Sources of weather data

This element is about where weather data comes from. The DPE wants two FAA-approved primary sources by name, a few supplemental sources you actually use, and a coherent story of how you assemble — and document — the picture before the flight.

The two FAA-approved primary sources

aviationweather.gov for the products. 1800wxbrief.com for the documented briefing. Together they satisfy §91.103 per AC 91-92.

aviationweather.gov

• National Weather Service's Aviation Weather Center
• Source of every aviation product: METARs, TAFs, prog charts, AIRMETs, SIGMETs, icing, turbulence, winds aloft
• Free, public, no login
• What every EFB and weather app pulls from

1800wxbrief.com or 1-800-WX-BRIEF

• Leidos Flight Service under FAA contract
• Documented briefing: standard, abbreviated, outlook
• Same logged record from the website as from the phone
• EFBs that deliver a Leidos-backed standard briefing carry the same documented-record status AC 91-92

Use both: aviationweather.gov for spot-checks, 1800wxbrief.com (or an EFB delivering Leidos) for the briefing of record.

Supplemental sources you'll use

These pull from the same NWS feed but don't on their own carry the documented-briefing status under AC 91-92:

EFB apps

• ForeFlight, Garmin Pilot, FltPlan Go
• Reformat aviationweather.gov + Leidos data for cockpit readability
• Many can deliver a Leidos-backed standard briefing — that does carry the logged-record status

On-airport observations

• ATIS — human-recorded at towered fields
• ASOS — automated, full sensor suite, most common
• AWOS — older, capability varies (AWOS-A through AWOS-3, 3PT, 3T)
• Hourly observation plus SPECIs for change events

Datalink weather

• FIS-B — free over 978 UAT ADS-B In, FAA-provided
• SiriusXM Aviation — subscription, satellite-based, lower NEXRAD latency
• Inflight reception of METAR, TAF, NEXRAD, AIRMET, SIGMET
• Limitations and the "strategic not tactical" framing are covered in K4

Consumer weather

• Local TV, weather.com, Apple Weather
• General awareness only; aviation-grade products live on aviationweather.gov

PIREPs

The only real-time human observation from cockpit altitude. Qualitatively different from every other product:

• Real-time — minutes old, not forecast
• From cockpit altitude, filling the gap between surface obs and upper-air analyses
• Human-judged — turbulence, icing, ceilings described as a pilot would

Two types per AIM 7-1-19:

• Routine (UA) — typical conditions
• Urgent (UUA) — severe or extreme turbulence, severe icing, low-level wind shear, hail, volcanic ash, tornado, funnel cloud, or waterspout

Read PIREPs when checking en route weather. File yours when conditions matter — sparse coverage is a national problem and silence helps no one.

What FSS does today

Leidos has operated Flight Service under FAA contract since 2007. Most physical facilities have consolidated; the service is now mostly virtual through 1-800-WX-BRIEF and 1800wxbrief.com.

Services that still exist

• Preflight briefings — standard, abbreviated, outlook
• File, amend, close flight plans
• File PIREPs from the cockpit via Flight Service on 122.2 MHz or by phone
• Lost-comm and emergency assistance
• NOTAM dissemination

Services that are gone

• HIWAS (Hazardous In-Flight Weather Advisory Service) — decommissioned 2020
• EFAS / Flight Watch on 122.0 — discontinued 2015
• TWEB (Transcribed Weather Broadcast) — discontinued

When the DPE asks "is HIWAS still around?" — the answer is discontinued, replaced by FIS-B, SiriusXM, and EFB delivery.

Worked examples:

• Cross-country to a non-towered destination with no ASOS or AWOS. Build the destination picture from the nearest TAF, the GFA covering the destination area, and METARs from the nearest reporting station. Pull a documented Leidos briefing via 1800wxbrief.com or an EFB that delivers one — that's the record satisfying §91.103.
• Local pattern work, towered field, severe-clear forecast. Home-field ATIS plus aviationweather.gov's METAR and area forecast covers it; §91.103 requires familiarization "for a flight under IFR or a flight not in the vicinity of an airport," so the strict-documentation expectation narrows for local ops. Still check, even when the formal record isn't required.