Which scenario meets SPECI criteria?

The scenario that meets the criteria for a special weather report, or SPECI, is when there are specific significant changes in weather conditions that could affect flight safety. In the context of the choices provided, one key criterion for issuing a SPECI is a significant change in wind conditions, particularly a change in wind direction that occurs rapidly.

In the first scenario, a wind speed of 15 knots combined with a wind direction change of 60 degrees within a span of just 10 minutes qualifies as a notable shift. This type of rapid alteration is critical for pilots and flight operations, as it can affect aircraft performance and safety during takeoff, landing, and flight.

While the other scenarios present changes—visibility dropping from 2.5 miles to 2 miles and the observation of a tornado—these changes do not unanimously fit the SPECI criteria. A minor decrease in visibility like the one mentioned may not warrant immediate reporting unless visibility falls below specific thresholds set for aviation operations. The presence of a tornado, though significant, is usually covered by a different reporting structure such as a severe weather alert rather than a SPECI.

Therefore, the swift and notable increase in wind direction in the first scenario aligns correctly with the conditions that necessitate issuance of a SPE