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5 - Indicator figure for pressure change group
a - Characteristic of barometric tendency in last three hours (for stations with barographs)
Code Description
0 Rising then falling. [barometer same or higher than 3 hrs ago]
1 Rising then steady; or rising then rising more slowly. [barometer higher than 3 hrs ago]
2 Rising (steadily or unsteadily). [barometer higher than 3 hrs ago]
3 Falling or steady then rising; or rising then rising more rapidly. [barometer higher than 3 hrs ago]
4 Steady. [barometer same as 3 hrs ago]
5 Falling then rising. [barometer same or lower than 3 hrs ago]
6 Falling then steady; or falling then falling more slowly. [barometer lower than 3 hrs ago]
7 Falling (steadily or unsteadily). [barometer lower than 3 hrs ago]
8 Steady or rising, then falling; or falling, then falling more rapidly. [barometer lower than 3 hrs ago]
ppp - Change of atmospheric pressure in three hours preceeding observation in tenths of hPa (millibars)
e.g.
0.1 hPa is coded 001
1.0 hPa is coded 010
10.0 hPa is coded 100
Notes

- The hectopascal (hPa) is numerically equivalent to the millibar (mb)
- Supplementary ships and Auxiliary ships do not report this group