Aviation Weather Services

in the Alaska Chart Supplement U.S. (formerly Airport/ 5. En route forecast—a summary of the weather forecast Facility Directory). These broadcasts are made available for the proposed route of flight. primarily for preflight and inflight planning, and as such, 6. Destination forecast—a summary of the expected should not be considered as a substitute for specialist- weather for the destination airport at the estimated provided preflight briefings. time of arrival (ETA). Weather Briefings 7. Forecast winds and temperatures aloft—a forecast of the winds at specific altitudes for the route of flight. Prior to every flight, pilots should gather all information The forecast temperature information aloft is provided vital to the nature of the flight. This includes an appropriate only upon request. weather briefing obtained from a specialist at a FSS. 8. Notices to Airmen (NOTAM)—information pertinent For weather specialists to provide an appropriate weather to the route of flight that has not been published in the briefing, they need to know which of the three types of NOTAM publication. Published NOTAM information briefings is needed—standard, abbreviated, or outlook. Other is provided during the briefing only when requested. helpful information is whether the flight is visual flight rules 9. ATC delays—an advisory of any known ATC delays (VFR) or IFR, aircraft identification and type, departure that may affect the flight. point, estimated time of departure (ETD), flight altitude, route 10. Other information—at the end of the standard briefing, of flight, destination, and estimated time en route (ETE). the FSS specialist provides the radio frequencies needed to open a flight plan and to contact EFAS. Any This information is recorded in the flight plan system and a additional information requested is also provided at note is made regarding the type of weather briefing provided. this time. If necessary, it can be referenced later to file or amend a flight plan. It is also used when an aircraft is overdue or is Abbreviated Briefing reported missing. An abbreviated briefing is a shortened version of the standard briefing. It should be requested when a departure has been Standard Briefing delayed or when weather information is needed to update A standard briefing provides the most complete information the previous briefing. When this is the case, the weather and a more complete weather picture. This type of briefing specialist needs to know the time and source of the previous should be obtained prior to the departure of any flight and briefing so the necessary weather information is not omitted should be used during flight planning. A standard briefing inadvertently. It is always a good idea for the pilot to update provides the following information in sequential order if it the weather information whenever he/she has additional time. is applicable to the route of flight. 1. Adverse conditions—this includes information about Outlook Briefing adverse conditions that may influence a decision to An outlook briefing should be requested when a planned cancel or alter the route of flight. Adverse conditions departure is 6 hours or more away. It provides initial forecast include significant weather, such as thunderstorms or information that is limited in scope due to the time frame aircraft icing, or other important items such as airport of the planned flight. This type of briefing is a good source closings. of flight planning information that can influence decisions 2. VFR flight not recommended—if the weather for regarding route of flight, altitude, and ultimately the go/no-go the route of flight is below VFR minimums, or if decision. A prudent pilot requests a follow-up briefing prior it is doubtful the flight could be made under VFR to departure since an outlook briefing generally only contains conditions due to the forecast weather, the briefer may information based on weather trends and existing weather in state “VFR flight not recommended.” It is the pilot’s geographical areas at or near the departure airport. A standard decision whether or not to continue the flight under briefing near the time of departure ensures that the pilot has VFR, but this advisory should be weighed carefully. the latest information available prior to his/her flight. 3. Synopsis—an overview of the larger weather picture. Aviation Weather Reports Fronts and major weather systems that affect the general area are provided. Aviation weather reports are designed to give accurate depictions of current weather conditions. Each report 4. Current conditions—the current ceilings, visibility, provides current information that is updated at different times. winds, and temperatures. If the departure time is more Some typical reports are METARs and PIREPs. than 2 hours away, current conditions are not included in the briefing. 13-5