Dr Jack's BLIPMAPS

I came across Dr Jack's BLIPMAP forecast page
http://www.drjack.net/BLIPMAP/NE/index.html

Probably a lot of good information if you know how to use it (and some very
pretty maps), but also not exactly intuitive and slightly overwhelming.

Anybody find good use of this material, and in an orderly process how do you
proceed to a practical forecast of what may happen thermal wise today at
your gliderport?

---------
(email reply, remove X's)

Most of the discussion so far can be found he

http://makeashorterlink.com/?B50B219A6

"Jim" wrote in message ...
I came across Dr Jack's BLIPMAP forecast page
http://www.drjack.net/BLIPMAP/NE/index.html

Probably a lot of good information if you know how to use it (and some very
pretty maps), but also not exactly intuitive and slightly overwhelming.

Anybody find good use of this material, and in an orderly process how do you
proceed to a practical forecast of what may happen thermal wise today at
your gliderport?

I started to respond privately since there has been extensive
discussion on RAS about blipmap. But then, when I did a google search
within RAS on "blipmap", so much came up about contributing, etc. that
I decided to post this to the site, knowing full well that many will
find this already known. But, I decided that minor inconvenience was
worth getting new people like Jim conversant in blipmaps.

Blipmap has proven to be the most useful thermal forecast tool most of
us (all of us?) have ever used. Compared to Reno FSS' soaring
forecast, which gives a single number for updraft strength and top,
blipmap shows where to find the lift. And, it's more accurate than
anything else I've seen. Early on, when Reno FSS' soaring forecast was
predicting 1500 fpm to 18k, and blipmap was predicting a poor day, I
had trouble getting over 10k out of Minden. Chalk up one for blipmap.
And many others have posted similar experience.

Blipmap is based on a 20 km square grid, so what you're seeing is an
average over each 20 km square. Hence, most of us have found that the
predicted updraft strength, while theoretically a gross figure, tends
to match our actual net climb rates (i.e., after subtracting our sink
rate). Similarly, while the boundary layer top predicts the very top
of the thermals, not the usable top, we have again found that this
tends to match the actual top of our climbs fairly well.

In addition to updraft strength and boundary layer top, I tend to look
at cumulus cloudbase (to determine if I can get to the tops of the
thermals and whether they will be blue or marked by cu's),
overdevelopment potential (numbers greater than 0 and esp greater than
1 indicate OD potential), wind speed in the boundary layer (preferably
under 10 or 15 kts), and B/S ratio if windspeed is significant (B/S =
buoyancy to shear ratio must be greater than 5 to prevent broken up
thermals), and BL max up/down. The last map shows areas of
convergence. Since this is in .01 kts, anything less than 50 (1/2 kt
updraft) produces little effect. Between 50 and 100 is likely to
produce good cloud streets along the convergence line (esp if
cloudbase is close to BL top), and anything over 100 means drop
everything and go for it.

These maps are available starting sometime between 6 PM and 8 PM (Cal
time) the night before and are updated throughout the night, so it's
good to double check in the morning and see if it's changed.

They are also available at different times of the day, but mostly 10
AM, 1 PM and 4 PM PST (talking as a mostly CA/NV soaring pilot) or
11AM, 2 PM and 5 PM PDT during the summer. These different times give
a good indication whether to start early or late.

As a final note, I should mention that Blipmap is available free of
charge, but is supported by donations to Dr. Jack. Until recently, not
only was he putting in unbelievable amounts of time, but also paying
for the web hosting and any other expenses. I strongly encourage you
to make an annual contribution to keep this great soaring tool alive
and well. And, when commenting on blipmap, please keep in mind the
volunteer nature of it's existence. Complaining about a missing
feature is not the way to make Jack and the other volunteers feel
appreciated -- or to keep blipmap alive. I've got my own list of
additions I'd love to see, but am grateful for how far blipmap has
taken us. On the days when the server is down, I feel almost lost
without it. And, many days that I wasn't planning to fly, but blipmap
encouraged me by a great forecast, have paid off handsomely. It's not
perfect, but it's a quantum improvement over what existed before.

Hope this helps.

Martin

Martin,
In trying to understand the basics of of what underlies Dr. Jack's
forecast, I also look at the following site (Link is on the good
Doctor's page at the bottom:
http://www-frd.fsl.noaa.gov/mab/soundings/java/
The advantage I see in this NOAA site is in the direct depiction of
"virtual soundings" for every hour of the forecast day. The site
predicts the air mass structure with temps, dew points and winds for
an airport of your choice, in my case Aurora (ARR), Illinois. The
little Java applet that loads with the page allows you to 'hover' your
pointer on the graph at your local altitude and predicted temperature.
Upon clicking, the program draws the dry and wet adiabates, showing
cloud bases and temperature spread. I usually look at the hours from
12PM to 6PM and get at very good idea of how the day is shaping up and
when it's dying.
Being so close to Lake Michigan I appreciate of course the mapping of
all the other parameters on Dr. Jack's site in determining what area
to fly in.
Herb Kilian, J7

(Martin Hellman) wrote in message
...Blipmap has proven to be the most useful thermal forecast tool most of
us (all of us?) have ever used. Compared to Reno FSS' soaring
forecast, which gives a single number for updraft strength and top,
blipmap shows where to find the lift. And, it's more accurate than
anything else I've seen. Early on, when Reno FSS' soaring forecast was
predicting 1500 fpm to 18k, and blipmap was predicting a poor day, I
had trouble getting over 10k out of Minden. Chalk up one for blipmap.
And many others have posted similar experience....

"Herbert Kilian" wrote in message
om...
Martin,
In trying to understand the basics of of what underlies Dr. Jack's
forecast, I also look at the following site (Link is on the good
Doctor's page at the bottom:
http://www-frd.fsl.noaa.gov/mab/soundings/java/
The advantage I see in this NOAA site is in the direct depiction of
"virtual soundings" for every hour of the forecast day. The site
predicts the air mass structure with temps, dew points and winds for
an airport of your choice, in my case Aurora (ARR), Illinois. The
little Java applet that loads with the page allows you to 'hover' your
pointer on the graph at your local altitude and predicted temperature.
Upon clicking, the program draws the dry and wet adiabates, showing
cloud bases and temperature spread. I usually look at the hours from
12PM to 6PM and get at very good idea of how the day is shaping up and
when it's dying.
Being so close to Lake Michigan I appreciate of course the mapping of
all the other parameters on Dr. Jack's site in determining what area
to fly in.
Herb Kilian, J7

Also, clicking and dragging out a rectangle allows you to "zoom in" on that
area of interest. So, for example, if you don't expect to get to 60,000
feet that day, you can get a rectangle that only goes to, say, 18,000.

Tim Ward

Tim, please explain how to do this clicking and dragging
of rectangles and what software might be needed. I
just went to a blipmap and couldn't find anything that
would drag.



At 17:24 29 November 2003, Tim Ward wrote:

'Herbert Kilian' wrote in message
. com...
Martin,
In trying to understand the basics of of what underlies
Dr. Jack's
forecast, I also look at the following site (Link
is on the good
Doctor's page at the bottom:
http://www-frd.fsl.noaa.gov/mab/soundings/java/
The advantage I see in this NOAA site is in the direct
depiction of
'virtual soundings' for every hour of the forecast
day. The site
predicts the air mass structure with temps, dew points
and winds for
an airport of your choice, in my case Aurora (ARR),
Illinois. The
little Java applet that loads with the page allows
you to 'hover' your
pointer on the graph at your local altitude and predicted
temperature.
Upon clicking, the program draws the dry and wet adiabates,
showing
cloud bases and temperature spread. I usually look
at the hours from
12PM to 6PM and get at very good idea of how the day
is shaping up and
when it's dying.
Being so close to Lake Michigan I appreciate of course
the mapping of
all the other parameters on Dr. Jack's site in determining
what area
to fly in.
Herb Kilian, J7

Also, clicking and dragging out a rectangle allows
you to 'zoom in' on that
area of interest. So, for example, if you don't expect
to get to 60,000
feet that day, you can get a rectangle that only goes
to, say, 18,000.

Tim Ward

"Nyal Williams" wrote in message
...
Tim, please explain how to do this clicking and dragging
of rectangles and what software might be needed. I
just went to a blipmap and couldn't find anything that
would drag.

I'm sorry, I thought from the context it was clear I was talking about the
Java applet at:
http://www-frd.fsl.noaa.gov/mab/soundings/java/
that Herbert Kilian was referring to, not BLIPMAPS.

I guess the context wasn't that clear after all.

Tim Ward

At 17:24 29 November 2003, Tim Ward wrote:

'Herbert Kilian' wrote in message
. com...
Martin,
In trying to understand the basics of of what underlies
Dr. Jack's
forecast, I also look at the following site (Link
is on the good
Doctor's page at the bottom:
http://www-frd.fsl.noaa.gov/mab/soundings/java/
The advantage I see in this NOAA site is in the direct
depiction of
'virtual soundings' for every hour of the forecast
day. The site
predicts the air mass structure with temps, dew points
and winds for
an airport of your choice, in my case Aurora (ARR),
Illinois. The
little Java applet that loads with the page allows
you to 'hover' your
pointer on the graph at your local altitude and predicted
temperature.
Upon clicking, the program draws the dry and wet adiabates,
showing
cloud bases and temperature spread. I usually look
at the hours from
12PM to 6PM and get at very good idea of how the day
is shaping up and
when it's dying.
Being so close to Lake Michigan I appreciate of course
the mapping of
all the other parameters on Dr. Jack's site in determining
what area
to fly in.
Herb Kilian, J7

Also, clicking and dragging out a rectangle allows
you to 'zoom in' on that
area of interest. So, for example, if you don't expect
to get to 60,000
feet that day, you can get a rectangle that only goes
to, say, 18,000.

Tim Ward

Jim wrote:
I came across Dr Jack's BLIPMAP forecast page
http://www.drjack.net/BLIPMAP/NE/index.html
Probably a lot of good information if you know how to use it (and some very
pretty maps), but also not exactly intuitive and slightly overwhelming.
Anybody find good use of this material, and in an orderly process how do you
proceed to a practical forecast of what may happen thermal wise today at
your gliderport?

Jim,

First, look at the "For New Users" section of
http://www.drjack.net/BLIPMAP/help.html

Second, how you use them depends to some degree on your weather
knowledge, your area, and your previous experience. Personally, for
where I live, I first look at the "Height of BL Top" prediction to see
if further investigation is worthwhile, and if it is then check out the
"W*" plot, the "Cumulus Potential" plot, and -- since this can be
important in my area -- the "Convergence" plot to see if they also look
good. Often that is enough, but other times I will also feel the need
to also look at other predictions, for example the "Buoyancy/Shear
Ratio" plot if I think the windspeeds may be strong or the "Cumulus
Cloudbase" if I think BL clouds might be a problem. Your needs may vary
- for instance, over the Nevada desert the "Overdeveopment" predictions
become important and should also be checked.

Jack