Where is My Balloon Going?

Prediction Basics

Weather near the ground and up to cloud level is only a small part of the story when launching a weather balloon to 100,000 feet, but that does not mean it is not an important part! Worldwide weather predictions, including winds, are updated continuously from twice-daily weather balloon launches,[1] and this data can be used with a number of different balloon prediction services.

Best Option for Most Missions

From my own searching for prediction calculators, recommendations from Edge of Space Sciences, and a guidance from a HAB Photography guide[2], the clear best option for most missions is the Cambridge University Spaceflight Landing Predictor[3], which is fed some data from the Balloon burst calculator[4] (see Balloon Sizing for more). If you want to get really fancy with your cameras, you can use the predictions to help you decide what angle to set the cameras at.

 Screenshot of Cambridge HABHUB predictor

Screenshot of Cambridge HABHUB predictor

Flight prediction example using the Cambridge HABHUB predictor.

Getting the Right Latitude and Longitude

You will want to feed any prediction program an accurate latitude and longitude. There are many ways to get this using GPS or address lookup services, but Google Maps is an exceptionally easy to use without having to leave your computer.

All you will need to do to get the latitude and longitude of your launch location is to find it on the map, right-click (or option-click), and then select “What’s Here?”. The exact location of the spot will be delivered in the needed decimal format at the bottom of the page.

 Example decimal latitude and longitude result from Google Maps that is already formatted for our use in a prediction service.

Example decimal latitude and longitude result from Google Maps that is already formatted for our use in a prediction service.

Understanding Latitude and Longitude

The measurement of latitude and longitude will vary from 0° to 180° and may or may not have a negative sign in front, depending on the hemisphere you are launching from. The location is delivered in the form (LAT, LON). It’s interesting that this is basically opposite the to standard (X, Y) ordered pairs in math...

Latitude is the number of degrees away from the equator you are, with negative numbers being south of the equator. Longitude is the number of degrees away from the Prime Meridian you are, with negative numbers being to the west of the prime meridian. This is shown generally in the image below.

 Clarification on the correct signs for latitude and longitude for each hemisphere. Modification to Miller Projection on Wikipedia by Strebe (Own work) [CC BY-SA 3.0[5]], via Wikimedia Commons[6]

Clarification on the correct signs for latitude and longitude for each hemisphere. Modification to Miller Projection on Wikipedia by Strebe (Own work) [CC BY-SA 3.0[5]], via Wikimedia Commons[6]

Other Prediction Websites

Please see the great prediction summary page by the Global Space Balloon Challenge[7] if you have other requirements or curiosities that are not satisfied here. The site states, “some prediction sites online offer real-time flight predictions. This allows a team to chase the landing site and not the balloon.” This sounds great, but it’s unclear which sites allow you to do this. You may also enjoy exporting the prediction results to a KML file, which can then be viewed with Google Earth.

Notes

[1] https://www.weather.gov/okx/Tour_Weather_Balloon

[2] https://balloonchallenge.org/HABPhotographyHow-to-1.pdf

[3] http://predict.habhub.org/

[4] http://habhub.org/calc/

[5] https://creativecommons.org/licenses/by-sa/3.0

[6] https://commons.wikimedia.org/wiki/File:Miller_projection_SW.jpg

[7] http://community.balloonchallenge.org/t/flight-prediction-overview/672