AIM 8/15/19  7/16/20  12/31/20 NOTE − 1. Details concerning the content, format, and symbols of the various data link products provided should be obtained from the specific avionics manufacturer. 2. NOTAM − D and NOTAM − FDC products broadcast via FIS − B are limited to those issued or effective within the past 30 days. 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 − 10. 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 − 28 , 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 AIM, Para 7 − 2 − 3, Altimeter Errors. 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 Meteorology 7 − 1 − 23