3.7 Weather Information Sources

3.7 Weather Information Sources

Knowing where to obtain reliable weather information is both a practical necessity and an exam topic. Remote pilots should use multiple sources to build a complete weather picture.

Primary Weather Sources

1. Aviation Weather Center (aviationweather.gov)

• The FAA's official aviation weather service
• Provides METARs, TAFs, PIREPs, AIRMETs, SIGMETs
• Graphical weather products (radar, satellite, forecast maps)
• Free and publicly accessible

2. 1800WxBrief (1800wxbrief.com)

• Leidos Flight Service — the FAA's contracted weather briefing provider
• Provides standard, abbreviated, and outlook weather briefings
• Available online and by phone (1-800-WX-BRIEF)
• Can request a standard briefing for your planned operation

3. National Weather Service (weather.gov)

• General weather forecasts and warnings
• Useful for understanding large-scale weather patterns
• Radar data and severe weather alerts

Types of Weather Briefings

Aviation Weather Products

METAR — Current conditions (covered in Section 3.4)

TAF — Forecast for 24-30 hours (covered in Section 3.5)

AIRMET (Airmen's Meteorological Information):

• Moderate-level weather advisories affecting flight safety
• Three types:
  • Sierra (S) — IFR conditions (low ceilings, reduced visibility)
  • Tango (T) — Turbulence (moderate) and strong surface winds (30+ knots)
  • Zulu (Z) — Icing (moderate) and freezing levels
• Valid for 6 hours
• Issued as needed

SIGMET (Significant Meteorological Information):

• Significant weather advisory that could affect ALL aircraft
• Severe conditions: severe turbulence, severe icing, volcanic ash, dust storms
• Convective SIGMETs — specifically for thunderstorms meeting severity criteria
• Valid for 4 hours (convective SIGMETs valid for 2 hours)

PIREP (Pilot Report):

• Reports from pilots already flying about actual conditions encountered
• Include turbulence, icing, cloud heights, visibility
• UA = routine PIREP; UUA = urgent PIREP
• Particularly valuable because they report real conditions vs. forecasts

Winds and Temperatures Aloft Forecast:

• Forecast of wind direction, speed, and temperature at various altitudes
• Reported for specific altitudes (3,000, 6,000, 9,000, 12,000+ ft MSL)
• Wind direction in true north (not magnetic — different from METARs)
• Useful for understanding wind patterns above the surface

Weather Radar and Satellite Imagery

Radar (NEXRAD):

• Shows precipitation intensity and movement
• Color scale: green (light) → yellow (moderate) → red (heavy) → purple (extreme)
• Essential for tracking thunderstorms and rain

Satellite:

• Visible imagery — shows clouds as they appear (only available during daylight)
• Infrared imagery — shows cloud-top temperatures (available 24/7; higher/colder clouds = brighter)
• Water vapor imagery — shows moisture in the upper atmosphere

Weather Decision Process for Drone Operations

1. Check METARs for current conditions at nearby airports
2. Check TAFs for forecast conditions during your planned flight
3. Check radar for precipitation and thunderstorm movement
4. Check NOTAMs/TFRs for any weather-related restrictions
5. Evaluate winds — surface observations and forecasts
6. Make the go/no-go decision based on all available information
7. Continue monitoring during operations — weather can change rapidly

For the Exam: Know the difference between AIRMETs (moderate conditions) and SIGMETs (severe conditions), and know what each AIRMET type covers: Sierra = IFR, Tango = Turbulence, Zulu = Icing (freeze).