Pennsylvania Historical and Museum Commission
Bureau of Archives and History
Pennsylvania State Archives
MG-288
U.S. WEATHER BUREAU RECORDS FOR PENNSYLVANIA
Series Descriptions
Winds-Aloft Computation Sheets (WBAN-20),
1967-1974.
(14 boxes)
{series #288.1} [Holdings]
Arranged alphabetically by name of reporting station, then chronologically
by date of recording.
Documents recording wind direction and wind speed at specified heights above the
Earth's surface, obtained from pibals and rawins (two different types of balloons
used to gather weather information), are contained in Series 1. Readings from
recording stations at Harrisburg, Philadelphia, Pittsburgh and Williamsport are
present. Information recorded on the sheets includes: pibal or rawin height above
the Earth's surface, observed elevation angle, distance in meters from observation
point, azimuth angle, wind direction and wind speed.
Summary of Winds Aloft Charts (WBAN-22),
1930-1964.
(5 boxes)
{series #288m.2} [Holdings]
Arranged alphabetically by name of reporting station, then chronologically
by date of recording.
Charts recording wind direction and wind speed at specified heights above the
Earth's surface, obtained from pibals and rawins, are present in this series.
Noted on the sheets are the stations which conducted the various observations,
as well as the year, month, day, and hour the observations were taken. Weather
conditions on days that measurements were not taken are also described on some
of the earlier forms. Cloud readings appear for various days between 1940 and
1942. The design of the charts, as well as the way data was recorded, change over
time. For example, a sixteen-point numbering system for wind direction instead
of the traditional "NW," N," "SE" designations was adopted
in the 1940s. Beginning in August 1936, four observations a day were taken, one
every six hours. The times at which they were taken changed over the years, including
a change on June 1, 1957 from 03, 09, 15 and 21 Greenwich mean time to 00, 06,
12 and 18 GMT.
Summary of Constant Pressure Charts (WBAN-33),
1946-1973.
(5 boxes)
{series #288m.3} [Holdings]
Arranged alphabetically by name of reporting station, then chronologically
by date of recording.
Charts containing data relative to constant air pressure, reported at the Pittsburgh
recording station. Information recorded includes: specific reporting station,
station identification data, elevation, scheduled time of release, actual time
of release, pressure reading, temperature, relative humidity, wind direction,
wind velocity, initials of computer and initials of verifier. Daily readings
were taken twice a day from 1946 through March 1954, then four times a day starting
in April 1954. The measurements were taken at 03, 09, 15 and 21 GMT, and were
changed 00, 06, 12 and 18 GMT beginning in June 1957. In October 1957 the readings
were scaled back to twice a day once again, occurring at 00 and 12 GMT.