Showing posts with label weather. Show all posts
Showing posts with label weather. Show all posts

Sunday, June 27, 2010

Aviation Weather Sequence (SA) Reports Make More Sense Than METARS

In 1996, a major change to weather reports for pilots occurred. In order to standardize with the International Civil Aviation Organization (ICAO) the replacement for the Aviation Weather Sequence Reports (SA) was something the Europeans called METARS.  The United States Federal Aviation Administration (FAA) lays down the definition in its publication the Aeronautical Information Manual as aviation routine weather report.


I think it is time to go back to the Aviation Weather Sequence (SA) reports format.   Nothing was gained for the US pilot with the change except added confusion when this new format called METARS was introduced.

The most important weather factors for most pilots are the ceiling and visibility.  These are the very first two elements of the Aviation Weather Sequence Reports (SA). Here is a sample of one for Raleigh Durham,  North Carolina:
RDU SA 0150 M50 OVC 10RW- 094/74/59/1009/982

Translation - Raleigh-Durham, observation at 0150 ZULU, measured ceiling 5,000 feet overcast, visibility 10 statute miles; light rain showers; sea level pressure 1009.4 millibars; temperature 74° F; dewpoint 59° F; wind from 100° true at 9 knots; altimeter 29.82 inches. 
The ceiling and visibility are found right up front and  is a measured ceiling 5,000 feet overcast and a visibility of 10 miles. 

Here is the corresponding METAR report for Raleigh Durham:
KRDU 271951Z 10009 10SM OVC050  74/59 A2982

In the METAR Report, the first item you see is the wind direction and velocity and you have to dig into the middle of the  METAR to discover the visibility is 10 miles and the  ceiling is overcast  at 5,000 feet. When you are looking at a large number of weather reports, the difference in being able to create a picture of the weather  is much easier using the Aviation Weather Sequence (SA) report format. 


I discovered that the WSI,Inc. web site still makes the Aviation Weather Sequence (SA) reports available for the convenience of pilots today. Many pilots are not aware they are still available.