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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,