It is widely recognized that there is not enough weather instrumentation over the open ocean. This is why the National Weather Service has become a participant in the World Meteorological Organizations Voluntary Observing Ships (VOS) program. VOS is a world wide organization involving 49 countries. Most coastal offices of the National Weather Service have a Port Meteorological Officer (PMO), who's main function is to recruit ships into the VOS program and take weather observations while at sea. Ultimately the more data that is collected the better NWS Marine forecasts will be.
Since our involvement in the VOS program, the United States has recruited the most ships totalling over 1600. New computers
installed in NWS Forecast Offices allows the meteorologist to view the ship observation in real time.
In addition, the PMO is responsible for maintaining the observing program of actively participating ships. The PMO must ensure the collected data is of highest quality. PMO's spend a majority of their time visiting ships in the harbors of
major ports. They primarily assist deck officers with observation practices, weather codes, and report transmission procedures. PMO's also distribute supplies such as observing forms, handbooks, and operating instructions. As a part of the visit, the PMO will calibrate the ships barometer or barograph and make corrections if necessary. The PMO will review completed observation forms, point out omissions or errors, and suggest methods for improvement.
The PMO's main point of contact is with the ship owner, shiping agents, port operators, shore radio stations,
or maritime academies.
Voluntary Observing Ship Program (VOS) and the Mariners Weather Log (MWL).