The tables presented below are taken from Federal Meteorological Handbook No. 1 and represent a variety of coded values as used in the surface METAR code as used by the United States of America. Table numbers are the same as used in the handbook.
| Table 12-1: | Reportable Visibility Values |
| Table 12-2: | Notation for Reporting Present Weather |
| Table 12-3: | Contractions for Sky Cover |
| Table 12-4: | Increments of Reportable Values of Sky Cover Height |
| Table 12-5: | Type and Frequency of Lightning |
| Table 12-6: | Units of Measure for Precipitation |
| Table 12-7: | Characteristics of Barometer Tendency |
| Source of Visibility Report | |||||||
| Automated | Manual | ||||||
| M1/4 | 2 | 9a | 0 | 5/8 | 1 5/8 | 4 | 12 |
| 1/4 | 2 1/2 | 10 | 1/16 | 3/4 | 1 3/4 | 5 | 13 |
| 1/2 | 3 | 1/8 | 7/8 | 1 7/8 | 6 | 14 | |
| 3/4 | 4 | 3/16 | 1 | 2 | 7 | 15 | |
| 1 | 5 | 1/4 | 1 1/8 | 2 1/4 | 8 | 20 | |
| 1 1/4 | 6a | 5/16 | 1 1/4 | 2 1/2 | 9 | 25 | |
| 1 1/2 | 7 | 3/8 | 1 3/8 | 2 3/4 | 10 | 30 | |
| 1 3/4 | 8a | 1/2 | 1 1/2 | 3 | 11 | 35b | |
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a. These values may not be reported by some automated stations. b. Further values in increments of 5 statute miles may be reported, i.e., 40, 45, 50, etc. | |||||||
| Qualifier | Weather Phenomena | |||
| Intensity or Proximity 1 |
Descriptor 2 |
Precipitation 3 |
Obscuration 4 |
Other 5 |
| - light moderate + heavy VC in the vicinity |
MI shallow PR partial BC patches DR low drifing BL blowing SH shower(s) TS thunderstorm FZ freezing |
DZ drizzle RA rain SN snow SG snow grains IC ice crystals PL ice pellets GR hail GS small hail and/or snow pellets UP unknown precipitation |
BR mist FG fog FU smoke VA volcanic ash DU widespread dust SA sand HZ haze PY spray |
PO well-developed dust/sand whirls SQ squalls FC funnel cloud tornado waterspout SS sandstorm DS duststorm |
| Reportable Contraction | Meaning | Summation Amount of Layer |
| VV | vertical visibility | 8/8 |
| SKC or CLR1 | clear | 0 |
| FEW2 | few | 1/8 - 2/8 |
| SCT | scattered | 3/8 - 4/8 |
| BKN | broken | 5/8 - 7/8 |
| OVC | overcast | 8/8 |
| 1. The abbreviation CLR shall be used at automated stations when no layers at or below 12,000 feet are reported; the abbreviation SKC shall be used at manual stations when no layers are reported. 2. Any layer amount less than 1/8 is reported as FEW. | ||
| Range of Height Values (feet) | Reportable Increment (feet) |
| < 5,000 | to nearest 100 |
| > 5,000 but < 10,000 | to nearest 500 |
| > 10,000 | to nearest 1,000 |
| Type of Lightning | ||
| Type | Contraction | Definition |
| cloud-ground | CG | lightning occurring between cloud and ground |
| in-cloud | IC | lightning which takes place within the cloud |
| cloud-cloud | CC | streaks of lightning reaching from one cloud to another |
| cloud-ar | CA | streaks of lightning which pass from a cloud to the air but do not strike the ground |
| Frequency of Lightning | ||
| Frequency | Contraction | Definition |
| occasional | OCNL | less than 1 flash/minute |
| frequent | FRQ | about 1 to 6 flashes/minute |
| continuous | CONS | more than 6 flashes/minute |
| Type of Measurement | Unit of Measurement |
| liquid precipitation | 0.01 inch |
| water equivalent of solid precipitation | 0.01 inch |
| solid precipitation | 0.1 inch |
| snow depth | 1.0 inch |
| Primary Requirement |
Description | Code Figure |
| atmospheric pressure now higher than 3 hours ago |
increasing, then decreasing | 0 |
| increasing, then steady; or increasing then increasing more slowly | 1 | |
| increasing steadily or unsteadily | 2 | |
| decreasing or steady, then increasing; or increasing then increasing more rapidly | 3 | |
| atmospheric pressure now same as 3 hours ago |
increasing, then decreasing | 0 |
| steady | 4 | |
| decreasing, then increasing | 5 | |
| atmospheric pressure now lower than 3 hours ago |
decreasing, then increasing | 5 |
| decreasing then steady; or decreasing then decreasing more slowly | 6 | |
| decreasing steadily or unsteadily | 7 | |
| steady or increasing, then decreasing; or decreasing then decreasing more rapidly | 8 |