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AIM

10/12/17

7

−1−24

Meteorology

TBL 7

−1−2

Product Parameters for Low/Medium/High Altitude Tier Radios

Product

Surface Radios

Low Altitude Tier

Medium Altitude
Tier

High Altitude Tier

CONUS NEXRAD

N/A

CONUS NEXRAD
not provided

CONUS NEXRAD
imagery

CONUS NEXRAD
imagery

Winds & Temps
Aloft

500 NM look

−ahead

range

500 NM look

−ahead

range

750 NM look

−ahead

range

1,000 NM look

ahead range

METAR

100 NM look

−ahead

range

250 NM look

−ahead

range

375 NM look

−ahead

range

CONUS: CONUS
Class B & C airport
METARs and 500
NM look

−ahead

range

Outside of CONUS:
500 NM look-ahead
range

TAF

100 NM look

−ahead

range

250 NM look

−ahead

range

375 NM look

−ahead

range

CONUS: CONUS
Class B & C airport
TAFs and 500 NM
look

−ahead range

Outside of CONUS:
500 NM look-ahead
range

AIRMET, SIGMET,
PIREP, and SUA/
SAA

100 NM look

−ahead

range. PIREP/SUA/
SAA is N/A.

250 NM look

−ahead

range

375 NM look

−ahead

range

500 NM look

−ahead

range

Regional NEXRAD

150 NM look

−ahead

range

150 NM look

−ahead

range

200 NM look

−ahead

range

250 NM look

−ahead

range

NOTAMs D, FDC,
and TFR

100 NM look

−ahead

range

100 NM look

−ahead

range

100 NM look

−ahead

range

100 NM look

−ahead

range

7

−1−12. Weather Observing Programs

a. Manual Observations.

With only a few

exceptions, these reports are from airport locations
staffed by FAA personnel who manually observe,
perform calculations, and enter these observations
into the (WMSCR) communication system. The
format and coding of these observations are
contained in Paragraph 7

−1−30 , Key to Aviation

Routine Weather Report (METAR) and Aerodrome
Forecasts (TAF).

b. Automated Weather Observing System

(AWOS).

1.

Automated weather reporting systems are

increasingly being installed at airports. These
systems consist of various sensors, a processor, a
computer-generated voice subsystem, and a transmit-

ter to broadcast local, minute-by-minute weather data
directly to the pilot.

NOTE

When the barometric pressure exceeds 31.00 inches Hg.,
see Paragraph 7

−2−2 , Procedures, for the altimeter

setting procedures.

2.

The AWOS observations will include the

prefix “AUTO” to indicate that the data are derived
from an automated system. Some AWOS locations
will be augmented by certified observers who will
provide weather and obstruction to vision informa-
tion in the remarks of the report when the reported
visibility is less than 7 miles. These sites, along with
the hours of augmentation, are to be published in the
Chart Supplement U.S. Augmentation is identified in
the observation as “OBSERVER WEATHER.” The
AWOS wind speed, direction and gusts, temperature,