Weather Station Message
Technical point of contact:
U.S. Department of Transportation
John A. Volpe
Transportation Systems Center
55 Broadway
Cambridge, MA 02142
Details:
| Parameter | Number of bits | Description | |
| Designated Area Code |
10 | The Designated Area Code will be 366 for the United States or 316 for Canada depending on the location of transmitter. |
|
| Function Identifier | 6 | FI=1 | |
| Reserved | 2 | ||
| Message ID | 6 | Message Identifier = 1 (00 0001 in binary) | |
| Binary Data | Max 768 | Message contains 1 to 4 weather station reports, each structured defined in next table. | |
| Total Number of bits | Max 792 | = 24 + N*192 | |
| N Total Bits | (Slots Required) | ||
| 1 216 bits | (2 slots) | ||
| 2 408 bits | (3 slots) | ||
| 3 600 bits | (4 slots) | ||
| 4 792 bits | (5 slots) | ||
Weather Station Report
| Parameter | Number of bits | Description |
| Timetag | 20 | Month, Day and Time of measurement, See UTC Time |
| Station ID | 42 | Seven 6-bit ASCII character ID |
| Longitude | 25 | Longitude in 1/1000 minute (±180 degrees, East = positive, West = negative. 181 degrees = not available) |
| Latitude | 24 | Latitude in 1/1000 minute (±90 degrees, North = positive, South = negative. 91 degrees = not available) |
| Wind Speed | 10 | Average Wind Speed in 1/10th Knot (0-102,2 knots, 1022 = 102,2 kts or greater, 1023 = not available) |
| Wind Gust | 10 | Wind Gust in 1/10th Knot (0-102,2 knots, 1022 = 102,2 kts or greater, 1023 = not available) |
| Wind Direction | 9 | Quantized to 16 compass points (Seaway only);Direction, 0-359 degrees, 511 = not available. For Saint Lawrence Seaway, refer to table below for descriptions of quantized values.
See Wind Direction Quantization |
| Atmospheric Pressure |
14 | Expressed in 1/10
th millibars. (16383 = not available) |
| Air Temp | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Dew Point | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Visibility | 8 | Visibility in 1/10 kilometers. (0-254, 254 = 25.4km or greater, 255 = not available) |
| Water Temp | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Total Number of bits | 192 |