on the basis of a ďwho could have known? defence. Think about the lawsuits over acres of hail damaged cars and wrecked aircraft if the bureau forecasts TS that then turn out to be monsters. If there is no forecast, well, you canít be liable can you?

The genesis of all this was the fatal Sydney - Hobart race when the bureau came close to getting sued.
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Old 14th Mar 2019, 13:10
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The inquest found that the Bureau did issue a number of forecasts to the organisers of the race the Cruising Yacht Club in Sydney warning of severe storm conditions developing however their importance was not well understood/received by CYC and were not passed onto participants (20 years ago that would not be an easy thing to do), and as such the case against the Bureau was dropped. Some of it what happened is in this link

Are Bureau public weather forecasters pilots or yachties? Probably not. I went to a talk by an ex CEO of the British Met Office who hated the use of the word "forecasters" which confined his meteorologists to be just a bunch of unseen boffins in a backroom running endless models and calculations in order to come up with a paragraph of text after which their responsibility ends. He wanted his meteorologists to be more relevant by having more engagement with industry rather than just producing a paragraph of text and calling it a day. Perhaps the Australian version can take a leaf out of his vision.

Of course more engagement will often generate better outcomes but can also expose you to more litigation when they don't.
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Old 14th Mar 2019, 13:57
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Are you talking about Brisbane hilton? If so, it seems to be a more regular issue than at other capital cities.
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Old 14th Mar 2019, 14:29
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I should add that the bom people i have met have always been friendly and helpful..
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Old 14th Mar 2019, 22:11
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Originally Posted by wishiwasupthere View Post
Are you talking about Brisbane hilton? If so, it seems to be a more regular issue than at other capital cities.
No not Brisbane but your close..ish. I too have worked with BOM people in briefing and as go to people when questioning conditions for runway changes etc. It is not a personal dig, however when a metar or speci is inaccurate due to a dodgy or restricted AWS, because BOM shut manned regional stations, they need to be as accurate not less. Technology doesn't understand local conditions such as why we just don't ever get LVO due to fog. Last night had an aircraft diverted here based on the AWS/metar and the TAF they may have found themselves with limited fuel in a world of pain....sound familiar.
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Old 15th Mar 2019, 09:20
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The reference to Mildura is, I assume, regarding the diversion from Adelaide due unforecast fog a few years ago. Why you would divert away from an airport with a functioning ILS has been the subject of debate ever since. Airlines require strict adherence to regs. ( of course) but still pressure crew to carry minimum fuel. Such is the dilemma confronting every Airline pilot on a daily basis.
Slezy9, does it mean that forecasting is better or worse than 30 years ago? I would venture that not too many forecasters look out the window any more. Nor do they use the basic [email protected] f%ck detector any more.
I am particularly amused by the joker who puts a CAVOK period in the middle of the day on the TAF in Darwin during the wet season. Funny guy... And theres many more.
And dont get me started on single runway requirements.
Use the the judgement they pay you for and keep yourself safe.
Everybody behind you will be thankful for it.
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Old 15th Mar 2019, 10:01
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Ballina Monday evening...
TAF “CAVOK”...... Actual BKN008
TwoFiftyBelowTen is online now  
Old 15th Mar 2019, 10:01
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With no data to hand, just casual observation, I would agree that the relative accuracy of BoM forecasting has declined of late. Certainly I've noticed the "basics" such as forecast maximum temperature have been somewhat "off", particularly in the Melbourne region over the last six months. I was once told by a forecaster in Perth that when the max temp forecast was out by x degrees (I think it was 5 degrees), then it was a "huge deal" at the Bureau - "heads would roll" and much embarrassment would ensue. At a recent CASA Flight Safety seminar, a BoM forecaster gave a presentation about some new weather charts. During the break I mentioned the previous day's weather exceeding the forecast max temp for Melbourne by 6 degrees - she seemed quite unfussed by what I had been led to believe was a big deal for a forecaster.
This is all hearsay and speculation - I've got no recorded data, just my fuzzy memory...
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Old 15th Mar 2019, 10:39
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I recall a few years ago when we got transferred to centre after t/off enroute ML-SY we where told SY now had a hazard alert due a strong Sthl'y now forecast requiring an additional 60 holding on top of the usual BS traffic fuel, nothing on the TAF about that an HR before at the planing stage just a FM period which would require a Rwy change, had to turn around go back for more gas and a new COBT, you can guess the clutter truck that created!
I'd hate to imagine if a single snow flake fell on Syd, they'd close the Airport for good! -
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Old 15th Mar 2019, 11:05
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The fact that any agency attempts to forecast weather is beyond me. It is just not possible!
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Old 16th Mar 2019, 00:44
  #17 (permalink)  
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To quote TwoFiftyBelowTen
VBallina Monday evening...
TAF “CAVOK”...... Actual BKN008
BKN008 is classed as CAVOK for CHTR and Gun (Bank) Runners.

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Old 16th Mar 2019, 03:37
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At best the forecast is a guess by a scientist based on statistical data and old observations.

The Broome based met Observer was there for years and could predict with uncanny accuracy fog, regardless of the wet/dry figures the Perth based forecaster was using.

An old Mentor of mine(fog expert of Fitzroy fame) said "I am never worried what the forecast says, it is what it doesn't/cannot/will not admit to it being a guess at best.
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Old 16th Mar 2019, 10:55
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Standby for it to get a whole lot worse at YSSY, which I’ve always found to be really good. They are the only location in Australia to have a dedicated met unit embedded in the ATC ops room, but the airlines have decided they’re too expensive and have demanded the Bureau remove them.
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Old 16th Mar 2019, 23:28
  #20 (permalink)  
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In my days as an ATC Instructor in the late 1970s with CFS "C" Flight, the CO had a sign above his desk: BEWARE THE WEATHER GUESSERS FOR THE TRUTH IS NOT OFTEN WITH THEM.

Guess not much has changed.

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