Center Weather Advisory is the unscheduled weather advisory used by ATC to alert pilots of existing or anticipated adverse weather within the next two hours. It fills a specific need when weather poses potential hazards but doesn’t meet the formal criteria for a SIGMET or when a more immediate, operational alert is required for coordination between controllers and pilots. This advisory is designed to be timely and concise, focusing on the area, the type of weather, and the expected evolution over the two-hour window so pilots can plan routes and ATC can adjust traffic flow as needed. Pilots’ PIREPs describe actual observed conditions from the cockpit, not an ATC-issued alert about forecast or developing weather. HIWAS is a continuous broadcast service that relays various weather advisories, not a single, situationally issued alert for a specific two-hour period. SIGMETs are formal warnings for significant weather hazards that meet defined criteria and cover longer ranges or more severe phenomena; CWAs target shorter, immediate, operational needs within a two-hour horizon.

Maintaining high situational awareness is what keeps you on top of everything happening on and around the runways. In a tower, you must know exactly where aircraft and ground vehicles are, what they’re doing, and where they’re headed at every moment. This mental picture lets you spot potential conflicts early—like a taxiing aircraft approaching a runway just as another is cleared for takeoff—and act quickly to stop or adjust movements before an incursion can occur. It also supports precise coordination: you can issue clear, unambiguous instructions, verify readbacks, and cross-check with radar or ground surveillance to maintain safe separation. Relying on less dynamic sources, such as reducing radio transmissions, would hinder timely communication and clarity when conflicts arise. Focusing solely on ground operations ignores the bigger picture of movements that affect runway safety, including aircraft in the airspace near the airport. Relying on ATIS for all decisions provides useful information, but it’s only a snapshot and doesn’t replace real-time observation and coordination with pilots and ground vehicles. So, staying aware of the current state and movements on the surface and in the immediate airspace enables proactive prevention of runway incursions through timely, precise actions.

Hazardous inflight weather advisories must be broadcast as soon as they are received. These warnings (like SIGMETs, AIRMETs, or Convective SIGMETs) are time‑sensitive and vital for flight safety, so they should be disseminated immediately to all appropriate frequencies and users in the area rather than waiting for a routine update or applying arbitrary distance limitations. ATIS provides routine weather information for pilots on the ground and is not the channel for real-time hazard dissemination. Limiting broadcasts to a fixed radius (for example, within 50 NM) or using only a priority frequency would restrict the reach of the warning and could leave some aircraft unaware of dangerous conditions.

In NOTAM text, the virgule (/) is used to separate runway designators that belong to the same runway pair at an aerodrome. The slash shows that the condition or status applies to both directions of that runway pair, not just one direction. For example, RWY 04/22 indicates that both the 04 and the 22 directions share the same NOTAM. It’s not about pausing or separating words; its function is to group paired runways under one notification.