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Refer to Figure 15. The KMEM TAF includes "PROB40 1220/1222 1SM TSRA OVC008CB". What does this mean?

Choices

  • ✓ A 40% probability, from 2000Z to 2200Z, of 1 statute mile visibility in a thunderstorm with rain and an overcast cumulonimbus ceiling at 800 feetcorrect

    PROB40 is a 40% probability group; 1220/1222 is the 2000Z–2200Z window; 1SM TSRA is 1 mile in thunderstorm/rain; OVC008CB is overcast cumulonimbus at 800 ft.

  • Winds will be 40 knots from 1220Z to 1222Z

    PROB40 is a probability, not a wind speed.

  • Visibility will improve to 40 statute miles after 2200Z

    PROB40 means 40% probability of the following conditions, not 40 miles visibility.

  • A guaranteed thunderstorm between 1200Z and 2000Z

    A PROB group is a probability (40%), not a certainty, and the window is 2000Z–2200Z.

Why

PROB40 1220/1222 1SM TSRA OVC008CB forecasts a 40 percent probability, during the 2000Z–2200Z period, of 1 statute mile visibility in a thunderstorm with rain and overcast cumulonimbus at 800 feet.

FAA source: FAA-H-8083-28 (TAF)browse the reference library →

This is taught in Decoding METARs and TAFs — study the lessons free, then practice with grading and mastery tracking.

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.

Refer to Figure 15. The KMEM TAF includes "PROB40 1220/1222 1SM TSRA… · PPL Free Ground School