TAFs will transition to a 30 hour format

[scottd]

...................

 

[flyingcheesehead]

Well crap. Why won't they give 30-hour TAF's to the rest of us? They have the models...

 

[flyingcheesehead]

Well, the TAF is re-issued every six hours, so honestly, I'm not sure it would really help most of us.

I can't tell ya the number of times I've stayed up until the wee hours, waiting for a TAF to come out and tell me whether I'll be able to make a flight (especially a return flight!) the following day.

 

[Steve]

Not a single airport on that list I fly to.

I want a user fee exemption.

 

[gprellwitz]

Not a single airport on that list I fly to.

I want a user fee exemption.

Since the same folks who do ORD also do DPA, MDW, and RFD, why aren't those listed? They are usually very similar!

 

[flyingcheesehead]

So when you get up the next morning

What is this "morning" of which you speak?

do you ignore the updated TAFs? No, I don't wait up to see the next TAFs, but I do check them in the morning and it will have covered the extra six hours you are looking for. That extra six hours on the end of these new TAFs doesn't really factor into the picture in my opinion.

Well, I'm looking at usairnet 2.5 days in advance (and every few hours thereafter) to watch how the forecast changes and to get an idea of what to expect, and that's practically like a TAF.

 

[dmccormack]

What you see on the web site you referenced is called Model Output Statistics (MOS) which is untouched by human hands. I helped build the MOS for the Nested Grid Model (NGM) many years ago. Forecasters at the local weather forecast office incorporate MOS along with several other forecast products to construct the TAFs. At a range of 24 hours and longer, there's a lot of room for error. The forecasters at the WFO normally can do a pretty good job knowing when the MOS is on the money and when it is not.

Of all the forecast products, TAFs seem the most consistently close to what will happen, IMHO.

Or am I deluded?

 

[dmccormack]

FWIW, a TAF is the most difficult forecast any meteorologist must make. You are basically asking them to make a forecast for an area the size of your neighborhood using numerical guidance (weather prediction models) that have a resolution twice the size of the terminal area. Moreover, they are predicting elements on an hour-by-hour basis where the guidance is typically provided every three to six hours into the future. Forecasting this information out to 30 hours is insane, IMHO.

I usually ignore more than 18 hours in any TAF (especially an older one awaiting update).

But for the short range stuff -- such as "Whats the likelihood of primary dual this afternoon at 1400 local?" it seems to be the most reliably accurate, even though locally they always seem a bit more pessimistic than what eventually occurs.

 

[CJones]

I have gotten to the point that I don't bet on TAF's past ~3 hrs out if there is actually weather in the area. If it is 'good' wx, and the TAF says it isn't gonna change much, I'll follow that model for the full extent of the TAF. If there is wx in the area, though, with low ceilings/etc. and the TAF is trying to decide WHEN that stuff will move out, I don't trust it more than ~3 hrs out. I've decided that nobody can determine when ceilings/vis will move out in stagnant air. I don't blame the forecasters, I just think it is too difficult of a task to ask any man (or computer) to decipher.

 

[flyingcheesehead]

Of all the forecast products, TAFs seem the most consistently close to what will happen, IMHO.

Or am I deluded?

I think they're about as good as it gets - Except for the one at OSH last year. That one was 180 degrees out of phase with the weather - TAF showed dire predictions, it'd be sunny. Then the TAF would say 10SM CLR and there'd be a thunderstorm!