Comparing Drjack XCSkies RASP and TopMeteo - U.S. Soaring - Comments?

[WaltWX]

I am interested in hear U.S. glider pilot comments on the pros/cons of all these sites for soaring forecasts. I have used them all at one time or another and find them generally comparable. But, some like RASP and DrJack do a much better job of locating convergence zones/shear lines. Geo-referencing data and ease of use varies a lot. The biggest difficulty is that archive and looking at past forecasts makes it difficult to do inter comparisons.

Your inputs will valuable to me as I am in the process of writing an article for Soaring magazine discussing the basic of Numerical Weather Prediction and how it relates to these soaring web sites.

Walt Rogers WX

[Michael Opitz]

At 22:22 30 October 2016, WaltWX wrote:
>I am interested in hear U.S. glider pilot comments on the pros/cons
of all

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>these sites for soaring forecasts. I have used them all at one time or

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>her and find them generally comparable. But, some like RASP and
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> much better job of locating convergence zones/shear lines.

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> data and ease of use varies a lot. The biggest difficulty is that
archive

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>and looking at past forecasts makes it difficult to do inter
comparisons.
>
>Your inputs will valuable to me as I am in the process of writing an

>articl=

>e for Soaring magazine discussing the basic of Numerical Weather

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> and how it relates to these soaring web sites.
>
>Walt Rogers WX

Hi Walt,
I use DrJack a lot here in the northeast. I find it a little pessimistic
in
forecasting cu development, but also pretty good for me to see the
maritime convergence setting up along the Hudson river going north.
RO

[fly...@gmail.com]

Hi

I use Dr jack NAM a lot and I am located in the north east corner.
Very good in most aspect. Specialy altitudes of cloud, thermal strengh...
High wind speed are often lower than predicted at altitude.
Wind

[Mike C]

In New Mexico I have found XCSkies NAM accurate when compared to the Global or Rapid Update forecasts.

Mike

[John Cochrane]

Dr Jack RAP and NAM were sufficient and quite good when I was flying in the midwest. Flying in Williams, Sierra, and Utah this summer, I find only the high detail rasps have the needed information. In particular convergences and cu vs. blue areas don't show up on the usual Dr. Jack scales. It would be great to have nationwide RASP. Thanks to the volunteers who put together the WIlliams, Sierra, and Utah rasp models.

John cochrane

[greeneg...@yahoo.com]

I like Dr Jack's forecast but if you compare the forecast high temperature to a commercial forecast it seems very often to use 4°F too low of a high temperature for the day. The really makes the Hcrit / top of lift to be too pessimistic. Has anyone else noticed this?
If you look at the "Thermal Hgt. Variability", often it make sense to just assume the more positive end of the spectrum, to get a more accurate forecast.

I also use TopMeteo, it is nice, but i perfer how Dr Jack shows the graphic for Hcrit. In TopMeteo you have to read the thermal height in numbers and it is harder to see it as a map instead of text. This makes it harder to get an overview of higher and lower thermal heights.

It would be really nice if TopMeteo would have an option to show the interstate highway system and maybe a few more gliderports on the maps so you know where everything is.

Chris

[herbk...@gmail.com]

Walt, I've been using TopMeteo together with Blipmaps for the entire season. Around Chicago TopMeteo has been quite good at giving me a running 4-day forecast toward the sparsely good conditions we have. As a result I had a good number of 500+ points OLC flights that I might have missed otherwise. It was quite different for the 2+ weeks I spent in Parowan. TopMeteo was consistently under reporting good days and especially convergence zones. Thanks to our weathermen Bill Gawthrop and later Bob Faris I broke some personal records for distance and speed. I will probably not renew TopMeteo.
Herb, J7

[Renny]

On Sunday, October 30, 2016 at 4:22:26 PM UTC-6, WaltWX wrote:

Walt,
I began using TopMeteo once I became aware of it at the SSA Greenville Convention. I signed up for a year after the promotional period and have used it for flights out of Moriarty this year. I did a lot of comparisons of the TopMeteo forecasts versus what actually "happened" at Moriarty and overall I was very pleased with the results. I like the fact that all of the data I need is on one page and I can print it out and bring it with me to review at the field prior to takeoff. Nothing is perfect, but generally the forecasts on thermal strength, flight top, winds aloft and cloud information are pretty accurate on most days. When the forecast was off it generally was not a significant variance. So, overall I am very pleased and will renew for 2017. Having used XC Skies for years, I have found TopMeteo to be a better service (at least for me) and I will probably not renew XC Skies next year.
Thanks - Renny

[Casey]

On Sunday, October 30, 2016 at 6:22:26 PM UTC-4, WaltWX wrote:

I started using XC skies around 2010-2011 and thought it was easy to use and felt like I did not have to decipher much. I liked the XC Potential and other bar graphs. Very easy to use. I also liked being able to save My Map Profile for different areas. I'm still learning Dr Jacks and have been hesitant to use much due to XC skies was so easy. I stopped using XC skies for I thought it was not being updated. The copyright is from 2005-2012, and the future development was last updated April 18, 2009. The owner of XC skies is supposably in Salt Lake City, UT. I don't think that I am the only one that seems to think its no longer updated by looking at the XC skies discussion board.

Casey

[2G]

I used Topmeteo and Blipmaps this last summer at Ely, Nv. I also did my own analysis using skew-T diagrams. What I really like about Topmeteo was:
1. The predicted cross country distance
2. The hourly forecasts
3. The detailed cloud types
4. Wind predictions
What I didn't like was the near total lack of geographic references (towns, roads, etc.), making it more difficult to get a frame of reference. Blipmaps has the Univiewer that is much more detailed.

Generally, I thought the accuracy of Topmeteo was good, but missed overdevelopment at times. The accuracy of the predicted cross country distance was all over the map, and I couldn't rely on it. At best, it could be used as an upper limit. Sometimes it predicted Cu and it never appeared, and other times it was vice versa. At least it was better than nothing.

My most insightful observation is the inherent error in atmospheric models. If you compare model soundings to actual balloon soundings there is a significant loss of vertical resolution. This means that inversion layers are washed out dramatically. This can impact predicted thermal heights by 3,000 ft, which is not an insignificant difference (actual thermal heights were generally higher than predicted. In fact it means you can fly much further distances than predicted. This happens because model heat from higher altitudes gets moved down to lower altitudes, limiting usable thermal height, and is unavoidable due to the vertical resolution of the models. Examining the skew-Ts also gives me a better idea of thunder storm probability (if you know how to read them). This is a real issue flying in out west in the high mountain deserts.

Tom

[JS]

WX:
The other day Allan Barnes used a new forecasting product called SkySight at the morning briefing.
https://skysight.io/
I'd rate it higher than any of the sites you mentioned.
At the moment it's only up and running for Australia and South Africa. Matthew will be adding other areas, but apparently server costs are quite high due to demand (people playing Pokemon).
Jim