AFOS:  Automation of Field Operations and Services. Computer system linking
NWS offices for the transmission of weather data. Replaced by AWIPS. 

AGRI:  Agricultural.

AIREPS:  Aircraft ReportS.

AIRMET:  An AIRMET (AIRman's METeorological Information) advises of weather
that maybe hazardous, other than convective activity, to single engine,
other light aircraft, and Visual Flight Rule (VFR) pilots. However,
operators of large aircraft may also be concerned with these phenomena. The
items covered are:  AIRMET Sierra (IFR):  Ceilings less than 1000 feet
and/or visibility less than 3 miles affecting over 50% of the area at one
time, Extensive mountain obscuration.  AIRMET Tango (Turbulence):  Moderate
turbulence, Sustained surface winds of 30 knots or more at the surface.
AIRMET Zulu (Icing):  Moderate icing, Freezing levels.  These AIRMET items
are considered to be widespread because they must be affecting or be
forecast to affect an area of at least 3000 square miles at any one time.
However, if the total area to be affected during the forecast period is very
large, it could be that only a small portion of this total area would be
affected at any one time.  AIRMETs are routinely issued for 6 hour periods
beginning at 0145 UTC during Central Daylight Time and at 0245 UTC during
Central Standard Time. AIRMETS are also amended as necessary due to changing
weather conditions or issuance/cancelation of a SIGMET.

AK:  Alaska/Alaskan.


ASOS:  Automated Surface Observing System.

AVN:  Aviation Model generated every 12 hours by NCEP. Renamed GFS model in
late 2002. 

AWIPS:  Advanced Weather Information Processing System. New NWS computer
system integrating graphics, satellite and radar imagery. The successor to


DEG:  Degree(s).

ETA:  "Eta" (from Greek) model generated every 12 hours by NCEP.

FCST:  Forecast.

FOUS:  These bulletins contain the initial numerical model analyses and
forecasts for points in the United States, Canada, and over the adjacent

GOES:  Geostationary Operational Environmental Satellite.  (ex., GOES-8 /

INTNL:  International.

JSC:  (Johnson Space Center?)

MAX:  Maximum.

MIN:  Minimum.

MOS:  Model Output Statistics.

MRF:  Medium Range Forecast model generated every 12 hours by NCEP.

MSG:  Message.

NATL:  National.

NCF:  NWS Network Control Facility.

NM:  Nautical Mile(s).

NWWS:  NOAA WEATHER WIRE.  Mass dissemination via satellite of National
Weather Service products to the media and public. 

NWR:  NOAA WEATHER RADIO.  Continuous, 24 hour a day VHF broadcasts of
weather observations and forecasts directly from National Weather Service
offices. A special tone allows certain receivers to alarm when watches or
warnings are issued.


NWS:  National Weather Service.

POPs:  Probability of Precipitation.

PRECIP:  Precipitation.

PRELIM:  Preliminary.

PROG:  Prognostic.

QPF:  Quantitative Precipitation Forecast.

RADAT:  Rawinsonde DATa are upper air soundings via balloon. More than 1000
points that take soundings once at noon and again at midnight zulu time.

RCM:  Radar Coded Message (RCM) images are derived from NEXRAD doppler
radars around the nation. Resolution is much coarser than doppler radars
(~12 km grid). Included in the RCM bulletins are information on storm tops,
cell movement, and locations of mesocyclones and tornado vortex signatures.
RCM imagery at Ohio State is updated twice hourly near the top and bottom
of the hour. 6-hour loops are updated at the top of the hour only.
Reflectivity intensities are represented by a color bar, with dark green
representing light precipitation and red showing areas of very heavy
precipitation. Radar sites operating in "clear air" mode are not included
in the image, since many exhibit spurious echos. Cell movement barbs are
only shown on the regional radar plots since they tend to clutter the
national image. Echo tops are in 100s of feet. Mesocyclone signatures are
represented by orange circles, while tornado vortex signatures (TVS) are
shown as red plus (+) signs.

RFC:  River Forecast Center. The Missouri Basin RFC is located in Kansas
City, MO. 


SFC:  Surface.

SHEF:  Standard Hydrometeorological Exchange Format.  Set of rules for
coding of data in a form for both visual and computer recognition.

SIGMET:  A SIGMET (SIGnificant METeorlogical Information) advises of
weather potentially hazardous to all aircraft other than convective
activity. In the conterminous U.S., items covered are:  Severe icing,
Severe or extreme turbulence, Duststorms and sandstorms lowering
visibilities to less than three (3) statute miles, Volcanic Ash.  In
Alaska and Hawaii, SIGMETs are also issued for the following events:
Tornadoes, Lines of thunderstorms, Embedded thunderstorms, Hail greater
than or equal to 3/4 inch in diameter.  For the lower 48 states and
adjacent coastal waters, Convective SIGMETs are issued hourly for
Thunderstorm-related aviation hazards.  These SIGMET items are
considered to be widespread because they must be affecting or be
forecast to affect an area of at least 3000 square miles at any one
time. However, if the total area to be affect during the forecast
period is very large, it could be that only a small portion of this
total area would be affected at any one time.  SMETs are issued for 6
hour periods for conditions associated with hurricanes and 4 hours for
all other events. If conditions persist beyond the forecast period, the
SIGMET is updated and reissued.

SNOWTEL:  The Natural Resources Conservation Service (NRCS) installs,
operates, and maintains an extensive, automated system to collect
snowpack and related climatic data in the Western United States called
SNOTEL (for SNOwpack TELemetry). The system evolved from NRCS's
Congressional mandate in the mid-1930's "to measure snowpack in the
mountains of the West and forecast the water supply." The programs
began with manual measurements of snow courses; since 1980, SNOTEL has
reliably and efficiently collected the data needed to produce water
supply forecasts and to support the resource management activities of
NRCS and others.

SPC:  The Storm Prediction Center located in Norman, OK. This office is
responsible for monitoring and forecasting severe convective weather in
the continental U.S. This includes the issuance of Tornado and Severe
Thunderstorm Watches. 

SYNOP:  Synoptic.

TEMP:  Temperature.

WSR-88D:  NexRAD Doppler Radar.

WX:  Weather.