Appendix 4. NWS RADIOSONDE/HIBAL
A-4-1. NWS RADIOSONDE/HIBAL FLIGHTS
Use the procedures in this appendix for National
Weather Service (NWS) radiosonde balloon releases.
A-4-2. NATIONAL WEATHER SERVICE (NWS) RADIOSONDE BALLOON RELEASES
a. Issue as Aeronautical Information at least 30
minutes prior to the release of a NWS radiosonde
balloon under the following conditions:
1. Delayed release. A radiosonde balloon that
will be released later than the scheduled times of
1130 or 2330 UTC.
2. Special Observations. A release that will be
made at times other than those specified for the
scheduled observations (1130 or 2330 UTC).
b. The Aeronautical Information shall contain the
1. The balloon release time.
2. The time the balloon is expected to reach
A radiosonde ascends at the rate of 800 fpm, reaching
10,000 MSL in 12 minutes and 25,000 MSL in 30 minutes.
c. The locations of radiosonde balloon release
points are listed in the Airport/Facility Directories.