WEATHER 05 / LEARN · EXPLORE · CHECK
Weather products
Match the question to the product. Then check its time and limits.
Your learning goals
- Decode the essentials of METARs, TAFs, and PIREPs.
- Match route questions to radar, GFA, winds, and advisories.
- Check time, coverage, altitude reference, and uncertainty.
What was observed?
METAR/SPECI: airport observations. Check the observation time; a SPECI reports qualifying significant changes. In U.S. reports, visibility is in statute miles and cloud heights are hundreds of feet AGL. The ceiling is the lowest BKN or OVC layer, or vertical visibility into an obscuration; FEW and SCT are not ceilings. Wind direction is true. RVR is runway-specific visibility, generally reported in feet in the U.S.
PIREP: a sample along a flight path. Read /OV location, /TM time, /FL altitude, /TP aircraft, /SK clouds, /TA temperature, /TB turbulence, and /IC icing. Altitudes are normally MSL. UA is routine; UUA urgent. Aircraft type adds context, but does not give a fixed turbulence conversion. No reports does not mean no hazard.
What might be there when you arrive?
A TAF forecasts the airport area within 5 statute miles of the runway-complex center. Read issue time, validity, amendments, and the groups covering ETA. FM starts a new prevailing forecast. TEMPO describes temporary fluctuations; carry forward elements it does not change. PROB30 means a 30% probability of the stated conditions. Neither temporary nor lower-probability weather should be ignored in risk planning.
GFA adds the route picture: clouds, visibility, precipitation, icing, turbulence, and winds. Check valid time, selected altitude, and the layer’s legend. Surface analysis shows a current pattern; prog charts show its forecast development.
Winds and temperatures aloft help compare altitudes, groundspeed, fuel, and freezing exposure in climb and descent. In the coded winds product, 9900 means light and variable below 5 knots. For 100–199-knot winds, subtract 50 from the direction code and add 100 to speed: 7306 means 230° at 106 knots.
Which hazards deserve special attention?
G-AIRMET Sierra: widespread low ceilings, reduced visibility, and mountain obscuration. Tango: moderate turbulence, strong sustained surface winds, and nonconvective low-level wind shear. Zulu: moderate icing and freezing-level information. Read hazard, altitude, and valid time; a polygon is not a physical wall.
SIGMETs address significant hazards such as severe icing, severe or extreme turbulence, volcanic ash, and qualifying dust or sandstorms. Convective SIGMETs address qualifying thunderstorms. A storm need not qualify for an advisory to be dangerous. A CWA is short-term guidance for developing or locally significant weather.
The picture has blind spots
Radar shows precipitation echoes, not guaranteed cloud clearance or a direct turbulence measurement. Satellite imagery adds cloud coverage and cloud-top temperature clues, not runway ceiling or a guaranteed ice-free level.
FIS-B uses ground broadcasts over 978 MHz UAT to compatible ADS-B In equipment; satellite weather is a separate service. Datalink mosaics combine scans from different times, and the displayed age can understate the age of the weather. Use them for broad strategic avoidance, not close thunderstorm maneuvering.
FLIGHT SCENARIO
What would change your plan?
Teaching report, not live weather: KCMI 161853Z 22012G20KT 4SM -RA BR SCT008 BKN015 OVC030 18/17 A2992. What is the ceiling, and what cannot this report tell you?
- NoticeWhat does this situation require?
- VerifyWhat evidence is still missing?
- DecideWhat keeps an option open?
Compare your reasoning
At 1853Z on day 16: wind from 220° true at 12 knots gusting 20, visibility 4 statute miles, light rain and mist. The ceiling is 1,500 feet AGL, not the scattered layer at 800 feet. Temperature/dew point are 18/17°C; altimeter 29.92 inHg. It cannot establish weather along the route or at a later ETA. Check trends, forecasts, terrain, and runway wind.
SUMMARY
Observed, forecast, and advisory are different jobs.
At 1853Z on day 16: wind from 220° true at 12 knots gusting 20, visibility 4 statute miles, light rain and mist. The ceiling is 1,500 feet AGL, not the scattered layer at 800 feet. Temperature/dew point are 18/17°C; altimeter 29.92 inHg. It cannot establish weather along the route or at a later ETA. Check trends, forecasts, terrain, and runway wind.
Before moving on, explain the decision in your own words: what would you verify, and what would make you change the plan?
PRACTICE
Flashcards and knowledge check
Six flashcards, then five questions with explanations.
Enable JavaScript for flashcards and the knowledge check. The lesson and scenario remain available without it.
Sources & lesson notes
Sources & lesson notes
- FAA Aviation Weather HandbookAtmospheric processes, clouds, fronts, hazards, and aviation weather products.
- NOAA Aviation Weather Center: product guideReport formats, forecast coverage, and advisory definitions.
- FAA AIM: MeteorologyBriefing, datalink limitations, and weather avoidance guidance.
Curriculum framework: the supplied Weather Theory and weather products documents. All scenarios are educational examples, not current weather. Content reviewed September 2026.