Dr. Jack's Wind Direction

Thank you, Ray, for giving BlipMap fans a chance to show their
gratitude and devotion to Dr. Jack by piling on. BlipMaps may be
hanging on by a thread. I think that Dr. Jack, as a scientist, would
prefer some systematic verification of BlipMaps to online thank you
notes, but something is better than nothing.

Sorry you got only a smart-ass answer from JJ. At least Andy Durbin
understood. It is quite reasonable to suspect any computer output is
180° degrees off, by design or error. Even a few years of uncritical
acceptance by users doesn't preclude the possibility of error in the
case of a seldom used feature. If R.A.S. was all it could be, you
would have been deluged with testimonials and quantitative validations
of the accuracy of the winds BlipMap by users. Sorry that didn't
happen. I think a 180° error would have been noticed, but who knows?
For quite a while the F.S.L. web soundings had winds that were
systematically off by up to 18°, but that is a lot harder to spot.

You might have waited to undertake a scientific study, when you
noticed something funny on a single flight. But I don't think it was
a terrible thing to ask on RAS about the interpretation of the winds
BlipMap. Neither was it wrong to ask about circling mode on an LNAV,
instead of reading the manual from the CAI site. In fact, an
intelligent answer from a person is usually faster and more to the
point than on-line help or the manual. It's easy to see why Dr. Jack
might not have the time to answer any or all questions, but RAS is a
different story. Probably, no one gave a serious answer, because no
one had seriously checked the winds BlipMap. However, 99% know that
winds are "from", and are thus equipped to post useless, smart-ass
replies. It is comforting to note that so few actually did!

Dr. Jack has had a constructive reaction in the past to anyone who
actually compares BlipMap outputs to the real world or to other
weather data sources. See these quotes from his website below.

Jonathan Gere

From the Dr. Jack Forum:
After more days of work than I had hoped I finally got things sorted
out and am now running a corrected program with the BLIPMAP cloud
predictions turned on. Bob Gibbons deserves kudos for having both the
initiative to critically evaluate the "Cumulus Cloudbase" prediction
and the knowledge to compare it to the simple surface-humidity LCL
condensation formula. Thanks, Bob.

The short story is that in the Sfc-umidity LCL calculation I found one
logic error and one place where I had used virtual temperature instead
of "actual" temperature (shame on me). While I am using an "exact"
calculation of the "Surface-humidity LCL", that is because I am a
persnickety scientist - it turns out the "approximate"
Surface-humidity LCL formula should generally agree with the "exact"
formula by within 5%, which is certainly adequate given the overall
error associated with cloud predictions....

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I only look at the webpages and maps that I use personally or that I
suspect might contain an error. If you notice a consistent problem
with either, please let me know.

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