4/20/23 

AIM 

Chapter 7.  Safety of Flight 

Section 1.  Meteorology 

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1.  National Weather Service Aviation Weather Service Program 

a. 

Weather service to aviation is a joint effort of the National Oceanic and Atmospheric Administration 

(NOAA), the National Weather Service (NWS), the Federal Aviation Administration (FAA), Department of 

Defense, and various private sector aviation weather service providers. Requirements for all aviation weather 

products originate from the FAA, which is the Meteorological Authority for the U.S. 

b. 

NWS meteorologists are assigned to all air route traffic control centers (ARTCC) as part of the Center 

Weather Service Units (CWSU) as well as the Air Traffic Control System Command Center (ATCSCC). These 

meteorologists provide specialized briefings as well as tailored forecasts to support the needs of the FAA and 

other users of the NAS. 

c. 

Aviation Products 

1. 

The NWS maintains an extensive surface, upper air, and radar weather observing program; and a 

nationwide aviation weather forecasting service. 

2. 

Airport observations (METAR and SPECI) supported by the NWS are provided by automated observing 

systems. 

3. 

Terminal Aerodrome Forecasts (TAF) are prepared by 123 NWS Weather Forecast Offices (WFOs) for 

over 700 airports. These forecasts are valid for 24 or 30 hours and amended as required. 

4. 

Inflight aviation advisories (for example, Significant Meteorological Information (SIGMETs) and 

Airmen’s Meteorological Information (AIRMETs)) are issued by three NWS Meteorological Watch Offices 

(MWOs); the Aviation Weather Center (AWC) in Kansas City, MO, the Alaska Aviation Weather Unit (AAWU) 

in Anchorage, AK, and the Weather Service Forecast Office (WFO) in Honolulu, HI. The AWC, the AAWU, 

and WSFO Honolulu issue area forecasts for selected areas. In addition, NWS meteorologists assigned to most 

ARTCCs as part of the Center Weather Service Unit (CWSU) provide Center Weather Advisories (CWAs) and 

gather weather information to support the needs of the FAA and other users of the system. 

5. 

Several NWS National Centers for Environmental Production (NCEP) provide aviation specific weather 

forecasts, or select public forecasts which are of interest to pilots and operators. 

(a) 

The Aviation Weather Center (AWC) displays a variety of domestic and international aviation 

forecast products over the Internet at aviationweather.gov. 

(b) 

The NCEP Central Operations (NCO) is responsible for the operation of many numerical weather 

prediction models, including those which produce the many wind and temperature aloft forecasts. 

(c) 

The Storm Prediction Center (SPC) issues tornado and severe weather watches along with other 

guidance forecasts. 

(d) 

The National Hurricane Center (NHC) issues forecasts on tropical weather systems (for example, 

hurricanes). 

(e) 

The Space Weather Prediction Center (SWPC) provides alerts, watches, warnings and forecasts for 

space weather events (for example, solar storms) affecting or expected to affect Earth’s environment. 

(f) 

The Weather Prediction Center (WPC) provides analysis and forecast products on a national scale 

including surface pressure and frontal analyses. 

6. 

NOAA operates two Volcanic Ash Advisory Centers (VAAC) which issue forecasts of ash clouds 

following a volcanic eruption in their area of responsibility. 

Meteorology 

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