Graphical Forecasts for Aviation

The Graphical Forecasts for Aviation tool at the Aviation Weather Center is now operational. It supplants the text Area Forecasts in the lower 48, plus it offers more information about current weather. AOPA has published more news about the swtich to the GFA here.

For more detailed information about the GFA tool, see this description (PDF) and this tutorial.

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New Edition of AC 00-6 Aviation Weather

FAA has published a new edition of AC 00-6 – Aviation Weather (PDF), the 1975 handbook that explains weather theory for pilots.

New scientific capabilities now necessitate an update to this AC. In 1975, aviation users were not directly touched by radar and satellite weather. In 2016, much of what airmen understand about the current atmosphere comes from these important data sources. This AC is intended to provide basic weather information that all airmen must know. This document is intended to be used as a resource for pilot and dispatcher training programs.

The new edition of the companion handbook, AC 00-45 Aviation Weather Services, which explains aviation weather reports and forecasts and the briefings available to pilots, is also available at the FAA website.

NWS to drop ALL CAPS, but not for aviation

The National Weather Service plans to drop ALL CAPS from some of its public forecast products. Alas, aviation reports and forecasts will continue to use the teletype-era format.

The NWS announcement is here. Excerpts:

April 11, 2016 LISTEN UP! BEGINNING ON MAY 11, NOAA’S NATIONAL WEATHER SERVICE FORECASTS WILL STOP YELLING AT YOU…

Better late than never, but the slow change was not for lack of trying. The National Weather Service has proposed to use mixed-case letters several times since the 1990s, when widespread use of the Internet and email made teletype obsolete. In fact, in web speak, use of capital letters became synonymous with angry shouting. However, it took the next 20 years or so for users of Weather Service products to phase out the last of the old equipment that would only recognize teletype…

Certain forecast products with international implications, such as aviation and shipping, will continue to use upper case letters, per international agreements that standardize weather product formats across national borders. [Emphasis added]

 

Experimental Graphical Forecasts for Aviation

The Aviation Weather Center has released new Experimental Graphical Forecasts for Aviation, described by the AWC:

The Experimental Graphical Forecasts for Aviation are designed to provide meteorological information equivalent to the textual Area Forecast (FA) in a graphical format, as requested by the FAA. This product includes observations and forecasts valid for the continental United States that provide data critical for aviation safety, overlaid on high-resolution basemaps. Please note that the text-based Area Forecast is still being produced.

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A tutorial on the new forecast is available here.

As FAA noted in a recent draft revision to  AC 00-45H, Aviation Weather Services:

The FA contains weather information in a format originally developed in the 1950s. By design, it carries a character count limitation and is prohibited from describing instrument flight rules (IFR) conditions over the CONUS and Hawaii (reserved for Airmen’s Meteorological Information (AIRMET) and significant meteorological information (SIGMET)).

While the FA met aviation weather information needs for many years, today the National Weather Service (NWS) provides equivalent information through a number of better alternatives. Plans are to discontinue the six FAs covering the CONUS and one FA covering Hawaii, which will then be replaced by digital and graphical products produced by the NWS. No near-term changes are planned for the FAs for Alaska, the Caribbean, or the Gulf of Mexico. (Appendix E)

You can complete a survey about the new forecast here.

Changes coming to Flight Service October 1, 2015

The latest FAAST Blast from FAA includes a teaser about forthcoming changes to Flight Services provided by Lockheed-Martin AFSS:

  • The 122.0 Flight Watch frequency will go away; services available from Flight Watch will then be available on current discreet FSS frequencies.
  • All flight plans, VFR and IFR, will be filed using the ICAO format.

The notice says in part:

General aviation pilots increasingly have turned to automation in recent years to file flight plans and receive pre-flight briefings. New technology such as ADS-B is providing more inflight options to pilots. Flight Service will incorporate the industry’s newest technologies and reduce or eliminate other functions to create efficiencies and value. The changes to Flight Watch and RAA are the first in what is anticipated to be a series of right-sizing initiatives surrounding flight services provided to pilots.

For details, see this link.

Flight Information Service (FIS-B): Weather and Info in the Cockpit

Like many pilots, I have long used portable GPS navigators with SiriusXM aviation weather to display NEXRAD, weather reports and forecasts, and TFRs in the cockpit. Having regularly updated (if not truly real-time) information about the weather has been a boon to safety and efficiency, making strategic decisions about weather-related diversions and other changes to the original plan for a flight much less cumbersome.

The introduction of aviation apps for the iPad and other tablets and the completion of the ADS-B ground infrastructure has more pilots using the free Flight Information Service (FIS-B) products that can be integrated into products such as ForeFlight, WingX, FlyQ, and Garmin Pilot–provided you have an ADS-B receiver, such as the Stratus, Garmin GDL 39, or Dual XGPS170, among others.

(SiriusXM has announced a new, stand-alone receiver for its subscription services. It works with the iPad and a dedicated app. Details here.)

SiriusXM and FIS-B: What’s different?

If you’re switching from the satellite-based weather and information services to FIS-B products, it’s important to understand several key differences between the information each provides, and the limitations of the FIS-B services, especially for typical general aviation pilots operating below the flight levels who want to check the weather more than 375 nm ahead.

Of course, it’s also important to understand that SiriusXM information is available even on the ground, assuming the antenna has a clear view of the sky. FIS-B services, based on line-of-sight transmissions from ground stations, typically are available only after you climb at least above pattern altitude; higher minimums often apply. You can view a map of and learn more about ADS-B coverage here.

First, the set of weather reports and forecasts available via FIS-B doesn’t include all of the products from SiriusXM (depending on the subscription plan you choose).

FIS-B includes the following text reports (see AIM 7-1-11):

  • Aviation Routine Weather Report (METAR) and Special Aviation Report (SPECI)
  • Pilot Weather Report (PIREP)
  • Winds and Temperatures Aloft
  • Terminal Aerodrome Forecast (TAF) and amendments
  • Notice to Airmen (NOTAM) Distant and Flight Data Center

FIS-B includes the following products in both text and graphic forms:

  • Airmen’s Meteorological Conditions (AIRMET)
  • Significant Meteorological Conditions (SIGMET)
  • Convective SIGMET
  • Special Use Airspace (SUA)
  • Temporary Flight Restriction (TFR) NOTAM

FIS-B also displays graphical regional and national NEXRAD composite reflectivity information.

Update Schedules

AIM Table 7-1-1 FIS-B Over UAT Product Update and Transmission Intervals shows the intervals at which fresh information is transmitted via the ADS-B network.

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Look-Ahead and Altitude Tiers

To avoid overloading the ADS-B transmitters, the amount of information sent to aircraft depends on the altitude of the receiver. The altitude tiers are described in AIM Table 7-1-2 Product Parameters for Low/Medium/High Altitude Tier Radios:

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Figure A-2 in AC 00-63A defines the altitude tiers:

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Most of us flying normally aspirated, piston aircraft fit into the medium altitude tier, which means that some information (e.g., METARs and TAFs) is available only when the reporting airport is within 375 nm of our present position.

The advisory circular notes that:

Pilots need to consider the performance of the aircraft as well as the update rate for a specific product. For example, a pilot of a light twin aircraft, flying at a medium altitude with a tailwind could easily have a ground speed in excess of 200 knots. Thus, traveling at over 3 NM per minute, a pilot may not have enough time to receive and decipher a pop-up TFR based on the 100 NM look-ahead and a 10-minute transmission interval.

Future FIS-B Products

AC 00-63A notes that FAA plans to add five new FIS-B products “in the next few years.” These products include:

  • Lightning. Graphical representation of each lightning stroke in a past 5-minute period.
  • Turbulence NOWcast. Two-kilometer resolution grid containing an eight-value turbulence intensity scale in each grid cell. The intensity scale depicts a weighted average turbulence for flight levels (FL) of 10,000 ft and above.
  • Icing NOWcast. Two-kilometer resolution grids, where each grid represents one of the eight 3,000 ft ranges from FL 030 to FL 240. Within each grid, each grid cell contains the four-value icing indication and the presence or absence of Supercooled Large Drop (SLD) formation.
  • Cloud Tops. Two-kilometer resolution grid indicating the altitude of the cloud top to an accuracy of 3,000 ft, ranging from FL 030 to FL 480.
  • One-Minute Automated Weather Observing System (AWOS). More frequent updates of METAR-formatted information.

More Information and Key References

You can find detailed information about FIS-B in the following key references:

In June 2012, NTSB released a Safety Alert about the limitations of NEXRAD displays in the cockpit.

AOPA ASI offers a free online course, IFR Insights: Cockpit Weather, to help you learn more about datalink weather.

Aviation Weather Center Updates

The National Weather Service has updated the design and features of its Aviation Weather Center website.

You can read about the changes here; background on the new design is here.

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