B5-24 PREPARATION OF CHARTS 
Relative Humidity 100 percent entered 100. 
Relative Humidity 20 percent entered 20. 
Dewpoint of 2.8°C entered as 2.8. 
Dewpoint of -26.4°C entered as -26.4. 
Dewpoint depression 14.4°C entered as 14.4. 
Wind direction from 272 degrees entered as 272. 
Wind direction from 62 degrees entered as 62. 
Wind speed of 5 meters per second entered as 5. 
Wind speed of 112 meters per second entered as 112. 
11.8 Other Entries. Enter a dash in the spaces for temperature, rela- 
tive humidity, dewpoint and wind data pertaining to constant-pressure 
levels below the level of the station. 
11.9 Doubtful Data. Temperatures believed tobe more than 1°C but less 
than 3°C in error, and altitudes computed from doubtful or missing tem- 
perature exceeding the limits specified in §B5-10.2, will be entered 
in the CPD blocks in parentheses. An altitude entry may be regarded 
as accurate even though the temperature entry for the same level is 
doubtful or missing. However, once altitudes are classified doubtful 
they will be regarded as doubtful for the remainder of the observation 
(see JB-10.3). 
12. Checking Records. Where possible, an observer other than the 
computer will check the flight records in detail before transmission of 
the raob message. This check and other checks deemed necessary before 
mailing will be done in accordance with the instructions issued by the 
separate services. 
13. Computation of Stability Index. The stability index for each raob 
will be computed at all radiosonde stations within the United States and 
the Pacific Region, except that Alaska stations will make these compu- 
tations only during the period May 1toSeptember 30, inclusive. The in- 
dex indicates the degree of stability of the layer of air extending from a 
level near the surface of the earth tothe 500 mb surface. The computa- 
tions consist of finding the temperature a particle of air at a selected 
level would have if itwere moved upward along a moist pseudo-adiabatic 
1-1-69 FMH#3 
