Appendix
Acronyms: U's
| U/S | Unserviceable |
|---|---|
| UAB | Until advised by ... |
| UCP | Unit Control Position |
| UDDF | Up and down drafts |
| UFN | Until further notice |
| UIR | Upper flight information region |
| UKMET | United Kingdom METeorological Agency |
| ULJ | Upper Level Jet |
| UN | Unable |
| UNA | Unable |
| UNAVBL | Unavailable |
| UNEC | Unnecessary |
| UNKN | Unknown |
| UNL | Unlimited |
| UNREL | Unreliable |
| UNRELBL | Unreliable |
| UNRSTD | Unrestricted |
| UNSATFY | Unsatisfactory |
| UNSBL | Unseasonable |
| UNSTBL | Unstable |
| UNSTDY | Unsteady |
| UNSTL | Unsettle |
| UNSTLD | Unsettled |
| UNUSBL | Unusable |
| UPDFTS | Updrafts |
| UPR | Upper |
| UPSLP | Upslope |
| UPSTRM | Upstream |
| URG | Urgent |
| USACE | U.S. Army Corps of Engineers |
| USBL | Usable |
| USBR | U.S. Bureau of Reclamation |
| USFS | U.S. Forest Service |
| USGS | U.S. Geological Survey |
| UT | Utah |
| UTC | Coordinated Universal Time |
| UV | Ultraviolet |
| UVM | Upward Vertical Motion. |
| UVV | Upward Vertical Velocity |
| UVVS | Upward vertical velocities |
| UWNDS | Upper winds |
