Winds Aloft Prediction

[Rocketclar]

There is a NOAA site for predicting upper level wind directions and speeds vs just surface winds. Ron Parsons of my old Austin based club use to run these winds aloft sims for us before a launch. I now have run these before launches at my new home in IN to see if a higher altitude flight would risk going towards power lines (a big no-no) near our launch site. The example shown in the attachment is for our site in Muncie. You can tweak for your conditions and constraints. While the example doesn't show many changes, there are times when the speed and direction of the upper winds are very different than the surface winds. https://www.dropbox.com/s/au6rk6n5wsvrlr4/Winds Aloft.pdf?dl=0

 

[Louis Wu]

there are times when the speed and direction of the upper winds are very different than the surface winds.

right you are... I use Windy.com app on my ipad (and widget on one website) and it can display winds at different altitudes.

 

[Cameron Anderson]

You could always use a pilot balloon...get some helium, fill and release a balloon of a known volume. You can look up ascent rates online for and then you measure the angle to the balloon from your point, compare the time-versus-altitude chart, and do the math to figure out the overall wind effect.

 

[kbRocket]

Our club launches in Brothers Oregon at about 4500’ MSL. I use three sources for upper level winds. Each has some good and some bad.

Windy airgrams have a great multi-day forecast that make it easy to see the direction and speed of the winds out for several days. Windy Brothers Unfortunately the wind information is plotted as a function of pressure in hectopascals, rather than altitude. You just have to quickly convert hPa into altitude and then subtract the elevation to get it in AGL. Easy peasy.

USAirnet in Winds Aloft has predictions of wind speed in 6, 12, and 24 hr increments up to 39000’ MSL elevation for 160 cities. It gets the data from NOAA. All info is MSL. Redmond 6 Hr or 12 Hr. Right now Winds Aloft seems unresponsive. I still have to make MSL into AGL, which isn’t too bad. The Redmond airport is also about 43 miles away from our site which isn't ideal.

This is the raw source of the NOAA data that USAirnet uses: www.aviationweather.gov model data 6 Hr or 12 Hr. These links are for the San Francisco region which includes the sites near me (RDM, IMB). The data comes from a table with other sites and it uses universal time, so it isn't really easy for normal humans to consume. Computers can get it and manipulate it easily.

Last year I was learning the Python programming language. I made a program that:

• Grabs the 6 and 12 hour NOAA data for the two closest sites to Brothers: Redmond (RDM) and Kimberly (IMB) OR.
• Blends the wind speed by distance from our Brothers launch site to these two locations
• Plots wind speed as a function of height AGL for our launch site for the next 6 hours in local time. A half line is 5 MPH, full is 10 MPH, filled triangle is 50 MPH.

• Integrates the wind speed vertically and predicts walking distance for a rocket falling at 75 ft/sec. A half line is 0.1 mile, full 0.2 mile, filled triangle 1 mile.

• Emails me the results with graphs and links.

It takes about 2 seconds to run. The code could use some cleanup, but it works.

I looked into putting it up as part of our local OROC site, but Python isn’t very compatible with our provider. It would be neat to extend the code to major launch sites and have it available on the www.