| AAA |
(or AAB, AAC, AAD... etc., in sequence) Amended meteorological message (a message type designator) |
| AAL |
Above aerodrome level |
| ABNDT |
Abundant |
| ABNML |
Abnormal |
| ABT |
About |
| ABV |
Above |
| Ac or AC |
Altocumulus |
| AC |
Anticipated Convection Outlook |
| ACC |
Area Control Center or area control |
| ACCAS |
Altocumulus Castellanus |
| ACCID |
Notification of an aircraft accident |
| ACCUM |
Accumulate |
| ACFT |
Aircraft |
| ACK |
Acknowledge |
| ACLT |
Accelerate |
| ACLTD |
Accelerated |
| ACLTG |
Accelerating |
| ACLTS |
Accelerates |
| ACPT |
Accept or accepted |
| ACPY |
Accompan |
| ACRS |
Across |
| ACSL |
Altocumulus Standing Lenticular |
| ACT |
Active or activated or activity |
| ACTV |
Active |
| ACTVTY |
Activity |
| ACYC |
Anticyclone |
| AD |
Aerodrome |
| ADA |
Advisory area |
| ADDN |
Addition or additional |
| ADJ |
Adjacent |
| ADL |
Additional |
| ADM |
Administrative Messages |
| ADQT |
Adequate |
| ADQTLY |
Adequately |
| ADR |
Advisory route |
| ADRNDCK |
Adirondack |
| ADVCT |
Advect |
| ADVCTD |
Advected |
| ADVCTG |
Advecting |
| ADVCTN |
Advection |
| ADVCTS |
Advects |
| ADVIS |
Headwater Advisory Program |
| ADVN |
Advance |
| ADVNG |
Advancing |
| ADVS |
Advisory service |
| ADVY |
Advisory |
| ADVYS |
Advisories |
| ADZ |
Advise |
| AFCT |
Affect |
| AFCTD |
Affected |
| AFCTG |
Affecting |
| AFD |
Area Forecast Discussion |
| AFDK |
After dark |
| AFOS |
Automation of Field Operations and Services |
| AFT |
After (time or place) |
| AFTN |
Afternoon |
| AGC |
Automatic Gain Control |
| AGL |
Above ground level |
| AGN |
Again |
| AGRD |
Agreed |
| AGRMT |
Agreement |
| AGRS |
Agrees |
| AHD |
Ahead |
| AHOS-S |
Automatic Hydrologic Observing System - Satellite |
| AHOS |
Automatic Hydrologic Observing System |
| AHOS-T |
Automatic Hydrologic Observing System - Telephone |
| AIRMET |
AIRman's METeorological Information |
| AK |
Alaska |
| AL |
Alabama |
| ALERT |
Automated Local Evaluation in Real Time |
| ALF |
Aloft |
| ALG |
Along |
| ALGHNY |
Allegheny |
| ALQDS |
All quadrants |
| ALSTG |
Altimeter setting |
| ALT |
Altitude |
| ALTA |
Alberta |
| ALTHO |
Although |
| ALTM |
Altimeter |
| ALUTN |
Aleutian |
| AMD |
Amend or amended (used to indicate amended meteorological message; message type designator) |
| AMDD |
Amended |
| AMDG |
Amending |
| AMDT |
Amendment |
| AMP |
Amplify |
| AMPG |
Amplifying |
| AMPLTD |
Amplitude |
| AMS |
Air mass |
| AMSL |
Above mean sea level |
| AMT |
Amount |
| ANLYS |
Analysis |
| ANS |
Answer |
| AOA |
At or above |
| AOB |
At or Below |
| AP |
Anomalous Propagation or Airport |
| APCH |
Approach |
| APCHG |
Approaching |
| APCHS |
Approaches |
| API |
Antecedent Precipitation Index |
| APLCN |
Appalachian |
| APLCNS |
Appalachians |
| APPR |
Appear |
| APPRG |
Appearing |
| APPRS |
Appears |
| APR |
April |
| APRNT |
Apparent |
| APRNTLY |
Apparently |
| APRX |
Approximate or approximately |
| APRXLY |
Approximately |
| APSG |
After passing |
| AQI |
Air Quality Statement |
| AR |
Arkansas |
| Arcus |
Arc Cloud |
| ARFOR |
Area forecast (in aeronautical meteorological code) |
| ARND |
Around |
| ARPT |
Airport |
| ARR |
Arrive or arrival |
| ART |
Automatic Radio Theodolite Master Control Unit As or AS - Altostratus |
| ASAP |
AHOS SHEF Automatic Processing System or as soon as possible |
| ASAPTRAN |
The software component of ASA |
| ASC |
Ascent to or ascending to |
| ASH |
Assistant Service Hydrologist |
| ASL |
Above Sea Level |
| ASMD |
As amended |
| ASOS |
Automated Surface Observing System |
| ASSOCD |
Associated |
| ASSOCN |
Association |
| AT... |
At (followed by time at which weather change is forecast to occur) |
| ATAD |
Automated Telephone Answering Device |
| ATDTDCS |
Automated Tone Dial Telephone Data Collection System |
| ATLC |
Atlantic |
| ATMU |
Air Transportable Mobile Unit |
| ATP... |
At... (time or place) |
| ATTM |
At this time |
| ATTN |
Attention |
| AUG |
August |
| AVBL |
Available or availability |
| AVG |
Average |
| AVN |
Aviation model |
| AWC |
Aviation Weather Center |
| AWHPS |
Area Wide Hydrologic Prediction System |
| AWIPS |
Advanced Weather Interactive Processing System |
| AWOS |
Automated Weather Observation System |
| AWT |
Awaiting |
| AZ |
Arizona |
| AZM |
Azimuth |
