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PSX weather options

Started by Hardy Heinlin, Sat, 30 Jan 2010 03:51

Peter Lang

The new verion of Active Sky (Active Sky Advanced) reads out the METAR, TAF and also the winds aloft for this airport. I did not check the upper winds with the charts. So I cannot say if these values reflect the real weather as the METAR and TAF do.

Peter

JRBarrett

Quote from: Peter LangThe new verion of Active Sky (Active Sky Advanced) reads out the METAR, TAF and also the winds aloft for this airport. I did not check the upper winds with the charts. So I cannot say if these values reflect the real weather as the METAR and TAF do.

Peter

Meteorlogical datasets for the entire world are available in gridded format from the U.S. NCEP (National Center for Environmental Prediction).

These datasets contain the parameters used to initialize the various standard computer models (GFS, MRF, RUC etc.) used by everyone from the National Weather Service to commercial sites like Accuweather, Weather.com etc. in predicting the weather.

The datasets are very large, (typically 100 to 300 MB) and contain enormous amounts of information - not just for the surface, but aloft as well - including temperatures, moisture content (dewpoint, mixing ratio, relative humidity), winds (in U, V vector format) vorticity and so forth. Typically the data is gridded to 1 degree by 1 degree LAT/LON coordinates covering the entire world, at multiple standard levels from the surface up to 20 or 30 km in altitude.

Although the actual computer weather prediction models, that use this data are not something that any home user would have access to - (the models run on supercomputers) there are several freely-available software packages designed for use on standard PCs (GRADS, Vis5D) that can make use of the NCEP data to produce static maps and/or graphs.

The data structures of the NCEP gridded data files are well-documented, and a software engineer well-versed in meteorology could easily write his own applications to extract whatever sub sets of the data he might need - i.e. the wind direction and velocity + air temperature at specific lat/lon coordinates and altitudes.

I believe that his is how ASA works. They (ASA) download the NCEP datasets which are generated every 12 hours, (or even more often for certain forecast models), massage the data using software written in-house to extract the information they need (such as winds and temps aloft), then provide the data to their clients (registered ASA users) via their own server. The NCEP-derived post-processed winds aloft data is combined with hourly METAR reports (available from multiple internet sources) to produce the complete "package" of weather information that the ASA client software uses to inject real-time weather into FSX or FS9.

That would really be the only way to make use of the NCEP data, (insofar as winds aloft are concerned) one would have to have a single computer that downloads the datasets and processes the data to extract the desired information, and then make it available to the end users.

For anyone interested, more information is available at http://www.iges.org/grads/grads.html   This is the homepage for the GRADS analysis software mentioned above - one of many publically-available programs that can make use of NCEP datasets.

Examples of what the software can do is available at http://wxmaps.org - there is a wealth of surface and upper-level weather charts here that would be of interest to both real-world and simulator pilots under the "Analysis of Current Conditions" page.

Note: GRADS, and most other freely available WX analysis software is intended to run under Unix/Linux - though it can be adapted to run on a Windows platform using the Cygwin Linux emulator.


Jim Barrett

Hardy Heinlin

Interesting. Thank you, Jim.

Unfortunately, for the initial PSX version this would require too much programming work. But it might be reconsidered in a later version. Or ASA may in the future offer their services also for PSX users. Injecting weather into PSX is just a matter of injecting text lines into PSX via TCP/IP. It's very simple.


Cheers,

|-|ardy


P.S.: Will, I've just removed the "Randomizer buttons enabled" checkbox :-) It makes no big sense as those randomizers are not as dangerous as a delete button. (In another corner of PSX there's a certain delete button that has an associated "enable checkbox" to prevent unintentional button pushes).

Jeroen Hoppenbrouwers

This weather aloft injection becomes a prime candidate for an add-on. Somebody with an internet server without a bandwith limit. Hmmmm...

Michel Vandaele

#24
I fly very often long haul flights in the sim (with adapted FS2004 B744 airfile presently) and also with PMDG B744,  and ASA is certainly providing and enjecting info (wind aloft) over the Atlantic and rest of world ( routes to HKG for exemple) which is coming "in the vicinity" of your Upper windcharts info we download from Jeppesen when we are preparing the flights.
So they must have a way. The transitiion isn't always so smooth but that seems to be an MSFS limition in the weather engine.  
Also FOC program is using real weather data for route fuel calculation, so I suppose all that must be available on the net, as this is needed for accurate fuelcalculations in the flightplan.  If no wind aloft in the sim envirimont is used, then these calcucations will never match
B. Rgds
Michel
Michel VANDAELE
Board member  FSCB
EBOS Scenery Designteam
My B744 project
http://users.telenet.be/michel.vandaele/sim1.htm

Hardy Heinlin

Do those downloaded Jeppesen wind charts indicate jet streams or polar fronts?

|-|

JRBarrett

Quote from: Hardy HeinlinInteresting. Thank you, Jim.

Unfortunately, for the initial PSX version this would require too much programming work. But it might be reconsidered in a later version. Or ASA may in the future offer their services also for PSX users. Injecting weather into PSX is just a matter of injecting text lines into PSX via TCP/IP. It's very simple.

I was thinking along that line too - perhaps ASA could be adapted to inject weather into PSX - but, as you say, that's something to be looked into "down the road".

I know that worldwide winds aloft data is available in pre-formatted text form from providers like Jeppesen - but at a considerable cost. The advantage of extracting it from the NCEP datasets is that the NCEP files may be downloaded for free.

I'm going to investigate the latter option in more depth just for my own amusement - it's been a while since I've played around with perl in Linux - perhaps I may come up with something that I can give back to the PSX community in the future.

Jim Barrett

JRBarrett

Quote from: Hardy HeinlinDo those downloaded Jeppesen wind charts indicate jet streams or polar fronts?

|-|
or

My favorite source for upper wind / jetstream charts is the NOAA aviation weather center site.

http://www.aviationweather.gov/products/swh/

From the link above, you can click on prog charts showing the current locations and max wind speeds of the polar and sub tropical jets. Unfortunately, there is no map covering central Asia, but the rest of the world is depicted, including the northern and southern polar regions.

These charts would be an excellent guide for manually setting the locations of the jetstreams in the PSX weather interface for any given date.

Jim Barrett

Hardy Heinlin

A PSX jetstream has six lat/lon anchors. The curved lines in between are autogenerated. If somebody can scan and vectorize the jetstreams on the NOAA charts some day, PSX will be ready for textual jetstream injections.

|-|ardy

Michel Vandaele

Yes Hardy,

Som examples of charts for that Atlantic Area - lots more available.

http://www.jetplan.com/jeppesen/weatherServlet?&action=show&graphicType=wxMapWT&img=uswt390

http://www.jetplan.com/jeppesen/weatherServlet?&action=show&graphicType=wxMap&img=ntfzsig12.gif:0

A lot more info and charts is available in the non-public area of Jetplan, but that info also can be downloaded from a lot of other sites on the net, maybe in a less graphical form.

B. Rgds
Michel
Michel VANDAELE
Board member  FSCB
EBOS Scenery Designteam
My B744 project
http://users.telenet.be/michel.vandaele/sim1.htm