Appendix E, Abbreviations, Acronyms, and Initialisms E-6
MCS Mesoscale Convective System
MDA Minimum Descent Altitude
MEL Minimum Equipment List
METAR Aviation Routine Weather Report
mg/m3 milligrams per cubic meter
MHz megahertz
mi mile
min minute
MIS Meteorological Impact Statement
MOS Model Output Statistics
mP Maritime Polar
mph miles per hour
m/s meters per second
MSL Mean Sea Level
mT Maritime Tropical
MVFR Marginal Visual Flight Rules
MWO Meteorological Watch Office
MWT Mountain Wave Turbulence
N North
N/A Not Applicable
NAM North American Model
NAS National Airspace System
NASA National Aeronautics and Space Administration
NAVAID Navigational Aid
NCEP National Centers for Environmental Prediction
NCO NCEP Central Operations
NCWF National Convective Weather Forecast
NDFD National Digital Forecast Database
NE Northeast
NESDIS National Environmental Satellite, Data, and Information Service
Appendix E, Abbreviations, Acronyms, and Initialisms E-7
NEXRAD Next Generation Weather Radar
NextGen Next Generation Air Transportation System
NHC National Hurricane Center
nm nanometer
NM nautical mile
NNE North-Northeast
NNW North-Northwest
NOAA National Oceanic and Atmospheric Administration
NOTAM Notice to Airmen
NW Northwest
NWP Numerical Weather Prediction
NWS National Weather Service
OAT Outside Air Temperature
ODP Obstacle Departure Procedure
OMO One-Minute Observation
OPC Ocean Prediction Center
OPMET Operational Meteorological
P Polar
PECASUS Pan-European Consortium for Aviation Space Weather User Services
PGF Pressure Gradient Force
PIC Pilot in Command
PIREP Pilot Weather Report
POES Polar Operational Environment Satellite
POI Principal Operations Inspector
Prog Prognostic
psi pounds per square inch
QA Quality Assurance
radar Radio Detection and Ranging
RCM Radar Coded Message
RCO Remote Communications Outlet
Appendix E, Abbreviations, Acronyms, and Initialisms E-8
RH Relative Humidity
ROFOR Route Forecast
RTMA Real-Time Mesoscale Analysis
RVR Runway Visual Range
S South
s or sec second
SAA Special Activity Airspace
SAB Satellite Analysis Branch
SAS Safety Assurance System
SATCOM Satellite Communications
SAW Aviation Watch Notification Message
SE Southeast
SFRA Special Flight Rules Area
SI International System of Units
SIC Second in Command
SID Standard Instrument Departure
SIGMET Significant Meteorological Information
SIGWX Significant Weather
SLD Supercooled Large Drop
SLWC Supercooled Liquid Water Content
SM statute mile
SMS Safety Management System
SO2 Sulfur Dioxide
SPC Storm Prediction Center
SPECI Aviation Selected Special Weather Report
SRM Safety Risk Management
SSE South-Southeast
SSW South-Southwest
STOP Special Terminal Operation Procedures
SUA Special Use Airspace
Appendix E, Abbreviations, Acronyms, and Initialisms E-9
SW Southwest
SWPC Space Weather Prediction Center
T Tropical
TAF Terminal Aerodrome Forecast
TCA Tropical Cyclone Advisory
TCAC Tropical Cyclone Advisory Center
TCF TFM Convective Forecast
TCu Towering Cumulus
TDWR Terminal Doppler Weather Radar
TDZ Touchdown Zone
TFM Traffic Flow Management
TFR Temporary Flight Restriction
TMS Traffic Management System
TMU Traffic Management Unit
TRACON Terminal Radar Approach Control
TUTT Tropical Upper Tropospheric Trough
U.S. United States
UAT Universal Access Transceiver
UCAR University Corporation for Atmospheric Research
UTC Coordinated Universal Time
VAA Volcanic Ash Advisory
VAAC Volcanic Ash Advisory Center
VAD Velocity Azimuth Display
VAG Graphical Version of the Volcanic Ash Advisory
VAR Volcanic Activity Report
VCP Volume Coverage Pattern
VEIA Visibility Estimation through Image Analytics
VFR Visual Flight Rules
VHF Very High Frequency
VMC Visual Meteorological Conditions
Appendix E, Abbreviations, Acronyms, and Initialisms E-10
VNR VFR Flight Not Recommended
VOR Very High Frequency Omni-Directional Range Station
VR Rotation Speed
W watt
W West
W m-1 K-1 watt per meter-Kelvin
WADL West African Disturbance Line
WAFC World Area Forecast Center
WAFS World Area Forecast System
WARP Weather and Radar Processor
WFO Weather Forecast Office
WIFS WAFS Internet File Service
WMO World Meteorological Organization
WNW West-Northwest
WPC Weather Prediction Center
WSP Weather Systems Processor
WSR-88D Weather Surveillance Radar—1988 Doppler
WSW West-Southwest
Wx Weather
yd yard
Z or z Zulu